Potential analysis for solar photovoltaic-Thermal (PVT) systems in educational institutions
| dc.contributor.author | Khoete, Lineo Grace | |
| dc.contributor.supervisor | Thamae, Leboli Zak | |
| dc.date.accessioned | 2026-06-17T10:03:34Z | |
| dc.date.available | 2026-06-17T10:03:34Z | |
| dc.date.issued | 2025 | |
| dc.description.abstract | Educational institutions in Lesotho, such as the National University of Lesotho (NUL), face challenges related to energy reliability and the increasing cost of grid electricity. These issues highlight the need for more resilient, sustainable and cost-effective energy alternatives. Solar photovoltaic (PV) systems are used for electricity generation and solar thermal systems for heating purposes. However, the combination of these two technologies into a single photovoltaic-thermal (PVT) system remains largely unexplored within the education sector. Therefore, this study investigates the potential for PVT systems to meet the energy needs of the student residences at the NUL using the POLYSUN simulation software. The PVT system was designed to provide 5,000 litres of hot water daily at a target temperature of 50 °C for one case study residence, and its performance was compared against a corresponding solar water heating (SWH) system. The PVT system design utilised a collector area of 75 m², whereas the SWH system employed 50 m². A comparative assessment is carried out to analyse the systems in terms of technical performance, cost-effectiveness and environmental impact. Simulation results indicate that the PVT system achieves a solar fraction of 88% and generates 46,398 kWh of thermal energy annually. Further, the PVT system produces an additional 23,773 kWh of electricity each year, with 20,818 kWh to be used directly on-site. This results in energy savings of 72,615 kWh. It also attains a performance factor of 4.5 and an overall efficiency of 40%, comprising 26.7% thermal and 14% electrical efficiency. Environmentally, the PVT system significantly reduces carbon emissions, saving 38,951 kg of CO₂ annually (26,199 kg from thermal production and 12,752 kg from electricity generation). From an economic perspective, the PVT system requires an initial investment of M1,425,000.00, which can be financed through 60% equity and 40% debt. However, this higher upfront cost is offset by improved financial performance over time. The PVT system achieves a levelized cost of energy of M1.62/kWh, a net present value of M1,546,935.60 and an internal rate of return of 17.7%. It also delivers an impressive return on the investment of 8.7% per year, a payback period of 9 years and annual energy cost savings estimated at M170,129.68. Therefore, the PVT system has the potential to meet the hot water demand and a portion of the electricity demand in educational institutions. To support broader adoption within Lesotho’s education sector, targeted policies, such as subsidies, incentives and accessible financing mechanisms, will be essential to offset the high initial costs. | |
| dc.description.sponsorship | National Manpower Development Secretariat | |
| dc.identifier.uri | https://hdl.handle.net/20.500.14155/2359 | |
| dc.language.iso | en | |
| dc.publisher | National University of Lesotho | |
| dc.title | Potential analysis for solar photovoltaic-Thermal (PVT) systems in educational institutions | |
| dc.title.alternative | NUL case study |