Chinese researchers have assessed the impact of residential rooftop PV arrays on energy use and surrounding air temperatures during extreme heatwaves. They found that panels with higher conversion efficiencies achieved the best results.
Scientists from research institutions across China have developed a model to evaluate the impact of rooftop PV on the energy use of residential buildings and their surrounding air temperatures during heatwaves. They revealed their findings in “Thermal and energy benefits of rooftop photovoltaic panels in a semi-arid city during an extreme heatwave event,” which was recently published in Energy and Buildings.
The study assesses the impact of rooftop PV arrays of varying energy efficiencies on mid-rise residential buildings. In particular, it investigates the impact on air conditioning use and surrounding urban temperatures. The researchers conducted the study in northeastern China, in a semi-arid area that was hit by an extreme heat wave in 2018.
They handled the numerical evaluation with the Weather Research and Forecasting (WRF) model, coupled with building effect parameterization (BEP) and building energy model (BEM).
“Forced by the atmospheric conditions on the lowest level of the WRF model, the system computes the surface momentum, heat, humidity and turbulent kinetic energy fluxes induced by the underlying urban surface and feeds back these fluxes to the atmospheric dynamic governing equations,” said the researchers.
The academics analyzed 12 simulations with different percentages of rooftop coverage and panel conversion efficiency against a control case. They assumed that the PV arrays were installed in parallel and at a certain height away from the roof. It was also assumed that every building in the city used an air-conditioning system during the modeled heatwave conditions.