Steady state calculation of heat pump long term performances based on utilization factor method

A hourly simulation in dynamic conditions of building-plant system is able to give a rigorous evaluation of seasonal performances of a heat pump using outside air as cold source. However in professional applications we have often the necessity of speed estimation of the energetic and economic opportunities of its introduction whose advantages are not always real and sure. For this reason various simplified methods have been proposed. A new procedure to estimate seasonal performances of an air source heat pump is proposed here, based on utilization factor method. This method, elaborated by CEN TC 89, permits to evaluate climatization energy requirements of buildings by steady-state calculations referring to monthly average weather data. The results obtained by this procedure are compared with those obtained by comprehensive dynamic simulations for different climate conditions.