The Design and Experimental Analysis of an Air Source Heat Pump for Extreme Cold Weather Operation

This research evaluates one method of increasing the performance of an air sourced heat pump to extend its operating range and eliminate the need for a backup heating system. A study was conducted using the Engineering Equation Solver software package to identify the performance improvements that are attainable with variations of a two stage heat pump cycle. An experimental apparatus was constructed to compare the performance of the best performing variation - a two stage economized cycle - to that of a traditional single stage heat pump. The two stage economized heat pump had a measured coefficient of performance of 1.45 when it was operated at an outdoor temperature of -31C making it an energy efficient option for most Canadian climates. In addition, the heating capacity of the system was increased by a factor of 2.5 when compared to the single stage system.