Theoretical And Experimental Study On A Novel Solar-assisted Multifunctional Heat Pump System

The paper reviewed the development of application technology of solar assisted multifunctional heat pump and proposed a novel solar assisted multifunctional heat pump system (New SAMHPS) based on the application background. The New SAMHPS integrates a solar water heater with a domestic air-conditioner, which can operate in all operation modes included in these three domestic appliances, such as common refrigeration, common room heating and solar water heating, but also in other four new energy-saving operation modes of solar assisted room heating, water heat pump, refrigeration with water heating and hot water defrost. The New SAMHPS possesses a simple and cheap structure. The common electrical controllable valves in the New SAMHPS pave the way to develop a reliable control system for applications in future.The System performance of the two key operation modes of the new SAMHPS has been simulated based on the simulation model, and the obvious energy saving has been verified in the simulation.The six operation modes have been functioned successfully and can be switched to each other smoothly on a purpose-made experimental apparatus. Experiment results showed that the COP was higher than 3.1 in the solar-assisted room heating mode with a water temperature of 6.6℃and a simulated solar radiation of 2500W and the average COP was higher than 2.2 when 150L water was heated from 10℃to 40℃at the outdoor temperature of 7℃in the heat pump water heating mode. The refrigeration with water heating and hot water defrost modes all showed a lot energy saving. Experiment results verify the reliability and feasibility of the switch between operation modes. And the key factors which impact the efficiency of the new SAMHPS are disclosed also.The New SAMHPS can operate efficiently and reliably all the year round. Therefore, the availability of the solar water heater and the domestic air-conditioner will increase greatly and the seasonal adaptability of them will be improved as well. The New SAMHPS is especially suitable for the regions abundant in solar radiation, such as the middle and eastern region of China, where the room heating, the common refrigeration and the water heating are required all the year round.