Desuperheater

A desuperheater is a heat exchanger that transfers waste heat from a ground source heat pump to a domestic hot water tank. Since the desuperheater only functions when the heat pump is operating it is almost always used to assist the primary water heater.

Research has shown that hot water savings from a desuperheater typically range from 10% to 40% based on the type of system, runtime and climate.  Some claim hot water savings up to 50% and even higher, but are not based on field studies or research.  Hot water savings in cooling dominated climates have proven to be higher than heating dominated climates.  In Florida, one could see up to 40% savings from a desuperheater, while in a colder climate like Chicago, you may see only 10-20% hot water savings.  In swing months, the heat pump is not running so all hot water will come from the hot water heater in the home.

As a conservative estimate, desuperheater savings in the 25-30% range is realistic and can be adjusted up or down based on climate. For information regarding how to model a desuperheater in Ekotrope, please read the appropriate section found at the bottom of this help article.

Here are links to supporting documentation on desuperheaters:

Ground Source Heat Pump and Desuperheater study in Minnesota - study in Minnesota on desuperheater field operations and hot water savings.  See page 78 for desuperheater savings in Minnesota at 12-22% for hot water.

Economic Viability of Desuperheaters - study to determine the economic viability of desuperheaters.  

Green Building Advisor on Desuperheaters - a general explanation of desuperheater operation.