Immiscible-Fluid Heat-of-Fusion Energy-Storage System. Final Report, June 1, 1976-May 31, 1979

摘要

Research aimed at evaluating the technical feasibility of a heat storage system using the latent heat of fusion of salt hydrates is described. The initial stages of this research involved: identification and bench scale evaluation of feasible salt hydrates; crystal growth studies on the selected salts; identification and screening of immiscible heat transfer fluids; and heat transfer rate and system geometry study. Based on these studies a demonstration unit of 55 gal capacity was designed and built. This final phase of the research sought to identify operational difficulties that might exist in a full scale unit, and determine whether any degradation in the phase change material was observable over an extended period of operation. Based on the bench scale studies, disodium phosphate was selected as the storage material for this study, and Exxon Marcol 72 was chosen as the heat transfer fluid. The design, operation and performance of the storage tank and prototype system are described. The disodium phosphate storage solution showed no signs of degradation during the course of a one month extended cycling run. The average thermal cooling efficiency was 72.0%. Based on the observed behaviour of the pilot system, recommendations for alteration of the system configuration to counteract the salt deposition problem have been made. It is concluded that no technical problems exist to preclude application of the direct contact-phase change thermal energy storage system.