A group of international scientists has developed a new model to assess rooftop photovoltaic solar panels (RPVSPs) in urban microclimates.
This model integrates the latest weather research and forecasting (WRF) system with the building energy model (BEM) and building effect parameterisation (BEP). It was tested against ten observation stations in Kolkata, India, using validated experimental data.
“While existing studies report the impact of RPVSPs on urban environments, most focus on building-scale simulations or in situ experiments,” the researchers explained.
“Our study addresses gaps by including new parameters such as convective heat transfer, aligning results with other studies using similar factors.”
The WRF/BEP + BEM model calculates heat exchange, humidity, and energy flux between buildings and the environment under stable atmospheric conditions.
It was initially tested in Kolkata and later validated in Sydney, Australia; Austin, Texas; Athens, Greece; and Brussels, Belgium, to confirm the findings apply across different climates.
The study conducted five experiments in Kolkata, exploring RPVSP coverage scenarios from 25% to full city coverage.
The results showed that RPVSPs could increase daytime air temperatures by up to 1.5°C due to heat absorption but reduce nighttime temperatures by up to 0.6°C. Surface temperatures rose by up to 3.2°C during the day and cooled by 1.4°C at night.
Similar patterns were observed in other cities, with Sydney experiencing a 1.9°C daytime rise and a 0.8°C nighttime cooling.
The research also found that RPVSPs alter urban energy dynamics and increase atmospheric mixing, raising the planetary boundary layer by up to 615.6 meters, which could reduce ground-level pollution.
The study, “Rooftop photovoltaic solar panels warm up and cool down cities,” was published in Nature Cities.
