Modelling and Simulation of Heat Pump Systems for Hybrid and Electrical Vehicles

Sammanfattning: Hybridization and electrification of modern vehicles is today a reality. This effects the construction of the heating and cooling systems in vehicles where earlier the waste heat from the combustion engine was a great heat source. Heat pump systems are commonly used in heating systems in buildings and can therefore also be used for heating the cabin and different components in a vehicle. Modelling a heat pump system and performing simulations gives the advantage of investigating the heating performance of the heat pump during certain conditions. In this master thesis, which is performed in a pre-study project that is performed under the Swedish Electromobility Centre, a heat pump is modelled and the heating performance when changing the vapour quality is investigated during cold environments. Also how the heating capacity for different refrigerants and changing size and speed of compressor is simulated. With the methods and assumptions used, especially isentropic compression, the results shows that decreasing the vapour quality increase the mass flow in the heat pump circuit but the decrease in specific heating is larger which results in an overall decrease in heating capacity. The goal of 10 kW heating capacity can be achieved by increasing the compressor size or make use of waste heat from other vehicle components.