Development of a Small Dual-Chamber Solar PV-Powered Evaporative Cooling System for Fruit and Vegetable Cooling with Techno-Economic Assessment

Abstract

This study evaluates a solar PV-powered evaporative cooling system for vegetable cooling. The system features dual cooling chambers with two different biomass pads, operating at different temperatures. To assess its potential, the research examines the evolution of temperature and humidity of the cooling chamber, evaporative effectiveness, cooling capacity, coefficient of performance (COP), energy metrics, greenhouse gas emissions, and overall cost. The results show that the system achieved a temperature depression range of 0.22 to 5.2 °C and 0.57 to 10.94 °C for wood shavings and polyurethane foam, respectively, under no-load conditions, while the values were 0.79 to 4.7 °C and 1.22 to 9.88 °C, with average values of 3.09 and 7.0 °C, for the same materials under loaded conditions. Loaded conditions also yielded a cooling capacity of 5.7 to 33.93 W for wood shavings and 8.13 to 75.55 W for polyurethane foam. The cooling efficiency ranged from 19.9 to 96.42% for polyurethane foam and 3.62 to 60% for wood shavings. The system’s COP was higher than that of solar-powered mechanical chillers, ranging from 2.37 to 22.92. The energy production factor was 2.3 to 2.4, with a lifecycle conversion efficiency of 0.5 and an energy payback time of 1.1 and 2.2 years for using polyurethane foam and wood shavings, respectively. The net present value was positive, and the levelized cost of energy was low, at 36.7 to 38.3 NGN/kWh (0.043–0.045 USD/kWh), making it a viable alternative to grid-based energy systems in Nigeria. Additionally, the system offers significant CO2 mitigation potential, with estimated carbon credits of NGN 65,059 (USD 71.56) and NGN 98,576.49 (USD 108.43) over its lifetime.

Keywords

• vegetable cooling
• solar energy
• greenhouse gas mitigation
• refrigeration
• cold storage