The heatpump, with more energy out than in (FACT)

[angryScientist]

Hi everybody (and ATT if you're still watching this tread), I must admit that I didn't perfectly understand the heat pump cycle when I first started this tread, and only recently grasped the core concept.

I thought that from what I had read at wikipedia, that the primery operation of the common heat pump was to compress and expand the working refigerant so that the temperature would then increase and decrease, and cause a following emmision and absorbation of temperature to its external environment.

But this is not the real reason to why it works so well, and even though someone on this tread mentioned it rougly well (I think it was angryscientist), I still had to ask a guy who knew it spesifically to understand it.

So yes, it is all about phase change, meaning in this case the change from liquid to gas and back again. And the "secret" of the heat pump is that the refigerant needs very little change in its pressure to do this. This also means that a theoretically high COP system needs a refigerant which is very close to evaporation and condensation pressure at all times, meaning that very little effort is needed to compress it into a liquid.

Also, all heat pumps should have been equipped with an slightly geared up turbine instead of a expansion valve, which wastes all the energy which the compressor generates when it creates high pressure air. There is actually (at least theoretically) a possibility to recover most of that energy used to compress the gass this way, but again losses of all sorts will make it less than what was originally expended.


Thinking in terms of phase change, it also intruiged and made me wonder if the opposite operation would be possible to solve the problem of creating mechanical work from heat, efficiently...
What if we had another system "thermally connected" to the heat pump, which used a refigerant which experienced a phase change in the temperature region between the hot and cold side of the heat pump?

We could then use that sudden hundredfold increase (and decrease) in volume to power mechanical pistons. These would then set a shaft in motion and allow us create useful work.

Could this be possible, in just the same way as the phase change in heat pumps is exploited to trick heat into flowing from cold to hotter, which could never happen without its interferrence?

Julian

Unfortunately there is no way to make the engine part of any device more efficient than %100. There is a way to exploit a phase change in an engine to make it more efficient. I brought it up in the following link to the thread. It's not exactly the same as the heat pump but it is pretty close. I got exited when I heard about it.

Sorry about not explaining well. I try to get every word to mean something. I like it brief and to the point. I guess some times I may be a little too brief.


http://www.overunity.com/index.php?topic=7814.msg192994#msg192994

[sparks]

    The device I am describing is basically a thermometer but you can stick it in the sun paint the bulb black and have it blow it's lid.  It does not work on latent heat principles.  It works like a steam engine but at greatly reduced temperature.  This way the heat is flowing into the system instead of out.  It is not a Stirling engine either.  The restorative force is the mass of the piston.

[Nabo00o]

Hey, sorry for the delayed response...

Sparks, how exactly is the piston supposed to use the heat in its water bath, or just regular sunlight?

Normally, the heat is supposed to be dispersed in a sink, thus giving a repeatable motion but also loss. I can see how there could be a harmonic motion because of the heat/pressure push, and then a low pressure pull combined with the frequency determined by the momentum of the piston, just like a spring.

Or, maybe the heat is supposed to leak out from the cylinder wall above water, which would turn it into a stirling engine?

Julian

[mscoffman]

I think the argument earilier in this thread has this solution. The Carnot
inefficiency of a heat engine...Is the maximum potential efficiency gain
of a Carnot heat pump. The heat pump cannot create temperature over
a volume of working fluid higher then the ineffciency of the heat engine
using that same volume of working fluid. A heat pump can create higher
temperatures but over a smaller volume of working fluid. You can also
use enviromental heat, lets say of a ground loop thermal system that
uses the ground collection of energy with a heat pump the same way
as using a solar pannel to collect solar energy directly.

:S:MarkSCoffman

[sparks]

    The unit I describe works above the boiling point of the refridgerant at all times.  It works on the pressure gain as the bulb is heated.   As the bulb pressure overcomes the weight of the piston the clamping mechanism is released.  This allows for a rapid expansion of the gas while the magnetic piston is forced through the load coils.    The expanding gas will convey it's kinetic energy to the piston and electrical load.  The gas pressure is now less as well as it's temperature.  Because of the heat lag of the bulb walls the weight of the piston compresses the cooled gas and the locking mechanism engages.  The bulb walls saturate or heat soak and the gas pressure increases.  Most heat exchangers use very thin walls so the exchanger will respond rapidly to any change in temperature on either side of the exchanger.  This is good when a fluid changes in heat load and an overshoot of the temperature and pressure due to the heat transport time through the exchanger would be detrimental.  In the case in question as wide a swing as possible in the working fluid pressure is sought.  Active management of the exchanger could also be used where just before release of the piston fluid is drained from a double wall exchanger.  This disrupts the flow of heat into the system while the gas is allowed to expand on unleashing the piston.   Gravity on the piston recompresses the cooled gas and allows the piston to return to the locked position.  The warm fluid is then returned to the cavity between the heat scource wall and the gas well wall and thermal energy is allowed to flow into the gas through the fluid again repeating the cycle.  I am probably reinventing the Stirling engine but the engine I describe is more of a pulsed output with gravity instead of a heatsink involved.