Impedance matching control strategy for a solar cooling system directly driven by distributed photovoltaics. (1st February 2019)

• Record Type: Journal Article
• Authors: Han, Youhua; Li, Ming; Wang, Yunfeng; Li, Guoliang; Ma, Xun; Wang, Rui; Wang, Liang
• Is Part Of: Energy. Volume 168(2019)
• Page Start: 953
• Page End: 965
• Publication Date: 2019-02-01
• Subjects: Impedance matching -- Control strategy -- Solar cooling -- Ice thermal storage -- Distributed PV; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2018.11.148
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: In this paper, an integrated control strategy for a solar cooling system directly driven by distributed photovoltaics (PVs) without a battery is proposed; this strategy matches the optimal operating impedance of the PV array by periodically perturbing the running frequency of the compressor. The theoretical working principle of the control strategy is explained, and two experimental processes are analysed under different solar irradiance levels. Furthermore, comparative tests of the control system with and without a controller were conducted to evaluate the performance of the solar cooling system. The results of the experiment under the impedance matching control strategy reveal that the average photoelectric conversion efficiency reached approximately 0.129 and improved by 83.7% relative to the control system without a controller. The coefficient of performance (COPsolar ) reached 0.263 using an ice thermal storage model, which was an improvement of 60.4%. The compressor ran continually when the instantaneous irradiance exceeded 143 W/m 2 . The average efficiency of the control system reached 0.96, and the average three-phase power factor was approximately 0.71. The COP of the refrigeration unit was 2.10, and the total cooling capacity was 103.5 MJ, which was sufficient for cooling a 25.5-m 2 air-conditioned room for 8.5 h. Highlights: An impedance matching control strategy for solar cooling system was proposed. The impedance matching relationship was verified with theory and experiments. Comparative tests with and without controller were conducted for proposed system. The compressor ran stably when the instantaneous irradiance exceeded 143 W/m 2 . The COPsolar reached 0.263 in ice-making thermal storage model.