When designing a PV array, a considerable focus is placed on effectively sizing the PV panels, but another crucial component is often overlooked: the inverter. Inverters play a pivotal role, as they convert the DC electricity generated by the panels into AC electricity, which is used to power the buildings electricity load.
Misconceptions
One common misconception is assuming that the inverter’s output remains constant under all operating conditions. However, just like PV panels, inverters also experience efficiency decreases in response to the temperature increases, and these impacts are projected to skyrocket due to climate change. This holds serious implications for the performance of PV systems.
Case Study
Consider Victron’s popular inverter, the MultiPlus-II 230V. It can produce a maximum power output of 15kVA under ideal conditions at 25°C. However, as temperatures increase, the continuous output power of the inverter decreases significantly. At 40°C, the output decreases to 10kVA, and at 65°C, it drops to just 7kVA – less than half of its full capacity.
The output power of the inverter acts as a bottleneck, regardless of the surplus energy produced by the PV panels. The energy output of the system cannot exceed the inverter’s reduced capacity, leading to energy losses and a limited system performance.
Optimisation
For optimal performance of a PV system, it’s crucial to consider several factors. Firstly, when sizing the system, it’s imperative to match the capacity of the PV panels to the inverters. Additionally, the system’s location and seasonal temperatures must be considered as they affect the maximum output. To mitigate the risk of underperformance, it’s essential to install the inverters in shaded areas with sufficient airflow. Where this is not possible, it is recommended that mechanical cooling be installed. Thus, by accurately matching the inverter’s capacity to the expected operating conditions, we can ensure that the system operates efficiently year-round.
References
Arnell, N. W., Lowe, J., & Osborn, T. (2019). Global and regional impacts of climate change at different levels of global temperature increase. Climatic Change Volume 155, 377–39.
Dubey, S., Sarvaiya, J. N., & Seshadri, B. (2013). Temperature Dependent Photovoltaic (PV) Efficiency and Its Effect on PV Production in the World – A Review. Energy Procedia – Volume 33, 311-321. Retrieved from https://www.sciencedirect.com/science/article/pii/S1876610213000829
Skyline Solar. (2023, July). How to Keep Your Solar Inverter Cool in the Summer. Retrieved from Skyline Solar: https://www.skylinesolar.com.au/how-to-keep-your-solar-inverter-cool-in-the-summer
Victron Energy. (2024). Data Sheet: MultiPlus-II Inverter/Charger. Retrieved from Victron Energy: https://www.victronenergy.com/upload/documents/Datasheet-MultiPlus-II-inverter-charger-EN.pdf