Design of low-energy consumption hybrid dryer: A case study of garlic (Allium sativum) drying process

As part of improving energy efficiency and quality of dried product, a hybrid infrared dryer was constructed by combining infrared (IF) and hot-air heating (HAD) systems and can be used to dry fruits and vegetables. This hybrid drying system is composed of hot-air drying and infrared heating system and was tested by drying garlic slices (3 mm) at 0.7 m/s using three temperatures of 40, 50, and 60 °C and infrared heating intensity of 1500, 2000, and 3000 W/m2. The Newton, Page, and Wang & Singh models were used to predict the moisture ratio (MR) and the results show that all the tested models exhibited MR prediction in garlic. The hybrid infrared dryer was efficient in energy consumption by conserving energy by 533–552% when compared with HAD drying system. Also, there was significant (p<0.05) improvement in rehydration capacity, allicin content and colour when compared with HAD and IF drying techniques. In effect, this hybrid dryer could provide a better drying alternative for industrial applications as it has the potential of saving energy and improving the quality of dried products.