Performance Assessment of Solar Assisted Anaerobic Digester System: Simulation and Application in Central Queensland Region

Biogas as an energy source is increasing its popularity in both small- and large-scale applications. The anaerobic digestion (AD) process requires heat to produce biogas effectively, which can be supplied via a solar system. The suitability of integration of solar thermal energy in anaerobic digestion was researched through this paper. With the help of TRNSYS software, a 0.2 m3 simulation model of the digestor reactor along with a 2m2 PV solar thermal system was built. A study was done in an atmospheric condition of Rockhampton in Central Queensland based on the thermal activity and dynamic behavior of the structure. Cow manure was used as a feedstock in the system. The simulation was run for predicting the daily average temperature within the AD of a typical month in summer and winter. The simulation was also done for predicting the biogas production in typical summer and winter months, and for all seasons in Australia. The simulated temperature was found to be the temperature of the biogas production at a mesophilic temperature of about 35°C. The result showed that the maximum predicted temperature was found to be 35.98 °C in the summertime and 35°C in wintertime. The result also showed that the maximum biogas production is 84.45L/day in summertime and 72.33 L/day in wintertime. So, the solar heating system can help increase the bio-digester temperature which contributes to the production of biogas in the AD system. Thus, the developed model can be considered as an accurate tool to predict biogas production in Central Queensland (Rockhampton) climate for solar assisted AD systems. It is expected that the simulation model can be extended to predict biogas production from solar-assisted AD systems in other climatic conditions.