3 ms·
drain water heat recovery is already a thing. It's code for new builds in British Columbia, Canada. It's only expensive due to the amount of copper. The actual
by theluketaylor 4y ago
drain water heat recovery is already a thing. It's code for new builds in British Columbia, Canada.
It's only expensive due to the amount of copper. The actual install has no moving parts and is completely passive.
https://www.nrcan.gc.ca/energy/products/categories/water-heaters/14568 https://www.nrcan.gc.ca/energy/products/categories/water-hea...
- dzhiurgis 4y agoWhat efficiency are these? Brainstormed this a bit and feels like shower cabins (pretty popular over NE Europe) should have such system as standalone... As in - it collects waste, collects heat and stores it for next shower. Dunno how much energy a typical refrigerant can store tho. Also great fit for Japanese-style smart baths (press a button and water of desired temperature fills and stays warm), tho they seem rare outside Japan.
- theluketaylor 4y agoI think they can recover up to 60-70% of the heat in the drain water. Not bad for totally passive. The installs I have seen are on the main drain for the whole house and located right next to the hot water heater. For it to really work you need a hot water tank, but I have seen some small tanks combined with tankless.
- shellfishgene 4y agoThere are systems that replace the shower drain with something like a heat exchanger, the water is warmed with the drain water right away, no need to store the heat. For example https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.html https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.h... (in German, but the image is simple to understand.)