Thermal storage improves the dispatchability and marketability of parabolic trough power plants allowing them to produce electricity on demand independent of solar collection. One such thermal storage system, a thermocline, uses a single tank containing a fluid with a thermal gradient running vertically through the tank, where hotter fluid (lower density) is at the top of the tank and colder fluid is at the base of the tank. The thermal gradient separates the two temperature potentials. A low-cost filler material provides the bulk of the thermal capacitance of the thermal storage, prevents convective mixing, and reduces the amount of fluid required. In this paper, development of a thermocline system that uses molten-nitrate salt as the heat transfer fluid is described and compared to a two-tank molten salt system. Results of isothermal and thermal cycling tests on candidate materials and salt safety tests are presented as well as results from a small pilot-scale (2.3 MWh) thermocline.
Development of a Molten-Salt Thermocline Thermal Storage System for Parabolic Trough Plants
Contributed by the Solar Energy Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF SOLAR ENERGY ENGINEERING. Manuscript received by the ASME Solar Energy Division, Nov. 2000; final revision, May 2001. Associate Editor: T. Mancini.
Pacheco, J. E., Showalter , S. K., and Kolb, W. J. (April 24, 2002). "Development of a Molten-Salt Thermocline Thermal Storage System for Parabolic Trough Plants ." ASME. J. Sol. Energy Eng. May 2002; 124(2): 153–159. https://doi.org/10.1115/1.1464123
Download citation file: