Performance analysis of a solar thermoelectric generation (STEG) system with spray cooling. (1st December 2018)

• Record Type: Journal Article
• Authors: Ge, Minghui; Wang, Zixuan; Liu, Liansheng; Zhao, Jun; Zhao, Yulong
• Is Part Of: Energy conversion and management. Volume 177(2018)
• Page Start: 661
• Page End: 670
• Publication Date: 2018-12-01
• Subjects: Solar thermoelectric generation -- Spray cooling -- Performance optimization -- Net generating efficiency; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2018.10.016
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: A STEG system with spray cooling was established. Compared with water cooling, the spray cooling can make better performance. There exits optimal operating parameters which can max the generating efficiency. The effects of structural and physical parameters were analyzed. Abstract: Use of an efficient cooling system is critical from the performance viewpoint of solar thermoelectric generation (STEG) systems. This study proposes the use of spray cooling as an effective technique for use in applications involving STEG systems. A mathematical model has been established to analyze STEG systems from the perspective of net generating efficiency and output power. Results demonstrate that compared to water-cooling, use of the spray-cooling technique results in enhanced generating efficiency, especially under high concentration ratios, owing to inherent advantages, such as high heat transfer performance, low power consumption, and no contact resistance. At a concentration ratio of roughly 200, the net generating efficiency when using spray cooling was observed to be 31.3% higher compared to that achieved when using water cooling. Under conditions of fixed module parameters and structure, there exist optimum values of the spray flow rate and concentration ratio that result in maximization of the net generating efficiency of STEG systems. This maximum efficiency of 13.203% occurs at a concentration ratio of 165 and corresponding flow rate of 0.35 L·min −1, at ZT = 1. Additionally, the net generating efficiency can be further enhanced by reducing the temperature of cooling water. The structural parameter γ is proposed to characterize the geometry of the thermoelectric module. As observed, there exists an optimum value of γ as well that tends to maximize the net generating efficiency of the system. Moreover, this optimum value of γ gradually increases with increase in concentration ratio. Results also demonstrate that optimum values of the spray flow rate and concentration ratio follow an approximately linear increase with increase in the ZT value of STEG modules.