| With the continuous improvement of social economic level and people ’ s quality of life,the proportion of building energy consumption in the total energy consumption of society is increasing year by year,so it is of great significance to use renewable energy and new energy-saving technologies to reduce building energy consumption.In this research,the dual-effect lithium bromide absorption heat pump is coupled with the parabolic trough solar collector for both cooling and heating,and a solar driven absorption heat pump cooling and heating system is proposed to meet the cooling and heating of building while increasing the proportion of renewable energy in building energy structure and reducing the fossil fuel use and pollutant emissions.The optimization design of the system was carried out.First of all,De ST,a building energy consumption simulation software was used to simulate the the annual hourly cooling and heating load for a five-storey building in Nanjing.The load characteristics were compared and analysed,providing the load data basis for the subsequent optimization of the solar-based cooling and heating system.Secondly,the integration principle,structural composition and operation mode of the solar-based cooling and heating system were analysed.The mathematical model of the system was established in MATLAB software,and the NSGA-II was used to optimize the configuration of the system in terms of energy use,environmental impact and economic efficiency using the fossil fuel saving rate,carbon reduction rate and annual cost saving rate as the optimization objectives.The results of the multi-objective optimization were analyzed.Compared to the reference system,the fossil fuel saving rate,carbon reduction rate and annual cost saving rate of the solar-based cooling and heating system can reach 71.46%,68.36% and 13.52% respectively,with better energy,environmental and economic performance.Thirdly,the relatively optimal capacity configuration was selected in the pareto front using the TOPSIS decision-making method on the basis of multi-objective optimization.The performance of its corresponding solar-based cooling and heating system was analysed,and the operating characteristics of the system on typical days during the cooling and heating seasons were investigated.The results show that the solar-based cooling and heating system corresponding to the optimal solution has the fossil fuel saving rate of 70.72%,the carbon reduction rate of 67.53% and the annual cost saving rate of 9.11%.In the typical daily operation of cooling and heating season,the output of the absorption heat pump meets 80.29%and 64.50% of the building energy demand,respectively.The water storage tank reduces the waste heat and the output of the solar-based cooling and heating system is highly matched with the building energy demand.Finally,the sensitivity analysis of the solar-based cooling and heating system was carried out.The results show that the system is more sensitive to the fluctuation of grid electricity price,with an average increase in the annual cost saving rate of 1.55% for every 10% increase in electricity price and an average increase in the annual cost saving rate of 1.41% for every10% increase in natural gas price.When the renewable energy penetration increases by 10 %,the fossil fuel saving rate and carbon emission reduction rate increase by 1.94 % and 1.70 %on average,while the annual cost saving rate decreases by 0.39 % on average.Compared to the office building,the fossil fuel saving rate of the solar-based cooling and heating system in shopping mall is lower by 1.01%,the carbon reduction rate is increased by 0.67%,and the annual cost saving rate is increased by 13.39%.On the premise of meeting energy demand,solar-based cooling and heating system can produce energy,environmental and economic benefits,and the coupling performance is better in commercial building. |
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