I am hearing about this as a low carbon method to heat or cool buildings but I can’t find a good article or video to see how it works. The closest I can figure is like a fridge in reverse… the pump or refrigerant gets hot and you use that heat. Cold climate systems supposedly extract heat down to -25c. How?
In: Physics
It’s a heat transport cycle either using evaporation or a chemical reaction. The evaporation one is simpler so I’ll explain that:
1. You evaporate a medium in your heat source at low pressure. It absorbs energy to make that phase change (low pressure means low boiling point)
2. You use a pump (compressor) to move the medium to the other side and increase the pressure
3. At high pressure the medium condenses (despite being warmer) releasing the stored energy
4. You let it stream back through a small opening that forces the pressure to reduce
Cycle closed. You transport a lot more energy than the pump requires, at least if the temperature difference isn’t too big. (Therefore the most efficient ones don’t use outside air but ground water that is around 10°C all year around, and in norway there is a large scale heatpump supplying district heating from 4°C fjord water)
The chemical variant replaces the evaporation with dissolving one medium in another and later forcing it out with pressure.
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