Experimental Study of a Thermal Storage Technique with Phase Change Material Closure for Solar-Biogas Hybrid Fermentation System

It is a key energy policy in China that developing biogas technology is to crack energy short problem in its rural areas. A pilot water thermal storage tank with phase change material insulation closure was developed to collect the daily solar energy for satisfying the heat loading required by biogas fermentation tank which should keep at about 35°C optimum efficient fermentation temperature in each winter day. The thermal performance of the water thermal storage tank was investigated under the different typical local winter air temperatures of 10°C, 5°C and 0°C. Both the numerical and experimental data demonstrate that the phase change material paraffin layer improves the thermal storage time of the tank effectively. This suggests that the proposed water thermal storage tank with phase change material insulation closure could be a promising heat storage device utilized towards solar-biogas hybrid system in rural regions of the middle and lower reaches of Yangtze river.