Thermal modelling of semitransparent photovoltaic thermal and flat plate collector integrated biogas plant for slurry heating: An experimental validation

Escalating energy costs, diminishing fossil fuel reserves, increasing energy consumption, and significant environmental impacts are key aspects of the severe global energy crisis. So, a hybrid renewable energy system with improved energy efficiency and advanced energy solutions is required. In this proposed model, a floating dome biogas plant was integrated with solar panels to maximize biogas production and establish a self-sufficient system capable of functioning in severe winter conditions and generating biogas throughout the year. An analytical expression for a biogas-integrated solar module's thermal and electrical energy output has been derived as a function of design parameters and the cold climatic conditions of RGIPT, Amethi, India. Furthermore, numerical computations using MATLAB 2021b were performed to investigate the impact of the number of SPVT-M water collectors, mass flow rate, and packing factors (β) on the performance of the SPVT-M water collectors. The experiment (26 Jan to 6 Feb 2024) showed a daily slurry temperature increase of 1.2–1.4 °C, from 19 °C to 35 °C, with 3.8 kW h/m2 daily solar radiation and 14.8 °C average ambient temperature. Validation of the mathematical model showed strong model correlation (r = 0.98, e = 2.23). Biogas production rose from 3.5 kg to 13.5 kg per day after integrating solar module heating. Validating the experimental results with mathematical modelling ensures the model's utility in optimizing biogas production under specific climatic conditions, which can lead to improved system design and operation.