Comparative Study of Temperature Control in a Hybrid Solar Dryer Using Gas and Electricity as Auxiliary Energy Sources

Achieving consistent drying performance in solar drying systems, especially under unpredictable climates, requires an integrated auxiliary energy source to maintain optimal temperatures. This research conducts a comparative analysis of temperature control within a hybrid solar dryer, investigating both gas and electricity as supplemental heating options. The methodology began with building a thermal model of the hybrid dryer using Phisim. Subsequently, we applied two control strategies: a PI controller for the gas-assisted setup and a Predictive Functional Control (PFC) method for the electrically heated configuration. The results show that the hybrid solar-gas collector achieved stable temperature regulation with a response time of about 10 minutes and a slight overshoot of approximately 5%, while the heating resistor reached the set point in approximately 5 minutes without overshoot, demonstrating excellent stability. These findings offer critical insights into the efficacy of each energy source and its corresponding control approach for stable and efficient drying.