Heat Recovery Devices

Waste-heat recovery devices, sometimes called hot gas reclaim systems, take heat where it is unwanted, from your air conditioner's or heat pump's outdoor heat rejection coil, and moves it where it is needed, to your hot water tank. In so doing, these devices can reduce water heating costs substantially while also reducing air conditioning costs.

It may sound too good to be true, but it works well, particularly in hot climates. In areas that have high cooling loads and a long cooling season, enough heat may be reclaimed to meet the home's entire hot water requirements during the summer months.

With a waste heat recovery device, such as a desuperheater, the air conditioner operates more efficiently, because it does not have to work as hard exchanging its waste heat. Instead of rejecting its heat to the warm outside air, it gets to reject it into much cooler water. Then the heat deposited in the water heater is essentially “free.” With the waste heat recovery device in place, a typical house air conditioner or heat pump produces about 25 gallons of water per hour heated to 130°F.

Since heat can be re-claimed only while the air conditioner is operating, the storage tank must have supplemental heating capabilities for when the air conditioner is not “on.” Even when it does not meet the entire demand, re-claimed heat contributes some heat that would otherwise have to be supplied by the water heater.

Waste heat recovery devices can be installed during construction or retrofitted to existing water heater storage tanks. Most are enclosed in metal cases and mounted either on a wall outside near the air conditioner condenser or inside near the water heater.

To find out about availability and performance for these devices in your area, ask a Service Technician or Utility Representative about waste heat recovery devices.