Research On Regional And Load Adaptability Of Solar-air Source Heat Pump Heating System Based On TRNSYS

According to data from the International Energy Agency,50% of global final energy consumption in 2018 was consumed in the form of heat energy,and heating accounted for40% of global carbon dioxide emissions.Taking only industrial and building end-use energy into account,thermal energy also consumes more than 50% of my country’s end-use energy consumption.Effective use of solar-air source heat pumps to meet heating,hot water supply and other needs will help my country achieve green development and carbon neutrality goals.The current performance evaluation and parameter optimization of solar-air source heat pump combined systems are mainly based on specific regions and specific heat loads.However,when the same system is applied to different regions and load conditions,its performance indicators and optimal values of design operating parameters will change.In order to achieve the best match between the system and the region and load,this topic based on TRNSYS software,for office buildings,conducts research on the region and load adaptability of solar-air source heat pump heating system.First,the DeST software is used to simulate and analyze the heating load of a typical office building in Beijing,Lhasa,Shenyang and Harbin,and the corresponding heat load of hot water supply is calculated.The results show that there is a large difference in heating heat load in the four regions of Beijing,Lhasa,Shenyang and Harbin,and the heating heat load in the four regions is 709.9kW,309 kW,990.9kW and 1108.1kW respectively.According to the specification,the calculated hot water supply load of the office building is 20.33 kW,and the combined hot water loads of the four district heating are 730.2kW,329.4kW,1011.2kW and1128.5kW respectively.Based on the calculation results,two load condition systems of heating only heat load and heating combined with hot water supply are designed.Secondly,the mathematical model of the main components of the solar-air source heat pump combined system is introduced,including the irradiance of the inclined plane,the heat collector,the hot water storage tank,and the air source heat pump.The mathematical model of the operation control strategy of the solar-air source heat pump combined system is analyzed,including the operation control of the solar collector side,the air source heat pump and the heating water pump.And calculate the relevant design parameters according to the specifications.Based on the TRNSYS platform,according to the mathematical model and design parameters of the main components,corresponding to the two load conditions,the simulation models of the solar-air source heat pump joint system in Beijing,Lhasa,Shenyang and Harbin were built respectively.Then,based on the TRNSYS simulation model,the operating characteristics of Beijing,Lhasa,Shenyang and Harbin under two load conditions were obtained,and the energy efficiency of the system was analyzed,including heat collection efficiency,solar energy guarantee rate,air source heat pump COP and system COP.The results show that the order of system energy efficiency from high to low is Lhasa,Beijing,Shenyang and Harbin.In the same area,the solar energy guarantee rate,air source heat pump COP and system COP under the heating load condition are higher than those of the heating combined hot water supply system,and the collector efficiency is lower than that of the heating combined hot water supply system.Finally,based on two load conditions in four regions of Beijing,Lhasa,Shenyang and Harbin,the collector area,air source heat pump rated heat capacity,hot water storage tank volume and collector area of the solar-air source heat pump combined heating system are analyzed.Four parameters of inclination angle are optimized.After optimization,the annual cost value from high to low is Harbin,Shenyang,Beijing and Lhasa;in the same area,the annual cost value under heating load conditions is lower.Under the condition of heating load,the annual cost reduction percentages of Beijing,Lhasa,Shenyang and Harbin are 21.06%,25.92%,33.68% and 26.59% respectively,and the percentage reductions under the combined heating and hot water supply load are 20.26%,20.09%,33.48% and 26.53% respectively.