Solar Thermal Energy Storage in Power Generation Using Phase Change Material with Heat Pipes and Fins to Enhance Heat Transfer

Phase change materials absorb or otherwise release heat at close to a constant temperature during its melting and solidification phases. This is a very sought after property in power generation, where a high temperature heat source is required within a narrow temperature range as heat input for the turbine. Solar tower technology provides a high temperature heat source, but unfortunately it is time dependent. A sufficient amount of this heat may be stored in a phase change storage system which can deliver dispatchable heat. In such a storage system the phase change material needs to be exposed to a sufficient heat transfer area to melt or solidify at sufficient rates. In this study this is achieved with heat pipes with metallic fins. The analysis of this design included testing an experimental module during heat absorption and heat removal cycles, as well as a numerical analysis to model the storage module. To determine the parameters for a specific phase change storage system in a high temperature solar tower application the validated numerical thermal response simulation is incorporated. Certain solar input conditions and load cases are applied to the phase change storage system model and the size and geometry of the solar thermal storage system are determined from this analysis.