Simulation Study On Frost Formation Mechanism And Frost Suppression Strategy Of Air Source Heat Pump In Tibetan Area Of Western Sichuan

Tibetan area of western Sichuan is rich in hydropower resources and lacking fossil energy.Therefore,the electric-driven air source heat pump is suitable for solving the long-term heating demand in this area.But the climate characteristics of "low temperature and high humidity" in Tibet area are obvious.The electric-driven air source heat pump is faced with the problem of frequent frosting,which seriously hinders its application and development in Tibet area.The existing research on frost suppression is mainly focused on surface modification,dehumidification system and applied electric field.These methods have different drawbacks in the process of practical application,which can lead to a wide range of application.Therefore,there is an urgent need for a practical and effective way to solve frosting problem.In order to find a more general and feasible way to suppress frost in the actual operation of the unit,the theoretical model of frosting on cold plate is established first,and the influence of air temperature and humidity and cold plate temperature on frosting rate is analyzed.Then,the frost map is drawn according to the frost rate.The evaporation temperature of the existing air source heat pump unit was only a single value function of the air temperature in the process of drawing the frosting map,and the effect of air relative humidity was not considered.But the relative humidity of air is also an important factor that affects the frosting process.By setting constraints,the author of this article set the heat transfer temperature difference as the coupling function of air temperature and humidity.The results show that the frosting rate increases with the increase of the air temperature and relative humidity,and decreases with the increase of the surfacetemperature of the fin.The sensitivity of different frost regions to heat transfer temperature difference is different.The area of heavy frost is the largest,followed by the general frosting area,and the light frost area is the smallest.After the heat transfer temperature difference has the coupling function of the air temperature and humidity,the evaporation temperature of the surface of the fin will increase with the increase of air humidity.Compared with the previous state,the evaporation temperature rises by21.5%,the average humidity difference decreases by 27.3%,and the frost rate decreases by 32.4%.