Solar thermal energy represents a mature and versatile pathway for harvesting solar radiation in the form of useful heat across a wide range of temperature levels. Unlike photovoltaic-based technologies, solar thermal systems directly address thermal energy demands in residential, industrial, and power-generation sectors, which constitute a substantial share of global energy consumption. This review presents a structured overview of solar thermal technologies and their practical applications using a temperature-oriented perspective rather than a conventional collector-based classification. Solar thermal systems are categorized according to their delivered heat quality, spanning low-, medium-, and high-temperature regimes, and the functional role of different collector concepts within each regime is discussed. The review further maps these temperature ranges to key application domains, including domestic heat supply, industrial process heat, solar-driven desalination, cooling technologies, and concentrated solar power systems. In addition, critical design and integration aspects such as thermal losses, heat transfer fluids, storage compatibility, and system-level challenges are examined. By reorganizing existing knowledge around heat demand and operating temperature, this review aims to provide clear guidance for researchers, engineers, and practitioners seeking to select and integrate appropriate solar thermal solutions for specific applications.
- Open Access
- Review
Solar Thermal Technologies towards Sustainability
- Bertrand Delpech 1,*,
- Marialuisa Acquaviva 2,
- Abdulrahman Alhajeri 1,
- Amani Alajmi 3,
- Heba Ghazal 2
Author Information
Received: 04 Feb 2026 | Revised: 14 May 2026 | Accepted: 27 May 2026 | Published: 30 Jun 2026
Abstract
Keywords
solar thermal energy | thermal collectors | heat quality | industrial process heat | thermal energy storage
References
- 1.
Alexopoulos, S.; Kalogirou, S.A. Solar Thermal Energy: Introduction. In Solar Thermal Energy; Springer: New York, NY, USA, 2022.
- 2.
Ravi Kumar, K.; Krishna Chaitanya, N.V.V.; Sendhil Kumar, N. Solar Thermal Energy Technologies and Its Applications for Process Heating and Power Generation—A Review. J. Clean. Prod. 2021, 282, 125296. https://doi.org/10.1016/j.jclepro.2020.125296.
- 3.
Osorio, J.D.; Zea, S.; Rivera-Alvarez, A.; et al. Low-Temperature Solar Thermal-Power Systems for Residential Electricity Supply under Various Seasonal and Climate Conditions. Appl. Therm. Eng. 2023, 232, 120905. https://doi.org/10.1016/j.applthermaleng.2023.120905.
- 4.
Hassanzadeh, A.; Jiang, L.; Winston, R. Coupled Optical-Thermal Modeling, Design and Experimental Testing of a Novel Medium-Temperature Solar Thermal Collector with Pentagon Absorber. Sol. Energy 2018, 173, 1248–1261. https://doi.org/10.1016/j.solener.2018.08.022.
- 5.
Neve, T.; Shimizu, M.; Yugami, H. Direct Normal Irradiance Forecasting for High-Temperature Concentrated Solar Thermal systems. Renew. Energy 2025, 255, 123748. https://doi.org/10.1016/j.renene.2025.123748.
- 6.
Mortadi, M.; El Fadar, A.; Achkari, O.B. Concentrating and Non-Concentrating Photovoltaic Thermal Collectors: Technologies, Applications, Exhaustive Assessment and Challenges. Sol. Energy Mater. Sol. Cells 2024, 271, 112858. https://doi.org/10.1016/j.solmat.2024.112858.
- 7.
Vengadesan, E.; Senthil, R. A review on Recent Developments in Thermal Performance Enhancement Methods of Flat Plate Solar Air Collector. Renew. Sustain. Energy Rev. 2020, 134, 110315. https://doi.org/10.1016/j.rser.2020.110315.
- 8.
Hassan, D.A.; Daghigh, R. Enhancing Thermal Performance of Evacuated Tube Solar Collectors through Integrated Turbulators, Expanded Copper Mesh, and Hot-Cold Water Separation. Case Stud. Therm. Eng. 2025, 76, 107473. https://doi.org/10.1016/j.csite.2025.107473.
- 9.
Shamsul Azha, N.I.; Hussin, H.; Nasif, M.S.; et al. Thermal Performance Enhancement in Flat Plate Solar Collector Solar Water Heater: A Review. Processes 2020, 8, 756.
- 10.
Supankanok, R.; Sriwong, S.; Ponpo, P.; et al. Modification of a Solar Thermal Collector to Promote Heat Transfer inside an Evacuated Tube Solar Thermal Absorber. Appl. Sci. 2021, 11, 4100. https://doi.org/10.3390/app11094100.
- 11.
Kim, H.; Chinnasamy, V.; Ham, J.; et al. Parabolic trough Collectors: A Comprehensive Review of Design Innovations, Optimization Studies and Applications. Energy Convers. Manag. 2025, 327, 119534. https://doi.org/10.1016/j.enconman.2025.119534.
- 12.
Bellos, E. Progress in the Design and the Applications of Linear Fresnel Reflectors—A Critical Review. Therm. Sci. Eng. Prog. 2019, 10, 112–137. https://doi.org/10.1016/j.tsep.2019.01.014.
- 13.
Olia, H.; Torabi, M.; Bahiraei, M.; et al. Application of Nanofluids in Thermal Performance Enhancement of Parabolic Trough Solar Collector: State-of-the-Art. Appl. Sci. 2019, 9, 463. https://doi.org/10.3390/app9030463.
- 14.
Abdul-Ghafoor, Q.J.; Abed, S.H.; Kadhim, S.A.; et al. Experimental and Numerical Study of a Linear Fresnel Solar Collector Attached with Dual Axis Tracking System. Results Eng. 2024, 23, 102543. https://doi.org/10.1016/j.rineng.2024.102543.
- 15.
Kasaeian, A.; Cheraghchi, A.; Maghdouri, Z.; et al. A Comprehensive Review of Exergy Analysis of Solar Parabolic Dish Collector Systems. Energy Convers. Manag. X 2026, 29, 101462. https://doi.org/10.1016/j.ecmx.2025.101462.
- 16.
Hernández, B.; Ferber, N.L.; Abdullah, M.; et al. Central receiver-based concentrated solar power plants part 1: A historical review. Sol. Energy 2025, 299, 113693. https://doi.org/10.1016/j.solener.2025.113693.
- 17.
Liu, J.; Li, R.; Chen, Y.; et al. Topology Optimization Method of a Cavity Receiver and Built-In Net-Based Flow Channels for a Solar Parabolic Dish Collector. Entropy 2023, 25, 398. https://doi.org/10.3390/e25030398.
- 18.
Madejski, P.; Muna, I.I. Simulation and Performance Analysis of a Solar-Integrated Steam Power Cycle. Energies 2025, 18, 4938. https://doi.org/10.3390/en18184938.
- 19.
Martinopoulos, G. Domestic Hot Water Solar Thermal Systems as an Energy-Security Alternative in the EU: A Parametric Analysis. Sustain. Energy Technol. Assess. 2024, 69, 103921. https://doi.org/10.1016/j.seta.2024.103921.
- 20.
He, Z.; Farooq, A.S.; Guo, W.; et al. Optimization of the Solar Space Heating System with Thermal Energy Storage Using Data-Driven Approach. Renew. Energy 2022, 190, 764–776. https://doi.org/10.1016/j.renene.2022.03.088.
- 21.
Kong, X.; Du, X.; Xu, Z.; et al. Predicting Solar Radiation for Space Heating with Thermal Storage System Based on Temporal Convolutional Network-Attention Model. Appl. Therm. Eng. 2023, 219, 119574. https://doi.org/10.1016/j.applthermaleng.2022.119574.
- 22.
Kumar, L.; Hasanuzzaman, M.; Rahim, N.A. Global Advancement of Solar Thermal Energy Technologies for Industrial Process Heat and Its Future Prospects: A review. Energy Convers. Manag. 2019, 195, 885–908. https://doi.org/10.1016/j.enconman.2019.05.081.
- 23.
Farjana, S.H.; Huda, N.; Mahmud, M.A.P.; et al. Solar Process Heat in Industrial Systems—A Global Review. Renew. Sustain. Energy Rev. 2018, 82, 2270–2286. https://doi.org/10.1016/j.rser.2017.08.065.
- 24.
Khan, M.I.; Asfand, F.; Al-Ghamdi, S.G.; et al. Realizing the Promise of Concentrating Solar Power for Thermal Desalination: A Review of Technology Configurations and Optimizations. Renew. Sustain. Energy Rev. 2025, 208, 115022. https://doi.org/10.1016/j.rser.2024.115022.
- 25.
Huang, J.; Zheng, H.; Kong, H. Key Pathways for Efficient Solar Thermal Desalination. Energy Convers. Manag. 2024, 299, 117806. https://doi.org/10.1016/j.enconman.2023.117806.
- 26.
Ibrahim, N.I.; Yahiaoui, A.; Garkuwa, J.A.; et al. Solar Cooling with Absorption Chillers, Thermal Energy Storage, and Control Strategies: A review. J. Energy Storage 2024, 97, 112762. https://doi.org/10.1016/j.est.2024.112762.
- 27.
Imran Khan, M.; Asfand, F.; Al-Ghamdi, S.G. Progress in Research and Technological Advancements of Commercial Concentrated Solar Thermal Power Plants. Sol. Energy 2023, 249, 183–226. https://doi.org/10.1016/j.solener.2022.10.041.
- 28.
Wei, L.; Pan, Z.; Shi, X.; et al. Solar-Driven Thermochemical Conversion of H2O and CO2 into Sustainable Fuels. iScience 2023, 26, 108127. https://doi.org/10.1016/j.isci.2023.108127.
- 29.
Agrafiotis, C.; von Storch, H.; Roeb, M.; et al. Solar Thermal Reforming of Methane Feedstocks for Hydrogen and Syngas Production—A Review. Renew. Sustain. Energy Rev. 2014, 29, 656–682. https://doi.org/10.1016/j.rser.2013.08.050.
- 30.
Zhang, F.; Chen, M.; Yan, H.; et al. In Situ Oxidizing Commercial Alloy to Achieve Selective Solar Absorption with High-Temperature Stability. ACS Appl. Energy Mater. 2023, 6, 10943–10950. https://doi.org/10.1021/acsaem.3c01735.
- 31.
Chen, M.; Li, S.; Yan, H. General and Scalable Fabrication of Plasmonic Solar Selective Absorbers by Electrodeposition. Appl. Phys. Lett. 2023, 122, 063301. https://doi.org/10.1063/5.0132829.
- 32.
Benoit, H.; Spreafico, L.; Gauthier, D.; et al. Review of Heat Transfer Fluids in Tube-Receivers Used in Concentrating Solar Thermal Systems: Properties and Heat Transfer Coefficients. Renew. Sustain. Energy Rev. 2016, 55, 298–315. https://doi.org/10.1016/j.rser.2015.10.059.
- 33.
Mubarrat, M.; Mashfy, M.M.; Farhan, T.; et al. Research Advancement and Potential Prospects of Thermal Energy Storage in Concentrated Solar Power Application. Int. J. Thermofluids 2023, 20, 100431. https://doi.org/10.1016/j.ijft.2023.100431.
- 34.
Khan, M.I.; Gutiérrez-Alvarez, R.; Asfand, F.; et al. The Economics of Concentrating Solar Power (CSP): Assessing Cost Competitiveness and Deployment Potential. Renew. Sustain. Energy Rev. 2024, 200, 114551. https://doi.org/10.1016/j.rser.2024.114551.
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