Why does the photovoltaic energy storage cabinet get hot

The integration of a thermal energy storage unit filled with PCMs into the system allows for the storage of thermal energy, effectively reducing the temperature of the PV cells, and thereby enhancing the overall energy efficiency of the system.

This huge share of solar energy absorbed by PV cells increases their temperature, leading to a decline in cells' electrical efficiency and lifetime [ 2 ]. To resolve these drawbacks and harness thermal power, photovoltaic thermal modules (PVT) are introduced.

Semiconductor Properties: Most photovoltaic cells are made from silicon, a semiconductor whose electrical properties change with temperature. As temperature increases, the band gap of silicon decreases, leading to fewer electrons being able to jump the energy gap to produce electricity.

For silicon PV cells, the average temperature coefficient for power output is around -0.4%/°C. This means for each degree above 25°C, the efficiency of the panel may decrease by 0.4%. Continuously operating at high temperatures can also lead to accelerated aging of photovoltaic modules. This can manifest in several ways:

The decrease in performance is often quantified as the temperature coefficient, typically expressed in percentage per degree Celsius (%/°C). For silicon PV cells, the average temperature coefficient for power output is around -0.4%/°C. This means for each degree above 25°C, the efficiency of the panel may decrease by 0.4%.

To ensure the system's feasibility throughout the year, it is essential to design it not only for hot seasons but also for colder weather. It is because PCM with high melting temperatures will not melt in November, resulting in insufficient thermal storage capacity.