Thermal and Performance Analysis of a Photovoltaic Module with an Integrated Energy Storage System

Abstract

This paper is proposing and analyzing an electric energy storage system fully integrated with a photovoltaic PV module, composed by a set of lithium-iron-phosphate (LiFePO 4 ) flat batteries, which constitutes a generation-storage PV unit. The batteries were surface-mounted on the back side of the PV module, distant from the PV backsheet, without exceeding the PV frame size. An additional low-emissivity sheet was introduced to shield the batteries from the backsheet thermal irradiance. The challenge addressed in this paper is to evaluate the PV cell temperature increase, due to the reduced thermal exchanges on the back of the module, and to estimate the temperature of the batteries, verifying their thermal constraints. Two one-dimensional (1D) thermal models, numerically implemented by using the thermal library of Simulink-Matlab accounting for all the heat exchanges, are here proposed: one related to the original PV module, the other related to the portion of the area of the PV module in correspondence of the proposed energy-storage system. Convective and radiative coefficients were then calculated in relation to different configurations and ambient conditions. The model validation has been carried out considering the PV module to be at the nominal operating cell temperature (NOCT), and by specific experimental measurements with a thermographic camera. Finally, appropriate models were used to evaluate the increasing cell batteries temperature in different environmental conditions.

Analysis of Operating Temperature of the Polycrystalline Solar Cell

“…At the same time, we can consider values of operating temperature ϑ P for silicon, temperature of environment ϑ E and measured temperature ϑ M on the glass in case 1. On the figure 11 we can see these calculations [12].…”

“…After substitution (10), (11), (12) into (9) we get next equation: (13) We are using another substitution:…”

“…Here was chosen Italian town Bologna [12]. These calculations of operating temperature ϑ P are shown in Fig.…”

“…Minimal value of operating temperature ϑ P for copper is 4,0126 °C and for silicon is 3,2387 °C. For comparison of results, the temperature of environment ϑ E was ascertained as average temperature for every single month in Italian town Bologna and the measured results from model described in article can be used [12]. Here is used nominal value of current I of polycrystalline solar cell and it is 8,36 A.…”

A Digitally Controlled Power Converter for an Electrostatic Precipitator

“…Measurements are taken on the case of the switches and on the heatsink near them. Additionally, the temperature profile, using both types of semiconductors, is analyzed with a thermal camera [37,38]. In this case, the mains are used as input voltage.…”