Cost Reduction by Combining Solar Thermal Technologies for a Dispatchable Steam Generation
Abstract
Compound Parabolic Concentrator’s (CPC) are usually not associated with the production of steam, as with the required high operating temperature to produce steam the thermal losses of the CPC are predominant. In this paper a system is presented to include a CPC solar field into the solar thermal generation of steam for a process heat consumer. The presented system includes a Parabolic Trough Collector (PTC) field to generate steam at 188°C/11barg. The CPC system is used to pre-heat the feed water to 95°C. This combined solar system is built by the protarget AG in Cyprus, Limassol at the premises of KEAN soft drinks Ltd. to provide heat for the orange juice production. In this paper it is shown how both technologies, the CPC system with 225m² collector gross area and the PTC system with 283m² collector gross area, are integrated in the same industrial process. The consumption of process heat at this specific application starts early in the morning with no sunshine available. Therefore, an arrangement including a Thermal Energy Storage (TES) for each of the technologies is found. The operating behaviour of both technologies contributing to the same energy consumer is presented. The innovation of combining these two technologies promises a cost reduction; therefore, a detailed economic analysis is shown and the cost reduction potential is explained. The economic calculation is indicating an advantage of the combined system instead of a solely PTC system. The PTC only system generated the steam at ca. +2.5% of the cost compared to a combined system considering a 1.25MW nominal thermal power application built in Limassol, Cyprus. This paper validates the benchmark calculation and how a variation of the installed system size will impact the cost reduction.