Why is hot waste water (shower, sink…) not reused for heating?

1.33K viewsEngineeringOther

Why is it not used again and wouldn’t it be very efficient to combine with a heat pump for reuse?
Especially since water from shower or sink isn’t usually very dirty, couldn’t it be stored for a while in an isolated tank so that e.g. a heat pump can run more efficient on it than on usually colder air or colder ground water?

In: Engineering

27 Answers

Anonymous 0 Comments

The water cools off shortly after hitting the drain. It’s not contained well or insulated so it is basically just going to cost lots of money to get a system to work the way you want. On the other hand, the heat it does radiate out of the pipe as it drains is raising the temperature of the space slightly so technically it’s already doing the work.

The HVAC system that is already used is called an “exhaust recovery ventilator” does something like what you are imagining. It has a system that uses outgoing air to pre heat/pre cool outside air in places like hotels, highrises and nursing homes that are typically closed up tight.

You are viewing 1 out of 27 answers, click here to view all answers.