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heat exchanger making method?

Question by UTKARSH002    |  last reply


Home heat exchanger or heat engine anyone?

I know for a fact that in the EU we can now have energy effient homes that utilise the heat from common sources like water heater, solar or just what is under the roof to generate electricity or heat other things.Started to wonder if ever someone tried something in that region on an affordable hobby level.Down here properly insulated homes are rare as a pearl in a supermarket oyster.So my main interest would in utilising the excess heat under the roof during the summer times.This season I measured and average of around 60°C during the day.On those day over the 35°C mark it went up close to 75°C in some areas.I guesstimate that if the draft areas are sealed off a bit a fan system should able to suck air at about 50°C out for about 6 to10 hours per day during the summer.If I would add a small heat exchange made from a solor hot water panel and some piping:Would hat combine heat output be enough to power an ammonia fridge or even freezer?What options are there that you guys created to generate some electricity from other heat sources?Thinking about the exhaust heat from the hot water system or heater.One thing I am planning on is a small solar heater for my big fish tank.Currently not anywhere near a window but would like some Arduino to control a water pump by temperature comparison to provide warm water during the winter months for free.Beats two 400W heaters if you ask me LOLThe potential for some easy to create heat exchange system to generate a bit of electrictiy or power heat exchange system is huge.Australia is full of badly insulated homes and the US is not far behind.And not matter how good they are all those homes still heat the roof cavities like hell.

Question by Downunder35m  


need replacement for Koolatron heat exchanger Answered

My refrigerator died. the heat exchanger won't test. It's 3.75 x 4 inches without the radiator fins. 40 watts DC. Apparently Koolatron doesn't carry them, planned obsolescence is unethical (unless you're a shareholder). Where do replacements come from?

Question by Jakey2    |  last reply


Severe black mold...heat exchanger???

Hi! we have this severe problem of black mold in every room, the wall is black... Water puddles on the floor.... Our surveyor and a builder told us (after cheeking everything) to solve the problem with a heat exchanger in every room... we are trying one in the kitchen but after 2 weeks i still found water on the floor and the mold in the corner seems increased... someone tried that? The cause of the mold are heat bridges and non existin insulation...

Topic by AlyssP    |  last reply


how to fix holes in a polyethylene/polypropylene solar heat exchanger Answered

This solar heat exchanger is a 5m sq flat sheet consisting of two layers of black polypropylene or polyethlene (not sure which)with rows of fine bore plastic tubes sandwiched between through which water is pumped from the pool at low pressure.The water warms whilst passing through the system, then empties back into the swimming pool, hence, free pool heating. After 2 seasons of use, there are a few leaks at the joints where the fine tubes meet the main inlet tube. I tried to seal them with glass fibre, then cyano-acrylate resin...nothing stcks to this type of plastic. Any ideas for sealing these holes? The plastic is too fine to use a heating method.

Question by MalKnowles    |  last reply


HOW DO I GET HOT WATER FROM WOOD HEATER

I WANT TO MAKE FREE HOT WATER WITH MY WOOD HEATER THIS WINTER.WHAT TYPE OF HEAT EXCHANGER SHOULD I USE A COIL OF 1/2 COPPER TUBING? I DO HAVE AN EXTRA ELECTRIC WATER HEATER THAT I CAN USE FOR WATER STORAGE, DO I NEED A PUMP? ANY HELP WILL BE GREAT....

Topic by rockytop44    |  last reply


Reclaiming Wasted heat to make electricity

I work in an aluminum casting facility and we're looking for ways to save energy etc... one thing that we've got no shortage of is heat (during the summer the temp near the ceiling above the furnaces is over 230F) i've looked into stuff like they do in steel mills in Germany where they run pipes through the furnace linings and then use the heat from the furnace to make steam and run steam generators. but i was thinking of something else today. would you be able to just mount a bunch (or one huge) peltier exchanger (or whatever they're called) on the ceiling above the furnaces and use that to make electricity? i'm aware that they create electricity because of temperature differences (and not specifically from being hot or cold in general) so would we have to cool one side of the unit for maximum efficiency? are there any other ways that anyone knows of to turn waste heat directly or indirectly into electricity?

Topic by crapflinger    |  last reply


How best to circulate wood insert heat into the bedrooms at the end of the house?

We have a decent size wood insert with dual squirrel cage fans in the center of the house on the ground floor.  It does a good job of heating the room its in, however none of the satellite rooms nor the upstairs bedrooms get much heat.  We have central air,  would running the system on circulate help, or will that just pull the warmest air out of each room (the returns are up high)?  Ultimately, I'd love an air/water heat exchanger to plumb into our HVAC but that doesn't seem practical from a house layout, expense or cosmetic perspective.

Question by hackneyed1    |  last reply


Best way to solder thin copper heat fins to soft copper pipe for radiator/heat exchanger with small butane blow torch?

Trying to attach 36cm (14") x 5cm(2") x 0.125mm(0.005") thick electrolytic copper heat-fins to 20 hollow soft copper tubes 6mm outer diameter, 0.4mm thick walled copper pipes. Would ideally like to use silver based solder rather than tin-based. Is it realistic to use high-silver-content solder on such thin copper, and with a small butane blowtorch (has to be small as fins only 1cm apart)? Can I use silver solder or do I need to use tin solder? Any help/suggestions welcome!

Question    |  last reply


Stirling AC, someone tell me why it wouldnt work.

Take a split type airconitioner unit (with heat exchanger / motor etc outside the house) remember that heat pumps have COPs >1 so they remove more energy than you put in. Now take a reasonably efficient stirling engine and bolt it onto the external heat exchanger so there is a gradient between the hot heat exchanger and the warm air outside and use it to pump the refrigerant around the system. Surely a heat-pump stirling engine combo can be made efficiently enough to effectively run itself once it has been started up, maybe with a few watts of electric to run some fans.

Topic by pyper    |  last reply


How it is possible to power up a 12V device using only 5V?

I had a power outage some time ago, and needed to use the internet for university search. i was with my notebook, EEEPC 1000H with 4 hours of batt. my internet is over a cable and it uses 12V for power; i had a cable for my external dvd reader (ad/dc pin to USB)that fitted into the modem, and i plugged it into my usb. it worked very well. however, the notebook started to heat up slowly, and the battery indicator dropped from 4:00 to 2:00; this was safe to do? could it damaged my notebook? how can be possible 12V into 5V?

Question by Shiron    |  last reply


How can you make a fridge more efficient? Uses of solar, heat exchangers, etc. Any ideas?

I was thinking of a heat exchanger, on one end a constant stream of cold well water, on the other end, the fridge coils. Or maybe use solar to cool it with peltier effect device? To keep it from coming on too often. Throw out any ideas, just though of this but have not seen it around, probably for a reason. It would be nice to use this idea at a cottage or camp eventually with little to no power, but at a cost worth building. The point would be to save money over the long run, so like a full blown solar would work, but it would cost a lot. Thanks again

Question by newinvestor23    |  last reply


Underground Tube Air Conditioning

I have long heard about using buried tubes/pipes to use as a heat exchanger to take the hottter air from your house, blow it through a system of closed loop underground pipes in order to use the earth mass as a heat exchanger. The earth mass removes/absorbes heat from the house air in the pipes and delivers cooled air back into the house. Can anyone direct me to web sites about this subject. Or, certainly, if you have knowledge about this, reply to me with it? Thank you, John333

Question by john333    |  last reply


Use car radiators for solar collectors. Any advice?

I have salvaged 2 car radiators, they aren't leaky. I want to use them for active closed loop solar collectors. Any advice? My current plan is to put them on the roof (in a hot box), then plumb them into an old water heater in the attic. My hope is they can recirculate glycol in a closed loop, convection only, but I may need to install a thermostat and pump. Anyone have experience in this? I want to dump the heat to my 2 water heaters in the basement (they are plumbed in tandem, so I can use the 1st tank for solar boost and 2nd tank for final temperature control). Heat exchangers: either the Butler Solar Wand, or Brazed Plate Heat Exchanger (single or parallel). Differential Temperature Controller from www.jc-solarhomes.com. Any advice or suggestions hugely welcome. thanks in advance, Chris

Question    |  last reply


Idea for a non-ideal Carnot cycle based engine.

Initial Stirling engine conceptFor some time I was contemplating an idea for a Stirling engine that would work quite differently than the other designs that I came across. Whole internal volume of an engine may be viewed as a closed-loop pipe, trombone-like slide mechanism allows this pipe to change its length. Electrical fan replaces displacer and pumps working fluid throughout the engine constantly and in one direction. Some portion of the pipe is replaced with branching structure that consist of two heat exchangers (hot and cold) and regenerator. On both ends of this structure special valves are located that connect one of the structure’s parts to the main pipe, so that whole engine forms one closed-loop. While this happens, both of the unused parts are completely bypassed.This design should have many advantages. Working gas is in constant motion and little energy is wasted on accelerating it. Gas may pass many times through heat exchangers, allowing for much better approximation of isothermal processes. Disconnecting unused heat exchangers from the rest of the engine should minimize volume of dead spaces.There are some drawbacks to. Slide mechanism allows only very small changes of total volume (compression ratio is low), and that limits engine’s ability to operate with higher temperature differences. Piston, which is part of the slide mechanism, and especially valves, are heavy and this makes them unsuited for high speed operation, making the whole engine bulky. I also except that an area of all surfaces that are sliding against each other and produce friction would be higher than in traditional Stirlings.Problems with Stirling cycleIdeal Stirling cycle (Fig. 4) consist of two isothermal processes (constant temperature) during which work is performed, and two isochoric processes (constant volume, no work performed). Isochoric processes function is only to change temperature of the working gas, and this takes a lot of energy to do so (especially if gas with high heat capacity is used). Regular Stirling engines try to minimize this inefficiency with regenerator. But when I tried to analyze this process mathematically, I noticed that even regenerator with very high heat capacity cannot store more than half the energy needed to perform next isochoric process (see lower left part of the spreadsheets for more details).Fig. 5 represents heat pump (or refrigerator) working in a modified Stirling cycle. Isochoric processes represent transfers of heat to and from the regenerator. Rest of the temperature change is performed by polytropic processes, during which heat flows to or from the heat exchangers and also work is performed. I chose to represent heat pump, instead of a engine because engine working with this modified cycle wold require isochoric processes to be performed midstroke (or transfers of heat to regenerator would have to be performed during polytropic processes, when working gas changes its temperature also due to work being performed).Note that I am using word polytropic to indicate processes where gas changes its energy both due to heat transfers and work performed. When special cases of polytropic process are mentioned (isothermal, adiabatic, isochoric) I use their specific names.Solving those problems with Carnot cycleLegendary Carnot cycle consist of two isothermal processes (just like Stirling cycle), but changes of temperature are accomplished by the adiabatic processes (no heat transfers with the surroundings), instead of isochoric ones. This has huge advantage, because when energy is added to the working gas during adiabatic compression, all of it can be later recovered during adiabatic expansion.Design I previously mentioned can easily be adapted to work as a Carnot engine. Only change that is necessary, is replacement of regenerator with the empty pipe (ADIABATIC PIPE in Fig. 2). When valves connect this empty pipe to the rest of the engine, there is no heat transfer between working fluid and thermal reservoirs. Any changes of engine volume modify temperature and pressure in a approximately adiabatic fashion. To model what happens with the engine I used slightly modified Carnot cycle (Fig.3). Just before adiabatic process end, short polytropic process begins. It is done so that loses associated with valves connecting both adiabatic pipe and heat exchanger to the main part of the engine for a short period of time can be better simulated. Heat pump working in this cycle is shown in Fig. 6.Design detailsEngine uses special valves, which external shape resemble truncated cone. Smaller base of this cone faces main part of the engine, larger one heat exchangers. Inside there is a pipe, with one opening right in the center of smaller base. The other opening is located off-center on the larger base, so it can connect to the one of the heat exchangers or adiabatic pipe (which are situated just like chambers of a revolver’s cylinder in respect to each other). As this engine engine will most likely operate under low RPMs, flywheel will have to be connected through a transmission with very high gear ratio. The flywheel will have to be quite bulky as well. This poses another challenge, as the pressure inside engine’s tubing will be higher than atmospheric, and at least space around the other side of the “piston” will have to be pressurized as well. If only the immediate surroundings will be pressurized, and gears, flywheel, electric motor/generator will be outside of the container, then very inefficient seal will have to be employed. If everything will be located inside the pressurized container, then fast moving parts will be working against dense gas. Pressure in this area ideally should have such a value, so that on every piston stroke energy is both added to the flywheel and extracted from it as to make energy storage requirements more manageable. This requirements may also be further reduced by employing some other energy storage form. And of course exchange of heat between main part of the engine and this pressurized section must be taken into consideration.Then, there is problem of heat exchangers. They can be either large diameter pipes with fins, or smaller diameter ones that are densely packed (this seems to be must popular configuration in Stirling engines). As heat transfer with the outside of the engine takes around half of the piston stroke, it might be a good idea to employ two pumps of heat transfer fluid per each of the two heat exhangers. One would work constantly to transfer heat from some large heat reservoir, the other would transfer heat to the working fluid only when it is necessary. Some another heat exchanger would have to be placed between those two circuits.And there is also a question of the piston. Basic trombone-like version could be replaced by the something similar to the design drawn in Fig. 7, where two parallel tubes, connected by U-shaped piston, are replaced by the coaxial pipes with volute on the outer section that allows connection another parallel pipe. Piston itself has then small tubular part attached which allows working fluid to pass from outer section to the inner section. This design has only one high pressure seal, is possibly lighter, but fan that pumps working fluid will probably need to be more powerful. Problem of sideways motion of the piston must also be analyzed, and it can be either resolved with piston skirts or the crosshead. Interesting aspect of this problem is that while most frictional forces in the engine are mostly independent of the engine speed, forces associated with this sideways motion of the piston increase with engine rotational speed.Another possible improvement would be making adiabatic pipe shorter than the heat exchangers, which would reduce volume of dead spaces.Engine parametersIn case of a engine that uses helium as a working fluid, has minimum volume of 46.7 liters, maximum volume of 70 liters, operates at temperatures of -5°C and 37°C with the speed of 15 RPM you can expect that it will produce 1138W of power at 8.13% efficiency.In the case of heat pump that operates at the same parameters you can expect that it will require 2300W of power and achieve COP 4.95You can find calculations, diagrams and the detailed descriptions inside non-ideal_carnot_engine.zip (it is unfortunate that Instructables do not support uploading .zip files and other file formats any more, and I have to use another website just to upload few spreadsheets).Possible applicationsI started thinking about this concept when considering applications of thermal energy storage. In more northern latitudes largest factor in domestic energy consumption is heating. So, at least in my opinion, any movement toward replacing fossil fuels with renewables should focus on this largest contributing factor. And this actually is quite fine because storing 1 kWh in a tank filled with water, rocks/concrete or simply in the ground is much cheaper than storing it inside lithium-ion batteries. And general idea behind this low temperature engine, was that some part of this large amount of energy stored to be later used to heat buildings, could be converted into electricity.It should also be able to work in reverse as a heat pump or refrigerator.

Topic by rarinn  


Question about thermodynamics??? Answered

The zeroth law states that any 2 or more objects that come in contact must exchange energy to create a thermo equilibrium.  Would 2 magnets of the same polarity in a vacuum still abide by this law?  Can someone give me a formula to explain it?  Can magnetic fields even make heat by themselves or rather is there any friction between the two??  Thanks much!

Question by shawneegeek    |  last reply


Solar Hot Water Preheater Idea?

Hi everyone, I'm new, from the UK, I will shortly be moving into a static caravan/mobile home on family land for a few years to save up, so with money saving being the aim, I'd like to run this little project by you all.  I'm thinking about making a solar collector and placing it on the roof of the home, as large as I can afford (caravan is 12 wide) and feeding that into a heat exchanger inside an old 47kg LPG gas cylinder (I have access to several old cylinders and believe it can hold around 110 litres, so could even use 2?) and having the mains inlet at the bottom and outlet to the boiler at the top.  For the heat exchanger, I'm thinking cut both ends off and drop a coil through from top to bottom and weld back up but i'm open to suggestions. I want to a heat exchanger instead of having the mains water go round the solar collector, as it can get cold in the UK at night, even in the summer and I dont want it freezing in the winter (i'll have enough worry of water pipes freezing anyway), so will use some form of copper friendly anti-freeze. I'll need a pump for this, as the collector will be on the roof, above the cylinder, so thinking to run it on a light sensor, but how complicated would a thermal switch be, so when the temp in the collector ir warmer then the cylinder be to make? If anyone knows of a  place for the circuits (or of the shelf product), I can see if it's something i'm competent enough to take on.  One last thing, Would having the cylinder painter black and left in sunlight be a good idea. Would it get hot enough to cause problems with the water mains pressure?  Look forward to your feedback and advise.  Tuns

Question by tuns    |  last reply


Compressor-free refrigerator may loom in the future

. From Compressor-free refrigerator may loom in the future at Penn State Engineering via Slashdot:University Park, Pa. - Refrigerators and other cooling devices may one day lose their compressors and coils of piping and become solid state, according to Penn State researchers who are investigating electrically induced heat effects of some ferroelectric polymers."This is the first step in the development of an electric field refrigeration unit," says Qiming Zhang, distinguished professor of electrical engineering. "For the future, we can envision a flat panel refrigerator. No more coils, no more compressors, just solid polymer with appropriate heat exchangers."

Topic by NachoMahma    |  last reply


Windows that self-close to regulate temperature

I like letting the outside air blow through my apartment, but I also like the temperature and humidity to be in a good range. So I go around opening all the windows when it's a good temperature outside, and then forgetting to close them later. I wish windows could be programmed to open themselves automatically to regulate the temperature. I bet this could save a lot of money on heating and air conditioning, while allowing fresh air from outside to come in. I'm imagining a bunch of slats of glass that can rotate like Venetian blinds that are controlled by bimetallic strips or something :) Maybe there would be two layers for better insulation, and one layer could open to allow more heat exchange but not air flow, and both could open at the same time to allow air to flow. For modifying an already-existing window, it would have to install motors and stuff. Anyone have any ideas about how something like this could be made?

Topic by endolith    |  last reply


Energy efficient, waterless, Copper strip based cooling system

Energy efficient ,waterless Copper stripe based cooling system:The presented Idea is based on Heat exchange principle.As per sketch there will be a conveyor belt system and some copper stripes will be connected with this belt.Each copper strip will have a moveable hook.The conveyor belt will move with a motor.Each copper strip will be separated with each other and with conveyor belt with the help of Insulation (wooden insulation).Each copper strip will be connected with the machine for 15 to 20 seconds to absorb the heat and after that this copper strip will be removed and next copper strip will be ready to absorb the heat.The removed strip will be cooled down after some time and will be ready to couple with the machine again.In this way each copper stripe will work one by one to absorb the heat to cool the machine and each strip will get cool down due to convection .What I thought is that if I use a continuous water jet to cool the motor then the motor will remain cool so if I use the copper stripes then the same effect will be occured.It will work in this way that temperature will be not increased of machine if I couple the device with the machine. It will be low cost,low maintenance,waterless solution to cool the machines. It will consume almost nil energy

Topic by vikram_gupta11    |  last reply


open loop solar water heater that wont freeze

(first paragraph is blah blah,  skip if you wish) As some of you know, there are two approaches to a solar water heater.  One is a close loop with a coolant type liquid that wont freeze.  The problem is that you must build and exchanger of some sort to gather the heat.  Expensive and troublesome.  The second is an open loop in which you circulate the water.  Possibility of freezes.  I have a plan for an open loop system that will latch on to an existing tank and supplement the heat but wont freeze.  What i need is a circuit that will shut off the pump when the sun is down and a water thermostat i can stick in the existing tank that will also shut the pump off.   I think they should be one circuit somehow and should be 12v DC so the pump can be solar powered. They should also be as cheap as possible. I'm not good with circuits so i could use some help.  Perhaps there is some way to reverse a dusk-to-dawn switch.  Please help.

Topic by dggriffi    |  last reply


Solar Power Towers Efficiently Using Brayton Cycle

I want to point out a solar to electric generation concept that has yet to be seen anywhere, even though it originated back during the Carter Administration's ERDA programs of the late 70's. I’m talking about solar power towers that convert solar energy into electricity at the hundreds of mega-watt level. While power towers do exist today, and the world currently does have a handful of them as shown in Fig-1, none use the Brayton Cycle nor can they boast an energy conversion efficiency at the mid to upper thirty percent level.  A group of engineers got together at a think tank organization called Sanders Associates in Nashua, N.H., several decades ago, and designed a unique Brayton Cycle, 100 MW solar Power Tower concept for generating electricity. This was accomplished under ERDA (Energy Research Development Administration) who gave us a phase-2 follow-up contract that took our phase-1 design and built a working scale model at the 10 KW level. This model was tested at the Georgia Tech Solar Research Facility and "registered" ~37% electric solar conversion efficiency. The system used ambient air as its working fluid, and was to be located in open-spaced desert regions. Phase-2 was lost to competition using a closed-loop liquid sodium system that boiled water into superheated steam at 900F to run a turbine that generated ~21% overall electric conversion efficiency.  Apparently, at that time ERDA would rather haul water out to the desert than use ambient air to generate electricity? The politics of their decision is beyond reason and clashes with improving the world’s development of green technology energy.  ERDA shut out our better technological performer and safely locked it away for another day! ERDA's official reason for turning us down: "this technology uses excessively high temperatures (2500F versus 900F) that are dangerous to workman maintaining the equipment". But that was back in the 70’s, maybe we’ve learned to deal with high-temp heat by now?   Solar Energy Concept Using Low Pressure Storage Our solar power tower would collect the sun’s energy by locating its ceramic heat exchanger on top of a tall tower as shown in Fig-1. The tower was located in the center of a field of active sun-searching mirrors (heliostats, Figure-2). These mirrors reflected sunlight onto our ceramic honeycomb heat exchanger, producing a concentrated flux intensity level that heated it to around 2500F. At the same time, low pressure fans generating only a few psi pressure would suck the ambient air through the honeycomb, heating it to just under the 2500F and then passing it through energy storage silos which stored the heat down to ~150F. We purposely designed the energy storage charging phase of our hot air system to work at only a few psi above ambient as a safety feature. The sun effectively acts as the combustor of our jet engine or Brayton cycle engine. Once the sun heats the air, it passes through heat exchangers consisting of a labyrinth of underground silos that are temperature segregated. These silos receive our 2300F airflow and cool it down to about 150F, transferring this heat into solid salt containers which turn to liquid once they have absorbed sufficient heat. Figure-3 is a schematic of this underground energy storage facility and shows the airflow being heated by a fully charged set of silos containing liquid salt-bricks. This airflow direction is reversed when we charge the silo’s salt-bricks. The bricks are kept in specially insulated, high pressure silos (located underground for added insulation) that store the heat energy at one atmosphere for later use. These underground silos act as our energy storage batteries, and when needed would discharge their heat energy accordingly into the moving airflow. This energy storage concept permitted the generation of electricity at night and during overcast days. Two sets of storage systems are required for continuous operation. One would be charging at low pressure while the other is discharging at high pressure through the Brayton engine to generate electricity.   Electric Energy Generation at High Pressure Electricity would be created by turning an electric generator at high speed. The generator was turned by running a jet engine connected to it.  The engine’s combustor for heating the air is effectively the sun, hence the name Brayton cycle for generating our solar electricity (Figure-4). The heat from the molten salt containers would increase the energy of the high pressure air coming from the compressor, and would then force it through a typical turbine that turns this energy into high rotational speed to run the generator and make electricity. Our solar jet engine sucks in ambient air using its compressor, as all jet engines do, and blows it through a series of silos at high pressure whose stacked bricks are held at different temperature levels. We start our airflow through a silo held as low as 150F and work our way up to ~2300F as we pass through our last, hottest silo which acts to complete the effective solar combustion process. This air preheating technique dramatically improves our energy turnover capability and allowed us to convert solar energy into electricity at near 37% efficiency. During our electric energy generation phase, the silos of our Brayton system requires operating at many atmospheres of pressure just as in any jet engine combustor using petroleum-based JP-fuel.      

Topic by RT-101    |  last reply


How inefficient are resistors? Answered

I know how to calculate resistive losses, but do different types of resistors have different amounts of losses (power in vs power-out, in watts) From my own observations, connecting a 10 ohm resistor across a barrey will cause significant heating in both the resistor and battery, and cause the wires to get warm. All of this is resistive loss, but when I exchange the resistor for a 10k resistor, there is virtually no heating at all. What if I use a 0 ohm resistor (direct short). The only thing getting hot would be the power supply, due to internal resistance. Does this mean higher resistance is less lossy and by definition, more efficient, or is this simply due to the fact that there is less current flow, and less power loss, and efficiency (% of power loss)  With an ideal constant current source, will the losses though any resistive load be equal? ( X amount of watts lost/dissipated @ 1A) Is it possible to limit current like a resistor without losses? (I know PWM techniques are more efficient, but I want actual resistance rather than chopping current flow and filtering with an inductor/capacitor RC filter)

Question by -max-    |  last reply


Induction heater 2.0

Some might have already tried my first induction heater, which was more a proof of concept than a modern device. Although I like to keep things simple where possible I want to upgrade my heater to a fully electronic version running on mains power. This time the base concept is to use a cheap induction cooktop for the control and power source. After using a few already as a communication device I realised it is a costly way of producing smoke signs but I am getting on the right track with the design now. So my obvious questions are: 1. Did actually anyone ever built my current induction heater and if so, can you provide some nice pics? 2. If you were interested in a hobby induction heater, what would like to do with it?     E.g: Just for curiosity on how it works, heat treatment of punches, chisels and similar,     heat treating knifes or even swords, sheet metal work.... 3. What would like to have included?     E.g: Water cooling for continous use, air cooling (mostly for smaller and quick jobs), exchangable coils,     additional micro controller for temp, water and remote control (foot panel or similar)... 4. Do you require a fully shielded version to avoid interference? 5. If you are based in AU (preferable VIC): Would you be able to donate me faulty (partially or fully) or working induction cooktops,     for example discarded units with broken glass tops?     Would you able to donate me copper tubing OD8mm or less? Leftovers from pluming installations, old LPS systems or similar?     Prefered lenght 1m or longer as the coils need quite a few turns... :(     Each donor will of course be listed in the Instructable unless you prefer to remain unnamed. Let me know what you think because this time I am not just building for myself, this time it is for you!

Topic by Downunder35m    |  last reply


Freezer panel home build

Some time ago I was approached by an old friend who got very lucky money wise.He wanted to build a really energy efficient house for himself - in terms of being well insulated.Should be easy to build as well he said...So with a few beer we got together one day and tried to figure out what options are available that the usual building companies won't or can't offer.Quite soo we realised that freezer panels seem to be the ideal solution.Sturdy, ralatively high load rating and additional supports, mounts and all are readily available.Funny enough there are even the right thicknesses available to be a perfect match for EU style tripple glazed windows and well insulated outside doors.And as always the initial euphoria meant we totally went over board here.Getting dimensions for selected doors and windows, calculating how many freezer panels are required to make the outside walls and roof...Even starting on 3D models to design the whole thing.Needless to say the dreams ended with an equiry at the council for a building permit for the dream home.Turns out that despite proper ratings on overthing a house can not be built with freezer panels for walls.Only bricks, wooden/steel frames and approved building materials...Either way we kept going as a theoretical game for the hope in a few years regulations around here might change.And you might be lucky to have your property somewhere with no such stupid regulations.One of the biggest problems we realised such a well insulated home would have is moisture and fresh air.Possible solution here is to use a heat exchange system for basically everything inside and outside the house.Options for this already exist for purchase and installation so nothing would need to be designed or developed from scratch.These system combine airconditioner, heating, hot water and air exchange in a quite compact unit size.The required ducting is a different problem though that should be included in the early design stages already.Solar panels double up as additional heat shields so to say and with enough roof space left it could be turned into a green and living roof to help with the carbon footprint and inside temperatures during the summer.So far for the easy part...All this would be impossible without home automation and integration.Sensors monitor conditions, a computer system decides on the right operating parameters and allows for user adjustments.Home automation isn't a new thing either, so called smart-homes are already in the portfolio of most good builder out there - at a price though.Using this technology to our advantage means the smart part now doubles up for the required input and sensor data.For a smaller home you would ideall opt for a rotating home that follows the sun...For a really big home you would aim for enough solar and wind power to make it self sustaining...Battery technology is on our side here and using Li-Ion tech is almost affordable as old style lead-acid batteries for this purpose.So why are there only so few people going this route?Would be very easy to create freezer panel styles that look like wood or bricks to be conform with local appearence...The real problem seems to be that it violates what we are used to.For starters it would be hard to explain why you should live in a big fridge with windows.The next problem is that such homes would be very easy and quick to build.You select your style and design features, pay for it and production starts.In time for the finnished foundations, plumbing and such the parts arrive and come together in a day or two.Connections are finalised and can move in within a week of commencing to build the actual house.Thausands of tradies would be jobless if this would be the general way to build new homes.Same for all those companies that currently supply the standard building materials, frames, roof tiles and such...Just imagine a tornado just turned your home into dust.Wouldn't it be great to be able to move into a new one within a few weeks instead of months?Even better if the new one would still be mostly unharmed after the next tornado....Living in a possible flood zone?Nothing easier than to add some barriers for doors if the house is fully sealed otherwise...Stay dry while the water is right under your window, just don't open the door...In other parts of the world so called kit-homes are already widely available but mostly only in mild climates.The benefit of using freezer style panel for homes in desert or cold climates seems to obvious though.Same for possible disaster zones like tornado alley.Is it time to re-think how we define a home?

Topic by Downunder35m  


"dry box" for drying clothes in humid weather

Hi all,I'm thinking of building something helping me to dry my laundry in the amazingly wet weather that I'm getting in the place I live now.I searched instructables for a while, but did not find anything that really applies. This might be due to the fact that I'm both new to instructables, and not a native English speaker. I might be using the wrong keywords.So I live in a very humid and foggy place, and it's winter now. When I hang my clothes out to dry, the process takes ages. Sometimes I think it might be working backwards: the clothes become wetter. Also, an unpleasant byproduct is that my clothes become smelly, despite they are clean. Sometimes, as a last resort, I hang my clothes inside the house. But my house is very small, and I do not really have a place for the clothes hanger. Plus, the house gets very humid and I am afraid I'm going to get mold. On the other hand, I have a rather large balcony, with a lot of place for the clothes hanger.Of course I could buy a clothes dryer. I actually use a coin-operated one for large items, such as bed sheets and large towels. But I'd rather not use a tumble dryer for my clothes.However I recently learned about heat recovery ventilation for houses, and I started wondering whether the same concept could be used to build a small-ish enclosure (a box) where air is kept warmer and dyer than outside, possibily in a controlled manner. Also, it would be very nice to get energy from the sun. Surely the walls of this box could be transparent, or black, to create some kind of greenhouse effect. Then I need a fan, to have the air circulating. The air could go through a heat recovery unit. This could probably solar-powered. On the other hand, I am not sure that solar panels would be helpful for heating the inside of the box by night (energy should be of course stored, but I do not think that would be enough).I see that something similar to what I'm thinking about is already on sale e.g. on amazon. These are called "portable clothes dryers", but they do not seem really optimized. They look like a combination of a hair dryer, a clothes rack and a tent. I do not think there is a real heat exchanger, or humidity control...Plus, they do not seem really safe, especially if operated outdoors.Can someone give me some advice, e.g. pointing me to projects that use similar ideas possibly for different purposes?Thanks a lotFrancesco

Topic by pieffebi    |  last reply


Free Air Conditioning, Free Water, Cheap CNC...

Function clickclear(thisfield, defaulttext) {if (thisfield.value == defaulttext) {thisfield.value = "";}}Sign-up for our newsletter subscribe August 23, 2007 Welcome back! Why just relax this weekend when there are tons of cool new projects to try out? Check them out below. How to make Evil Childproof caps easy to open With no kids in the house, why deal with childproof caps?posted by SFHandyman on Aug 22, 2007 How to Harvest Squid Ink Clean your own squid, and collect ink for printing or cooking! posted by canida  on Aug 23, 2007 Life-size Skeleton Pumpkin Carving! Get ready for Halloween early with this advanced bit of pumpkin carving.posted by mcraghead on Aug 21, 2007 FeatureIn-line headphone amplifier Use a single AAA battery to amplify the sound from your PC.posted by neelandan on Aug 20, 2007 Cart Bike Shopping cart + bicycle = a DIY system for moving lots of groceries.posted by zieak on Aug 20, 2007 $1,500 top prize! Share your quick and delicious recipe and get published in Real Simple! Propel yourself to greatness. Hack a Toilet for free water Add a sink to your toilet and wash your hands without wasting any water.posted by nak on Aug 20, 2007 Drinking Glasses from Wine Bottles Put those colorful bottles to use by making them into attractive water glasses.posted by fstedie on Aug 20, 2007 Easy to Build Desk Top 3 Axis CNC Milling Machine Make your own CNC for well under $200.posted by Tom McWire on Aug 17, 2007 How to make a $20 ice pack for $2 Make your own gel pack and soothe those sore muscles.posted by royalestel on Aug 17, 2007 Free Air Conditioning Technically it's a heat exchanger, but it's still a free way to get cool air.posted by Vyger on Aug 16, 2007 Now go build something awesome, and I'll see you next week! -Eric

Topic by lebowski  


Refrigerated Dog Bed

Ahoy-hoy, My first post on Instructables! Anyhow, we own a 10-month old Great Pyrenees and live in the drought stricken and warm Southern California climate. As summer approaches we have been looking at options to help keep her cool and we haven't had the greatest of luck with cooling beds available on the market, our Coonhound tore up the first one as a 50 lb pup during his first summer. I was thinking about potentially re-purposing an old mini-fridge coolant system into a cooling bed. My very initial thoughts are as follows: 1. Salvage working mini-fridge 2. Disassemble cooling system 3. Create bed surface using sheet metal (our Pyr won't sleep on the any of the multiple plush beds available to her, only concrete or dirt) 4. Create mount base for bed, ideal scenario would have a force sensitive switch that would only turn on refrigeration unit when dog is on the bed. 5. Thermally attach refrigerator expander coils to the underside of the bed, most likely via solder but could bolt together with thermally conductive paste 6. Rig up an enclosure and support structure for the compressor, heat exchange coils, and electronics. I imagine the bed surface resembling the weight scales at the vet but with some provisions to attach a padded fabric cover. Things to be addressed: 1. Ensuring proper temperature regulation...she has a thick durable coat but don't want to over due things. Temperature feedback shouldn't not be too much of a hurdle using an Arduino or using the existing "twisty-turny" nob in the fridge 2. Properly disassembling the salvaged fridge, don't want to unnecessarily release the refrigerant and defeat the whole purpose 3. Make this thing sturdy enough to survive the wear and tear of one and/or probably two 85 lb plus dogs Is this too far fetched (no pun intended, my dogs aren't retrievers)? Any thoughts and advice would be greatly appreciated. Thanks, Rich 

Topic by richardwdyer    |  last reply


Options to improve cooling and reduce consumption for portable coolers

I recently had to start learning how to service airconditioners on the fast and that learning got me thinking about my portable coolers.... Some of us like to go camping or on longer fishing trips, so there might be one of those 3-way fridges in use or a better cmpressor model. The one thing they all have in common is that they can only cool down to a difference in ambient temperatures. No matter which way we turn it the cooling produces heat and that needs to get away somehow. The other big thing is the cooling cycling - or the lack of it on a warm day. After some reading and thinking I came up with some ideas that might be applicable to your existing cooler if you are willing to mess around a bit. Let's start with the produced heat, shall we? Down here in Australia most people either have the fridge in their4WD or camper. In a car or small camper trailer there is often the problem of airflow, so the cooler might be doing overtime for no other reason than a lack of airflow. If you check online sites like Amozon and Ebay you quickly find fan systems meant to be installed inside the cooler to get lower temperatures and a quicker cooling of fresh goods. The thing is that the box is quite well insulated and the benefit of the airflow goes only as far as it can reach. And even if the box is quite empty and you would have a benefit of the cold air moving around it won't change the fact that "improved" cooling always comes with more heat in this case. But if we use one of these fan systems to actually improve the airflow on the hot side we not only get better cooling but also a reduce power consumption - something worth considering if you have no backup power generator.... This of course brings us to placement. As I have done the mistake myself you might be tempted to put a 3way cooler onto your seat. Opening it with the back free means the lid always gets stuck on the seat, do it the other way around and you block the airflow. If you do put it on the seat then make sure two things match: 1. The thing is secured properly. 2. The airflow from your aircon is able to reach the hot side of the cooler. Even permanent installations in a camper benefit from a good airflow. Often the fridge or freezer is built into some sort of bench and the airflow behind might be very limited. A simple solution here is to add a vent on top of the bench to allow the hot air to escape. A better one is to use a fan that is powered together with the heating element or compressor and drives the hot air to the outside. How to improve the cold side of the box or fridge? Well, to be honest there is not much that can be done unless you are prepared for some serious work. Depending on compartment size, contents and how full it is a little fan can help to keep the temperatures even but it won't help to get it cooler or reduce the cycling periods for the cooling. The only really working way that I found is to use a "battery" for the storage of the cold. The cooling works by checking the inside temp of the box and if above the set temp the cooling won't stop. This is all well and good while we have a constant supply of power but once we are on batteries it would be great to keep the active time to a minimum. A working solution is to build a container that fits around the cooling element. Smaller types often use an aluminium heatsink, bigger types might come with a compressor and an evaporator. In either case proper sealing is important! Most good models are fully waterproof, meaning even if you would fill them with water they would not leak in other areas than the door. But double check and if in doubt use a bit of silicone to make sure. Ok, but how do we "store" the cold coming from the device? Cold packs ;) These things contain a ready to use mix that holds cold temperatures quite well. Another really good alternative is alcohol or radiator coolant, although the last has limited capabilites in terms of holding capaity for the cold as it is desinged to exchange heat fast rather than to keep it. With a suitable sized and sealed box around the active cooling element we will need longer to actually see any cooling happen (with a warm "battery") but that can be compensated for by good planning or a frozen water bottle. If the cooling element is covered with a box of cooling gel then it has to cool this first before anything happens inside the box. But once it does the pack is already far below the normal temp it would have during normal operation. Remember the inside of the cold pack cools down first before the outside will get cold ;) So once the set temperature is reached the device will shut off. But since the cold pack is far below the set temp it will continue to cool our box until the core is warmer than the set temp. Quick thinkers will now say the benefit is lost as the time required to cool the "battery" down again is much longer than the normal cycle time - and they would be correct. But as we get much colder temps inside the gel box the overall running will still be less compared to normal operation. And since from the second cycle on the gel is only warming up to operating temp of the box it will be much faster than with a warm box. Another benefit might be the ease of cleaning and ice removal. Some peltier driven coolers have big cooling fins or a quite bad design for the heatsink allowing mould to grow where you can't remove it easy. If the box is made from stainless steel and flush with the back wall of the box we won't have that problem anymore. Ok, but how much is good or too much for the size and gel content? You got me there as it is bit tricky. You don't want to loose much usable space for starters and you don't want to wait hours for the gel to cool down if the box was not used. IMHO the size should fit the cooling element with about 20% to spare all around. If stainless steel is not an option than aluminium is the next best choice. Thin sheets can either be be cold formed with a hammer or "brazed" with a good torch and the right rods. Ok, before that route is there anything I should consider or do first? Depends ;) 3-way systems usually use a flame or heating elements to heat an ammoia solution. After years of neglect corrosion can form and reduce the amount of heat transfered into the system and reducing the efficiency this way. It might help to take the heating elements out once a year or so to clean them and the contact areas from any corrosion or dirt build up. With a fixed shedule for this you won't have the problem of never noticing a badly corroded heating element either - and this is the main failure on these systems.... Modifying your camper or making a few mods to your 4WD drawer system is not for the faint of heart and should be done with consideration. The last thing you want to do is rush things to find out it was not necessary. Before cutting holes check if you can't find the room for the fan in a different spot and use ducts to control the airflow - sometimes it is easier to blow air in than to get air out ;) When it comes to creating vents or connections for air to the outside always make sure it is waterproof and insect safe! If you can let the outlet go downwards so water won't run in, for 4WD trailers consider a flap to prevent water from going during a river crossing. Flyscreens will not only prevent insects from coming in but on the inside also prevent dust to go eerywhere - allow to the removal and cleaning! The salts used in these cold packs can be corrosive, so you have to make sure there are no leaks and that there is no steel to come into contact with gel - this includes screw ends hidden in through-holes. If in doubt use a coat of paint but keep it as thin as possible. Even on peltier systems it might be impossible to remove the heatsink without massive surgery on the internals. So before you take it all apart to gain access check if it is far easier to seal around the box opening and possible screw connections using silicone. The cooling battery can be screwed on and sealed with silicone as well as an easy escape route. Although for this to work you need to check if the material of the box allows for a proper bond with the silicone! Some materials just won't allow anything to stick at all, even after sanding them. So do a test first in an area where you would be able to cut the silicone away without causing damage. If you can rip or peel it off the surface you should not try to use a cooling battery screwed to the wall, only use a box that is fully sealed with the cooling element and has a seperate back - one complete unit around the cooling element. I have a 3-way system with a freezer compartment that does the cooling for the fridge too - what can I do? These units either provide good freezing with the fridge temps too low or good fridge cooling with no freezing capabilites - depending on the thermostat used. Our problem is that is next to impossible to add a cooling battery of the normal kind to these systems. The L-shaped freezer box can really only be added with a L-shaped cooling battery from underneath. Only if you don't need any freezing at all you could add a cooling battery to fit into the freezer box shape. In either case the benefit is somehow limited by the way the thermostat is used. If there is no temp control for freezing it should be fine. Warnings... Only peltier driven coolers are free from refrigerants. Every 3-way or compressor system uses refrigerant as evident by more or less piping and heating elements. Never attempt to screw anything into a cooling element containing refrigerant! Even if you think between the channels all will be fine it won't be! The material is just pressed to form the channels and any damage caould mean refrigerant leaking out! Use silicone instead and make sure all surfaces are properly cleaned before applying it, also wait until the silicone is really fully cured before putting any stress on it. As said, these cooling gels can be corrosive, especially if DC voltage is involved. Make sure that everything that is not aluminum or plastic is properly sealed before allowing ongoing contact with cooling gels. Do not attempt any of this if you have to ask yourself what tools you might need or how make a suitable container for the gel. If in doubt check Google on how to work with aluminium or stainless steel if there are not enough Instructables for it. The gel will expand a little bit if it freezes, this no problem in a metal container if you allow for a bit of flex or on the side added strength  - whatever suits you better. Another option is to get a few different cold packs (by the active ingredient) and to do a check in a little container. Freeze it and note whe level cold and warm. Little to no difference means nothing to worry in terms of expansion during freezing.

Topic by Downunder35m  


Soldering tips and tricks for complicated metals

Whether you are just a hobby builder or do your own electronics projects, you know how to solder...Then one day you find yourself in the position that your solder just does not want to stick...My first moment of total defeat happened when I was a teenager.Was building some simple motor with instructions from a book but substituted what I could...Ended up with some stainless steel contacts and being unable to solder my wires to them...If you ever had problems like this then read on ;)What are easy to solder metals?Basically everything that does not form an oxide layer on the surface and is able to bind with tin, lead or silver.Copper is one of the easiest metals to solder on but every plumber certainly knows how important a clean and corrosion free surface is.Any coating or alloy that prevents oxidisation or provides a harder surface usually means with normal, electornics solder we might be lost.Nickel for example can be a true pain and same for chrome.So lets start with the hard metals first.Steel, nickel, stainless...If the part size does not already mean trouble to get it hot enough, then we face the problem of how to "wet" it with our solder.Normal steel is usually fine if you give it a fine sanding right before the soldering, however getting the heat onto the part is crucial.Even something simple like a 5mm thick steel rod can be a pain with a normal soldering iron.I good way to cheat is to preheat the part or area with a blow torach on a soft flame - not a hot, blue flame.Try to do this away from the area you need to solder as the temperature difference usually causes some initial condensation on the surface.Most steels that play a vital role don't like to be overheated as it can affect the hardness an other things, so be careful here.Rosin core solder works fine on steel and it also indicates when the temperature gets too hot by boiling and smoking badly.If you still struggle to wet the surface try to scratch it with your solder - if it does not melt the surface is not hot enough.Nickel coatings are usually very thin and a slight sanding quickly reveals the layer underneath.If the metal used is not copper already then a copper layer will be electroplated on before the nickel coating.Either way the key is to get through the nickel without going through the copper, for example if steel contacts were used for durability reasons.After that soldering is as easy as directly onto copper.Steinless steel however can be a true pain, same by the way if you need to preserve the nickel coating as best as possible and can sand it off.Without using chemistry the only way I found is to use a stainless steel tip in the soldering iron.But as the preperation of one requires chemicals anyway we might start with them first.The passivating layer of layer or stainless steel can of course be pre-treated by sanding.Especially very shiny surface benefit from it.After this I prefer to wet the surface with Phosphoric Acid - you can find it in the harware store as "Rust remover".It is a food grade acid used in many of your favourite fizzy drinks, so skin contact is not a big deal - just wash it off.The phosphoric acid is not strong enough to break the oxide layer but it keeps air away.And once you start scratching the hot metal with your stainless steel soldering tip it will prevent a new oxide layer from forming.This method however requires a low temperature solder and quick work as the acid boils off quickly.In the plumbing section of your hardware store your find various fluxes for soldering.Look for something containing both Ammonium Chloride and Tink Chloride.Around here a common brand name is Bakers Fluid.Usually if it has a red danger label on it you will find the above ingredients on the lable somewhere.Be careful with it as it is very corrosive and harmful to your health!Good thing is that all remains can be washed off with just running water.What does it do though?Unlike the phosphoric acid, the chlrodies directly attack the metal.Especially once getting hot, so if in doubt wear proper protection as advised on the label!The oxide layer is not only being eaten away, there is also an ion exchange happening, so a product with more than 30% of zink chloride is prefered here.The zink binds with the stainless steel or nickel and provides an easier way to bond for the solder.Key is to work quickly and with precision!Flux paste is good for brazing but not so good for soldering.The flux liquid, unlike the paste will start to boil right when the metal get to soldering temperatures.That is if you use standard lead based solder, most lead free types should be ready a bit sooner.Start to scratch the metal with the solder and use a soft flame from the other side or close to the soldering area - do not apply the flame directly onto the flux covered area.Why? Well, the flux isolates the metal from the heat of the flame and it will boil off way before the metal gets hot enough ;)On smaller parts and when using the soldering iron create a small bubble of solder and keep scratching the surface while it heats up.In case the flux dries off apply a bit more before this happens!Once the solder starts to wet the metal a tiny bit it is usually very easy to spread it out to the desired size and shape.With the heat applied from the underside the solder will always flow to the area of most heat!Once done it is best to let the part cool down then to give it a good wash under running water to remove all remains of the flux.Failing to to do so will result in quick and ongoing corrosion, so do it properly...Aluminium, the bad metal...I encountered it first when I could not welding or brazing on a quite small part.Plus, of course, the problem of having to add a copper wire as well.Then again when I had to solder some aluminium wire.Acid won't work, chlorides only make it worse, so don't bother with either for aluminium.Standard rosin core solder also fails.But there is a suprisingly simple solution to the oxide problem on aluminium.Mechanical work...There are quite few videos out there showing how someone solders onto some aluminium foil.It is so simple because the foil is thin - use it to test your new skills.A thing though that is often done wrong is the surface preperation.It usually starts with a fine sanding - to remove the oxide layer.....The some oil is applied and soldering starts under the oil cover.And if pay attention then it is often a painful process of scratching with the soldering iron while trying to make the solder bubble wet the aluminium.That's why foil is so simple here....What happened in those videos?Quite simple: Aluminium oxidises right away while you sand it.Even if you are quick with the oil it already happened.So why not do the sanding after the oil was applied?A fibreglass pen or a stainless steel wire brush (usused on other things!) work quite well here.The oil prevents the air from attacking the aluminum.If in doubt use some clay and form a little dam around the soldering area to prevent the oil from running off.Petroleum jelly, vaseline and all other identical things work fine here same for clean engine oil.But you have to use rosin free solder, no flux core, just plain solder.If you don't have it simply melt some normal rosin core solder to a nice drop and clean the rosin off ;)Since there is no real oxide layer with this way of pre-treating the soldering and wetting happens right once the aluminium get hot enough to melt the solder.You might find it sticking nice right away but don't be fooled!You need to heat the aluminium until you actually see the solder forming a nice puddle.With careful sanding you create very clean boundaries.Other soldering tricks...Getting cholired based flux for a single job might be overkill.If you happen to have one of these tip cleaning stones for your soldering iron then you have what you need ;)Simply scrape some of it off and dissolve it is a tiny amount of water.Will only be ammonium chloride and requires more scratching on stainless steel but works...Preparing a stainless steel soldering tip sunds as easy as finding a suitable piece of wire and grindinga tip onto it.If you every changed the tip on a soldering iron them you know there is two types.The simple one for the cheaper irons uses a set screw or similar to hold the tip.The better ones are hold in place by a collar or other type of screw fitting.And well, those have a thicker part in their body.If you need to solder stainless steel more than once or twice it makes sense to buy a cheap but powerful soldering iron and to make sure it uses a straight piece of metal with no thicker parts to hold it in place.If you can't find some stainless steel wire or round bar of suitable thickness you can go slightly below or much thinner if you require a thin tip.Just make a copper or aluminium collar for the tip to hold it in place, like a sleeve to go around.Grind the tip to your desired shape before fitting it in....You won't need a mirror finnish and it can be helpful if the the surface is quite rough.After all, you want to scratch around on stainless steel with it and you can't harm it this way.To get a nice and clean cover of solder onto the tip you need the mentioned flux from above.Use a small cup and fill some of the flux in it so you can dip the tip of the soldering iron into it.If there is no temperature control start with a cold iron and the tip sanded off a last time right before dipping it into the flux.Use some clamps or whatever you feel like to help keeping the tip in place.If you get flux onto bits you don't want to cover with solder then wash off and try again.Turn the iron on observe the tip.As soon as you see tiny bubble forming take it out and quickly start rubbing your solder onto the tip.It helps to have a thick enough solder so you can apply some pressure here.And of course the solder should be nice and shiny and not covered by oxides...Special cases like titanium or othe metals that usually fail to bond with solder....Let's face it: whenever soldering is not feasable we are happy to revert back to crimping or screwing.Nothing wrong with it either and often the better option when it comes to being able to do a quick repair at a later stage.Most of thes special metals, including your favourite heating wire can still be solder using the right surface prep and flux but it really should be avoided if you can.And real bond like you get when soldering copper would only be on a surface level and mechanical strenght questionable.On a professional level ultrasonic soldering is used to make the impossible possible.The cavitation effect breaks through the surface oxides or passivating layers and the solder just wets the surface like it would be copper.On a hobby level things look different though.Unless you decide to build your own solar panels from scratch the investment into some low end ultrasonic soldering machine already set you back a few grand....There is a way to cheat on the cheap though if you are into experimenting and building things....More on that in my other topic about making an ultrasonic soldering tank. ;)

Topic by Downunder35m  


Aircon or fridge compressor to solar?

Sometimes I get weird ideas that I can't shake off :)When I was looking into options for a 12 compressor fridge freezer combo I was stunned.You a get a fullsized frrezer for far less!A further check revealed that it is mainly the linear compressor that makes the price plus the usual mark ups.Efficiency and especially start up is far better with thes compressors than out standard rotary and piston drive models.But why would it be so impossible to replace the motor from a standard compressor with a brushless DC one?I focussed on three things for the start:Lubrication, cooling and sealing.There is no such thing like a simple compressor with a piston system that does have some leaking.So apart from the noise the enclosure really needs to be welded and sealed again.Everything moving inside is lubricated by the drive shaft - it acts like a little pump.Same for the cooling of these vital parts.The oil flow exchanges heat through the big metal housing.A replacement motor would need to be suited to run in such a messy enviroment.Of course something to provide a proper oil flow needs to be created too if the drive shaft is replaced.With some basic enineering this might be possible, same for the motor mount and wiring to the outside.But what to do about the full load starting conditions that can happen?Even with no load from the cooling system the motor needs massive torque to get the piston moving.A bypass valve that closes once the motor is at proper speeds might work but hard to implement in a tight space.Any ideas?Did you ever try something that stupid?Could you make it work?What about a rotary compressor with external drive?We use ice blenders that have a magnetic base and the actual connection is made through the magnetic forces alone.A scroll compressor has lots of space without the original motor inside.Plus, a round pipe is easier to work with when it comes to adding or removing things.Small scroll compressors from an airconditioner or small industrial freezer wouldn't have to do much work in a small setup.Best thing is that with a variable speed the cooling power can be adjusted.How feasable would it be to use some polycarbonate end plate and a magnetically coupled drive ?Modern BLDC motors offer great performance and suitable gear systems are readily available.N52 neodymium magnets of the block type provide several kg of force if close enough to each other - should be enough to make a compressor spin...In return it could mean to have a nice freezer or even airconditioner that runs directly on solar power.No massive losses from inverters, no need for huge battery banks either.As long as the sun is out you have free power, once down you can still switch to a power supply for the motor or use battery power.Just imagine you come home after long day of work and the house is already cool.And you did not have to pay a cent to get it cool or wait for hours for it to reach this temperature!We love to add solar panels to our houses in the hope to get a few cents back from our energy providers.The sad reality often is that you might be able to power all your needs during the day but the excess that goes back to the grid often pays next to nothing.But if you could power a lot more things like a compressor directly with the electricity from your panels....Then these kWh would not appear on your usage bill either.Means you neither use what the power provider compensates you for nor is it "wasted" thorugh this bogus compensation.The normal solar setup can then provide you with this little extra money while an additional set powers the motors for your big freezer or little airconditioner - little being relative to what you make of the idea ;)If you really dare than you could even use your bike and legs to power your fridge directly ;)Use your imagination :)

Topic by Downunder35m    |  last reply


3D printed vortex tube for spot cooling

These tubes are available as industrial supplies by the dozen but quite costly.Tried a few designs available on the net but either they are next to impossible to print using FDM or fail to provide any significant temperature difference.Just to be clear: If amient air temp is 25°C then I would like to get below zero on the cold end.And well, I would like to be able to salvage a small fridge compressor with considerably less air flow than a shop compressor.Now to the problem(s) I face:1: The temp on the cold end is affected by both the length of the tube and by how much air can escape on the hot side.Makes finding a suitable diameter and length quite tricky if you don't have fancy simulation software at your disposal :(2: The standard cylindrical design for the "engine" is not really that efficient :(To make them work a lot of pressure is required, usually they won't do anything below 85PSI and most require about as much air volume as a little air grinder.3: 3D printed parts with complex insides are a true pain to clean, seal and make sturdy enough to last more than a few minutes under these conditions.I am currently experimenting with PETG as it is a bit more temp resistant and stronger.My understanding of these vortex tubes is that the outer vortex, created by the engine, travels up the tube.At the outlet valve the vortext is split so that the fastest and hottest air escapes while the colder air is directed dow, through the outer vortex and at a significantly lower speed for the rotation.Scientists can't really agree on the directions and spin of the inner and outer vortex :(My theory is that the hot air is created by a pressure increase towards the end of the tube.As this also expands the air, the inner vortex will be choked off so to say.Only option for it is to go through and by doing so loosing a lot of pressure on the exit - the stream cools down.The circulation around the vortex spin however means that speeds of well over the speed of sound are reached.I can only assume that at this speed there will also be some energy exchange happening based on the static electricity created where the two stream "rub" against each other.So far only models with a finely sanded inner tube actually performed at all.Will one day have to try using a thick plastic straw as a liner...Questions:1. Do you think a complex, conical nozzle is required?The commercial ones all use them.However I tend to think that a slotted approach might be better.Instead of adjusting the gap of the needle valve two half cylinders with slots can create a finely adjustable outlet.Way easier to desing if all parts shall be printable....2. If 1 is not a a real requirement:How to best design the slots for the correct air flow??In the direction of the rotation?Straight?Or even against the rotation so the air will be forced out onlyby the pressure but not by direction?3. Is there any easy workaround for Sketchup that would allow me to create sphere with the required channels along the inner wall to create a fast vortex?I can do screw, nut and bolts, a sphere is no problem either.But I can't seem to find a way to comine both techniques so they work on the inside of a sphere :(Why a sphere you wonder? ;)I like harmony for these things a an egg or a sphere is way more harmonic than a cylinder.On top of that it would allow to create a vortex to my specs instead of chance.Ideally the "threads" would get a smaller pitch with every turn.This forces the airstream to not olny increase in speed (decreasing diameter) but also to be "compressed" before even entering the tube section.The inner stream would pass through a tube inside this sphere, after passing through the tiny gap the upgoing airstream created.My hope is that such a design would allow for the low flow rates of a fridge compressor while being quite small in size as well.Anyone with good ideas or tips?

Question by Downunder35m    |  last reply


Ancient technologies revisited - solar cells during the bronze age!?

In this second part of my series I will discuss the theory(ies) of the existence of solar cell like technology.If you have batteries you have something that needs electricity - DC.But you might also need some easy way to charge them unless you have a generator...We only "recently" developed solar cells, although the theoretical idea behind the is a bit older.In ancient Aegypt was enough sun to use solar cells it still is.But you would need to know how to grow silicium crystals first...And you also need a way to cut very thin slices of them in the right orientation...Not so mainstream scientists already showed us advanced maching marks and impossible accuracy being used throughout ancient Aegypt.So we can rest assured they knew how to deal with precision and complex math.Still growing crystal is far fetched, especially considering that through ancient times being one with nature and the gods was priority number one.A group of now dishonered scientists came up with the theory that in ancient times the sun was used more indirectly to generate electricity.Their claim based on some pictured carvings and other things the found goes like this:Arrays of tubes where used that contained a biological matter.Alternating tubes used different metals and were connected by non conductive joints.A slot in the top, throughot the length of the tubes allowed sunlight to get in.Apart from a lot of waste gas this biological matter than caused the tubes to get charge through an ion exchange process on a cellular level.A good theory should always be double checked and peer reviewed by independent schientists.If you can replicate the findings it must be true.A bad theory should not get you more than a bit of laughter and mean reports in related publications.So these scientists must have really overdone it, right?After all, they lost all credibility and most of them now have unqualified jobs far away from anything they ever studied - like stockig supermarket shelves...By really pure conincidence NASA developed a "bio matter (Re)Re-generator" just little over two years after our group of scientists lost their jobs.What does it do you wonder....Well, for long missions away from earth it makes sense to find better ways of dealing with (human) organic waste.Recycling the water from it is one thing but it requires lots of energy that could be used for other things.And it still leave a "$%'& load of soild waste.NASA "found" a bacteria capable of reducing organic waste products in a liquid supension very quickly into most basic end products.Easy to recycle, re-use or if in doubt discard as there is only around 3% or the original solid waste left.The bateria only needs enough sunlight be become realy active.Double bonus: It won't produce any CO2 as a gas but instead produces a soild form of calcium "waste".Calcium is not only what makes our bones, it is also very useful for other things.The seperation of this valuable solid calcium waste comes with the side effect of producing electricity at the catalyst arrays.An "unforseen" side effect that is since then subject to further research.I did say coincidence already, did I ?Another is that the bacteria found by NASA is from the same family our disgruteld scientists claimed to might have been used.Ok, twice is still plausible, isn't it?But using the same material for the "catalyst arrays" as our scientists suggested for the slotted tubes make three....In some old Indian texts we find hints to giant "anti-mirrors" used by the gods to harness the sun.Studied close up they appeared like highly polished silvery metal.But hit by full sun and they turned black and stopped to reflect any light.We know that if the later would have been true this black would have had to be less reflective than Vanta Black and similar inventions.Assume it was true...A "solar cell" that utilises almost all incoming light would have an efficiency grade we could not even dream about.Would also mean it would still be very efficient on a cloudy winter day.The "black" would also mean they should have heated up like no tomorrow but they were claimed to feel extremely cold even on the hottest day...From interpretation of ancient stories of the folks from south america we know the gos use "lightning" as a weapon against enemies as well as for contructions and "artwork" on a big scale.So there was electricity widely used on our earth at times where our books tells us we only had oil lamps and at best bronze tools...If the really had solar technology might remain a mystery forever but we at least know they knew how to use electricity...

Topic by Downunder35m  


External aquarium heater with digital control

I lost about 300 fish just a few days ago when my tank heater decided to stay on when it failed.(examination showed the theromstat contacts were fused together)So far I never worried about failing heaters as so far they just wouldn't heat anymore once the failed.This time I lost about $400 in living creatures and 2 years of breeding.Guess that is the punishment for being away for a few days - a bit over 50°C in your tank...Normal tank heater come in the submersible form or with the clear instruction NOT to submerge them abvoe a certain line - usually under the rubber capEither way they all love to fail within a few years if you are lucky, otherwise sooner.The one thing I always hated is that you need to find ways to hide them in your tank, in some cases you even need to a heat shield to protect sensitve critters in your tank.I though that there should be a cheap and easy way to eliminate most of the annoying factors....Simple, digital temperature controller....You find digital thermostats for your fridge and freezer for around $30-100 bucks, depending on the brand and features.Downside is they all activate the output once the temperature gets too hot.For under $10 you can get universal thermostat controllers- just a tiny white box with the display, two buttons and a few wires...Won't place a link but with the above you should find them on Ebay and Amazon for as said under $10.These can be set with the min temp being above the max temp - this effectively reverts the output state ;)Looks a bit weird when setting the temps this way but after that the power on the output is alive once the temp is BELOW of the set temp.And you can set the differential as low as 0.1°C if you like, but 2-3°C are fine for most tanks.Abandoning the internal heater thermostat....As the number one cause of failure apart from water getting inside we should not use the internal thermostat anymore now.To do this without messing around the temp is simply dialed way above what you will need for your tank.E.G.: If you want 24°C in your tank over the digital controller than the heater thermostat is cranked to 27° or higher.The on-off will be handled through the power our new digital controller provides.Sealing a heater....You should not have to do this but an awful lot of heaters simply fail because water makes it inside somehow.I use a bead of UV curing resin or UV curing epoxy glue for the first stage.The glass won't really expand, so the rubber from the cap won't expand much either.All we do is to add another layer of sealing protection.That stuff however is not always fully qualified for being suberged or just in contact with water a lot.So we add another bead of aquarium grade silicone on top.This also protects our tank from any harful chemicals the UV glue might otherwise release over time.Going external...With an external filter pump it just does not seem to make much sense to have a heater insde the tank.For some reason those filter manufactureres though about almost anything, including build in UV sterilisation - but not a heater...Using a bit of 5mm PVC drain pipe, two end caps and some hose fittings for your aquarium hoses we are set again.A bit of stainless steel wire from the gardeing section of hardware store helps too - the soft, flexible kind, not the really stiff and hard wire please!Design of the external heater:In one end cap you want to drill a hole of the same diameter as your heater tube, a mm bigger won't hurt too much but don't make so small that you need brute force to get the heater through the hole.Seal the inside and outside of the cap with silicone.If you want the heater to be replaced easily in case it does fail again (which it should not!), then you a pipe with a screw fitting and a screw on cap.Keep the assembly steady and secured while the (aquarium grade!) silicone cures - if in doubt let it cure for few more days.The lenght of the pipe should be so that there is enough space left in the bottom so the heater will have about 6cm until it would touch the other end cap.The pipe connections can be for one on the other end cap if you mount the pipe somehwere, otherwise both connectors should on the side of the pump and as close to the caps as feasable.Again, seal the inside and outside of these connections with silicone and let it cure.It helps if the fittings are of the screw in type with a backing nut.Downsides of having an external heater...You need to clean it out when you clean your filter, an added few minutes.If the heater thermostat is set too high and your pump is not running the water in the pipe and hoses will rise to the set temperature of the heater.For a medium sized tank that is no problem, for really small tanks it should be considered though - set the thermostat of the the heater not to the max if you think you might forget the water circulation one day ;)Upsides of having an external heater...The biggest benefit of having and external heater with a digital temperature controller is the lifespan.I used a dirst cheap 400W tube heater like this for over 6 years until finally the actually heating element failed.With the nicely illuminated temp display the times of checking the sticker on the tank or trying to read this tiny floating thermomoter are over as well.Possible upgrade options if you know how to solder or at least know how to correctly wire a relay...With an external tube comes the option to include a UV sterlisation lamp on the other end.The tube will be accordingly longer but a submersible lamp only costs a fraction of these ready made solutions that you still need to attach your your hoses somehow - and they are often quite big...Apart from that there is the option to modify a digital fridge thermostat (about $20-100 bucks) like the STL-1000.As most of them can't be re-programmed for other than cooling use and only have a single output for the compressor the internal relay needs to be replaced.Just select one that somehow fits inside once the original is removed and wire the NC and common output for your heater.Not in mood to fiddle with a controller and solder? No problem either!Just wire another relay to the output.Means the power that the controller switches on it will then switch your additional relay on.This gives you the option to use the proper contacts again to turn your heater on.Using a normal fridge controller this way however requires thinking the wrong way around for the temps.Remember!! : The frige controller "turns on" when the temp goes ABOVE a set temperature!!If you use it like this and connect your heater directly it means it will only turn off once the temp is BELOW the set temp and it will never again go below, only up and up and up....The added or exchanged relay however gives us the option to reverse this to some extent.You set the controller to the MAX temp that you want in your tank.Let's say 24°C , by default this gives a 3°C hystersis, meaning depening on the programming of the controller it will turn on at 27° or close to it - keep that in mind add realise that it means your 24° might need to be set to 21° so the temp won't go over 24° in your tank.Ok, got it, but what exactly happens now and why does it work?When the controller reads below the set temp, like when setting up a new tank with cold water from the tap, it won't provide mains power on the compressor output.It knows the "fridge" is fine right now.Our added relay will be off for the same reason, however we connected our mians power to the common contact of the new relay, the heater on the NC (normally closed contact) and from there back to neutral.Means our heater will get power when the temp controller in the OFF-state.Now the temp start to go up in your tank and sooner or later it will reach the set temp you adjusted the controller to.Suddelny the controller sees a risk for your food in the fridge to go bad and decides to turn the compressor back on to cool it down.As we added our relay it means it will turn on as well.Our NC, normally closed contact, opens and the heater turns off.From ther is just continues within the range of about 3°C....You added digital temp display to your nice fish tank, don't have to worry anymore about your heater prematurely failing and if you like:Some controller offer an alarm output.This can be used with an added relay the same way as before and would then warm you if you heater burnt out and the temp in your tank goes too low.Why so "complicated" if there is microcontrollers?Anyone can use some Arduino and do the same with ease - if anyone can program what it is required.However, even our average Joe with no electronic skills can to the above mods within a few hours excluding the curing time for the silicone.Back to the basics, and after all we already have a microcontroller inside out firdge controller ;)And as said, if in doubt then even a $10 one will do the trick without any mods to it.What about that stainless steel wire?? Don't tell me I wasted 5 bucks for nothing!You did not...Long heaters or UV lamps certainly benefit from it.But even a smaller one is much more stable inside the pipe if you create a simple wire cage for it.The stuff usually comes in a rolled up form of a 10 or 20 meters.With that it is easy to make some loop with the heater ube in the center.Just make a wrap around the pipe with enough left either end to form a ring or spiral that fits inside the pipe.There is not much spring action happening with this wire, so the loops can be quite big and you just push them inside inside while decreasing the diameter until they slide in.If you have a 3D priter you also just print a ring with a hole for the heater and some spokes to cneter it in the pipe.What about heat transfer and even temps in my tank?With the usual in tank setup you have to ensure anyway that the heater is in the waterflow.Otherwise one side of the tank warms up more than the other.With the heater being in the flow of the external pump directly we pump in warmer water and suck out the colder water the other end.Results in a more stable and even overall temperature especially on long tanks.Enjoy!

Topic by Downunder35m  


The risks of DIY carpet cleaning and how save a buck or two....

I am writing this partly because of bed experiences with rental angents/landlords and as a general help.Here in Australia as well as other parts of the world it is common pratise that a real estate agent goes through your rented home multiple times a year to check if you keep it clean and undamaged.In most cases these visits go without any hickup until you move out.At this point agents often try to make your life a misery.Some expect you get the house back to the state it was 10 years ago when you moved - an impossible task.Carpet cleaning is usually done with a rented machine.This mean you pay a deposit for the machine and "rent" is made by the highly overpriced cleaning fluid you have to use with the machine.But more and more people see that a $100 machine from the discounter is a "money saver".So lets start with the main differences between a rented, commercial grade machine and those you find at the discounter to buy.The later comes quite small and in plastic, the commercial one is usually all metal and has huge water and waste tank.And lets be honest here, if a good vacuum cleaner sets you back more than twice what your new floor cleaning machine costs.....For me the real difference is in the sucktion.If you start with 10 liters in a commercail machine then you should expect to get over 8 liters back in the waste tank.The added waste often makes it seem much more though ;)The cheap discounter vesion however often struggles to get half of the water back out of your carpet that it drained into it!This is not only due to the weaker vacuum created but also due to the general design and lack of sealing the area that is sucked up.But during a hot summer week this makes no vital difference as it dries off anyway, or does it?Dryness and contamination....If you wash your clothes than you let them fully dry before you wear them.With a freshly cleaned carpet we often don't have that luxury and if the weather won't play nice you might end with a moist carpet for weeks.A proper wash of the carpet would require that water is actually flowing through the fabric.This is achieved by designing water outlets and sucktion areas to be in close proximity.However, most carpets these days are thin and flimsy, the underlay brings the comfort and often the required insulation from the cold floor.Fun fact: Most quality carpets in the EU come with a rubber or foam like backing which prevents that little spills go through and also leave the carpet basically dry after a cleaning.If the amount of water your machine collects does not get very close to what you filled into the tank then you end with a quite wet carpet and underlay.Cold from underneath and with basically no airflow through it.And if you ever removed an old carpet that was cleaned every few years you do know why you wear a protective suit, gloves and a filter mask on your face....It is simply impossible with a handheld machine to prevent water and contaminants from getting into the foam underlay of US and AU style carpet assemblies.Once fully dry there is little chance for anything to grow, but every time you clean the carpet you add the water required...I had it in two rentals that when I cleaned the carpets with a really good machine that stains from within the underlay came back up into the carpet.A job planned for a day then turned into three days of using heater fans and living in a sauna while washing carpets :(The same is true if you end up with fresh dirt or such on the carpet while it is still moist underneat - it gets worked ino the carpet and becomes even harder to clean.Is a commercial cleaning the better option?Sadly I have to say this highly depends on your agent/landlord and how much time and money you have.In some areas agents simply ignore the law and demand from you that the carpet looks at least as good as when you moved in.And if old stains you did not know about come from the filthy underlay a rented machine can come close to the cost of getting a commercail team in to do the job once you vacated.Either way you get an invoice for the service and a statement about the condition of the carpets before and after the cleaning.These guys come with a big van and before it fires up with water only the vacuum is used.Imagine a monster sized vacuum cleaner head on steroids that connects to an industrial sized evacuation fan in the van.It literally lifts your carpet from the underlay and leaves nothing loose behind.The actual cleaning and sanitation works the same way only with the big difference that the water is sprayed with pressure through the carpet and into the underlay.Final round is done dry and with vacuum only, means the carpets are dry enough to walk on them without getting wet feet.A complete dry state is usually reached within 2 days during the summer unlike rented machines that keep the humidity in your house up and high for about 2 weeks until back to normal.Main benefit of a commercail cleaning is that you won't get any issues with your agent/landlord unless you damaged the carpets or made them impossible to clean - ever dropped an ink jet printer refill kit? ;)If I do it myself with a reasonably good machine or a rented one : Do I have options for the cleaning solution used?Trust me, I had to figure that one out quickly when I moved into my first rental down here.4 bedrooms, entire house with carpet except for the kitchen and wet areas.They appeared reasonably clean at a first look but when I used a UV flashlight at night the story was shocking....In what must have a room for a baby the carpet looked like a psychedlic art impression under the UV light.The living room was not much better.As a result the rented machine ran out of cleaning fluid quickly.Bought 2 bottles that were supposed to be suffient for the house size but if you need several rounds per room.I "finnished" the former baby room and was one bottle down already.Called it a day and in the dark the UV light showed a slithly fades art impression but nowhere clean :(The shop had a heavy duty cleaning solution but I did not consider it with a price twice as high.Instead I wondered what would make my carpet different from my clothes in my washing machine....So I got a canister of Oxy-cleaner - sometimes called nappy soaking powder, or similar.Just make sure you get one that does not foam up too much.I used a bucket to dissolve a good amount of the powder before filling it into the machine - at about 40°C.What ended in the waste tank when using this cheap alternative looked digusting to say the least!With that encouragement I decided to make a new bucket with some added washing powder, just a tablespoon worth or just over.Washing powder for front loader does not foam up much, unlike the stuff for top loader, so choose wisely.That was, all counted, the forth cleaning round for the former baby room but after this the UV light showed a clean carpet that also had nice spring fresh smell thanks to the washing powder.Using the same appraoch of lots of oxy cleaner and a bit of washing machine powder in semi hot water made cleaning the rest of the house a breeze!When going slow with the machine it was like mowing the lawn, it left a clean path behind.Not all carpets might tolerate oxy cleaners though, especially if they are quite colorful, so do a spot check first if you never used the stuff to clean up a little spill of red wine before.And please keep some of the commercial cleaning fluid at hand to give the machine a quick wash through with it, otherwise the shop might ask you if you used non approved cleaning stuff with it ;)Tips for adjustable cleaning machines....Some of the rented machines come with several possible adjustments you can make.In the most basic form you can adjust the amount water used and how strong the machine sucks.Keep the sucktion as high as possible unless you actually want to pre soak the carpet.The amount of water should be adjusted to the type of carpet not to how dirty it is!You want just enough water to soak the carpet without going into the underlay too much.A clear sign of using too much water is if you waste tank is only half full when the water tank is empty.A few of the really good machines let you adjust the distance between the water outlet and sucktion area.In most cases there pre-set to what, from experience is the most commonly type of carpet in the area.Your might be different though...A greater distance means more time for the cleaning solution to do its job.This works especially well for thicker carpets with amount of water turned down to below 50%.For thin carpets a short distance is better as the water does not have to go deep into the fabric.Here you can even increase the water flow for very dirty areas without risking to soak the underlay too much.In either case you should check the machine before taking it home and if adjustable have the options explained to you in the store.Anything for really bad areas?The entrance area is often subject to whatever our shoes collected outside, especially if you have kids or playful dogs.A bit of oil from the road, some sticky residue of something, dust, small gravel and sand....Vacuum out what comes out first, then use a suitable, not too stiff brush if your vacuum cleaner does not have a rotating brush in the head.Use a spray bottle and prepare a solution of warm water with a bit of washing machine powder and a shot glass worth of methylated spirit.Slightly wet the soiled area with the spray bottle without saturating it.Use the brush to agitate the carpet fibres - preferably directional and with even strokes.If they are not wet in the deeper areas spray a bit more.Again: you don't want to soak it you want to wet it.Give it about 20 minutes on a warm day a bit longer if the insede temps are below 25°C.Check with your hand if the area is still wet, the alcohol should speed up the evaporation here.Before it dries up repeat the process and check with a paper towel if it picks up the stains already.If so then run over the area with cleaning machine.Best results are achieved if you manage to get the fibres wet all the way down with the brush and won't let the area fully dry off again after the spraying.How can I speed up the drying time?The only way to speed things up is heat and airflow.If outside humidty is quite high then you will struggle.Even in the summer times the humidity levels over night can get well into or even over the 80% region.Opening doors and windows then to get the carpet dry won't really help you.Best time to clean your carpets is actually at night because by the time you are done the sun is out and the humity levels much lower.On a good day below 30%.This is true even for the winter times.Put a few fans up and make sure the temperatures are well above the 20°C mark.If in doubt you have to turn the heater on.Once the humidity inside is sky high you open up all windows and doors to have an exchange of air.A few minutes suffice here unless there is wind at all.If it is a hot summer day you can of course just let it all open until the sun goes down again.During colder times pay special attention to cold areas, like your toilet, bathroom or in general areas that won't warm up properly.Even if the room was not cleaned the moisture can accumulate here and cause mold and mildew.If in doubt make sure the ENTIRE house is warm enough until your carpets are fully dry again.A humidity sensor or gauge certainly helps, two are better so you can check inside and outside at the same time.

Topic by Downunder35m  


TEDxBaghdad - Iraq - violence, dust storms and open sourced manufacturing

Baghdad Iraq. It was once the jewel of the Muslim empire and epicenter of knowledge in the Eastern world. Now it is best known for corrupt governance, bombings, and dust storms. It was also my parents’ home. After visiting once in 1991 as a child the few memories I have of Iraq seemed to be shouting matches as my parents yelled over the phone making overseas calls. Names of Uncles I had never met were mentioned and a phone was handed to me and I was left to nervously fend for myself with my weak Iraqi slang and an Uncle who apparently knew all about me while I knew nothing of him. The country was an impenetrable black box to me that would spit out another refugee somewhere in the world every few years or so. Sixteen years later the first wall between Iraq and me was broken. In 2007 my nuclear family had traveled to Syria and for the first time I met family members who still lived in Baghdad. I knew them now. My uncles and cousins grew flesh and blood. I could feel their prickly faces as we greeted with the traditional Iraqi 4 sided cheek kiss. They could graciously give me their dishdashas as gifts. Names finally had faces, but those faces were deep, sunken and afraid. 2007 was a bad year of sectarian war in Iraq, which is why the Damascas district of Harasta was flooded with Iraqis. The sound of construction continued through the night to keep up with the massive (ab)use of the "tourist" visas. I saw something in the Iraqis in Syria that I hadn't seen before; something that scared me. I saw hopelessness. It was then I settled on a long-term project to return to the country and share something that I had just discovered around the same time: the future doesn’t come prepared -- we make the future. The do-it-yourself attitude that was growing in America was being combined with the culture of sharing that you find in hackerspaces, at instructables.com and in open source technology. This atmosphere made anything possible. You want to build a vertical generator without any spinning parts? Sure! How about a walking quadraped robot with a sofa? Do you want to quit your job, write zines and sell them in the crafting circle? Sure! Start a business! Write a novel! Organize a benefit concert! Sure - sure - sure! “Make your own future” was the message. It was a message of hope - it was the message that I wanted to share in the Middle East, and especially in Iraq. In 2011 the opportunity to work on sharing this beautiful message in the Middle East presented itself to me, so I quit my robotics job and took it (sorry Andrew). A few friends and I started a tiny organization called GEMSI - The Global Entrepreneurship and Maker Space Initiative. We funded ourselves through Kickstarter and our first project was a Three-Day Maker Space hosted at Makerfaire Africa. We were hoping to let people experience the feeling of the Maker Movement first-hand. We collaborated with Emeka and the team from MFA, Cairo Hackerspace, along with many amazing egyptians from all over the country. We had a successful first attempt at sharing the message of "Yes you can!” It was a great start, but Iraq was still an impenetrable fortress to me. It took till 2012 and a chance encounter with friends in Cambridge, MA for me to find my first avenue back into Iraq. Via my friends, I met someone who’s friend was affiliated with TEDxBaghdad. A few steps removed, sure, but when I heard about TEDxBaghdad I knew I had found my way in. I knew TEDx and the types of programs they hosted; I knew they were hopeful, inspired, and shared a vision for a brighter tomorrow. I started communicating with Emeka from MFA, who also works with TED, and he put me in touch with Yahay. After my first skype call with Yahay I knew I was going. Someone else had done it - someone broke that barrier, did amazing work in the country, and survived. It wasn't the death trap my family was telling me it was. There was a new narrative being woven and I knew what I needed to do. I booked my flights before I even finalized any workshops. I needed to meet the TEDxBaghdad team. Later, I called my parents and told them I was going to Baghdad and they said, "Shinu?! Inta Makhabal?!" That probably means exactly what you think it does. Needless to say, they had their concerns, but I was going regardless. Now that the tickets were bought, we started planning. Yahay put me in touch with Abdal Ghany, one of the Iraqi organizers living in Baghdad. He coordinated everything. It was amazing. These guys kick some serious planning butt! Ghany basically told me, “Show up and give your workshop. We'll take care of the rest.” This was a welcome change from the hours of facebooking, planning, and coordination I usually have to go through to schedule events. It really seemed like this was possible. I was going to give an Arduino and 3D printing workshop in Baghdad and I was really excited! I sent an email to Sparkfun and Makezine asking them for open source electronics donations since I knew bringing my electronics box through the airport wouldn't be a good idea. They sent me a nice goodie-bag of beautifully packaged Maker products. These two organizations have given me a tremendous amount of help throughout the years, for which I am extremely thankful. I packed a suitcase filled with 2 3D printers, 25 Arduinos, an assortment of other open source hardware and sensors and headed out looking a bit like a bomb development lab. Yeesh! Somehow I made it through China, Saudi, and Turkey without any serious interrogation. Mostly just really quizzical looks from my unzipped bag up back to me... "You're a teacher?" they ask. "Yes," I say, "yes I am." Turkey was the stop before Iraq. Turkey was brilliant, sunny, lush, and seemed to be comprised of mostly happy smiling people walking by the sea. Coming from the deserts of Mecca, this was a welcome sight. I let the green of Turkey wash away the dust of Saudi Arabia. The mishmash of cultures, sounds, foods, religions gave me a great feeling of liberation. This was a lively place and the two hackerspaces I met up with there, Base Istanbul and Istanbul Hackerspace were fantastic hosts. Furkan and I spent a lovely day together chatting about Maker culture as it spreads through the Middle East and then in the end we had a potluck BBQ with members from both hackerspaces by the rocks of the sea. It was great to see these two Turkish hackerspaces and to be reminded that this movement is truly global. My dream of hackerspaces empowering people globally is really possible – and it’s great to know that it is a dream that is shared by others. I left them full of enthusiasm and flew directly to Baghdad. Landing in Baghdad was strange and a bit concerning. Looking out of the window all I could see was a brown cloud. We were landing in a dust storm. I had heard about the turab (dust) of Iraq, but this was the first time I saw it in person, and it would be one of the things most often on my mind. Getting a visa for me was surprisingly easy, except for the fact I forgot my passport on the plane and two guards had to escort me one to each side back to the airplane to retrieve it. But once I had my passport, I told them my laqab, which is the full name that includes ancestry. Showed them a copy of my dad’s passport and my Iraqi birth certificate and I was in. I was hoping for a nice stamp, perhaps with some Iraqi relic on it. But they took my passport and wrote in it: "Originally Iraqi", so there it goes, it's official. Ahmed, my cousin, was not at the airport when I took my paper work and headed out to the lobby. The airport was sparsely populated and heavily regulated. I barely managed to snap a picture before a guard came up to me and had me delete them from my phone. In the lobby I met a man just released from a Swiss prison. The Swiss had given him the option to be sent back home to Iraq, or be jailed. He chose to leave and come back to Iraq. This becomes a theme later as I see more and more people, all of whom desire to leave the country to become refugees elsewhere. It seems that when hope runs out for the country you live in, the only option is to find a new one. This story is one of a million various stories of struggling to find a new life. Each varies in its details, but all have survival at their core. Ahmed arrives 30 minutes late, apologizing. He's wearing jeans and a polo. His hair seemed freshly cut and his face was serious. We had never met before. The only thing I knew of him was that he thought I was reckless for coming. He had been spending hours on Skype with me attempting to convince me that coming would be a bad idea: "You have no idea how bad the bugs are. Just wait till you see the dust storms. The heat will kill you... etc" But once I saw him in person it all changed. I didn't think I'd grow to like Ahmed, but I grew to appreciate his ways and he became like a brother to me before I left. He took me to Mansour, a neighborhood in Baghdad, telling me stories about Iraq as we travelled. This is the neighborhood where the house my dad designed and family built stands. On the ride home we had our car checked for bombs at least 4 times by what Iraqi's call Saytarat, which is the equivalent of a checkpoint and, to me, seemed a total nuciance. They were the reason he was late. What would normally be a 20 minute drive can become three hours long because every car is checked for bombs. They are everywhere; throughout the city, on every road. We passed the guard who watches over my family’s neighborhood, and he takes his hand off his machine gun to wave at Ahmed, and I begin to recognize that weapons, car inspections and burned out cars are normal here, so they don't think to comment on it - like an empty lot in Detroit, or the homeless in San Francisco. We got to my family home with no time to rest. I had to leave to meet up with Abdul Ghany and the crew at a Cafe in an hour and then conduct the workshop in two. Ahmed comes with me - he doesn't trust people we'd never met before and won’t let me out of his sight. I trust first till proven otherwise, he has learned to do the opposite. It’s a telling sign of how different our lives are on a day-to-day basis. As soon as I met the TEDxBaghdad crew, I felt at ease. MNA, Abdul Ghany and the entire crew were thoughtful, hardworking, and inspiring people. I was really happy to have intersected with them and they helped me in more ways than I could count. We first met up at Everyday, a local Mansour café. Everyday cafe was hyper airconditioned and everyone seemed to think it was hotter than it was. The crew was awesome, they were really a great first introduction to the excited young people of Baghdad and they certainly have the famed Iraqi hospitality. But here's a tip: do not order a fajita in Baghdad ;D. Mohammed Al-Samarraie pulled out their iPads and started showing me video production work he was doing for TEDx. Abdul Ghany comes a little late and we have head out to the workshop. The workshop was held in a two story office building surrounded by palm trees. Looking out the the tinted back window we could see the muddy river run past, winding and dark. Slowly the TEDx people started trickling in. Then I started to get nervous. The checkpoints didn't bother me, the tanks in the streets were not an issue, but here were these people coming to learn something from me. What could I share that would really matter to them when they had so much to deal with daily? What could I share that could be relevant to people who see bombings as I experience lightning storms? I have been to other places in the world to share this kind of information, and some of those places have had political problems and ongoing revolutions. But Iraq was the first country I had been to that really seemed like a war zone. I decided that first I needed to learn from them! What were their projects? What did they hope for? I hoped they would learn from each other and get excited about their projects and I wanted to be able to share things that were relevant to them. Thus, everyone was encouraged to talk about who they are, how they learned about TEDxBaghdad and to share their project, share with us their mission, or share an inspiring story. I was amazed to hear about all the incredible initiatives the crew was doing. From intercultural exchange programs, to street clean ups, to historical artifact preservation, each of them shared and I started realizing something. They were not as interested in new technology as they were interested in arts and culture and after hearing about a few of their projects I started realizing why. Learning about culture and paying attention to the arts gives people the ability to pay attention to details. They can look at another human being and see all the subtleties that make us who we are. We each fall in love, we struggle, we question, and have doubts. Arts give depth to a black and white world. Sectarianism is difficult when we pay attention to the commonalities that tie us all together. What would the world be like if anyone who wanted a weapons license was required to have visited India, could pass an art history exam and could play stairway to heaven on the guitar? We were in a sort of office building near the river which ran by dark and muddy looking through the tinted windows. One by one, they stood up in front and gave their short presentations. There were doctors, engineers, and designers in the crew. They each stood up and told the story of how they found out about TEDxBaghdad and it was incredible. Each of them had a friend recommend it to them, and it was mostly done through Facebook. Some people's projects were related to health, culture, antiquity preservation, and connecting Iraqis with the rest of the world. While they spoke I made a graph of the things that connected all of their ideas together. It was a beautiful thing to see. The common themes were to help Iraq as a country through the integration of new ideas and how to bring a new face of Iraq and present it to the world. To have the news about Iraq be about amazing things, inspiring things, rather than explosions. Being in that room with that energy made me feel like we were already on our way. I pulled out the boxes of donations given to us by Sparkfun and The Make Shed and now it was my turn. I told them about my story coming into contact with my friend Alex through instructables.com, how being in San Francisco and Cambridge opened my eyes to a new way of entrepreneurship using communities and open source technology. And how they could make anything they could imagine if they got together to do it. We discussed how sharing and collaboration was a common value that held the entire system together. I used the concept of the LED throwie, which is a simple idea by Graffiti Research Labs to connect an LED to a coin battery and a magnet. They used it to throw at ferrous buildings as a form of electronic graffiti but once they uploaded it to instructables the idea was out there and people were inspired to take it and derive many other projects. You can never know what will happen when you share something or when you create a tool and share it. People created outlined throwies, LED floaties in balloons and finally we start seeing LED floaties which are sequenced to act like a light show at a phish concert. Hahaha! We then talked about the Arduino an easy to use microcontroller designed for artists. It's a bit of technology that is a simple and easy to use platform to build interactive projects. We talked about how the open nature of the project people can use the Arduino and then use shields to add features like being able to connect to the internet or play MP3s. Open source tools make building new products a lot like using legos. We were in the middle of using some of the sensors The Maker Shed had sent us to make a DIY heart rate monitor when the power went out and all went dark except for the LED throwies we had made. It suddenly felt very intimate. We put all the LED throwies in the center of the room and huddled around it for story time. The feeling of connection was palpable for me. Sure the lack of power meant that we were not going to be able to 3D print, but being in the dark with TEDxBaghdad was one of my favorite memories of this trip. The lights went on and we had a long question and answer session / photo shoot. Some of the doctors were interested to use the Arduino based heart rate monitors to replace the broken ones in the hospital. I heard about this and was flabbergast that the most basic and cheap tools I had brought with me might have a direct impact and may even save lives. Technology might not solve the political problems of the country but it seems that there was a lot of room for development and that the crew I was with was creative and excited to make use of it. I passed out 20 Arduino kits that day, including the Lillypad which is a version of the Arduino intended to be sewn into clothing. Although there were very few engineers in the audience, everyone seemed to be buzzing with ideas and ways to use the Arduinos. What a great workshop! I was super excited because not only had they understood the message, they seem to have been infected with the feeling of capability! Now to seal the deal, we were all going to go out and eat a classic Iraqi dish Simach Masguf. Ahmed has been calling me hourly making sure that I was OK, but I felt safe enough with my new friends so we all headed out to a fish spot by the river. Hours go by, lots of fish is eaten, and lots of juice is drunk. Some of the crew smoke some sheesha. It was like I was with new old friends. My Iraqi slang was improving hourly and although we had just met I knew me and TEDxBaghdad we're going to be working together again very soon. I would have stayed all night eating and chatting about future projects and the problems to solve in Iraq, but the cerfew was about to set in and we had to jet. Yeah, there is still a curfew. On the ride home my head is filled with contradictions. Hope and confusion mix in my head as my family rings 4 more times. I get home safe and decide that the only way to deal with the complicated situation in Iraq was to act with irrational hope and optimism. That's the way TEDxBaghdad seemed to work. And that's going to be mine as well. The next day there were five explosions in Baghdad so TEDxBaghdad and I decided against going out to the Iraqi National Museum even though we had to request permission to go. We meet instead back at Everyday and there we solidify our commitment to working for a more beautiful Baghdad and a country which will become a producing nation once again. Sharing with the world it's art, science and literature like it once did years ago. +BG

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