A new system design and analysis of a solar bio-digester unit

Mesophilic Anaerobic digestion is, by far, the most used bio-digestion technique worldwide. The coupling of renewable energy sources with such a system is of a great importance for the Challenge of transitioning to the world's 100% clean energy. The aim of this paper is to introduce a new conception of a solar anaerobic digestion unit treatment production to achieve energy self-sufficiency, by developing a dynamic thermal model for predicting and analyzing the solar anaerobic digestion unit treatment performance, as a function of climatic conditions (ambient temperature, solar irradiation, rain intensity, flow rate effluent, subtract type, (...)). For this purpose, a modeling simulation for an Up-flow Anaerobic Sludge Blanket (UASB) digester coupled with a new conception and design solar thermal system have been developed and manipulated under TRNSYS platform. The results of the platform developed allowed identifying phenomena leading to major energy consummation from the solar digester unit and technical solutions were recommended to maximize its efficiency and reduce heat losses in an anaerobic digestion treatment process. The present model constitutes a powerful predictive tool for assisting engineers in determining the optimal design of solar heating systems and digesters, as well as in the investigation of the influence of climate-weather type on the reactor heating requirements. The energy analysis results of the solar-UASB digester unit, concludes that the power demand of the current solar digester treatment unit is around 1.2 kW and 3 kW for summer and winter season respectively. Further, the current development platform allows saving 100% of energy consumption for almost ten months per year and 70% for two cold months per year. Also, the results indicated that with the current strategy heating process the solar fraction reaches 85% for all year. The thermal efficiency of the solar collector was computed and found to be about 69% according to the EN12975 standard. The solar treatment unit that can treat a quantity of 65 liters of waste of paper carton recycled per day for 60 liters UASB digester volume. The dynamic thermal analysis of our system shows a fluctuation interval of +/- 1 degrees C for winter and an interval of +/- 0.3 degrees C for summer which indicates that the mesophilic condition is very respectful and suitable.