Performance analysis of thin layer drying of okra (abelmoschus esculentus)

Studies on the thin layer drying kinetics of okra (Abelmoschus esculentus) in passive and active methods with open, heat pump dry, and greenhouse dry using various film materials, including UV Polyethylene sheet and drip lock film, have been conducted. Food products are dried to lower their moisture content, increase shelf life, and decrease post-harvest waste. In total, it took 16 hours for the okra to dry under open sun drying (OSD), 14 hours in an UV poly-ethylene sheet greenhouse dryer operating in passive method (UVPM), 13 hours in a drip lock sheet greenhouse dryer operating in passive method (DLPM), and 12 hours in an UV polyethylene sheet greenhouse dryer operating in active mode. HPD achieved the highest dryer efficiency of 38.78% whereas Drip Lock Sheet Active Mode (DLAM) greenhouse drying had the lowest efficiency of 14.15%. When drying okra, HPD produced a lower effective moisture diffusivity of 1.04 x 10−10 m2/s compared to other modes, which produced a higher effective moisture diffusivity of 2.09 x 10−10 m2/s. The Heat Pump dryer (HPD) exhibited a higher Specific Moisture Extraction Rate (SMER) of 2.60 kg/kWh when compared to conventional drying methods. It was discovered that HPD dried materials more quickly than greenhouse drying, yet greenhouse drying is more economical from an economic standpoint.