Development and characterization of Eco-materials for sensible heat storage in concentrating solar power plants

Abstract

Renewable energy is anticipated to play a vital role in the future to meet the global energy demand for low carbon transition. Solar energy presents the inherent characteristic given by the nature of the resource (intermittent availability). This observation highlights the need for thermal energy storage system. This PhD thesis was more focused on thermal energy storage for concentrating solar power plant, as well as its two essential components such as heat transfer fluid, storage materials and solar field. The analysis of the thermocline storage system and parabolic trough collector performance is achieved through the development of new thermal energy storage material, Direct normal irradiance data collection and numerical approaches. An innovative alternative solution for the storage materials consisted to use sand, clay and coal bottom ash to manufacture ceramic balls for thermal energy storage. The new material can store heat at temperature up to 610 °C. The new material showed good compatibility with Jatropha Curcas oil during 2160 h of heat treatment at 210 °C. After numerical analysis the new storage system (ceramic ball and JCO) can provide a discharge efficacy up to 94% depending on the storage tank size. In addition, Jatropha curcas oil is an innovative heat transfer fluid for parabolic trough collector (PTC) which can provide an average thermal efficiency up 83% to the collector. The connection of both TES system and parabolic trough collector (PTC) shows that a mass flow rate of 2 kgs-1 is necessary to charge a TES system of 2 12ℎ>? with a collection area of 460 m2 before 3 pm under Ouagadougou and Agadez Climate condition. So, we propose, Jatropha curcas oil as heat transfer fluid (HTF) in medium-size (up to 1 12@A) PTC plants using Organic Rankine Cycle power generation unit during 24h integrating the new TES system. It is a suitable technology in any region where the maximal DNI can reach 750 W.m-2. The originality of the new composite material for thermal energy storage combines performance, materials availability at industrial scale and waste to energy approach while reducing environmental and financial impact.