Experimental investigation and dynamic modeling of an air-to-water residential heat pump with vapor injection and variable speed scroll compressor

This paper presents experimental results of a residential air source heat pump using a scroll compressor with variable speed and vapor injection. The system is modeled using the Modelica language and a comparison with the experimental results is performed. It was shown that there is still room for improvement on the control of the system. In fact, the tested gain scheduled PID controller showed limitation to maintain a low and steady superheat on both the suction and injection lines due to dynamics associated to the vapor split line or heat exchangers. The presented model of the system could be used in order to develop model based control and increase the system performances.