Defrosting of Air-Source Heat Pumps: Effect of Real Temperature Data on Seasonal Energy Performance for Different Locations in Italy

Abstract

In this paper, dynamic simulations of the seasonal coefficient of performance (SCOP) of Air-Source Heat Pumps will be presented by considering three different heat pump systems coupled with the same building located in three different Italian municipalities: S. Benedetto del Tronto (42°58′ North, 13°53′ East), Milan (45°28′ North, 9°10′ East), and Livigno (46°28′ North, 10°8′ East). Dynamic simulations were conducted by employing the software package TRNSYS and by considering real weather data (i.e., outdoor air temperature and humidity as well as solar radiation) referring to the three abovementioned cities for a period of 8 years (2013–2020) and collected from on-site weather stations. Attention has been paid to the modeling of the heat pump defrost cycles in order to evaluate their influence on the unit’s seasonal performance. Results show that, when referring to different years, the thermal energy demand displays huge variations (in some cases it can even double its value), while the effective SCOP is characterized by scarce variability. Sensible variations in SCOP values are achieved for Livigno.

Renovation Results of Finnish Single-Family Renovation Subsidies: Oil Boiler Replacement with Heat Pumps

“…It is also important to add that the defrost cycle of AWHP is not directly analysed in this study. The specific defrost cycle of the heat pump depends on the manufacturer's solution and can also affect the seasonal COP of the AWHP system [48].…”

Effect of real temperature data on the seasonal coefficient of performance of air source heat pumps

“…That Figure shows that Unit 1 and Unit 2 behave similarly referring both to the thermal power and the COP, while Unit 3 displays higher thermal power values. As in [12], the considered heat pumps are selected in order to totally satisfy the thermal energy demand of the building, i.e. to guarantee the set-point temperature for the indoor air of 20°C when the outdoor ambient temperature reaches the winter design temperature, reported in Table 2.…”

Influence of different heating systems on thermal comfort perception: a dynamic and CFD analysis

“…According to market data [3], in Europe the most widespread typology of heat pumps employed in residential sector for heating and cooling are air source heat pumps, ASHP. The prevalence of ASHP is related basically to the availability of the air as heat source and to the limited installation cost respect to other types of heat pumps as for example ground source heat pumps [4,5]; air source heat pumps, on the other hand, are characterized by reduced performances with respect to ground source heat pumps, and their performance strongly depends on weather conditions and frost formation on the external evaporator, as suggested in many papers in the literature [6][7][8]. The transition towards more sustainable energy sources in building heating, however, should not overlook the importance of thermal comfort and indoor air quality.…”