Calculate the Coefficient of Performance for ground source heat pumps. Evaluate heating and cooling efficiency based on system parameters and operating conditions.
The Coefficient of Performance (COP) measures how efficiently a heat pump converts electrical energy into heating or cooling energy. A COP of 4.0 means the system delivers 4 units of heat for every 1 unit of electricity consumed.
Ground source heat pumps benefit from stable underground temperatures (typically 10-15°C year-round), making them more efficient than air source systems which must cope with extreme outdoor temperatures.
Key factors include ground temperature, supply water temperature, system design quality, loop configuration, and operating conditions. Lower supply temperatures (e.g., underfloor heating) improve COP significantly.
A good COP for a geothermal heat pump typically ranges between 3.5 and 5.0 during heating mode and 4.0 to 6.0 during cooling mode. This means for every unit of electricity consumed, the system delivers 3.5 to 5 units of heat energy.
The COP is calculated using the formula: COP = Heat Output (kW) / Electrical Input (kW). The total electrical input should include the compressor, circulation pumps, and any auxiliary equipment for a true system COP.
Key factors include ground loop temperature, supply water temperature, loop flow rate, heat exchanger design, compressor technology, building insulation, and seasonal ground temperature variations.