Vol. 7, Issue 3, Part B (2025)

Heat pump dryers and traditional tray dryers were used in experiments to dry guava slices from an initial moisture content of 84.73% (w.b.) to 18-25% (w.b.) at temperatures of 40 °C, 45 °C, and 50 °C, with an airflow rate of 0.46 m/s. The guava's moisture content decreased exponentially with drying time, and higher temperatures led to faster drying rates. Guava slices are mainly dried during the falling-rate period. Energy consumption was 16%, 21%, and 14% lower in heat pump dryers compared to tray dryers at 40 °C, 45 °C, and 50 °C, respectively. Drying behaviour was best described by the Page model, with a higher R² value at 50 °C for the heat pump dryer. Heat pump dryers were more effective at lower drying temperatures and humidity levels, offering a faster drying rate and better-quality retention than tray dryers while using less energy. In summary, heat pump dryers are a more efficient option for guava drying because they preserve quality and conserve energy compared to conventional tray dryers.