Thermal modelling and experimental validation for biogas production in anaerobic digestion

The thermal model was developed to calculate the anaerobic digester's heat loss or gain. In addition, a daily comparison of the predicted and actual biogas production from the 2m3 KVIC anaerobic digester has also been completed. When compared to the slurry inside the digester (5000 kg slurry with an average of 60 J/kg per day), the heat gain/loss from the biogas inside the gas holder was found to be very low (1.5 kg biogas with an average of 400 J/kg per day). On the other hand, the average heat energy retained in biogas was 154.69 and 465.49 J/kg, while the minimum and maximum average solar radiations were 37.23 and 216.36 W/m2, respectively. The developed model's validation was assessed using RMSE and RRMSE. The RMSE and RRMSE values were found to be 0.105 m3/day and 7.96 %, respectively, confirming a good correlation between the predicted and measured values.