| "Haze" has become a major social issue related to people's basic livelihood.The influence of rural winter heating on haze cannot be ignored.In 2017,the measures of "coal to gas" and "coal to electricity" were vigorously promoted in China,but they encountered bottlenecks in the implementation process.Therefore,taking measures in accordance with local conditions for rural heating has become a breakthrough to alleviate haze.Renewable energy(biomass and solar)heating technologies are developing rapidly as a key means of alleviating fossil fuel shortages and environmental pollution.Thus,this paper uses questionnaire survey,software simulation and experimental research to study the optimization of Shanxi rural heating system of renewable energy.(1)By investigating the building characteristics and heating modes in rural areas of Shanxi Province,frequency analysis of the data obtained from the questionnaire survey shows that the building envelope in rural areas has poor thermal insulation performance,high thermal consumption and poor indoor thermal environment,and most buildings are not built according to building energy-saving standards.Based on the clustering analysis and regression analysis of SPSS software,the regression equation was established to obtain that the impact factor of exterior wall and roof on energy consumption was the highest.Therefore,the energy-saving renovation should mainly strengthen the insulation performance of exterior wall and roof to improve the air tightness of buildings.(2)The rural heating system is a multi-factor system project.This paper selected evaluation indexes from a qualitative point of view for different rura l heating system solutions,and established an evaluation system model based on AHP/FCE.According to the maximum membership degree principle,the solar/biomass boiler heating system is best.(3)Combined with the technical and economic performance of different heating modes,this study was carried out the farmers financial benefits evaluation and national economic benefits evaluation for solar/biomass boiler heating system,and calculated the payback period of life cycle cost,financial net present value(FNPV)and economic internal rate of return.The results show that the proposed scheme can produce good indirect benefits,and there is still a certain policy space in the relevant incentives,which can further enhance the enthusiasm of farmers to choose solar/biomass boiler heating mode through price transfer.(4)The environmental assessment of different heating methods was performed,and the dust,SO2,and NOx emissions were calculated.The environmental benefits of gas-fired boiler are best calculated by quantitative,followed by solar/biomass boiler,air source heat pump,electric boiler and coal-fired boiler.However,natural gas is not the main resource in China,and the comprehensive use of natural gas is not the key measure to achieve atmospheric cleaning in China.Therefore,this study recommends the use of solar/biomass boiler for heating.(5)The renewable energy comprehensive utilization demonstration base was established,and winter thermal load and energy consumption of rural residential buildings were simulated using Energy Plus.Breaking the control mode of controlling the start and stop of solar energy heating system by comparing the temperature of solar collectors and the setting water temperature of heat storage tank,the automatic control strategy of solar/biomass boiler heating system with temperature compensation was designed independently to maximize the use of solar energy and realize the smooth switch between heat sources.(6)During the experiment,the heating system ensured the stable equilibrium of indoor temperature(16~18 ?)and provided users with a comfortable,clean and convenient living environment.By experimental test,the thermal efficiency of solar thermal panels-array is mainly concentrated in the range of 60%~70%.The heat storage water tank has a heat conversion factor in the range of 0.94~0.98.By simulation with Energy Plus,the heat load index per unit area is 46.86 W/m2 and cumulative heating energy consumption with 100 m2 house is 24.3 GJ during a heating season.The total annual energy demand of the solar/biomass heating system is around 35.91 GJ,with the solar energy share of 63.31% and biomass energy share of 36.69%,and their usage hours are 1935 and 1239 respectively during a heating season.The primary energy efficiency and exergy efficiency of the solar/biomass rural heating system are 67.66% and 16.17% respectively.The solar energy/biomass boiler heating system has the characteristics of high automation and comprehensive utilization of energy,which is of great significance for improving environment and alleviating energy crisis. |
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