Solar Wall Hot Air System For Farmhouse In Cold Rural Region And Analysis Of Its Impact On Indoor Environment

China’s rural energy conservation work is behind the cities’, especially for cold rural areas where heating energy consumption accounts for 60% of total building energy consumption. Their traditional way of heating has low thermal efficiency and causes great pollution, resulting in harsh indoor environments. Solar energy is ideally suited to clean energy use in rural areas, but it is difficult to blend with the architectural forms while solar wall can be directly used as building facades and thus solves this problem. Aiming at indoor environmental and heating energy problems of farm houses in cold area, in order to improve indoor environment, the economic effect and the energy efficiency of heating, the solar wall hot air system is designed as an auxiliary heating device used in conjunction with kangs for farm houses in cold regions. The effect of the system, especially its impact on rural house indoor environment is studed through measurement and simulation analysis.Traditional solar wall system only heats fresh air, return air is introduced on this basis to enhance the heating capacity of the system. The new system has running modes like ful l fresh air, full return air, hybrid ventilation and shutdown. The research group completed building solar wall hot air system in Wujia Vil age, Yushu City, Jilin Province in the summer of 2014, and did running tests for the system during the entire heating period from October 2014 to April 2015, recording temperatures of various parts of the system and the environment, air speed, solar radiation, wind volume, indoor pollutant concentration and other parameters.The relationship between the intensity of solar radiation and the air temperature inside the collector chamber was analysed, the temperature rises rapidly while reduces slowly, according to which the run time of solar wall system and kang in the farm house are set; according to the calculation and analysis of air supply volume and room temperature in the coldest month, the solar wall can improve air temperature in farm room by 4~7℃, making room temperature of farm house up to standard requirements, heating power of the system is between 3.55 ~ 5.35 KW, different modes in descending order of heating capacity are full return air, hybrid ventilation and full fresh air, using regression analysis, the linear relationship between air temperature and the indoor temperature was obtained; By contrast of the inner side temperature of the south and east outer wal s, solar wal’s ability to significantly lower wall heat loss to outer environment was found; After analyzing fresh air volume and pollutant concentrationss of different modes in typical time periods, the results show that the solar wall system significantly improved indoor air quality, the full fresh air mode works with the bset ventilation effect, then in order come the hybrid ventilation and the full return air mode. When the solar wall is enabled, not only fresh air replacement volume rises from 18 m3/h to 199.84 m3/h, which meets the indoor comfort requirements, the concentration of indoor pollutants can also be reduced by up to 76.5%; Using the expanded PMV model and indoor and outdoor temperature fluctuation ratio respectively, indoor thermal comfort and thermal stability of the solar wall farm house were evaluated, PMVs predicted by theoretical calculation provide a quantitative basis for rural residents to select different operating modes and indoor dress.This paper established a mathematical model of the solar wall collector cavity and the room, the theoretical analysis of the system verified the results form measurement, and based on simulated fields of temperature, air flow rate, pollutant concentration, the impacts of the system on indoor environmental parameters like vertical and horizontal temperature differences, concentration distributions of different pollutants were analyzed, complementing the conclusions from actual measurements.