Research On Solar-Air Energy Coupling System For Nearly Zero Energy Public Building In Qinghai Regions

It is a focus for people to make full use of renewable energy resources and reduce carbon emissions,due to the increasingly prominent energy and environmental issues.There is the energy consumption structure dominated by fossil fuels and the climatic conditions characterized by high altitude,long heating cycle,and low oxygen content in Qinghai regions,which has led to a large building heating demand and carbon emissions.However,there are long sunshine hours,high solar irradiance,and abundant solar resources in Qinghai regions.Therefore,it is of practical significance for buildings in Qinghai alpine regions to make full use of solar energy resources and reduce carbon emissions.The climatic characteristics of Qinghai alpine regions are considered in this article.Research on a solar-air energy coupling heating system is carried out,based on a nearly zero energy public building.Simultaneously,the operating characteristics and benefits of the system are evaluated.First,the structure and basic theories of solar-air energy coupling heating system are analyzed.The structures and operation strategies of the system,the mathematical models of the simulation module,and the selection methods of the main equipment models are studied theoretically.The design building model,the benchmark building model,and the dynamic simulation model of the solar-air energy coupling heating system are established respectively,based on the basic theoretical of the system.Then,a field test is conducted based on a nearly zero energy public building.The test results show that,during the heating period on 24th and 25th,the average of temperature test data can reach 20°C,the air change rate is 0.58 h^-1.Simultaneously,the field test data and simulated data of temperature are used to verify the reliability of the dynamic simulation model of the solar-air energy coupling heating system.Results show that the mean absolute percentage error between the field test data and the simulated data of heating temperature,supply water temperature,and return water temperature is less than 14%.In addition,the operating characteristics of the solar-air energy coupling heating system are analyzed from the aspects of temperature,heat supply,and energy consumption of the heating season.Results show that,during the heating period of the whole heating season,the average heating temperature is21.38°C,the average COP of the air source heat source system is 3.35.Finally,the application of solar-air energy coupling heating system in a nearly zero energy public building is evaluated from four aspects:technical benefits,energy-saving benefits,economic benefits,and environmental benefits.The results show that the comprehensive energy price is 0.056 yuan/MJ,which is lower than the local electricity price.The collection efficiency of the system is 58.5%,the average solar fraction is 75.1%.Therefore,the comprehensive performance of the system can be judged to be level II（the highest level is level I）.In addition,the standard coal that can be saved by the coupling heating system is 2038.81 kg.Among them,the emission reductions of CO2,SO2,and dust are 5035.87 kg,40.78 kg,and 20.39 kg,respectively.