Half a croissant, on a plate, with a sign in front of it saying '50c'
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Heat powered heat pump

Make steam, make vacuum, condense
  [vote for,

I recently read about "Steam jet cooling" on wikipedia -- a type of air conditioning that was used on railroads, back when trains were steam driven.

In the original system, waste steam from the pistons was passed through a steam injector, which sucked water vapor out of a water-filled evaporator.

The water in that evaporator boiled then boiled at a very low pressure, and absorbed heat from the train's passenger compartment, providing cooling.

The output of the steam injector (the original steam sent in, plus the steam sucked from the evaporator) was then sent on to the condensor.

A second steam injector was then used to move liquid water from the condensor back into the boiler.

It seems to me that the same setup, (boiler, evaporator, condensor, and two injectors) minus the mechanical power generating parts of the steam engine, could be used to create a heat-powered heat pump.

It would be a vapor compression heat pump, but with no moving parts.

Assuming that it works, it could be used in the same kinds of applications as an absorbtion chiller or absorbtion heat pump.

The advantage this idea has over a conventional vapor compression heat pump should be obvious:

1) There are no moving parts, so it should last indefinitly, and be fairly quite.

2) It consumes heat (solar heat perhaps, or else combustion of oil, gas, wood, etc.), not electricity as a power source. Thus, it wouldn't contribute to brownouts or blackouts, nor would it be much effected by a brownout.

3) Any refrigerant can be used, even water. Water is as nontoxic as you can get, and has a fairly high COP, but conventional (electromechanical) vapor compression heat pumps using water need a large or fast (and thus expensive) compressor. A steam injector might possibly be a cheaper type of compressor.

In comparison with absorbtion heat pumps / absorbtion chillers... item number 3 above is probably the only real advantage... but, considering that many absorbtion heat pumps use ammonia as the refrigerant, this is still an important benefit.

goldbb, Aug 27 2009

Steam Jet Cooling http://en.wikipedia...i/Steam_jet_cooling
[goldbb, Aug 27 2009]

Absorbtion Cooling http://en.wikipedia...rption_refrigerator
[goldbb, Aug 27 2009]

Einstein - Szilárd unit http://en.wikipedia...nstein_refrigerator
An absorbtion cycle.system. [8th of 7, Aug 28 2009]

Solar Steam Cooling Solar_20Steam_20Cooling
Similar, but using a Hilsch Vortex, instead of evaporation [goldbb, Sep 01 2009]

Flame-powered refrigeration http://www.lehmans....igerator___rge400ng
As mentioned in an annotation. [Vernon, Aug 16 2011]


       // consumes heat .... not electricity //   

       Entropy, entropy ... there is no free lunch.   

       Yes, you might be able to make a unit work on direct solar power, but it would require a very large collector.   

       Sounds like a very large and expensive unit for a relatively modest cooling return.
8th of 7, Aug 28 2009

       I know there's no such thing as a free lunch, but by using heat instead of electricity *will* reduce the amount of loading on the local power plant.   

       And if the heat source were from a CHP system, this would be even more true :)   

       What makes you think it would need to be large an expensive to work?
goldbb, Aug 31 2009

       I actually ran the numbers as a College project, and a roof top evacuated flat panel collector can provide enough heat to an absorption chiller to provide cooling for 2-3 normal homes.
MechE, Aug 31 2009

       Fascinating, [MechE]. Your anno has tipped me bunwards [+]   

       Do you have a link to your project? How large was the collector panel in your model?
BunsenHoneydew, Sep 03 2009

       // Water is as nontoxic as you can get, and has a fairly high COP,//   

       Is COP: Coefficient of performance?   

       Yes... here is a quote from a patent on a refrigerant:   

       /The term "coefficient of performance" used herein means the ratio of refrigerating capacity to compressing work. The refrigerating capacity is the quantity of heat removed per a unit time from the substances being cooled, and the compressing work is the work volume achieved per a unit time by power for operating the refrigerator. Accordingly the coefficient of performance corresponds to the refrigeration efficiency of the refrigerant. /
goldbb, Sep 03 2009

       I sat with my friend in the Solel (now Siemens) building and we were both sweating, although the "solar cooling system" was running, till finally he turned on the electric (regular) air conditioner.   

       How do I contact you? Can you contact me? my user at gmail.
pashute, Aug 15 2011

       The problem isn't so much turning solar or any other heat source into steam (latent energy) because you don't pay a large cost to entropy. This doesn't apply to the transition from heat energy to electrical energy which is well defined and is 'well-ordered'. The consequence is that you have a low efficiency of converting heat to useful energy/work.
EatAlbertaBeef, Aug 16 2011

       I'm pretty sure that there is --or was-- a variety of kitchen refrigerator that is powered by burning natural gas, and is not powered by electricity. Which means this Idea was actually Baked many years ago. Although I must admit that doing it with solar power is an excellent alternative on a sunny day.
Vernon, Aug 16 2011


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