Drainwater Heat Recovery Systems
DOE- Drain-Water Heat Recovery
Drain-water heat recovery technology works well with all types of water heaters, especially with demand and solar water heaters. Also, drain-water heat exchangers can recover heat from the hot water used in showers, bathtubs, sinks, dishwashers, and clothes washers. They generally have the ability to store recovered heat for later use. You'll need a unit with storage capacity for use with a dishwasher or clothes washer. Without storage capacity, you'll only have useful energy during the simultaneous flow of cold water and heated drain water, like while showering.
Some storage-type systems have tanks containing a reservoir of clean water. Drain water flows through a spiral tube at the bottom of the heat storage tank. This warms the tank water, which rises to the top. Water heater intake water is preheated by circulation through a coil at the top of the tank.
DOE- Drain-Water Heat Recovery |
Recovering heat from drain water
After space heating, water heating is the biggest user of energy in most Canadian homes, accounting for between 20-30% of total energy consumption. In fact, Canadians spend billions every year to heat water for bathing, laundry, dishwashing and many other uses.
Typically, this hot water goes down the drain
after a few minutes of use. Now a simple, low-cost
technology is available that allows homeowners
and businesses to capture the heat in drain water
and reuse it to heat more water.
Recovering heat from drain water |
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