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Cycle Skates

I once read that technology never dies.  There are people today that still make flint knives and start fires by friction.  Furthermore, these skills have been passed down generation to generation.  To prove the hypothesis, the authors got an old Sears Catalog from the 1890s and picked out two pages of stuff they had never heard of.  They found all of them still available for purchase somewhere. Why then, can I not find the Cycle Skates in this 1923 video?   https://www.youtube.com/watch?v=UjtPn4orR9A They were apparently invented in 1870. (http://pedespeed.blogspot.com/2007/07/following-is-from-leonard-de-vries.html) I cannot find the patent info as they seem to be from France. I know in 2004 someone "re-invented" them as Chariot Skates.   Anyway, I would like to learn how to make my own 1870 / 1923 style cycle skates.    Anyone out there who can help?

Topic by justjimAZ    |  last reply


deep cycle batteries

Can we and how do we convert a normal lead acid battery into a deep cycle battery?

Topic by sankyc    |  last reply


fridge cycle logger

Hello all, I'd like to know how efficient my fridge is. To do this, I need to have a record of the on/off cycling that the fridge does: I need to know how frequently it cycles and how long it stays on for. Does anyone know if this gizmo exists? (in the UK) If not, how would I go about making one? Thanks, mm

Topic by marquee.moon    |  last reply


Cycling Desktop Backgrounds

I would like to be able to have an automatically cycling desktop background, like the option on Mac OS X. I'm running Windows XP. Are there any utilities or something available to do this? No, I don't want to create a GIF file of the different wallpapers, that would be enormous.

Topic by CameronSS    |  last reply


Cycling activity, need help?

Next week, I will have a cycling activity, and I want to buy cycling shorts for my girl friend. Has any one tried http://www.outbackbikers.com/? It seems very cheap, but I am afraid of the bad quality.

Question by Hughes Jessica  


What is the duty cycle of a welder? Answered

Is a 6% duty cycle good? Bad? Terrible? Worth blowing up?

Question by bowmaster    |  last reply


50% duty cycle circuit

Hello i want to make 50% duty cycle circuit frequency is no problem : any frequency thanks

Topic by aymanok    |  last reply


Tron™ Light Cycle is for sell

I was just checking out Hammacher Schlemmer and I saw this. I can't believe the technology we have today. If anyone has $55,000 and is willing to spend it on anything, this is for you.

Topic by Dr. Pepper    |  last reply


Cycling Power Meter Details? Answered

Hello, I was wondering if someone could tell me what the specific electronic components of a typical cycling power meter are and how they work together?  The picture is of one by Power Tap that is located in the rear wheel hub.  I'd like to try to build something similar.  All I know is that it uses strain gauges.  I have zero electronics experience but I'm hoping to learn by working the problem backwards. Thanks in advance.

Question by Starbuckaneer    |  last reply


Cat Genie Faster Cycling?

Thank you for all your helpful information on Cat Genie.  I used your rotation arm instructions as soon as I got my Cat Genie 2 years ago.  They were simple and easy to follow I am also resetting my cartridges and saving tons of money. I am wondering if you could help with these two additional issues for Cat Genie 1) Inexpensive Cat Genie granules subsitute 2) Speeding up or making the cleaning cycle faster, reducing the time it takes for each cleaning cycle to complete. Thank you! Dave Stern Las Vegas, NV 702-416-4700

Question by desmisc    |  last reply


Up-cycle an electric blanket? Answered

Our non-woven electric blanket has become unreliable and has been retired.    Is there anything useful I can do with the cords or blanket itself?  It's a lot of bulk to put in the trash.  The wires in the blanket make it undesirable as a regular blanket or quilt lining. 

Question by mole1    |  last reply


deep cycle battery pack

Does anybody know what parts I'd need to make a 12v rechargeable battery pack for an upcoming road trip? I also need to know where I can find deep cycle sealed lead acid batteries for this project. I waited long enough to make a lithium ion pack, but now I changed my mind on the battery type to get 12v, and now I have no idea of what protections and electronic components I need for it. I'l post more info on available casing later, but I'll tell you now that it's like a small blue lego briefcase from when I was little. It's about the size of a texbook and I'd like to be able to put it in a small backpack to carry around school sometimes for my windows tablet. Update: I am available to buy any particular case, but wiring in a case can sometimes look bad, so I'd like it to store all wires internally and have a friendly look. Appearance was part of why I switched my plan from li-ion 18650s to lead acid. A block with printed volt and amp information looks better than a group of oddly sized cells. Also, no clocks.

Topic by leaf26    |  last reply


4 wheeled Quad-Cycle!

Has anybody made or thought about making an Instructable to make a 4 wheeled bike-like a car? I've seen them on the Internet for $3-4000. Thought it would be interesting because of higher gas prices.

Topic by potofgold    |  last reply


cycling machine for father with traumatic brain injury

I am seeking a very resourceful, intelligent builder.  My 79 y.o. father suffered a traumatic brain injury 15 mos ago.  He is minimally conscious and immobile.  We get him into a wheelchair but he gets no movement.  This machine will cycle his legs while he lies in bed.  It is over $9,000 and Medicare does not pay for the device.  I am in leaving a web site address that has information about the machine.  I have alot of other information if anyone might be interested.  http://www.medimotion.co.uk/motomed_models_letto.php I realize that this is a long shot but I thought I might try. 

Topic by carolb4    |  last reply


My Cycle Two Stroke Engine

Hello everyone, I wonder if any one can help me? I have fitted a two stroke engine kit to a cycle of mine, the thing was running perfect for 220 odd miles then starting stopping and would start again after a few minutes of pedalling. I have changed the petrol mixture and this has seemed to alter things slightly, now it will go but will not rev and only goes to a certain speed then starts kangarooing. When I engage the clutch it will not ideal it just conks out. Could there be something wrong with the accelerator perhaps? Thanks a very frustrated Paul

Topic by Paulygriff    |  last reply


need help with 2 cycle motor

So i am having some severe issues with a motorbike i am building. i have an old 2 cycle mccholluch pro-scaper weed eater. i took it apart, cleaned it, put it back together with a brand new plug and it ran nicely. Now, a few days later, it wont even start, not even a putter. i have tried everything, even a hefty shot of ether in the carb, but still nothing. i know i am getting volts to the plug b/c i checked with my meter, but im not sure if im getting spark. it is a brand new plug. any help would be greatly appreciated. thanks.

Topic by the mechanical engineer    |  last reply


60 cycle hum in a power supply

I recently scavenged a 5 VDC phone charger to use as a power supply for my small FM transmitter. I have the transmitter plugged into the computer so I can listen to my favorite internet radio station on the stereo in the living room, rather than only in the office. The whole thing works really well, except that during quiet songs or in between songs, I can hear that 60 cycle hum coming from the radio. Does anybody have any suggestions (cheap, free, or re-purposed parts are a plus) on how to minimize this? I don't want to spend money on this, and simple is my favorite adjective with electronics projects. Can I put a capacitor across the + and - wires to smooth out the power? If so, what size would be good? Thanks for your help! ~PC

Topic by Poppa Chubby    |  last reply


Can I use fuel prepared for a 2 cycle engine in a 4 cycle engine? Answered

I wonder if it is safe to use the fuel prepared with the 2 cycle engine oil in a 4 cycle engine lawnmower.

Question by blkhawk    |  last reply


transponder reader?

I need a small reader built to read the chips we use for cycling.

Question by katiecannon    |  last reply


Sheldon Brown... 1944-2008

If you didn't know - Sheldon Brown has passed away :(http://sheldonbrown.com/harris/This makes me sad :(

Topic by trebuchet03    |  last reply


How to control DC motor off and on cycles.

I need to control a radio control boat,  i want to cycle the motor on and off to extend the life of the batteries 6 - 12 v 40A my feed would be a normal radio control speed controller Thanks Ian 

Question by ian.collins.771    |  last reply


How to control DC motor off and on cycles. Answered

I need to control the speed at which a pager motor is on or off. I don't need to control the motor speed, just the timing of off and on. What would be the easiest way to accomplish this? (I have some 555 timers and an Arduino Uno so either of these would be preferred methods). I've tried but failed with the 555 timer and a pot to do this.  Eventually I would like to have two pager motors cycling between off and on (pulsating effect). Thank you, -shortdiesel

Question by shortdiesel    |  last reply


Peeponics doggy urine nutrient cycle system

Hi, I have a dog at home who uses a litter tray. It's basically a large plastic water run off tray with some AstroTurf. Currently, I have a pump that draws off liquids and deposits them into an empty soda bottle, which I flush down the toilet. But I was wondering if there is an easy way to convert the urine into nitrates which I could use in an aquaponics, or peeponics, system? Possibly using an attractive under water garden in a 25 gallon fish tank?

Topic by jmlidea    |  last reply


Perfect battery?, deep cycle, SLA, help!?

Hello, I am one of a group of people that has designed a mobile ice cream cart.  https://www.instructables.com/answers/Got-any-cool-ideas-for-our-Arduino-run-LED-dance-f/ We are currently using 6 of those 7.2 sla batteries. They are set up as a 24v system. But its not good. They are hard to charge. And have begun to swell. We want two smallish deep cycle batteries, set on two battery chargers. Does anyone know a good place to purchase such batteries? Say, 25 or 30 A/hr. Are there batteries for trolling motors? How much should we expect to pay? There are also larger SLA batteries, but I just don't think they are meant to be drains so deeply. (we play this thing for 12 hrs at a time) Thanks in advance! Tor

Question by torclausen    |  last reply


how to make a inner cycle tube at home Answered

I need to make a small inner tube for a project. I cannot get a custom one made at a smaller size. The length of the tubing should be just 110 mm. i have to use a valve that is made of rubber, plastic or stainless steel ( last option) . The tube goes into a magnet, so i have to be careful that the valve i use must not be iron or any attracting materials. Is there a possibility to make it at home.

Question by Solidwrks    |  last reply


Recumbent cycle: "blue sky" design query

I am not one of nature's cyclists. I didn't actually learn properly until I was in my twenties. My bike is very old, very rusty and very, very heavy.However, I feel that I "ought" to cycle more, for shopping trips and the like. I quite like the idea of switching to a recumbent, but they are expensive (current available funds: zero).So, I'm playing with the idea of rebuilding my mountain bike into a recumbent (and learning how to weld on the fly?).In the sketch below;The black section is the back of the old bike, turned upside down.The blue section is the front of the donor bike.The red part would need fabricating somehow.I haven't thought properly about steering mechanisms, but probably under the seat, via cables to arms welded to the forks of the will-be-the-back wheel.Would the bike, as I have sketched it, in principle, work?I'm bothered about stability, especially at take-off and landing. Am I worrying unnecessarily? I have access to a second donor cycle. Is there any mileage thinking about "doubling up" the blue section, to make a trike? Not massively wide, but I could add luggage space, or an extra rear-facing chair-style seat.Brakes: before I cut up the bikes, am I right in thinking that I just remove the cables and levers from the handle-bars and add them to the under-seat steering?Gears: the donor bike is a mountain bike, but I never used all the gears anyway. This area is pretty flat - can I get away without any gears?Coasting: although the back of the donor bike ends up upside-down, it is still turning the same way, so I can still coast OK.I'm sure I've missed something obvious...Anyway, even though I've not decided to do this for certain, I'd appreciate any comments or thoughts.

Topic by Kiteman    |  last reply


Help me and win a 3 months PRO membership!

Here's the deal: I won a 3 months PRO membership with this Ible and I need some help. So why not combine the both? So far I have launched my website and people are picking it up. I have done (some) Google Search Engine Optimization and joined a very appropriate Group on Flickr called "Take pictures while riding a bike". However, that's not enough. I would like to intesify my Internet marketing effort so I am looking for: 1. Sites that review new products that are related to cycling and / or photography. 2. Good blog-spots that review these kind of articles as well. 3. Other internet places like, social media, where I could join similar discussions / groups. I promise, I won't just Spam. Note to point 3: I don't have any Facebook friends simply because I don't have a Facebook account (measured in Internet time, I'm a dinosaur). Should I join anyway? Just for this purpose? Share your ideas and sites with me, the best answer (to be decided by me) earns a 3 month PRO membership! Hope to hear from you!! UPDATE: I have rewarded the 3 month PRO membership to Waterbaby. Thanks everyone for all the useful suggestions!

Topic by bertus52x11    |  last reply


What is the best way to turn 6 volts ac from bike hub dynamo into 12 volts dc battery? Answered

I have a bike hub generator and normally you use them to run 6 volt lights but I have 12 volt lights and a 12 volt battery.  I need to change the ac from the dynamo into dc and change the voltage from 6 volts to 12 volts.  I hope in this way to have a bike which will never need to be recharged from mains, as long as I use less electricity than I make from the dynamo.

Question by Noblenutria    |  last reply


HELP! DRIVEWAY WARNING SYSTEM FOR CYCLISTS

My wife and I are moving to a new house that has a hidden driveway on a bend of a busy road that obscures our visibility as we exit. We are avid cyclists and ride around town on scooters, too. Does someone have a suggestion on a remote activated light system that could call drivers' attention to the driveway as we pull out? We have multiple lights on our bikes, but nevertheless, I'd like to enhance the safety of exiting. My only thought was to hook up some sort of lights to a darkroom timer and activate it for two minutes as we leave, but that would require burying a cable in pvc as far as I could tell, and the driveway is long. In short, it would be super inconvenient. What would be ideal is a remote activated flashing light set on one or both sides of the driveway, powered by battery that activated by the remote and turned off after a short period of time. Any suggestions on products or designs would be appreciated.

Topic by johnson.drj    |  last reply


How to use an LED Driver Cycle Flash Controller?

Can this device (w/o any other IC's) be used to sequence/chase LED lights.

Question by cgc  


charging deep cycle batteries using solar panels?

Hey everyone:) my dad asked me to build a set up to charge a deep  cycle battery or two using solar panels... if you could point me to a few good instructables i would greatly appreciate it cause i like working with electronics but i'm pretty much self taught and still a noob at it so i'm on here Quite frequently?

Question by qwerty924    |  last reply


Reading the max voltage of a low duty cycle PWM?

How do I measure the maximum voltage reached by a very low duty cycle PWM signal without having to alter the signal. The multimeter shows no reading or gives a very brief wrong reading and falls back to zero. I don't have an oscilloscope. Are there any other alternative set-ups to measure just the voltage in this case. Please suggest.

Question by raftor    |  last reply


ge adora pours water during gentle cycle?

Had this front loading GE Adora washer for 2.5 yrs. OVer last few months it has begun to leak on every cycle except speed wash. Have cleaned out filter, drained water, but it comes back. Don't know if associated, but washer will "dance" and rattle throughout. When the water leaks, it sounds like an open facet. Any help would be appreciated. DId not want to call GE (unknown # and no warranty)

Question by tokyotea    |  last reply


Temperature and duty cycle controlling PWM help needed! Answered

Hello, I am working on a Hydrogen generation project. I am using a PWM (pulse width modulator) to control the Generator from going into thermal runaway. However, the current PWM's on the market dont offer temperature control. Only duty cycle control. So I need some help here. I need a way to control a potentiometer to increase or decrease resistance based upon a temperature range from 80 to 95 degrees. I dont want this to turn the unit off, only lower the duty cycle when the peak temp is reached. Then also, when the unit is cold on start up, it would release full amps into it until it reached it peak operating temp. The idea is to make a PWM control the generator via duty cycle (amperage draw) and temperature. Make it a "set it, and forget it" system. My thoughts are using two surface mount thermostatic switches. One for low limit the other for the high limit. Then a relay and another potentiaometer. Theory of operation: On initial start up, the generator is offered full amperage draw of 40 amps(100% duty cycle) until it reaches its operating temperature of 80 to 95 degrees. Once it reaches the peak of the operating temp the upper limit switch kicks open causing a relay to offer a differing resistance (80% duty cycle) that would effectively make the PWM still keep producing hydrogen, but cool down. When or if the lower limit of 80 degrees is reached the lower limit thermostat would close allowing again 100% duty cycle to the generator.  Thus, this system would keep the generator operating at an optimal temperature at all times regardless of outside temperature, and conditions. Current PWM's require the user to manually get them set. If the outside temps are colder the system will work less effectively. If the outside temps are hotter the temps may cause thermal runaway. All operating conditions require the user to be constantly fiddling with, and keeping an eye on the amp draw, temps, and voltage. This means eyes not on the road while driving. Bad ju-ju. I'd like to make this device super simple to operate, and build. With off the shelf items, not custom IC's. Any ideas?

Question by ydeardorff    |  last reply


Self-cycling & Filtering Water system for science project?

I am doing a science project to test the difference in number of suds between different types of foam sponges and nylon loofahs. At my booth, I would like to demonstrate the difference in suds by having water available and adding soap. My question is: Does anyone know of a way that I can build a system that would allow me to dump and filter/recycle the soap water into clean water so that do not have to keep running to the bathroom to get fresh water? Any help is appreciated!  Thank you!!

Question by donotfreeze    |  last reply


How do i make a Stirling cycle cooler? Answered

I would like to thank the following users for their help: Kiteman, The Skinnerz, steveastrouk, rickharris, Vyger, AndyGadget, iceng.    I would like give a special thanks to "steveastrouk " for telling me to find old papers and work from the first cryocoolers.    I also found out that these are relatively cheap (compared to the other cryocooler systems).    What do i need on building this?    Can everyone give me a help on this?    Thank you :D

Question by jamesc4    |  last reply


can I reverse the cycle on a refrigerator to warm the inside?

So I have just built (mostly) a workshop shed, and it's about time to move in work benches, tables, small appliances, etc.  I want to be able to move some temperature sensitive stuff out, too, and I don't want them to get too cold. I'm probably over thinking this and there's a simpler solution, but a refrigerator is already a well sealed, temperature controlled, shelf. If I could get a second hand or scratch and dent, could the condenser be put on the inside to make a "warm box" for winter?  

Question by harlyquin    |  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  


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


Comber greenway opening.

Saturday 8th November the Comber greenway will be officially opened in Belfast, which is kind of odd I've been riding it for nearly a year since they paved it and a few years when it was an assortment of dirt tracks and swamps. A Community Carnival cycle to celebrate the opening of the Comber Greenway has been organised on Saturday 8th November starting at 9:30am at Walkway Community Centre, Finvoy Street, East Belfast. Full details of the days activities are available below.Carnival program9.30am - Welcome and Wobble Activities at Walkway.Porridge for Pedal Power!Tree PlantingBicycle Obstacle RaceSlow Bike Race10.30am - Ribbon Cutting Ceremony: The Comber Greenway is Open.Community Carnival Cycle to Comber with Paddy Bloomer artist, inventor, explorer and plumber the most exciting mobile spectacle since Mickey Marley's roundabout!Tullycarnet Tuck Stop12.45pm - Eats at the Enler River (provided)1.15pm - Carnival Cycle Continues2.00pm - Pedal Parade into Comber - Refreshments2.45pm - Homewards for the Holywood Arches to arrive by 4:30pmChildren under 16 must be accompanied by an adult and wear a helmet. Information taken from Sustrans.org.ukMore information on the greenway at Comber greenway.tkI'll have updates on this and more late saturday or sunday, it's a big thing for many cyclists and I here in Northern Ireland since it's been threatened by a high speed bus route, the track used to be a railway and it's a lovely ride, though calmer than my usual...

Topic by killerjackalope  


how to make magnetic and fluid resistance based exercise cycle?

Make a stationary exercise cycle with fine control on resistance to rotation

Question by anil.gadgil    |  last reply


a brand of deep cycle battery , helping me to find it , thanx

I speak french , and I would like to know how in french ,deep cycle battery is translated , because don't know where to search this sort of battery , what society brand this product???a exemple for me ??a model??thank you peopleand good trance!!?

Question by mierda-lokataire    |  last reply


SMALL 4-CYCLE INTERNAL COMBUSTION ENGINE USING PROPANE?

WHO MAKES USEFUL GARDEN AND YARD TOOLS USING PROPANE AS POWER/ I'M TIRED OF CORNGAS PLUGGED CARBS.

Question by YARDBUTCHER    |  last reply


Turn Signal Jacket, Soul Cycle Chopper, Ride in Style

  Turn Signal Jacket Soul Cycle Chopper Ride in Style Scraper Bike Wheels Reflector Bag Badge Bike Gear Belt Wobble Bike Bike Guide Granny Chopper Bicycle Car Horn DIY Bamboo Frame Change a Bike Tube Twisted Flower Spoke Bright Bike Mountain Bike Scooter  

Topic by randofo  



Powering 12v LEDs from 12v Deep Cycle Battery

Hey all, I'm trying to power some 3528 LED strands to hang from a shade structure I have outside. I picked up a 115 Ah 12v deep cycle marine battery, but I just wanted to make sure I could wire them directly to a distribution block without blowing anything up. The strands draw 6A of current so I was going to find the closest fuse to that value (10A?) to prevent any chance of overpowering the control boxes. Does this seem correct? Image shows roughly what I'm trying to do (black boxes around red wire are fuses, 1-3 are the LED control modules) Greatly appreciate any help!

Topic by synaptech    |  last reply


What is causing the deep cycle battery charger fuses to pop?

Mobile Wheelchair battery wiring: Two young 12v 26AH wired in ceries? is poping charger fuses. with newly accuired controller The chair contoller has been newly doneup and could be the cause Look at Mobile chair battery line diagram operating with newly acuired reconstructed second hand controller it pops charger fuses, the battery's are near new the, motors is not connected yet in fear of damage from a dead short somewhere.The motors operated fine whith previous controller.americantwintowers@gmail.com

Question by Water-for-Africa    |  last reply


What tricks would people like to learn?

Well after a request for an 'ible on basic bike tricks as a follow up to this cycling 'ible I'm wondering what tricks people would like to know about so far the list is:Pulling a wheelieStoppies/endos (stopping or moving with the back wheel in the air)BunnyhoppingSliding in a reasonable manner (as in tailslides)I'd like any other suggestions, the 'ible will include all requested tricks that I can do, heck got any for me to learn? Just throw them at me. If I can I'll add stalls and stuff to this but considering where I live finding a good place to do so is hard (it's still a building site for the most part...)EDIT: The instructable is now up

Topic by killerjackalope    |  last reply


difference between marine and normal oil

I need to mix gasoline with 2-cycle oil for my 2-stroke chainsaw and i only have marine 2-cycle oil. is it ok if i use this or do i need to use regular 2-cycle oil?

Question by Sun Gear    |  last reply


how would i attach a small led onto a cycling glove?

I am doing a project at college and i am redesigning a cycling glove, i have decided to design it with a led lighting system as indicators i have done drawings and come up with some good designs how ever i do not know electrics at all. i am asking any one who can help me please to give me some idea so i know where to start. the led prfereable wants to be small with a micr switch. thanks

Question by TommyTike    |  last reply