Brine geothermal heat exchanger
A brine geothermal heat exchanger or brine geothermal heat exchanger (abbreviated to brine-EWT) is a heat exchanger that is used in ventilation systems in buildings . In contrast to the classic geothermal heat exchanger, in which the air exchanges heat directly with the ground, with the brine EWT, ground heat is absorbed via plastic pipes (usually a glycol / water mixture) introduced into the ground and via a separate brine / air heat exchanger released into the air. As with the "classic" EWT, heat energy can also be extracted from the air in summer.
Advantages compared to "classic" geothermal heat exchangers:
- less installation effort, as there is no uniform gradient in the collector pipes
- lower material price due to the collector pipe material used
- No cleaning of the heat exchanger located in the ground necessary, as there is no "food air in hard-to-reach underground lines"
- The desired air temperature for winter preheating or summer pre-cooling can be set in a wide range by varying the flow rate of the brine,
- No bypass flap required in the outside air intake for outside temperatures of 7–20 degrees.
- Depending on the boundary conditions, 12-18 kWh of useful heat or useful cooling can be obtained per kWh of electricity.
Disadvantages compared to air duct geothermal heat exchangers:
- Auxiliary energy for the brine pump required. With high-efficiency brine pumps no longer matters.
- Overall more building services (controller for brine pump, temperature sensor, membrane expansion tank, etc.)