Cost-effective and sustainable heating solutions for indoor swimming pools: A comparative study and LCOH assessment of PV-heat pumps and solar thermal collectors

• A comprehensive techno-economic analysis of three swimming pool water heating system configurations. • The evaluated configurations include a flat-plate solar collector with a diesel boiler backup, an evacuated-tube collector with a diesel boiler backup, and a grid-connected photovoltaic plant combined with a heat pump. • The payback period, levelized cost of heating, and CO2 emissions are assessed. • Sensitivity analyses are conducted on key system inputs. This study presents a comprehensive technoeconomic analysis of three water heat system configurations to satisfy the heating requirements of an indoor swimming pool in Fez, Morocco. The assessed configurations included a flat-plate solar collector with a diesel boiler backup, evacuated-tube collector with a diesel boiler backup, and grid-connected photovoltaic (PV) plant combined with a heat pump. The analysis emphasizes multicriteria evaluation and sensitivity analyses as distinguishing features. The analytical results demonstrated that the configuration with a grid-connected PV plant combined with a heat pump outperformed the other configurations in terms of economic viability. This configuration exhibited a short payback period of 4.415 years, indicating a rapid return on investment. The levelized cost of heating (LCOH) for this configuration was 0.0258 $/kWh, highlighting its cost-effectiveness. However, this configuration allowed avoiding CO 2 emissions up to 35.63 tons/year, which is considerably lower than solar thermal heating systems. Sensitivity analyses revealed that the coefficient of performance (COP), diesel cost, and collector/panel cost were critical factors influencing the performance and economic feasibility of the compared systems. Optimizing the COP and efficiency of heating systems, combined with lower technology costs, can significantly improve the payback period, reduce the levelized cost of heat (LCOH), and enhance CO₂ emissions mitigation. Expanding the analysis to other Moroccan cities helped identify optimal locations for solar heating systems. Errachidia emerged as the most promising site, offering the best energy, economic, and environmental performance due to its exceptional solar energy resources