Effective use of venetian blind in Trombe wall for solar space conditioning control

Trombe wall can effectively gain solar heat for space heating to achieve energy saving in heating season. However, due to limited control capability, the system causes unwanted heat gain in cooling season. Thus, Trombe wall presently is not widely adopted. Modification with integrated venetian blind can enable operational control to regulate shading and air flow in the cavity of the solar wall, resulting in air-conditioning effect. In this study, the thermal performance of Trombe wall with venetian blind in cooling season was analysed by coupling Computational Fluid Dynamics (CFD) modelling and Building Energy Simulation (BES). The CFD model was employed to determine the air flow, heat transfer and ventilation rate of Trombe wall under cross ventilation mode and outside circulation mode, providing inputs to BES for the construction of building energy model throughout the cooling season. The results show that the air flow induced by the slat blind can perform cooling and save energy in cooling season. The proposed Trombe wall with venetian blind under cross ventilation mode can reduce the cooling energy consumption by 3.8%, 2.5% and 4.6% compared with the traditional Trombe wall for service, office and domestic buildings, respectively. Under outside circulation mode, the cooling energy savings of the Trombe wall with venetian blind are 5.7%, 5.0% and 5.8% compared with the traditional Trombe wall for service, office and domestic buildings, respectively. System configurations affect the air flow performance of Trombe wall. Larger gap between the slat and inner wall and larger slat angle can enhance the natural convective flow rate and reduce the air temperature, leading to better cooling effect and less solar radiative heat gain of the external wall.