| In order to achieve the "dual carbon" goal,rural "coal replacement" is in full swing.The solar energy resources in China are abundant,solar heating technology is mature,the economy is better,but there is a problem of instability in solar heating.The air source heat pump is energy-saving and environmentally friendly and is not limited by geography,but it has the problem of high operating costs in cold areas.In order to improve the stability of solar collector heating and greatly reduce the cost of air source heat pump heating,this paper puts forward the concept of air source heat pump auxiliary solar vacuum tube collector and maximum utilization of solar heating.and builds a Solar collector-air source heat pump system is builted in weiling township green village of Qilihe District,Lanzhou City,Gansu Province.The performance of the system under four typical working conditions,namely high ambient temperature,sunny,overcast and cloudy is studied experimentally.TRNSYS software is used to simulate the performance of the system throughout the heating season.Then evaluate the economy,energy saving and environmental protection of the system.The main results of the study are as follows:(1)Under the four typical working conditions of high ambient temperature,sunny,cloudy and cloudy,the effective heat gain of the collector is 92.7 k W·h,75.5 k W·h,4.1 k W·h,49.2 k W·h.The collector efficiency is 67.8%,61.3%,26.5%,55.2%.The average COP of the solar heat pump is 3.6,3.6,3.4 and 3.6,respectively.The average COP(coefficient of performance)of the air source heat pump is 0,0,2.9 and 3.1.The system heat supply is 99.2k W·h,113.4 k W·h,125.9 k W·h,124.8 k W·h.The system power consumption is 22.8 k W·h,33.4 k W·h,50.5 k W·h,42.7 k W·h.the system solar guarantee rate is 93.4%,66.6%,3.3%,and 39.4%,respectively.The system energy efficiency ratio is 4.4,3.4,2.5 and 2.9respectively.(2)The system is modeled on the basis of experiments to obtain the performance of the entire heating season,the effective solar energy heat is 6479.3 k W·h,the system heating capacity is 16529.5 k W·h,and the system energy consumption is 5618.4 k W·h.Average daily solar vacuum tube collector sets the maximum thermal efficiency is 65.1%,the average is around 38.7%.Solar energy heat pump units,the average maximum COP value can reach 4.0,with a mean of 3.5.The average daily air source heat pump COP maximum up to 3.9,with a mean of 3.2.The highest daily solar guarantee rate in the heating season is 100%,the average value is 44.9%.The maximum system energy efficiency ratio is 4.9,the average value is 2.9.The solar direct supply mode accounts for 17.2% of the total heating season,the solar heat pump heating mode accounts for 43.7%,and the air source heat pump heating mode accounts for 39.1%,and the system uses solar energy for a long time,which greatly saves electricity consumption.(3)Compared with air source heat pump and solar vacuum tube collector-electric heating system the cost of heating season operating of solar vacuum tube collector-air source is 2,809 RMB,which is 32.0%,56.9% saving than the simple air source heat pump and solar vacuum tube collector-electric heating.The primary energy saving rate is 64.2%,16.8% and47.4% higher,respectively.The system energy efficiency ratio is 2.9,which is 0.9 and 1.6higher,respectively.The carbon dioxide emission reduction is 10597.5 kg.The emission reduction of sulfur dioxide and dust is 87.5 kg.The emission reduction is 36.8% and 284.4%higher,respectively.In this paper,the construction and performance of a solar vacuum tube collector-air source heat pump heating system is studied according to the climatic characteristics of cold regions,with solar energy as the main heat source and air energy as the auxiliary heat source to solve the problems of unstable solar heating alone and high operating costs of air source heat pumps alone.The research results demonstrate the feasibility of the solar vacuum tube collector-air source heat pump system for heating in cold regions. |
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