Garlic dehydration inside heat exchanger-evacuated tube assisted drying system

Food is one of the essential requirements of living beings for their existence. With the increase in population, the food requirement also increases. Garlic dehydration Produced food needs to be conserved by reducing the various post-harvest losses to meet the food requirement. Solar dryers are the setup to harness solar energy for drying crops or grains or other nonagricultural products. Edible items (fruits, vegetables, cereals, etc.) are mostly spoiled due to their high moisture content. Effective method to preserve the crop from being deteriorated is drying them up to a safe moisture level.During drying, the moisture level at which the crop is considered safe for storage with a minimum loss in its nutritious qualities is termed as a safe moisture level.

Dried agricultural produces had various advantages like better quality,low after harvest losses, and longer storage time.Color of food products plays a notable role in quality aspect and it is also an index of the integral best quality of the product. Color index was observed using the hunter colorimeter. Color data of dehydrated garlic in HGSD of Lo,ao, and bo significance are 60.42, − 0.95, and 11.54. The retention of yellowish color in HGSD is about 20% which is superior to the OSD,which looks to be a great advantage of solar dehydrating.

Lamnatou et al. integrated an evacuated tube air heating collector and evaluated the thermodynamic performance of the system. Experiments conducted on drying apples, carrots, and apricots showed that the temperature levels suitable for drying agricultural products are achieved through warm outlet air from the collector without preheating (Lamnatou et al., 2012). Solar vacuum tubes were used to heat the stream of ambient air to a higher temperature by Mahesh et al. Setup was tested to dry different fruit and vegetable samples. Open sun drying takes almost 1.5 times compared to vacuum tube type dryer used a double function heat pipe evacuated tube solar drying system and produced hot air at 45.5 ◦C.

Heat exchanger evacuated tube assisted drying system (HE-ETADS) was analyzed in terms of drying parameters such as DR, SC, and SD efficiency for a sample. Performance investigation was done at various water flow rate i.e. 10 L/h, 20 L/h, and 30 L/h throughout the sunlight periods between 09:00 h to 18:00 h. Ambient and operating parameters such as air and drying cabin temperature, RH, and solar isolation were recorded throughout the experiment. Better performance of drying system (SD) was enhanced at 30 L/h water flow rate was observed throughout the experimentation. Findings of the present research are better and within acceptable range with previous research’s outcomes.

Maximum drying air temperature was recorded as 79.50 ◦C during maximum solar intensity (1290 W/m2). Temperature seems to reduce because it is proportional to the solar intensity. As the solar intensity reduces, temperature also reduces. Required MC for safe storage of dehydrated garlic was attained in 9 h. Maximum DR of the sample was achieved 1.48 kgH2O/kg dry solid/h at 30 L/h water flow rate. Its value reduced with increasing drying period.