Determining the Working Conditions of Heat Pump Components According to Running Modes

Abstract

In this study a detailed exergetic analysis is made of the components of heat pumps by changing the heat source and heat sink fluid as either water or air. To realize this aim a multifunctional heat pump test system was used, which can be run in four modes, air to air, air to water, water to air and water to water, using one compressor. When the system is run in water to air mode compressor exergy efficiency reaches its highest value. When the system is run in air to water mode the exergy efficiency of the compressor falls to its lowest value. In the heat pump’s water to air mode the exergy destruction rate of the compressor becomes minimal. Exergetic performance of the condenser is best when the system is run in water to air mode. When the system runs in air to air mode, the exergy destruction rate of the condenser is at maximum, and falls to minimum when the system runs in air to water mode. Water to water is the running mode in which evaporator exergy efficiency is the best. Exergy efficiency of the evaporator decreases when the temperature of the evaporator fluid increases. Maximum compressor exergy efficiency increases according to an increase of mass flow rate is seemed in the air to air mode. The heat pump mode in which the exergy destruction rate of the compressor is minimal, is water to air mode. The running modes in which the condenser and compressor work with maximum and minimum efficiency are the same: water to air, and air to water modes. The compressor is the component which has maximum exergy efficiency with an average of 61.04% for all tests. Exergy efficiency of the condenser is lowest for all tests with an average of 14.25%.