Impact of direct solar irradiance on heat transfer behind an open-jointed ventilated cladding: Experimental and numerical investigations

This paper is based on the study of an experimental wooden-framed house, equipped with a ventilated cladding, located in France. The focus is on investigating the heat transfer taking place in the ventilated air gap behind the cladding and on estimating their impact on heat transfer in the insulated part of the walls.Preliminary CFD simulation made it possible to describe the airflow in the ventilated air gap when buoyancy was acting as the main driving force. It was found that the airflow velocity could reach 0.8 m s−1, when exposed to 570 W m−2 solar irradiance. This was verified experimentally. A correlation to assess airflow rate in the air gap behind the cladding has been developed based on temperature differences and on experimental conclusions. The correlation is adapted to energy performance simulation and efficiently represents the average cavity airflow at different height for various irradiance and temperature conditions.

► Tests were carried out on an open-jointed cladding exposed to solar irradiance.
► The air flow magnitude is strongly influenced by solar irradiance.
► It is also greatly influenced by secondary flows coming in through the openings.
► The insulated wall is ±1 °C homogeneous in rough cases.
► A correlation to assess air flow rate behind the cladding has been developed and validated.