Simulation Research On The Systme Combined Solar Energy With Biogas Boiler For Heating Biogas Plants

In cold area,air temperature are very low,there are many problems about producing biogas.For example,the efficiencies of producing and using biogas are low,the serious phenomenon is that the digester fermenting is freezed.It presents a new system that heats up digester fermenting with solar energy associated with biogas boiler in accordance with these problems.The hot water produced by associated system heats up fermenting via plastic pipe at the bottom and circumambience of the digester fermenting in order to keep the digester fermenting at a best temperature: 35 degree in winter; 55 degree in summer. The dissertation gives priority to simulate, analyse and calculate the associated calefaction system under different weather condition.The dissertation validates the associated system is feasible in cold area.It presents detailedly basic theory about solar radiation,soil temperature field and the influence on generating biogas by the temperature.And it establishes the math model of heat transfer around the digester fermenting. The math model is dispersed by the use of control volume integration.Then, it presents detailedly design,analysis about the associated system.It calculates detailedly the dimension of the digester fermenting and the area of solar energy collecting system.It makes certain the system circulate situation under different weather condition.In the aspect of simulation, it makes use of FLUENT Software to simulate the temperature field of digester fermenting. On the base of simulation result, it distills the loss quantity of heat through digester fermenting and analyses the temperature field of pool bosom,heat preservation layer and the around soil. Acorrding as the analysis result, it carrys through optimizing analysis design to associated system.At last, it chooses the furthest cold month to calculate the quantity of solar radiation,quantity of heat collected by solar collecting system,the loss quantity of heat through digester fermenting. It calculates assurance ratio by solar energy in different month during the all year and validates the system dependability. Then it further validates the associated system is feasible in cold area.And this system has reference value for designing middling scale digester fermenting in cold area.