Study of hybrid dry cooling systems for STE plants based on latent storage

Abstract

This work focuses on the study of a hybrid cooling system for a solar thermal electricity (STE) plant composed by a latent storage module and an air-cooled condenser. In a first approach various commercial products have been studied in order to determine their feasibility as PCMs for the latent storage module. Differential scanning calorimetry (DSC), heat capacity (Cp) measurements and daily thermal cycling tests have been performed in order to determine the thermal properties of the selected PCMs and their melting/freezing behavior. Form these tests the product RT35HC has been chosen as PCM for the latent module. In order to evaluate the advantage of using a hybrid versus a conventional dry cooling system, the annual performance in terms of electricity production of a STE plant located in Ouarzazate (Morocco) has been simulated with both kinds of systems. Simulation results show that 0.31% increase in electricity could be obtained per year if a hybrid cooling system was used. However, the feasibility of this concept strongly depends on economic issues like electricity prices along the plant lifetime and both materials and equipment cost for the latent storage system.