Research On The LPG Vaporization System Based On Regenerative Solar Assisted Heat Pump

Inexhaustible and clean energy have been paid more attention due to the shortage of the normal fossil energy and the pollution of the environment.In order to reduce the energy consumption used to vaporize LPG,a regenerative LPG vaporization system utilizing direct-expansion solar assisted heat pump(named as RDX-SAHPV)has been presented.And the dynamic simulation and theoretical study of the system have been carried out.First of all,based on the domestic and foreign literatures on phase change thermal storage,the phase change material storage device of RDX-SAHPV system is designed from four aspects: phase change material,regenerative cycle,device structure and heat storage capacity.Besides,the melting/solidification model of the Fluent software has been used to simulate the thermal storage sphere with different radius.The result shows that the heat storage sphere with radius of 60 mm has a reasonable storage and release time,which is easy to process and the thermal storage shell will not occupy too much heat storage volume of the heat storage tank.In addition,by calculating the annual investment cost and annual operating cost under different heat storage capacity of the phase change heat storage unit,it is concluded that the recovery period is the lowest when the thermal storage capacity is 40 MJ.Secondly,the RDX-SAHPV system has been proposed and designed,and the working principle of the system has been introduced.The operating conditions and control strategies of the system have been analyzed and fourteen operational modes of the system have been studied in detail.The results show that the system can select the best operation mode according to the meteorological condition and the change of gas load.Finally,the dynamic simulation model of RDX-SAHPV system has been established,including DX-SAHP model,storage tank and phase-change storage tank model,gasifier model,auxiliary heat source model and the calculation model of PCM in the device.Among them,the DX-SAHP system model uses the lumped parameter method and the phase change thermal storage model uses the finite volume method.Based on the mathematical model of RDX-SAHPV system,the dynamic simulation of the system has carried out by using Matlab software.And then the annual operation condition of the system is obtained and the operating characteristics of the system are studied in depth.By analyzing the simulation results,it is concluded that the RDX-SAHPV system has a high heating performance,the lowest COP in winter can reach 2.76,the highest COP in summer can reach 3.42 and the annual average COP is 3.12.In addition,the working time of DX-SAHP in the RDX-SAHPV system is extended by 11.6%,the power consumption of DX-SAHP increases by 532 k Wh,the power consumption of the auxiliary heat source is reduced by 1694 k Wh,the annual energy savings are 1162 k Wh and power consumption reduced by 14%,which have good economic and environmental benefits.