Thermal performance prediction and analysis on the economized vapor injection air-source heat pump in cold climate region of China

The air-source heat pump with an economized vapor injection technique has the distinct advantages of performance and stability for space heating and hot water supply in cold area. However, it is unreasonable to evaluate and predict the thermal performance by the nominal working conditions in different areas and environmental conditions. The experimental set up of economized vapor injection air-source heat pump (EVI-ASHP) system was established in cold region of China. The experimental results showed that the air-source heat pump with the EVI technique could improve thermal performance 4-6% than that without EVI. The relationship of COP and condenser inlet and ambient temperature difference was linearly dependent in the same environmental relative humidity. In order to obtain the empirical equations of COP, the linear and negative exponential corrections of the temperature difference of ambient dry-bulb and wet bulb were used when the electromagnetic valve is on or off, respectively. The monthly and hourly thermal performance of four cities in cold and severe cold region in China was compared and analyzed in the climatic condition of the typical meteorological year.