Numerical research on air-based cooling photovoltaic roof

Abstract

As a new type of building material for plants, photovoltaic roof building materials can be used as roofs of ordinary plants to reduce damage caused by secondary construction to the roofs, and can also absorb and utilize solar radiation to make full use of renewable energy. This article combines photovoltaic modules with air channels to form building material structures with ventilation ducts, establishes physical and mathematical models for photovoltaic roofs in three different inlet modes, and studies the flow and heat transfer characteristics inside air cooling integrated photovoltaic roofs. The simulation results show that the staggered-overlap-joint waterproof double-inlet photovoltaic roof can prevent rain and snow infiltration, and meanwhile, has a cooling effect on the PV panels significantly better than that of the traditional single-inlet air cooling system and the ordinary parallel double-inlet system, and its temperature difference between the inner and outer surfaces of the PV panels is increased by 19.88% compared to the traditional single-inlet air cooling system and by 15.12% compared to the parallel double-inlet system at the maximum. When the included angle between the PV panels of the staggered-overlap-joint waterproof double-inlet photovoltaic roof and the roof is 3°, the change in average temperature difference between the inner and outer surfaces of the PV panels is maximum, which is increased by 3.88% compared with that at 2°. The thickness of the air channel has small influences on the temperature change inside the air channel, the temperature difference between the inner and outer surfaces of the PV panels, and the outlet temperature. When the thickness increases from 50 mm to 200 mm, the change in outlet temperature does not exceed 0.3 K, but the increase in thickness of air layers increases the airflow velocity, which helps to take away more heat.