Estimation of the Seasonal Coefficient of Performance of Air-to-Water Heat Pumps in Temperate Climate

In the last two decades, a significant increase in the share of heat pump systems, used to maintain the microclimate in residential, public and municipal buildings, has been observed. The electrical energy consumed by this type of machines depends on the coefficient of performance, which in turn is a function of the outside air parameters, as well as on the type of technology used. In the presented study, an attempt is made to determine the seasonal coefficient of performance of heat pump systems, considering three machines of different power, to partially or fully cover the thermal load of the object for which they are proposed. Through the use of four different methodologies, the seasonal coefficient of a given heat pump system, designed to operate in each of the nine considered climate zones in moderate climate conditions, is calculated. The analysis shows that when using a simplified methodology for calculating the seasonal coefficient, the specified coefficient according to the manufacturer’ s technical passport, without taking into account the conditions of the climatic zone, leads to an error in the seasonal coefficient by 20,6%, which is a significant error when calculating the energy consumption. On average, between 5 and 10% is the error in determining the seasonal coefficient for different climate zones in a moderate climate.