The EcoDrain is a clever heat exchanger with no moving parts. It is designed to take the excess heat from the waste shower water and use that to pre-heat the cold-water inlet to an electric shower. This means you can cut the energy used by the water heater by up to 25-40%!
The diagram above demonstrates how it fits with the plumbing of a household shower. The EcoDrain is made from stainless steel, which has a non-stick coating on the inside of the waste water pipe. The non-stick coating is designed to stop the drain becoming clogged from soap and dirt. The energy from waste shower water is wasted anyway, so it makes sense to try and use it somehow.
It would be interesting if a variation was used to help heat water tanks or underfloor heating from waste hot water throughout the house. That’s a lot of untapped waste energy! A great innovation though!
Source: Inhabitat