## On the ‘would someone make’ front..

I’d like to see the math done as to how much energy could be saved by a heat pump water heater that had a tank for the greywater coming from the shower/bath. The idea is it could use a normal air exchange when no hot water was available that had returned from the bath, but it could extract the heat from the hot water coming back from the shower/bath if there was any. It seems like this ought to lead to considerable energy savings for a tanked heat pump hot water heater in normal usage since it would be pumping only slightly uphill. One can envision a system where the heat exchanger wrapped around a pipe leaving a insulated tank and a valve opened to empty the cold water and fill with more hot whenever the water had been pumped down to ambient.

### 3 Responses to “On the ‘would someone make’ front..”

1. Jonathan Pullen Says:

ChatGPT sez:

Recapturing the heat from greywater leaving showers and using it on the cold side of a heat pump hot water heater could save a significant amount of energy. The amount of energy that could be saved depends on various factors, such as the volume and temperature of the greywater, the efficiency of the heat pump, and the temperature of the incoming water.

According to a study by the US Environmental Protection Agency, recapturing the heat from greywater can save up to 60% of the energy used for water heating. The study found that a heat exchanger could recover up to 40% of the heat from greywater and that a heat pump water heater could increase the temperature of the incoming water by up to 15°F, resulting in further energy savings.

In practice, the amount of energy saved by recapturing greywater heat will depend on the specific circumstances of the system being used. However, it is clear that this technique has the potential to significantly reduce energy consumption and could be a useful strategy for households and businesses looking to lower their environmental impact and save money on their energy bills.

2. Jonathan Pullen Says:

This might especially be worth doing at facilities like laundrimats.

3. Swipes Says:

Might be useful with the length of baths you take sometimes. 😉