Research On Application Technology Of Air Souce Heat Pump Based On Earth-to-Air Heat Exchanger

At present,the energy shortage problem is very serious and has become one of the problems that constrain China's economic and social development.As an important part of the national energy strategy,building energy consumption has attracted more and more attention.For a long time in the future,China's energy structure is still dominated by fossil energy.Therefore,improving the comprehensive utilization efficiency of energy and increasing efforts to develop renewable energy are important trends in the future development of China's energy.Shallow geothermal energy is a kind of renewable energy.For more efficient use of shallow geothermal energy,a soil-to-air source heat pump system based on soil-to-air heat exchanger is constructed.This system solves the problem of low energy efficiency of air source heat pump caused by low outdoor-temperature in cold regions,which can extend air source heat pump applications.This system also avoids ultra-high investment and groundwater and soil pollution.Based on the soil parameters of Laoting in Tangshan,the calculation model of soil temperature field is summarized,and the original temperature field of soil layer at different depths is calculated.The temperature wave attenuation and delay are the main reasons for soil temperature change.Firstly,the reasonable parameters of the depth of the soil--to-air heat exchanger,the inlet flow rate and the pipe diameter are determined by analyzing the data.Under the above conditions,the heat transfer performance of pipe lengths to the soil-to-air heat exchanger is simulated by ANSYS FLUENT.Secondly,based on the pipe length of 80 m,the influence of different inlet temperatures on the heat transfer performance of the heat exchanger was simulated.By analyzing and calculating inlet temperatures,and selecting a reasonable temperature,the reasonable inlet and outlet temperatures of the soil-air heat exchanger in the system are determined.The air source matching the soil-air heat exchanger parameters under this condition is calculated.The heat pump heat,power,heating coefficient COPparameter value.Finally,the system is compared with the traditional air source heat pump,and the energy consumption and economy of the system are evaluated by using the above calculation data.