Long-term performance analysis of a hybrid ground source heat pump system in Finland

This study investigated methods for improving the long-term performance of a hybrid GSHP system coupled to district heating and an air-cooled chiller. These methods include adjusting indoor air setpoints and dimensioning air handling unit (AHU) cooling coils. The system performance was analysed based on 25-year simulations in IDA ICE 4.8. By using the studied methods, the minimum outlet brine temperature was increased by around 3°C in the last heating season, the average heat pump COP in the last heating season was increased by 3 % and the share of the GSHP heating energy in the last heating season was improved by 2 percentage points. However, ensuring long-term operation still required extra solutions.