We recently installed an energy recovery unit on a house in Raleigh. This device, also called a desuperheater, transfers some of the heat from the air conditioner or heat pump into your hot water tank. It’s not much to look at, but the energy savings can be substantial.
Energy Recovery Unit or desuperheater with cover removed
What you see in the photo above is the desuperheater with it’s cover open. The blue and red lines coming in the bottom are water from the hot water tank in the house – you can also see a circulation pump which returns the heated water back to the tank. The desuperheater is hooked into the refrigerant circuit of the heat pump, on the discharge side of the compressor. Hot refrigerant gas leaves the compressor and immediately flows through a couple of loops of copper that are surrounded by the water from the hot water tank. Heat is transferred from the refrigerant to the water. This has two effects, first it heats the water. Second it reduces the refrigerant gas temperature and pressure (when you cool a gas the pressure decreases). Since the pressure right after the compressor decreases, the compressor does not have to work as hard since it has less pressure to push against. A desuperheater can cut the load on the compressor by 15% or more – this means a 15% decrease in electricity usage.
Desuperheaters are simple devices, and not very expensive. They make even more sense on a busy restaurant where the air conditioning runs almost year round because of the heat in the kitchen. Contact us if you’d like learn more.