Tom Booth

Right What kind of "differential" are you referring to here ? Pressure differential or temperature differential ? A "vacuum" ? The air isn't drawn through the turbine exactly. It is pressurized above atmospheric pressure and injected into the turbine through a nozzle. In a sense, I guess you could say that the atmosphere is your "vacuum". At least a partial one as compared to the air under pressure. Same as with an air tool. The air is drawn in from the atmosphere and compressed and then decompressed or expanded through the turbine back to the atmosphere. My idea does not use a motor to compress the air. It uses the temperature differential created by the "air cycle system" heat exchanger. When air is heated it expands and the same air contracts when it is cooled. A Stirling engine uses this principle to drive a piston. The "displacer" in a Stirling engine drives air back and forth against the top and bottom of the displacer chamber, one end of the chamber is hotter than the other so the air alternately expands - creating pressure, then it is driven to the other end where it cools and contracts - creating a partial vacuum. This expansion and contraction drives the piston in a Stirling engine. At first I was working on having a Stirling engine drive a compressor, but I figured, why use the pressure differential in a Stirling engine to drive a piston to turn a crankshaft to turn a pulley to drive a belt to turn another pulley to drive another crankshaft in the compressor to drive a piston to compress air and trap it behind a check valve to get pressurized air to have a pressure differential to drive the turbine ? I just eliminated all those redundant moving parts and put some check valves in the displacer chamber to make a kind of direct "Stirling compressor" out of a Stirling type displacer chamber. You get the same, (or possibly greater) pressure differential with just one moving part and very little friction. It takes very little energy to move a displacer, much much less energy than what you would theoretically get back by using this principle to convert some of the available heat in the atmosphere into pressurized air. In this concept, as the air is driven back and forth by the displacer - causing it to alternately heat and expand then cool and contract, first the expanding air, instead of driving a piston some of the air is allowed to simply escape through a port where it is trapped behind a check valve. Then as the displacer moves causing the remaining air to impact the cold end of the chamber and lose heat and contract a vacuum is created which draws in more air which is trapped in the displacer chamber behind another check valve. In other words, you have an air pump which operates on a temperature differential to create a pressure differential. You could think of the check valves as acting like a set of diodes in an electrical circuit used to convert alternating current into direct current. The check valves convert the alternating pressure in the displacer chamber into direct pressure to run the turbine. (theoretically). This is difficult to visualize because the air is invisible. It would appear that the "displacer" is just moving up and down in an empty chamber, not doing anything, however, when the air hits the hot end of a displacer chamber it expands explosively in a Stirling engine driving a piston with enough force to drive the engine. Instead of using this expanding air to drive a piston I'm just letting some of the air escape through a port where it is trapped behind a check valve. It's only escape route back to atmosphere is then through the turbine. Before it reaches the turbine, however, it must pass through a narrow tube in the displacer chamber where it gives off some heat - similar to how electricity gives off heat when passed through a thin wire - due to the resistance. With a gas passing through a narrow tube your resistance comes from the tendency of the air to cling to the inner wall of the tube converting the kinetic energy of the moving pressurized air into heat to heat the top of your displacer chamber and increase the temperature differential within the displacer chamber. The remaining heat is extracted by the turbine to do work (run an electrical generator) causing the air to become very cold. This cold air is then sent through another set of coils in the bottom of the displacer chamber before being evacuated back to the atmosphere. Merged post follows: Consecutive posts merged Ummm... I don't think you would get it to do much work that way. That's like saying, why not throw a car engine into a furnace. Now you're getting the idea! That's like saying why not just run a car engine without gasoline. "The rest of the contraption" as you say, is your "fuel" delivery system. It is what compresses the air to run the turbine. I think you thunk correctly. If you consider compressed air to be a "fluid". More like a gas I think. Technically, this is an "expansion turbine" as it uses expanding gas (in this case, compressed air released through a nozzle) to drive it. The turbine, in this case, is not driven by a temperature differential, it is driven by a pressure differential. Compressed air in, expanded air out. In this case, the air is compressed by the expanding air in the displacer chamber where it is then trapped behind a check valve. Since the air is working against itself, instead of the heat/kinetic energy in the air being lost to work against a piston the energy in the air used to compress more air is conserved (transfered air to air) until it reaches the turbine. (except for some that is used to heat the hot end of your displacer chamber, but this heat/energy too is recirculated back into the system)

In an Air-Cycle system the turbine doesn't get hot, it gets cold. One of the problems encountered with an air-cycle system is ICE forming on the turbine blades. Usually this means that moisture must be removed from the system prior to entering the turbine, but I'm hoping that by using a Tesla Turbine (bladeless turbine) this will not be a problem as ice would have a difficult time sticking to smooth disks (hopefully). The turbine doesn't get hot. The Heat energy in the compressed air powering the turbine is CONVERTED into "pure" kinetic energy. As I'm sure you are aware, virtually the only energy available to a gas is in the form of "heat" (actually the kinetic energy of the air molecules) so when the gas is made to do work, such as turning a turbine or pushing a piston in a hot air engine, the heat energy is converted into kinetic energy (the motion of the turbine or piston) and the air expanding through and then exiting the turbine then tries to recapture that lost heat energy (i.e. the air gets extremely "cold"), similar to how a gas in the expansion phase of a refrigeration system seeks to recapture lost heat i.e. gets "cold". "Heat" is partly potential energy and partly kinetic energy. In a gas it consist almost entirely of the kinetic energy of the gas molecules. A gas, expanding through a turbine loses its kinetic/heat energy to the turbine and gets very cold - potentially it can drop to near cryogenic temperatures, but this does not make the turbine hot as the "Heat" has been converted to another form. If the turbine is turning a generator, then the "heat" has ultimately been converted into electricity. If I'm mistaken, then I'm afraid that guy that had his brain cryogenically preserved so he could be reanimated some day is going to be out of luck, because that is how a cryogenic freezer works, from what I understand.

Hi, I just happened upon this thread while doing some research for a "Stirling Turbine" of my own design. Doing research, because I haven't built it yet, and I was trying to figure out if it could really work or not. Maybe you folks would like to help me out. I was not at all aware of this "Kender" engine until just arriving here now, but it appears to be based on the same theory as my "Stirling Turbine" idea. Originally I was just trying to maximize the efficiency of a solar powered Stirling Engine I was working on. As I refined the design and had this machine running in my head... Well, I envisioned the sun going down... but it (The Stirling Turbine) just kept on running drawing indirect solar heat energy from the air. (Note, this was just ~in my mind~ and I don't know if it could actually work or not but I'm having a difficult time trying to figure out why it wouldn't) BTW.. in response to the "where is the heat sink ?" question... I would respond that the "heat sink" is the power turbine. The turbine works (in part) by converting heat in the air into kinetic energy, thus your "heat sink". That is, the heat in the air is not traveling to a conventional heat sink, rather, the heat is being CONVERTED into kinetic energy. This is how an "air cycle" refrigeration or "air cycle" air conditioning system works. Relatively warm or hot air goes into the turbine... The air molecules impact the turbine blades (Or disks - in a Tesla Turbine) giving up some of their energy. The only energy that a gas has to give up is in the form of heat, so the air temperature drops,... not only due to expansion but ALSO due to the heat energy being converted to kinetic energy. This is easy to see if you have ever used an air tool for any length of time. When an air tool is under a load, you will see frost forming around the air outlet as the air exiting the turbine is very very cold, not just due to expansion but also due to having given up some of its HEAT energy, even though the air entering the turbine may be quite warm - it exits ice cold (or colder). This type of refrigeration system is used on cryogenic freezers due to the extreem cold that can be produced using a turbine air cycle refrigeration system. Unlike the Kender engine there is nothing secret about my design... It has been posted on this Stirling Engine Forum where the theory is explained in detail: http://stirlingengineforum.com/viewtopic.php?f=1&t=461 And here are a few illustrations I made recently of different designs: http://prc_projects.tripod.com/stirling_air_turbine.html http://prc_projects.tripod.com/stirling_air_turbine_2.html In short, you are creating your "cold spot" for your temperature differential by converting the heat into kinetic energy through the turbine. This can be accomplished only if the turbine is actually doing some work. While under a load, such as turning a generator, the heat in the air or gas passing through the turbine is converted into kinetic energy then the kinetic energy is converted into electricity by the generator. In effect, this is your heat sink where the excess energy to maintain your temperature differential is being "dumped". But, in this case, instead of just being dumped as "waste" heat it is being CONVERTED into a usable form of energy. I would be happy to hear your comments and criticisms in regard to the theory and design of this "Stirling Turbine". BTW. I am using an open air cycle system rather than a closed system, though this could also be a closed system with the addition of another heat exchanger between the intake and the exhaust, but I thought, if you consider the atmosphere itself as part of the system... this becomes your "heat exchanger" - i.e. cold air is exhausted where it is re-heated by the sun and ambient air is drawn into the intake. So the air itself acts as both your heat/energy source and your "refrigerant". This should be relatively simple to build I think. Just to see if it works...