Numerical Study And Analysis On The Performance Of The Series-type And Parallel-type Heating Systems Of Solar Assisted Air Source Heat Pump In Lanzhou Region

A country's energy strategy is closely related to its development and future.At present,the global energy transformation upgrades continuously,and environmental pollution problem becomes more and more serious.Against this background,General Secretary Xi proposed new requirements of speeding up the reform of the ecological civilization system and building a beautiful China in his report at the 19 th National Congress.The renewable energy,such as solar energy,wind energy,biomass energy,tidal energy,geothermal energy and so on has been applied widely,which improves the energy consumption structure dominated by coal in China.Meanwhile,heat pump is considered as a new type device of energy-saving technology to have been used widely in heating,ventilation and air-conditioning engineering filed as well.The combination of new energy and new energy-saving technology can reduce the traditional energy consumption and implement the goal of energy-saving and emission reduction and environmental protection.In view of this,by combining the technologies of solar photo-thermal conversion and heat pump and considering an office building in Lanzhou area with abundant solar energy resources as a heating plant,this paper proposes the design schemes,technological processes and the related running modes of the series-type,parallel-type and switching two-type of heating systems of solar assisted air-source heat pump(HSSAASHP).Based on TRNSYS(Transient System Simulation Program)software,the configuration,the corresponding operational situations and performance analysis of these three heating systems are carried out,respectively.The results indicate that all systems are feasible in theory.Moreover,the optimization of key parameters of the series-type of HSSAASHP is also implemented by particle swarm algorithm.The main research tasks and contents in this paper are as follows:1.Based on the proposed design schemes and technological processes of HSSAASHP,the series-type and parallel-type of HSSAASHP are set up by means of a series of modules such as collector,heat pump,water tank and controller in TRNSYS,and the simulation of the corresponding control strategies under different operation modes is carried out.The simulation results show that the two types of HSSAASHP have their own advantages in operational energy consumption and COP of heat pump for heating.2.Based on the performance analysis of the series-type and parallel-type of HSSAASHP,a switching two-type of HSSAASHP is also proposed,and theoperating conditions of this system at different switching temperatures are simulated.The results indicate that this system can effectively synthesize the advantages of the above series-type and parallel-type of HSSAASHP,which leads to the energy-saving benefits.But there exists the defects of reducing indoor comfortable degree.3.By docking data between TRNSYS and GENOPT(Generic Optimization Program),the particle swarm optimization algorithm(Particle Swarm Algorithm,PSA)with constriction factor is used to optimize some key structural parameters of serial-type HSSAASHP that has better performance in energy-saving.Thus,reducing the operating cost of this system and the comprehensive benefits of energy conservation,consumption reduction and emission reduction can be achieved.4.On the basis of the above research,considering serial-type HSSAASHP as a representative system,this paper analyzes the applicability and the corresponding benefits of energy conservation,economic and environmental for HSSAASHP in Lanzhou area,which indicates the potential application of this kind of system in this area.Meanwhile,the above research results have certain reference for the application of solar energy in the future energy transformation in northern region.