Thermodynamic analysis of a spectral-splitting hybrid PV-thermal system with LiBr/H2O absorption heat transformer. (1st December 2021)

• Record Type: Journal Article
• Authors: Hu, Yue; Zhang, Luobin; Zhang, Hanting; Lv, Hui; Xu, Cheng
• Is Part Of: Energy conversion and management. Volume 249(2021)
• Publication Date: 2021-12-01
• Subjects: Multi-junction solar cell -- Absorption heat transformer -- Spectral splitting -- Concentrating photovoltaic-thermal; 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.2021.114868
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: The photo-electric and photo-thermal processes are decoupled by the spectral splitter. Absorption heat transformer is introduced to upgrade the surplus heat from SSPVT subsystem. Energy/exergy flow characteristic of the proposed system is deeply analysed. Abstract: In order to improve the comprehensive utilization efficiency of solar energy, a spectral-splitting hybrid PV-thermal system integrated with LiBr/H2 O absorption heat transformer (SSPVT-AHT) is proposed. The adopted solar spectral splitter decouples the photo-electric and photo-thermal conversion processes to achieve high temperature heat collection and high efficient electricity generation simultaneously. The absorption heat transformer is beneficially utilized to recover the surplus heat from the spectral-splitting PV-thermal subsystem to produce high temperature thermal energy. Through mathematical model establishment in MATLAB, a parameters analysis and thermodynamic evaluation are carried out. Then, the detailed energy/exergy distributions of the SSPVT-AHT system with and without parameter optimization are compared. Results show that the optimization of the main parameters, including the upper and lower cutoff wavelengths, LiBr/H2 O solution concentration, cell temperature, absorber temperature, could improve the surplus heat utilization and boost the overall efficiency of the proposed system. Consequently, the overall energy efficiency reaches 59.26%, which is 25.56%-points higher compared with the situation without parameter optimization. Meanwhile, the overall exergy efficiency is 37.51% and the largest exergy destruction occurs in the solar cell, accounting for 73.98% of the total exergy loss, which mainly restricts the further improvement of system performance.