The Influence of Weather in Heat Pump Systems

Abstract

The aim of this work is analyze the influence of the weather in the operation and behavior ofheat pumps. They are similar, the difference between them being the evaporator. Oneoperates, with an evaporation temperature 9° C below the ambient temperature (system 1) andthe other one (system 2) with a constant evaporation temperature equal to 0°C whereverpossible. The purpose of the heat pumps was for heating a small office. For both systems aconstant temperature of 20ºC was set to be kept in the office. The working fluid is the R134.In order to analyze the influence of the ambient temperature upon the energy consumption ofthe heat pumps, three different cities were chosen: Porto, Bragança and Faro located inPortugal. The study was carried out monthly for one typical year of these cities. With theseresults it was concluded that the design of a heat pump depends on the local weather as wellas the time of the year in which it operates, the energy consumption being higher in monthswith lower temperatures. It was also possible to conclude that the work expended by fans,necessary to increase the coefficient of heat transfer in the heat exchanger of the system, canbe decisive in the economy of the energy consumption. These reasons lead to system 2 whichis more efficient in locations with mild climate and system 1 better in colder climates.