Economic Analysis Of A Novel Air-Source Heat Pump Heating System With An Energy Storage Tank

With the development of society and improvement of economy,energy shortage and environmental degradation had become a problem which we cannot be ignored.Nowadays,more and more people wanted to use clean energy which was also a trend in the heating system.Heat pump developed rapidly and utilized low-level energy and pollution-free effectively.As one of the most widely used heat pump,air source heat pump had occupied a large market share in China,but it also had some problems in defrosting and high electricity cost,therefore,we had to pay more attention to these problem in the further promotion process.In this paper,we proposed a new air source heat pump system which could supply heat continuously and operate economically.It contained a compressor,an indoor side air heat exchanger,a throttling device,two outdoor side air heat exchangers,a variable frequency circulating water pump and a water tank.Under defrosting mode,the heat pump system could absorb heat from the outdoor air to defrost and supply heat.During the heating season,using different price in peak and valley,the fixed supply and returned pipe different pressure frequency conversion control could achieve lower cost,therefore,it had a strong economic prospect.In order to study the economics of new system,we built a simulative model of the heat pump system using in a small villa building which located in Xi’an.Firstly,the hourly load of this building was obtained by using Energyplus in the heating season.Then three different models were built based on the Trnsys simulation platform.During the whole heating season of the constant flow heating system,the operation,variable-flow heating system and new air-source heat pump thermal storage heating system were simulated and analyzed.Finally,the simulative results were used to calculate and compare with the economics of three scenarios,and analyzed the economic effects of the project under different subsidy conditions.The result showed that the new air source heat pump thermal storage heating system had certain economic advantages.The annual operating electricity cost was not only significantly lower than the central heating cost,but also saved 33.1% and 29.3% compared with the conventional air source heat pump fixed/variable flow heating system.And the calculation of the annual cost value is also reduced by about 8.0% and 6.8%,respectively,compared with the two conventional heat pump systems.According to the existing subsidy policy for further economic analysis of the system,the central heating cost of Xi’an was used as the standard to calculate the change of the net value and dynamic recovery period of the plan under different circumstances.The result showed that the new air source heat pump had high economic values under a small subsidy,and it could recover the investment cost faster under the current subsidy policy in many regions.The calculation results could provide designers or policy makers with some references.