Design and economic analysis of a solar thermal pre-cooling system for agro-produce cold chain in Lesotho
| dc.contributor.author | Yengane, Mpho Lucas | |
| dc.contributor.supervisor | Mpholo, M | |
| dc.contributor.supervisor | Mokeke, S | |
| dc.date.accessioned | 2026-06-15T12:31:26Z | |
| dc.date.available | 2026-06-15T12:31:26Z | |
| dc.date.issued | 2023 | |
| dc.description.abstract | The agricultural sector in Lesotho faces considerable challenges related to post-harvest losses. When fresh vegetables are exposed to field temperatures of up to 35°C, even for a short period, it can lead to compromised cold storage quality, shortening their shelf-life by 20 hours. These post-harvest losses amount to an estimated 30-40% of the harvest, exacerbating poor economic performance and poverty. Solar thermal cooling, leveraging Lesotho’s abundant solar energy resources (4.5-6.5 kWh/m2/day), holds great potential for solar-powered refrigeration. This research aims to design a solar thermal cooling system tailored to the specific needs of preserving fresh agricultural produce. Also, a comprehensive economic analysis, encompassing TRNSYS and MATLAB evaluations, is conducted to assess the system’s financial viability. The TRNSYS simulation determines optimal values for the coefficient of performance, solar fraction, collector efficiency, exergy efficiency, and primary energy savings, while the MATLAB economic analysis scrutinizes various key economic metrics, including levelized cost of energy, net present value, savings to investment ratio, and discounted pay-back period, to thoroughly evaluate the system’s performance and economic feasibility. The outcomes reveal that even at the lowest considered coefficient of performance value (0.5), the solar thermal absorption cooling system demonstrates a more cost-effective levelized cost of energy when compared to the average electricity cost for refrigeration in Lesotho. The proposed solar thermal cooling system incorporates evacuated tube collectors and an auxiliary boiler to effectively manage a cooling load of 7.318 kW, ensuring the preservation of fresh vegetables at a temperature of 6.1°C. The optimized system design entails the selection of a chiller with a coefficient of performance value of 0.8, a collector area of 12 m², and a hot storage volume of 0.2 m³. This configuration maximizes solar energy utilization, resulting in higher solar fraction values and improved energy efficiency. Remarkably, this optimized configuration yields the best values for levelized cost of energy ($0.085/kWh), net present value ($9,200), discounted pay-back period (12 years), and savings to investment ratio (achieving 1 in year 13). These findings unequivocally highlight the financial feasibility and profitability of the solar thermal cooling system, positioning it as a highly promising investment option for addressing refrigeration needs in Lesotho. | |
| dc.description.sponsorship | National Manpower Development Secretariat | |
| dc.identifier.uri | https://hdl.handle.net/20.500.14155/2332 | |
| dc.language.iso | en | |
| dc.publisher | National University of Lesotho | |
| dc.title | Design and economic analysis of a solar thermal pre-cooling system for agro-produce cold chain in Lesotho |