Vibrationsdämpning av värmepump

Sammanfattning: Thermia Värme AB is one of the market leading manufactures of heat pumps. In order to maintain this position, the company wants to improve the vibration characteristics of their products. The aim of this thesis is to develop product design changes that lead to a reduction of vibrations in the heat pump Thermia Diplomat 8. The main cause for vibrations in the system is flow pulsation and mechanical forces induced by the scroll compressor. Vibration is transmitted through the compressor piping and received by the heat exchangers, from where it is further transmitted to the connection points for the radiator and heat source circuits. A number of design changes in order to improve the vibration characteristics have been evaluated through calculations and practical experiments. The changes have included the compressor and heat exchanger mountings, the compressor suction and discharge line piping and also pulsation dampening. The results of the experiments show that the vibration levels in the connections for the heating and brine circuits can be decreased strikingly through changes in suction and discharge line piping. Further improvements concerning the vibration levels in both the heating and brine connections and the framework of the heat pump are achieved through detaching the heat exchanger mountings from the compressor mounting plate. Furthermore, a number of proposals to additional improvements of the system have been lightly described. These suggestions include modification of the heating and brine circuit piping. Significant improvements are considered to be achieved through using the big mass inertia of the hot water tank as an isolating element for the piping connections. Also a replacement of copper tubes that have unwanted natural frequencies with shorter pipe lengths or flexible hoses would decrease the vibration transmission.