Assessing strategies for retrofitting cooling systems in historical buildings

Historical buildings, such as the museum constructed in 1933 which is the focus of this study, often face challenges in maintaining thermal comfort due to aging air conditioning (AC) systems and changing environmental conditions. This study presents a building information modeling (BIM) framework for generating a building energy model (BEM) to evaluate different AC retrofitting strategies while preserving the building's historical features. The study acknowledges the potential impact of climate change and urban heat islands on historical buildings but does not directly analyze these factors. Instead, it focuses on the deterioration of AC system components, which can lead to a decline in system efficiency and thermal comfort. This deterioration is treated as a maintenance issue, with the understanding that system operation can be restored through component repair or replacement. The decision-making matrix used in this study compared various AC options, with the variable refrigerant flow (VRF) system emerging as the preferred choice. This retrofitting strategy led to a significant improvement in the predicted mean vote (PMV) index of thermal comfort, reducing the average PMV index for the whole building during the cooling period by up to 31%. This study contributes to the body of knowledge by providing a detailed outline of the process of restoring an HVAC system in a historical building. The findings can be beneficial to designers and engineers involved in historical building restoration, offering a unique perspective on the use of BIM-based BEM in this context.