Hybrid Solar Thermal Energy System for District Heating Application





Solar Thermal, Hybrid Systems, Thermal Energy Storage, District Heating


Solar district heating (SDH) systems can be good alternatives to conventional systems when they are optimized with hybrid configurations and thermal energy storage (TES). In this scope, a hybrid renewable thermal energy system (RTES) model has been built combining flat plate collector (FPC) solar system with parabolic trough collector (PTC) system via a heat exchanger and coupled with TES. To undertake the hybridization of the system, System Advisor Model (SAM) software was modified, which allowed control over configurations and more accurate modelling of heat transfer between the collectors. The model is first compared to an existing hybrid solar district heating systems (DHS) system in Taars, Denmark. The results showed a good correlation with an overestimation of only 6.4% compared to most recent heat output. Then the same system configuration was modeled in different geographic locations to investigate the impact of changes in direct normal irradiance (DNI) to the heat sink thermal output of the hybrid system. The results showed that the annual net thermal power output in California, USA can be three times more than the annual net thermal power output in Taars, Denmark. Finally, multiple hybrid configurations with varying solar field sizes were simulated based on the heat demand of two different university campuses DHS. The results showed that, retrofit applications of this hybrid DHS system coupled with TES could reduce the natural gas consumption of the existing systems between 25% and 41%. The use of hybrid RTES highlighted in this paper can be extended to many more opportunities.


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Meliß and F. Späte, “The solar heating system with seasonal storage at the Solar-Campus Jülich,” Solar Energy, vol. 69, no. 6, pp. 525–533, Jan. 2000. https://doi.org/10.1016/S0038-092X(00)00116-X

J. Formhals, F. Feike, H. Hemmatabady, B. Welsch, and I. Sass, “Strategies for a transition towards a solar district heating grid with integrated seasonal geothermal energy storage,” Energy, vol. 228, p. 120662, Aug. 2021. https://doi.org/10.1016/j.energy.2021.120662

S. Furbo, J. Fan, B. Perers, W. Kong, D. Trier, and N. From, “Testing, Development and Demonstration of Large Scale Solar District Heating Systems,” Energy Procedia, vol. 70, pp. 568–573, May 2015. https://doi.org/10.1016/j.egypro.2015.02.162

N. J. Blair, N. A. DiOrio, J. M. Freeman, P. Gilman, S. Janzou, T. W. Neises, and M. J. Wagner, “System Advisor Model (SAM) General Description (Version 2017.9.5),” NREL/TP--6A20-70414, 1440404, May 2018. https://www.nrel.gov/docs/fy18osti/70414.pdf

Z. Tian, B. Perers, S. Furbo, and J. Fan, “Annual measured and simulated thermal performance analysis of a hybrid solar district heating plant with flat plate collectors and parabolic trough collectors in series,” Applied Energy, vol. 205, no. C, pp. 417–427, 2017.

NREL, “Download - System Advisor Model (SAM),” 2021. [Online]. Available: https://sam.nrel.gov/download.html. [Accessed: 04-Dec-2021]. https://doi.org/10.1016/j.apenergy.2017.07.139

K. F. Beckers, H. Pauling, A. Kolker, A. J. Hawkins, S. M. Beyers, J. O. Gustafson, T. E. Jordan, P. M. Fulton, and J. W. Tester, “Geothermal Deep Direct-Use for Low-Carbon Heating: A Case Study at Cornell University,” in GRC Proceedings 2021, San Diego, California, USA, 2021. https://publications.mygeoenergynow.org/grc/1034388.pdf

C. R. Galantino, S. Beyers, C. Lindsay Anderson, and J. W. Tester, “Optimizing Cornell’s future geothermal district heating performance through systems engineering and simulation,” Energy and Buildings, vol. 230, p. 110529, Jan. 2021. https://doi.org/10.1016/j.enbuild.2020.110529

J. O. Gustafson, J. D. Smith, S. M. Beyers, J. A. A. Aswad, T. E. Jordan, J. W. Tester, and T. M. Khan, “Risk Reduction in Geothermal Deep Direct-Use Development for District Heating: A Cornell University Case Study,” in PROCEEDINGS, Stanford University, Stanford, California, 2019, vol. 44, p. 23. https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2019/Gustafson.pdf

UC Davis, “UC Davis AggieData,” 2021. [Online]. Available: https://aggiedata.ucdavis.edu/#all. [Accessed: 17-Aug-2022].

C. Chung, “Central Heating & Cooling Plant,” Facilities Management, 16-May-2019. [Online]. Available: https://facilities.ucdavis.edu/utilities/chcp. [Accessed: 17-Aug-2022].

M. Bhadury, “Wattson Explores the Campus Heating System,” Facilities Management, 04-May-2021. [Online]. Available: https://facilities.ucdavis.edu/news/central-heating-and-cooling-plant-part-1. [Accessed: 17-Aug-2022].

NSRDB, “NSRDB Solar Radiation Data Viewer,” 2022. [Online]. Available: https://maps.nrel.gov/nsrdb. [Accessed: 09-Aug-2022].

IRENA, “Renewable Power Generation Costs in 2020,” International Renewable Energy Agency, Abu Dhabi, United Arab Emirates, ISBN 978-92-9260-348-9, Jul. 2021.




How to Cite

Akar, S., Kurup, P., Boyd, M., & McMillan, C. (2024). Hybrid Solar Thermal Energy System for District Heating Application . SolarPACES Conference Proceedings, 1. https://doi.org/10.52825/solarpaces.v1i.671

Conference Proceedings Volume


Analysis and Simulation of CSP and Hybridized Systems

Funding data