5 ms·
No, the source is the waste water, the target is the fresh water. You could either use a heat pump to move the heat from the colder waste water to the hotter fr
by namibj 4y ago
No, the source is the waste water, the target is the fresh water.
You could either use a heat pump to move the heat from the colder waste water to the hotter fresh water, or use a direct heat exchanger to pre-heat the freshwater while chilling the waste water down, to then put a resistance heater between the heat exchanger's freshwater outlet and the shower head's input.
But it should be more efficient to run a heat pump against the heat exchanger's inefficiency/delta then to let it happen and compensate with an ohmic heater.
Yes, the wastewater discharge with a 100% efficient heat pump might actually leave colder than the fresh water comes, due to heat loss to the room exceeding the work required to pump the heat against the exchanger's losses.
- Schroedingersat 4y agoAmbient temperature water is entering the system somewhere. You'd put your heat exchanger there. The replacement for the lost heat would happen to the equilibriated water and could happen with a heat pump. In principle (if your heat pump and exchanger is perfect) this generates no entropy so is more efficient than putting things with finite temperature delta in contact. In practise it's probably just simpler and requires a smaller heat pump. Whether you use the waste water (which will still be a degree or two above as exchangers aren't perfect) or whatever your normal source is (ground source may be warmer) would be about cost and making the heat pump work for not-the-shower too.