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banderso3391
27-05-2007, 10:47 PM
My idea is simple but maybe not too practical.
Is it possible to make a heat pump that would make cold air or ice from one end and steam out the other end.

Does any manufacturer make such a unit for a small to medium size apartment building? If not do you know of compressors, and refrigerants that could produce such a result.

Thanks,
Brock

US Iceman
27-05-2007, 11:23 PM
Hi banderso3391,

Welcome to the RE forums.



Is it possible to make a heat pump that would make cold Air (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=17) or ice from one end and steam out the other end.


It's possible to make steam with a heat pump I think. The highest temperature I have achieved so far is +/- 170-180F (76.6-82.2C).

Heat pumps to generate ice are also possible, although I have not tried both steam and ice at the same time.

This is an unusual question for a software engineer. Might I ask why?

taz24
28-05-2007, 11:59 AM
My idea is simple but maybe not too practical.
Is it possible to make a heat pump that would make cold air or ice from one end and steam out the other end.

Does any manufacturer make such a unit for a small to medium size apartment building? If not do you know of compressors, and refrigerants that could produce such a result.

Thanks,
Brock

In theory yes. In practice why?
The costs involved to produce steam would make the system unviable.
The ice production would be easy but the heat produced would need boosting to produce the discharge temps that would generate steam.
The cop would be so low and the stress to the system would (in my oppinion) make it uneconomical.

Cheers taz.

US Iceman
28-05-2007, 03:01 PM
...the heat produced would need boosting to produce the discharge temps that would generate steam.


Taz, the problem is not discharge temperature, but rather constant condensing temperature to generate the steam. This is one of those areas to be careful of.

The actual discharge temperature although high does not have very much heat content (enthalpy difference) available for heating. Actual discharge tempertaures are always higher than the condensing temperature.

Most of the heating effect occurs due to latent heat during condensation.

This means we have to have the condensing temperature greater than the final desired temperature. In this case, steam at a minimum of 100C (212F). However, this is simply saturated steam, so we need some superheat. This is where the actual discharge temperature is required to superheat the steam.

taz24
29-05-2007, 01:27 AM
This means we have to have the condensing temperature greater than the final desired temperature. In this case, steam at a minimum of 100C (212F). However, this is simply saturated steam, so we need some superheat. This is where the actual discharge temperature is required to superheat the steam.

You have explained my point better than me:) .

I agree with what you say and that is why I asked him why he would want to do it. I feel that the cost of generating usable quantities of steam by this method would be prohibative.
It could be used to heat water to a certain point but then extra heat sources would be required to take the final temp above 100C (212F)

Cheers taz.

US Iceman
29-05-2007, 02:02 AM
Whether it's cost effective or not is the main issue. You have to look at the cost to produce steam the convential way, and then compare that to the cost of producing steam with a heat pump.

I think it's possible and have been waiting for a willing party to participate in a little reasearch project.

BigJon3475
29-05-2007, 04:16 AM
This may be totally impossible idea but just a thought. What if you had the water that was to be steamed in a lower pressure or vacuum environment not needing as much heat to make it boil. It would present a problem though if you needed this steam at atmospheric conditions. Then you would just be wasting time and money. What exactly is the steam needed for or is this top secret? :D

star882
30-05-2007, 01:54 PM
Some clothes dryers use compressors to recycle heat. I'm not sure exactly what temperature they operate at but I wouldn't be surprised if the condensing temperature approached 100C. I do know it can be easily up to 80C in combination washer/dryers that also use the compressor to heat water for the "antibacterial" mode.
Good luck trying to freeze and boil water at the same time with a single compressor. A cascade, however...

US Iceman
30-05-2007, 03:15 PM
...Good luck trying to freeze and boil water at the same time with a single Compressor (http://www.refrigeration-engineer.com/forums/glossary.php?do=viewglossary&term=60).


Luck has nothing to do with it. Common sense and following basic principles are required to do this. This type of an application will require some careful engineering though, that's for sure.

banderso3391
30-05-2007, 04:50 PM
Sorry I was a little vague. My concept is to take the condensing/discharge heat and create steam to power a generator. The evaporing side would actually be a by product generating air conditioning or ice to be sold. I thought since a compressor creates both cold and hot(action/equal and opposite reaction and all that) why not use both in one application. Am I all wet or just full of hot air??

Brock

US Iceman
30-05-2007, 09:05 PM
Speaking for myself only, I think it's possible. Although, it will take some R&D and money.

Dan
02-06-2007, 12:45 AM
Am I all wet or just full of hot air??

LOL! I think you would be disappointed in the ability to drive a steam engine with discharge gas from a refrigeration compressor. Steam generation requires very hot temperatures and a large amount of flow to accomplish the work required. You would most likely have an insurmountable first cost once we crunch the numbers. Still, it might be a worthy exercise to do come calculations.