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

[Tempest]

Hi guys, I have been reading this thread for the last couple of day and this popped in to my head. Will take no offence to improvements to the design.   

@ATT from your back ground, you should be able to do some calculations on this, although it could take a lot of time.

There are two loops in this system. The Freon loop which starts at cylinders 1 and 2. These cylinders are heated by solar or some thing. (At first I was just looking at designing a solar motor). At top dead center the valve closes. After the crank is past top dead center and it is pulling some vacuum, the injector fires and put some liquid Freon into the cylinder. The heated cylinder expands the Freon and pushes the cylinder down, turning the crank. At 180 degrees the valve opens and exhaust the Freon to the condenser which drains into the liquid tank.

Note 1: set Freon pressure to about 5 degree above ambient temp.

The second part was an add-on after I was reading this thread and researching air engines. Cylinders 3 and 4 are used to bring in ambient air and pressurize it to heat up cylinders 1 and 2, then exhaust in to the air. Or you could use it to cool the condenser after it depressurizes.

Note 2: nothing is to scale, the cylinders could be different sizes and the crank is definitely not the right size, comparatively.

[ATT]

.

Hi guys, I have been reading this thread for the last couple of day and this popped in to my head. Will take no offence to improvements to the design.

@tempest

Nice schematic, good detail.

Tempest, since you're getting into Organic Rankine Cycle here, you might want to have a look at another thread I'm on (Tony Triola: it's short, only three pages), it'll help to get us all on the 'same page' with ORC and maybe give you a little insight to the ups and downs of getting in to all this:

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/269605551/m/2551084412

Have you had a chance to read through the pdf I posted earlier in this thread?
http://www.labothap.ulg.ac.be/cmsms/Staff/QuoilinS/TFE_SQ010607.pdf

It takes us through the cycle with a rotary expander and is pretty complete.

Reciprocating expanders such as the one you show are popular too, just depends on the application.

What you want to keep in mind is the word 'leverage' (not necessarily in the Archimedian sense...), which is to say, use as much off-the-shelf stuff as you can to cobble up your proof of concept so you don't tie-up your talents reinventing the proverbial 'wheel'.

But, hey, yeah, check out that other thread to see what a couple of us were batting back and forth earlier, there might be some resources listed there you can use (in this case, you will be 'leveraging' work on this idea somebody else has already done, it might save you some hassle...).

Tony
.

[Tempest]

excellent links, thank you very much. and sorry if I was off topic

[Nabo00o]

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

[sparks]

The phase change you refer to is just used to decrease the size of the machine.    The action of the compressor is to lower the vapor pressure over the top of the liquid so that it can boil easier.  As the atomized mist is sprayed into the evaporator the liquid boils at a decreased temperature.  The atoms leaving the liquid drops the thermal energy remaining in the liquid state as there are fewer collisions between atoms because there arent as many in there to bang around.  The compressor must continue to maintain a low vapor pressure or the flow of heat is now absorbed by the gas molecules and the liquid and there are soon just as many gas atoms condensing as there are evaporating.  A good heat pump would be operated above the boiling point of the refridgerant.  The pressure would rise and this pressue could then drive a piston.  The piston would have to be retained while the pressure built up.  The heated gas upon release of the piston would loose its kinetic energy and the interior temperature of the heat exchanger would drop.  This would allow for the effortless return of the piston where it would wait for enough thermal energy to raise the pressure on the piston head to the trigger actuation.  The materials of the heat exchanger could be such that even though the temperature drops drastically on movement of the piston it does not allow the transfer of heat fast enough into the gas which allows for a window of oppurtunity for the piston to return to a few degrees after top dead center.  This machine already exists and could have been refridgerating our food for many years know.  It was designed by Lord Kelvin.  But they chose not to do build commercialize it for obvious reasons.