THERMAL ENERGY STORAGE FOR PARABOLIC TROUGH SOLAR THERMAL POWER GENERATION: A REVIEW
Publication Date : 17/07/2019
The parabolic trough is the most matured solar thermal power generation technology with most commercial plants in the world utilizing this technology. A thermal storage system is required for the stable and uninterrupted operation of solar thermal plants. In this paper various thermal storage methods applicable to parabolic trough technology were reviewed in order to establish the status of thermal storage in parabolic trough plants and present researches going on to improve performance and cost effectiveness of various thermal storage methods. There are basically three methods of storing thermal energy: chemical, sensible and latent. Chemical storage is at the developmental stage and very ex-pensive. The sensible and latent heat storage methods are the most considered for parabolic trough plants. Three technologies have been researched over the years under the sensible storage methods: Concrete Tube Register (CTR), two-tank system and the single tank thermocline. The two-tank indirect system is currently the state of the art. The challenge with this technology is it is expensive due to high storage material requirement, the use of two tanks and has high parasitics. The use of single tank thermocline system offers lower cost and reduced storage material inventory. This technology has been demonstrated on small scale. The main challenge of the single tank thermocline system is thermal ratcheting. The use of Latent heat storage system offers smaller storage volume and higher efficiency. The low thermal conductivity of potential PCMs and the lack of PCMs to cover the operating temperature range have hindered the capability of producing a more cost-effective system than the two-tank system.
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