Cost analysis of effective drying of onions using hybrid solar drying solution

Abstract

The utilization of staple food items such as onions, whether fresh or dehydrated, is influenced by various factors beyond just their price point. Nowadays, the feasibility of obtaining dehydrated onions at a reasonable cost has become plausible, thanks to the emergence of new, sustainable solar drying technologies. This research focused on onion dehydration utilizing the Solar Conduction Dryer and its variations. Through this drying process, the initial moisture content of 86% was reduced to 7%, resulting in the extraction of 84.95 kg of water from 100 kg of fresh onions to attain the desired moisture level. Economic evaluations were conducted, considering parameters such as life cycle cost, capital investment, variable expenses, internal rate of return, and payback period, among others. The findings revealed that daily savings for onion dehydration using conduction dryers were $41.61, $42.87, and $35.16 for the Solar Conduction Dryer (SCD), Corrugated Solar Conduction Dryer (CSCD), and Corrugated Solar Conduction Dryer with Electric Backup (CESCD), respectively. The capital costs and dryer efficiencies for SCD, CSCD, and CESCD were as follows: $6015 and 50.62%; $3760 and 84.37%; and $5640 and 84.37%, respectively. Notably, the CSCD exhibited superior performance in terms of dryer efficiency and capital investment compared to other conduction dryers. Moreover, the utilization of solar conduction dryers facilitated an annual reduction of approximately 120 tons of CO₂ emissions, making a significant contribution towards greenhouse gas mitigation.