| With the rapid development of society,human needs for energy are also expanding.In 2018,China’s primary energy consumption accounted for 23.6% of the total global consumption,and the proportion of fossil energy in the energy consumption structure is relatively large.On the other hand,with the rapid development of urbanization in China,the energy consumption of buildings has increased significantly.The winter heating energy consumption in northern China accounts for 30%～40% of the total local energy consumption,and consumes a lot of fossil energy.The resulting energy crisis and environmental pollution problems cannot be delayed.Therefore,the development of renewable energy and new heating technologies that use energy conservation and environmental protection have a positive effect on improving energy structure and reducing environmental pollution.Solar energy resources are clean and easy to obtain,but the instability makes it only considerable as a heating auxiliary heat source;the air source heat pump is flexible to install and has less investment,but it is greatly affected by outdoor air temperature and frosting problems,and it is difficult to ensure the extreme environmental operation effect;Source heat pumps are highly efficient and operate inexpensively,but are sensitive to changes in soil temperature and require thermal equilibrium measures for long-term operation.On this basis,this paper combines three heat utilization technologies and proposes a multi-source complementary heating system based on solar heat supplement.In this paper,the complementary heating system is designed based on the building of a living area in Luoyang.Secondly,the simulation model of the complementary heating system is constructed by using TRNSYS software,and the simulation of the different heating and stopping modes of solar heat and heat pump unit is carried out.The optimization variables were used to optimize the key variables of the system,and the principle of matching parameters was obtained.Finally,the economic and environmental benefits of the system were analyzed.The main work of the thesis is as follows:(1)The energy demand and available resources of existing buildings were analyzed,and the preliminary applicability of the complementary heating system was determined.The building load calculation model was established and the building heat load was calculated.The complementary heating system was designed and the subsystems were introduced in detail.The design flow and equipment selection optimize the optimal heat source matching scheme;the solar heat compensation and heat collection control strategy based on temperature difference and the heat pump start-stop control strategy based on the return water temperature are given.The design has certain reference significance.(2)A simulation model of the complementary heating system was built on the TRNSYS platform,and the different startup and shutdown modes of the solar heating and heat pump units were simulated and analyzed.The results show that compared with the no-compensation heat in the transition season combined heating season,the outlet water temperature of the buried pipe increased by 3.54 °C within one year,and the soil source heat pump COP and the system average coefficient of performance increased by 8.7% and 4.3%,respectively.Within five years,soil temperature,soil source heat pump COP and system average coefficient of performance were maintained at 15.07 ° C,3.82 and 2.62 respectively;the start-stop mode based on partial load rate was compared with the start of the soil source heat pump.Mode,increased by 9.9%,compared with the air source heat pump-based start-stop mode,increased by 12.3%.The rationality of solar heat supplement and heat pump start-stop mode was confirmed.(3)The optimization simulation model of the complementary heating system was built on the TRNSYS platform,and the annual cost of the system was optimized.The Genopt optimization software and the Hooke-Jeeves optimization algorithm were used to collect the diver angle of the collector,the azimuth of the collector,and the area of the collector.The four key variables of the hot water tank volume were optimized simultaneously.After optimization,the ratio of the collector area to the tank volume was stabilized at 39.7m~2/L,and the collector inclination angle was φ-6.3° at the local latitude.At 1.3°.Compared with before optimization,the accumulated power consumption of the optimized system is reduced by 8.8%,and the annual cost is reduced by 52,200 yuan.It proves that the optimized system has advantages,and the parameter matching principle can provide some guidance for the application design of such systems.(4)Based on the annual cost and pollutant discharge as the evaluation index,the optimized complementary heating system and the conventional four heating methods were compared and analyzed economically and environmentally.The results show that the complementary heating system has significant economic and environmental benefits. |
