Structure parameter analysis and optimization of photovoltaic-phase change material-thermoelectric coupling system under space conditions

Phase change material (PCM) as highly efficient temperature control material has been used in terrestrial photovoltaic-thermoelectric (PV-TE) coupling system to achieve higher power generation efficiency. However, the mass increase results from addition of PCM limits its application in space system. In present paper, a two-dimensional model for PV-PCM-TE coupling system was developed to investigate the energy transfer and conversion performance under space conditions. Firstly, the suitable PCM was selected, both the pure PCM and its metal foam composite PCM (MFCPCM) are used. Then, performance comparison for PV-TE, PV-PCM-TE and PV-MFCPCM-TE systems were performed. The results show PCM can significantly enhance the total efficiency, but causes power density dramatically decreasing. The average total efficiencies for PV-TE, PV-PCM-TE and PVMFCPCM-TE are 29.50%, 30.50% and 30.61%, and the corresponding average power density are 30.34 W/kg, 22.39 W/kg and 21.20 W/kg, respectively. After that, an orthogonal experiment was designed to reveal the effects of structure parameters on power generation efficiency and power density of PV-MFCPCM-TE system. The optimum geometric parameters to achieve the best power generation efficiency and power density were derived. The results show that after optimization, the average total efficiency and power density of PV-MFCPCM-TE are 30.83% and 31.35 W/kg, both of them are higher than those of the traditional PV-TE system (29.50% and 30.34 W/kg). The present work is beneficial for the application of PV-PCM-TE system in space conditions.