Modeling and optimization of integrated earth air heat exchanger and direct evaporative cooling system using ANN and RSM approaches for preserving fruits and vegetables

Abstract

Conventional air‐conditioned storage systems are more energy intensive which requires a consistent supply of electricity. Apart from this, it is costly and not suitable in remote areas where electricity is almost inaccessible. Therefore, the present study aimed to test the performance and feasibility of an integrated earth air heat exchanger and direct evaporative cooling system for storage of fruits and vegetables. The effects of air velocity (4–6 m/s), water flow rate (0.032–0.096 kg/s), and thickness of the cooling pad (50–150 mm) with corresponding responses were investigated in order to develop response surface methodology (RSM) and artificial neural network (ANN) models and compared them to predict temperature drop and humidity rise. Using RSM model, the optimum values for maximum temperature drop (16.80°C) and humidity rise (70.85%) within a range of input variables were found to be 4 m/s air velocity, 0.065 kg/s water flow rate, and 150 mm thickness of the cooling pad. For predicting the temperature drop and humidity rise, the higher (0.992 and 0.998) lower MAE (0.045 and 0.064), RMSE (0.187 and 0.266), and values (0.028 and 0.001) were observed in the ANN model. The developed ANN model was better than RSM models, and the model prediction was in good agreement with experiment values within the range of ±5% uncertainty. The results of this study indicate that the proposed cooling system can be successfully applied to store horticultural commodities.Practical ApplicationIntroduced hybrid cooling technique is low‐cost and eco‐friendly, and can be commercially used for on‐farm storage of fruits and vegetables to enhance their shelf life. The system is helpful for smallholder farmers/retailers to maintain the quality of the commodity during storage, minimize post‐harvest losses, and fetch good market value for the commodity.

Development and evaluation of earth air heat exchanger cum evaporative cool system as an energy‐efficient method for storage of tomatoes

“…12 Cold refrigerated, controlled atmospheric storage (CAS), modified atmospheric storage (MAS), hypobaric, and other modern storage techniques are also used in developed countries to store fresh tomatoes. 10,13 However, in developing countries like India it is not easy to afford these energy-intensive facilities (except evaporative cooling), which require substantial installation and maintenance costs at each stage of the supply chain. 14 Moreover, they are not feasible for on-farm storage where there is no electricity grid, especially in remote or rural locations.…”