Thermodynamics

Is it possible to take a low heat spread over a large area and convert it into a high heat in a small area? For example a normal fireplace can't melt cast iron, but 2 or three create enough energy. Could you concentrate that? (thats just an example, I have a much more brilliant plan) Thanks

Topic by LinuxH4x0r   |  last reply


Thermodynamics for Highschool

So, I work at a science center and we have our annual Engineering Olympics coming up and we've been brainstorming something about thermodynamics. The general format is 6 teams from different highschools in the area are given a task to complete from one engineering discipline, such as construct windmill blades to achieve the highest amperage from an attatched motor or insullate a container of water with random materials to prevent it heating up when submerged in boiling water. This year, I haven't really found an idea for thermo that really excites me. Thermo isn't the easiest thing in the world in highschool, and since we're dealing with kids from different schools, we have no way of knowing how advanced they are. So, any ideas of a project to test their thermodynamic mettle?

Topic by Dinkum Thinkum   |  last reply


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


No More Electricity!

This is more of a discussion then a question. Lately I have been wondering about the small amount of space that we have on Earth. In those thoughts, I began pondering about Thermodynamics (particularly, of course, the first law). Since energy can't be created nor destroyed - it only changes form - that most certainly means there is a limited amount. There's a capacity. Much like a battery, it can only hold so much energy. The Earth is essentially, then, one huge battery holding millions upon billions upon trillions upon trillions of energy units (it cannot be specified to electricity since it can change form). If that is correct, then my theory makes sense. If there is only so much energy, and electricity is energy, then one day we will reach that capacity, right? Let's create a hypothetical situation - we massively overbuild the world with the biggest skyscrapers that, with the newest technology, go thousands of feet in the air. Standard homes no longer exist, and the smallest of homes are at least four stories. These conditions cover every corner of the world. Power-plants are at a massive draw. Now everybody knows that you can't really "use" electricity for good, for it always returns to another form of energy - it can't be destroyed. So what if, with this extremely advanced society, electricity was used quicker then it was replaced? And this massive usage was continued until all of the energy that is "stored" in planet Earth is being used at one time. That brings me to the real question of debate - doesn't that therefore mean that all power-plants will one day, when this "Complete use of energy" comes, will no longer generate electricity? Is it impossible to believe that they will have no energy left to "grab" (electrical power plants don't create electricity, just generate and convert it"? Now, I may be entirely wrong. This theory could be 153(nice even number) percent wrong, but it's what I brainstormed. Any feedback or debate is appreciated ;)

Topic by freethetech   |  last reply


Why don't superchargers and turbochargers break the laws of physics and HHO generators do? Answered

I saw an article today on how HHO generators are just a scam.  There are of course many scams associated with it, but I have yet to test the whole thing myself so I have yet to form a solid opinion on the whole thing.  One of the biggest arguments is that based on the laws of thermodynamics, the same energy is required to split the water as is released when they recombine.  This is true, but couldn't there be other benefits to the whole thing which are being ignored.  If that statement was true wouldn't eco-boost engines be a scam.  The turbocharger can't just create energy can it.  The exhaust which spins up the turbo causes back pressure on the engine right. Then there are friction and slip as well.  It seems very lossy right, but it works. It isn't a scam.  The same goes for a supercharger, the same energy of the added compressed air is taken from the engines drive train.  Now I understand that the compressed air causes a better burn similar to mixing KNO3 with sugar vs just burning it in plain air.  But what if you mix gunpowder and sugar, why is that any different.  I feel like this analogy accurately displays what is going on in both cases, and I feel like there could be an argument for the benefits of HHO. Again I have no experience in the subject yet, but it all seems reasonable. The HHO isn't being used as a fuel, it is being used as a booster which pulls more energy, more efficiently from the petrol.

Question by jj.inc   |  last reply


Small heating element, possibly ceramic, to sense and maintain temperature.

I am trying to make a heating element that would only turn on once the element itself reaches a certain temperature. This element, possibly ceramic, would be dormant until it reached an internal temperature from an external source (liquid) of 100 deg F. Once it is triggered, it would produce heat to maintain the liquid at 100 deg F. Ive been trying to figure out the best way to do this and how much power would be required. Say the liquid, well go with water, was 12 fl oz. how would I build a circuit that can be sensing temperature without using power, and once it reaches the desired temp, turns on the heater until the temperature either goes too high or drops too low so that it is not trying to work too hard. Open to suggestions on heating element types or anything that could help with my project. Thanks in advance!

Question by AndrewN144   |  last reply


efficiency (not efficacy) of CPUs/computers? is all the power input technically converted into heat? Answered

It has recently been fairly hot where I live, especially in my room, where computer hardware seems to be increasing the temperature by a good 5-10*F over other rooms. This got me thinking, and was wondering if any computer engineers/physicists may know the answer to this one. If I am running a power-hungry intel CPU, coupled with RAM and maybe SSD storage (I wish!) is all the power fed into my system being converted into heat? In other words, if my rig consumes a good 250W-400W, and there are no transducer devices drawing power (LEDs or lights, speakers/microphones, monitors, motors, heaters, phone chargers, etc,) and all the energy is used for data collecting, and calculating, then is *ALL* the energy converted to 250W-400W of thermal energy (heat)? or do the data operations themselves in fact require energy and maybe entropy or something plays a role? where it would seem that 400W of input yields an apparent 399.981W of energy output + data.

Question by -max-   |  last reply


Dubious instructable: free energy???

Have a look here https://www.instructables.com/id/RotoVerter/?ALLSTEPS It doesn't scream "free energy" (thus contradicting the first law of thermodynamics) as loud as other weird projects of this kind. Yet I think this instructable either needs some serious TLC or removal. It reads like an advertisement in some parts.

Topic by TomK32 


know of any small scale Rankine cycle engines that are classroom safe for a presentation?

Have a school presentation on a thermodynamic process and would like to present a Rankine Cycle but i havent been able to find one that i can build and run within a classroom just looking for a design or directions, even a video that i can use to build one

Question by SLC Student   |  last reply


Nano-buble_ #tech_#eng_#design_@thermodinamics

Hi, I'm looking for some help to develop a nano-buble bubeling device.(thermodynamics, control logic, sensing, material technology - I touch all this subjects but in content) It will be for a good cause, like humanity, affordability, clean water at affordable costs. Also, electolisys has a higher efficiency in generation if H2o. It might not be the solution but it's still on the books/on the table. Get in touch @: remembereco@gmail.com or post comments on this platform. A great idea! Best wishes, ip

Topic by JagodaN   |  last reply


A Deceptive Thermal Question for PCB Layout? Answered

Alas ... I was never strong in thermodynamics. This is for you  Printed  Circuit  Wizards Here is my problem in a White LED  layout,  See first picture Trying to pass excess LED heat to back side copper through VIAs I know the larger the VIA Dia the lower the thermal impedance. Intuitively as the hole grows it will eventually make heat transfer much worse  What or how do I find the OPTIMUM VIA Diameter for Heat TRANSFER ??

Question by iceng   |  last reply


Energy Revolution

Greenpeace writes:Our Energy Revolution outlines a global plan for a sustainable renewable economic future. It shows us how we can get from where we are now, to where we need to be to avoid a climate change disaster. It was developed with specialists from the Institute of Technical Thermodynamics at the German Aerospace Centre (DLR) and more than 30 scientists and engineers from universities, institutes and the renewable energy industry around the world.More info on http://www.greenpeace.org/international/campaigns/climate-change/energyrevolution

Topic by comodore   |  last reply


I have idea for infinite energy!

I have idea for an infinite energy or perpetual motion. I know that perpetual motion is impossible because it contrary with firs and second law of thermodynamics. I have learned those laws on  school too but I asked my physics teacher ( I'm in high school now 16 years old) and he said that it looks possible. The problem is that I'm from Kosovo,and there is no any labs of that type where I can make my experiment. If you have any idea about any of this labs which are interested on infinite energy experiments. I would appreciate your help.

Question by Mrfatjonable   |  last reply


Looking For Game Show Contestants

DISCOVERY SCIENCE NOW CASTING A NEW GAME SHOW!!! The producers are looking for builders, scientist, inventors, engineers, carpenters, welders, mechanics, architects... who love to invent new gadgets; build robots; racing power tools; weld together bizarre machines that drive, fly, climb, shoot flames or launch projectiles... for a team challenge that will show off your handy skills such as: welding, knowledge of aeronautics, auto mechanics, hydraulics, carpentry, pyrotechnics, thermodynamics, aerodynamics, material science, electronics... If you, or someone you know, is a gonzo engineer/scientist or just a high-energy, creative, fun, builder Then email, your name and contact information to: icnbld@yahoo.com This Game Show is for thinkers, dreamers and doers, who are eager to let their inner Mac Gyvers be seen, and are ready to collaborate with a team of other builders to beat the clock in order to "SAVE" the BIG PRIZE!!

Topic by demolition399 


Good Manners

There has been a shift to much younger children on this great site,  kids who think that we who provide answers to their impossible dreams, are free site service robots  just for them.  ( Not leaving out a great many grateful individuals ! ) A lot of these kids believe we are clairvoyant about their specifics, some behave with poor street manners. My grand kids are being raised with good manners including respect. I hope you, with your children, here and other countries can avoid the,  throw_away_attitude mindset. Speaking for myself, I would happily welcome being recognized a living human resource more often... A Thank you is as pleasing a response as a BA... I even get along with Violators of thermodynamic laws.. There are individuals cutting your text, Keep your Guard-Up ! Regards and Thank You for reading my rant, ICeng...

Topic by iceng   |  last reply


Would this idea to prolong battery life work? (NOT perpetual motion, just extended life!) Answered

A few days ago, I designed a self-charging battery system using a dc motor attached to a rechargeable battery pack that turns a generator via gears, similar to how a car battery works, converting kinetic energy from the motor to electrical energy with the generator and looping back to the battery. I've modified the idea to reduce friction as much as I can so that the motor and generator are directly attached now, keeping energy from being lost to friction between gears. Here's a crappy diagram:    |-----|--------------|                     |--------------|-----|    |       |  Motor       |-------||-------|Generator|      |    | | ---|--------------|                     |--------------|---| |    | |------------|----------------|------------------------| |    |--------------|  Battery      |--------------------------|                       |----------------| I know that 100% efficiency is impossible, I'm not trying to get all the energy back, and I'm not trying to create energy. I'm trying to loop the energy that isn't lost to friction and other factors back to the battery, hypothetically charging the battery up a little to somewhat extend the life. I realize that it will eventually go dead no matter what I do due to the laws of thermodynamics. What I want to know if this would increase the battery life enough to be worth incorporating in a design. (I know the motors should be attached to the battery by two different ends but its actually supposed to be a rechargeable battery pack so one motor is attached to input in to charge the battery and the other is output so the battery powers it. Plus if I tried to draw the wires like that it would've taken forever.)

Question by ALogan97   |  last reply


Perpetual motion & free energy is it possible? Answered

Hi Eric/Instructables, Basically I have been looking at perpetual motion and am led to believe that it is impossible due to the laws of thermodynamics meaning heat/energy has to be transferred somewhere, so I came up with a few designs which may challenge this theory.  Without wanting to reveal my designs and ideas too much I will explain what I am trying to accomplish and would love your opinion as to whether you think they are viable. I have 2 ideas, one is to use 'rare' magnets (which aren't rare at all so cost and obtaining them is not as hard as it sounds!) and have the magnets propelling round like a wind turbine design using the opposite poles effect to repel the magnets and get the turbine started.  Once the turbine is in motion I will harness the electricity created by the movement of the turbine/motor in a capacitor or kinetic store. This stored  electricity  can be used to keep the magnets magnetized by wrapping wire coils round the magnets and passing the stored current through the coil to keep the magnets repelling each other and spinning the turbine. Idea number 2 is a similar concept just dropping the use of magnets and using the method of so called free energy where you can get a small voltage from using a radio antenna, capacitors and germanium diodes (there are several example videos on the internet) again using a wind turbine effect to keep re-fueling the capacitors so the voltage drop when the load is applied is nulified. Perpetual motion is the dream and I think the transfer of heat/energy caused by friction can be harnessed and put back into the workings of the appliance/design, Many thanks for your time in reading this and hope for any replies positive or negative the dream will live on in my head and heart  :)  Mark Smith 

Question by McJesus   |  last reply


Small generators.

Most everyone here knows (I assume) how the generators work in RC cars and there's an instructable that shows it can be used to output electricity. Elementary science at it's best. If any of you have took them apart you'd notice it draws eletricity from touching the center metal pole. Two little brush/copper/zinic contacts. Basically I've been trying to think of ways to extract eletricity without having a need for them. They cause friction. Uh-oh, a few lightbulbs lit up in peoples minds by now and they're going "oh no not another person trying to beat the laws of thermodynamics and acheive perpetual motion" Yep. As we all know eletricity CAN jump if it's powerful enough and arc, but this doesn't make it too safe either. However it's a small scale model to start out and can be contained so the arc won't be a problem. My other problem is the calculations. They need to be precise. To get it working I need a low rpm generator that will generate high output. For this it requires torque which kinda kicks me, it will also need to use (I assume) rare earth magnets. So basically lets stick with my latter problem since it's more down to earth. I need a fairly small generator if possible (It can be larger if no other solutions are present) At least the size of a walnut I don't plan to make anything immense in size as I lack the funding. As pointed, small is key. Not to be redundant but to paint a clearer picture. It will also need to generate decent voltage at a low rpm speed. I cannot emphasis this enough because it's one of the key parts to make my idea function. Hum... Yeah that about covers it. So if any tech wiz's are out there that know of such thing I'd apperecaite it if you'd part the knowledge to me :P I'm also very aware that perpetual motion is eh, impossible... by current standards. The intention of this project is to deepen my knowledge and figure out why things won't work, figure out solutions and on so forth. A learning project for now and perhaps one day it might become something far more awesome.

Topic by Dark-half   |  last reply


Technology Makes Cheap Drinking Water from Air

INTRODUCTION:   How can we best apply basic technology to help the underprivileged and/or disaster-hit countries like Haiti? Daily hygiene and nourishment are among the top needs for disaster ridden regions!  Simply put, no water means no hygiene. The Romans understood that over two millennia ago and created their complexly beautiful aqueduct networks for handling both fresh and wastewater! Other ingenious water systems like “air wells” have been found in the city of Theodosia (cf: discovered in 1900 by Zibold, see Zibold’s Collectors/Dehumidifiers) dating back to Greco-Roman times during the Byzantine Empire. These were strictly passive systems that naturally dehumidified air, collecting its potable water in underground basins. All air, even in relatively dry desert regions, will precipitate or release its natural water content (initially in the form of vapor) through condensation when it hits its dew-point temperature and below. That means you “chill” it to an appropriate level that is anywhere from 5F to 50F below its current air temperature, depending upon how much water content (relative humidity) it has locally absorbed. The condensation of the water vapor releases its internal latent heat (reheating the cooled air) which must be constantly dissipated (absorbed by something) in order for water formation to steadily continue. So how do we dissipate this resultant vapor-heat and chill our air without any infrastructure or electricity, in an underprivileged or disaster-ridden region? We simply bury a long cast-iron or any metallic drain-pipe sufficiently underground where the temperature of the earth is naturally held to a constant at around 45F to 55F. That’s our “free” chiller gift from nature. One end of the pipe, Figure-1,  sticks out of the ground to suck-in local outside hot air, and the other end dumps cooled dry air and water into an underground cistern where it gets collected and is piped to the surface to both exhaust the cooled dry air and connect to a water pump. We need a hand operated water pump to lift up the water above ground, and we need an electric fan to constantly pump air through the ground-chilled piping system. We can even force the cooled piped air to exhaust into a tent-like structure where it provides air conditioning as an added bonus, but this adds the penalty of both power and the increased fan size necessary to drive our required airflow further into an enclosure! While this concept is not “passive” (requiring electricity to work) like those clever Byzantine air-wells, it will produce much more potable water and within a smaller volume than those elegantly passive historic devices. The electricity for our fan power requirements can be produced by any one of four ways using either “active” or “passive” techniques: 1) An active playground or bike-pedaling-person or oxen-driven mechanism-generator, 2) A passive windmill generator, 3) A passive solar energy collection system that directly generates electricity, or 4) A passive thermo-electric system that directly generates electricity using the Peltier effect, operating solely on temperature differences between the cell’s top and bottom surface (we jury-rig the cool pipe and hot ambient air to contact separate sides of the cell). Depending upon how much water is needed, the required air volume plus pipe length and diameter, together with the fan will be sized accordingly. We can also configure groups of parallel fan-driven air pipes that are radially fed into the cistern. The sizing of this underground network depends upon the ambient air’s local average temperature and relative humidity (how much water gets absorbed into the air) plus buried pipe depth and effective underground temperatures achieved. The basic concept is one where we “wring” water from air at some given humidity content. The higher its relative humidity the more water is recovered from the air. The air-wringing process simply chills the air as it scrubs along the cooled internal pipe surface until it starts to rain inside the pipe from condensation onto its surface. The condensation is like the dew that forms on car windows, grass or any cooled surface in the early morning, before the sun comes out and evaporates the dew back into the heating air. A further bonus is that our dew-formed water is naturally distilled and very clean. It is potable water ready to drink without the need for additional sterilizing agents. Of course, we must make sure that the interior piping and cistern network is biologically cleansed before burying it underground. The hand pump with its 10 to 15 foot extended piping to reach the underground cistern must also be cleansed. The beauty of this constantly replenishable water supply is its convenient underground installation anywhere! After the in-ground installation, we have a virtual, partially passive, no moving parts, non-breakdown system containing above ground total access to all moving parts that could breakdown, namely the water pump and electric fan. Also, it is easily maintained, with few moving parts (water hand-pump and electric fan) and basically lacking any technical complexity which makes it ideal for technologically backward regions. The example below uses a relatively small industrial fan moving air at 1500 CFM (Cubic Feet per Minute) with a DC motor rated at 1kW. This fan together with our underground piping system will conservatively generate 12 GPH (Gallons Per Hour) of potable drinking water without need for any purification chemistry. Based on an average electrical cost of 14-cents per kWh (kilo-Watt hour), the typical commercial distillation of one gallon of drinking water costs roughly 35-cents as compared to our cost of only 1.2-cents. Furthermore, if we decide to go green and use solar energy for generating our water, it would effectively cost us nothing beyond the initial installation! USING A PSYCHROMETRIC CHART TO SIZE OUR WATER SUPPLY: The following gets a little technical and is only provided for those die-hards who are truly interested in how the science works. Those non-technically schooled may skip this part and not miss the basic concept. Figure-2 shows a Psychrometric Chart for air. This chart summarizes some of the basic thermodynamic properties of air throughout its typical range of operating temperature. The chart uses six basic air properties that defines the physical chemistry of water evaporation into air:  (1) the enthalpy or total energy contained within a unit of air which is a combination of its internal and external energy, expressed as the amount of BTU-energy per unit mass of reference dry-air, (2) the specific volume or the ratio of a unit volume of local air to its mass of reference dry-air, (3) the humidity ratio or the amount (mass) of moisture in a local unit of air divided by its reference mass of dry-air, (4) the percent relative humidity per unit of local air, or the mass ratio (expressed in percentage form) of the partial pressure of water vapor in the air-water mixture to the saturated vapor pressure of water at those conditions (the relative humidity depends not only on air temperature but also on the pressure of the system of interest),  (5) the dry-bulb temperature or the locally measured air temperature, and (6) the wet-bulb temperature or saturation temperature which is the local air temperature experienced during constant water evaporation (a wet-bulb thermometer is typically used:   a thermometer that measures resultant temperature while wrapped in a water wet-gauze and spun to generate local air movement and max-evaporation)  1.0   The Process and A Sample Calculation Our Psychrometric Chart uses six thermodynamic properties that help to determine the amount of water available for extraction from the local ambient air as a function of its temperature, pressure and relative humidity.  Let’s assume the following local ambient conditions for the region we plan to construct our water system at:  (1) Typical daily air temperature Td = 106F and one atmosphere pressure assumed at sea-level, (2) Relative Humidity, RH = 55%, and (3) Typical underground temperature down at six feet is measured at Tu=55F (at 12ft. it drops to ~45F). This yields the following calculated results for obtaining a steady-state supply (changes at night) of water to fill the cistern:      1)      In our example, the “local” air (dry-bulb) temperature is Td=106F, at a relative humidity of RH= 55%.  Fig-2 indicates that the resultant Humidity Ratio is HR= 0.0253 Lbs-water/Lb-Dry-Air (intersection of Td=106F line and RH=55% line, then horizontal to HR value).  We then determine the “gulp” of air volume containing the HR Lbs-water which corresponds to the point of intersection of Td and RH. Interpolating on specific volume “mv” yields mv=14.7 ft3/Lb-Dry-Air (this value sets the optimum unit airflow for our given ambient conditions, and creates a ballpark pipe length to diameter ratio needed later). It represents the basic unit of air volume that will enter our underground pipe per given time, and ultimately defines the size of our fan and piping network. For increased water creation, multiples of this unit volume will scale up the additional amounts of water that can be collected. 2)      As the inlet air cools down to a temperature of Tu=55F, from contact with the relatively cold underground pipe, we follow the constant enthalpy line (red upward left-diagonal) from the intersection of Td and RH to its saturated air temperature condition of Ts= ~88F, which is its dew-point temperature where the corresponding local RH=100%.  At this temperature or under, the air precipitates and releases its moisture content, resulting in water condensation onto the pipe walls.  Since our air will chill to a final pipe temperature of Tu=~55F, we follow the RH=100% saturated curve (green) down to yield an HR=~0.009 Lbs-water/Lb-Dry-Air. This is how much water is left in the air when it gets to 55F.  Therefore for every pound of local outside air that enters the pipe, mw=0.0253 – 0.009 = 0.0163 pounds of absolute pure, distilled potable water precipitates onto the inside pipe wall (per pound of dry air that is cooled and dehydrated) to gravity-flow out the pipe exit and into the cistern. 3)      We now convert pounds of air per unit time into a unitized volumetric airflow that yields gallons of hygienically pure potable water production per unit time. For every Va=100 ft3 of local volumetric air movement per minute (CFM) through the pipe, which translates into ma=Va/mv= 100/14.7 = 6.8 lbs. of dry air per minute or 6.8 * 60 = 408 lbs. per hour (PPH), to yield a water-flow of mwf=ma * mw = 408 * 0.0163 = 6.65 PPH or 6.65/8.345 = 0.8 GPH of water.  An industrial fan rated at 1kW DC will typically move 1500 CFM at a pressure of 8-iwc, to continuously produce 15 * 0.8 = 12 GPH of pristine potable water. 4)      Not shown here are the design details of sizing our pipe, fan and solar collection system for electric power requirements using heat transfer principles coupled with a thermodynamic heat balance, and aerodynamic fan performance assessment. These details help to size the electric power generation requirements plus margin used to properly size a solar collector containing further margins for overcast days. The engineering involved here is straight forward but beyond the scope of the current project.

Topic by RT-101   |  last reply