Research On Solar-air Source Heat Pump Heating System Based On Municipal Heating Network Supplemen

In recent years,China’s urbanization and residents’ living standards have continued to improve,and the demand for heating has developed rapidly.However,the development of heat sources cannot meet the needs of heating development.Due to the implementation of national energy-saving and emission reduction policies,traditional heat source development is restricted,and finding new clean energy heat sources has become an urgent problem.Solar energy has become the choice of many people due to its significant environmental advantages and widespread distribution.However,the heat collection of solar energy is affected by many factors such as season,daylight time,and weather conditions,and the stability of heating is poor.Auxiliary heat sources need to be set up to ensure the continuity of heating.As a clean energy heating equipment with simple installation and small floor space,air source heat pumps have been widely used in building energy conservation.However,the decrease in heating performance and frosting phenomenon of air source heat pumps under low temperature conditions in cold regions have become the main factors restricting their use.As of the end of 2020,the length of urban centralized heating pipelines in China has reached461,493 kilometers,and there are abundant waste heat resources.For some communities that can only use solar energy and air source heat pumps for heating due to the difficulty of expanding the municipal heating network,introducing surrounding available municipal heating network return water waste heat as defrosting heat sources in winter plays an important role in improving the reliability of solar energy-air source heat pump heating,expanding the supply and return water temperature difference of the municipal heating network,and improving the energy utilization rate of low-grade heat in thermal power plants.Therefore,this article proposes a new type of solar energy-air source heat pump heating system that can utilize municipal heating network return water waste heat,and studies its operating characteristics through the establishment of a heating system simulation model,providing a theoretical basis for the application and promotion of the system.Firstly,a certain office building in Zhengzhou was taken as the research object,and hourly energy consumption analysis was carried out on the building model to study the dynamic load variation during the heating season.Based on this,equipment preliminary selection for the simulation system was conducted according to relevant specifications.A new heating system simulation model was constructed and combined with optimization software.Using an algorithm with the cost year value as the optimization objective,parameters such as the collector area and storage tank volume of the new system were optimized.Finally,frost characteristics of the meteorological parameters in Zhengzhou were analyzed to study the overall impact of using district heating to suppress air source heat pump frost during the frost period.The results showed that compared to the equipment pre-selection based on relevant specifications,the heating system optimized using software for the solar collector area,the volume of the thermal storage tank,the installation angle,and the flow rate of the collector pump had a solar collector area increased from 373m2 to 560m2,the thermal storage tank unit volume decreased from 100L/m3 to 75L/m3,and the optimal tilt and azimuth angles for solar collectors in the Zhengzhou area were 55.1° and 18.5°,respectively.The solar guarantee rate increased from 20.28% to 30.24%,and the heating system’s Seasonal Coefficient of Performance(SCOP)increased by 13.7%,with an 11.8% decrease in energy consumption.The study also obtained the optimal values for the solar collector area and the thermal storage tank volume under different loads in the Zhengzhou area.The study of the frost formation period of the air-source heat pump in the Zhengzhou area showed that the frost formation period during the heating season accounted for about one-third of the total heating season duration.By analyzing the system’s operating state changes when using the municipal heating network’s return water waste heat to supplement the air-source heat pump during the frost formation period,it was found that after adding the supplementary heating device,the system’s energy consumption decreased by 7.8%,and the system’s SCOP increased by 8.5%.