Comparative analysis on performance of PV direct-driven refrigeration system under two control methods

The concept of the PV direct-driven refrigeration system has been proposed to reduce the cost of the PV refrigeration system. In the PV direct-driven refrigeration system, the system control method has great impact on system performance. In this paper, a dynamic model of the PV direct-driven refrigeration sys-tem is proposed and validated with experimental results. This model contains a PV-compressor coupling model, which can reflect the relationship among solar irradiance, compressor load and compressor speed. Based on the model, two control methods for the PV direct-driven refrigeration system are compared, which are the maximum power point tracking (MPPT) method and the compressor speed prediction (CSP) method. According to the comparison results, the following conclusions can be summarized. Firstly, the MPPT method is more efficient than the CSP method. And the difference of two control methods can be reduced if the control model in CSP mode matches well with the system. Secondly, the drop of solar irradiance causes the decreases of daily operation time and total cooling capacity in both MPPT mode and CSP mode. Finally, the MPPT method is more adaptive to the variations of ambient temperature and water temperature. (c) 2021 Elsevier Ltd and IIR. All rights reserved.

Automated summary

The concept of PV direct-driven refrigeration system is proposed to reduce cost. System control method impacts performance. Dynamic model of PV direct-driven refrigeration system is validated. PV-compressor coupling model is included in the model, showing relationship among solar irradiance, compressor load, and speed. Comparison of MPPT and CSP control methods shows MPPT is more efficient. Drop in solar irradiance decreases daily operation time and cooling capacity in both modes. MPPT method is more adaptive to temperature variations.