Courtyard design variants for optimum indoor thermal performance of single storey fully-enclosed courtyard house in temperate-dry climate of Nigeria

Abstract

Courtyard houses are common in Nigeria due to their numerous benefits, one of which is the ability of the courtyard to enhance the indoor thermal performance of the building. However, such benefit may not be achieved if the appropriate application of the Courtyard Design Variant (CDV) are unknown to the architect, even right from the design stage. While previous studies on CDVs in different climatic regions have been common, the same cannot be said about the temperate-dry climatic zone of Nigeria. Therefore, the aim of this study is to propose the most suitable CDV for optimum indoor thermal performance of single storey fully-enclosed courtyard houses in Nigerian temperate-dry climatic region. The optimum parameters of the CDVs namely Courtyard Shape Factors (CSFs), Courtyard Aspect Ratio (CAR), Orientation, Courtyard Overhang and Window-to-Wall Ratio (WWR) were established and their impacts on indoor thermal comfort were determined. The documentary survey and field measurement methods were used to determine the types of CSFs and CARs and their indoor thermal performances; while the simulation software -Integrated Environment Solution-Virtual Environment (IES-VE) - was used for the simulation experiment. The software was validated with a digital model of the selected case study courtyard house. This study reveals fourteen (14) types of CSFs and CARs. The smaller CSFs were found to have favourable indoor thermal performance than the larger ones. Four (4) optimum CSFs were established and the North-south orientation was established as the optimum of all CSFs models. The optimum courtyard overhang depth and WWR were also determined. This study concluded that smaller CSFs improve indoor thermal performance than the larger ones, while 1200mm courtyard overhang depth and WWR 16% have significant impact on indoor thermal comfort. Finally, CDVs for the design of thermally conducive single storey fully-enclosed courtyard houses in Nigerian temperate-dry climate was proposed. The significance of this study lies in its quest for a conducive courtyard house while the proposed CDV is its main contribution.