International Conference on Innovations in Energy Engineering & Cleaner Production IEE CP 21 1 IEECP’21, July 29-30, 2021, Silicon Valley, San Francisco, CA – USA © 2021 IEECP – SCI-INDEX DOI : https://dx.doi.org/10.6084/m9.figshare.14546634 Improving Energy Performance and Thermal Comfort for Heritage Buildings: A Case Study Murabaa Palace Abobakr Al-Sakkaf Department of Building, Civil, and Environmental Engineering Concordia University Montréal, Canada abobakr.alsakkaf@concordia.ca Sherif Ahmed Mahmoud Department of Architecture Engineering Military Technical College Cairo, Egypt sherif_ahmed@mtc.edu.eg Eslam Mohammed Abdelkader Structural Engineering Department, Faculty of Engineering Cairo University Giza, Egypt eslam_ahmed1990@hotmail.com Abstract Heritage Buildings are significant of their historical and architecture added value, which require in deep and precise preliminary brainstorming when considering upgrade or retrofitting of these valuable buildings. This study opts to spotlight on some passive design architecture interventions to improve the thermal comfort and the required cooling energy for the building. The Murabaa Palace in Riyadh was selected as a case study. The design builder software was used to evaluate the energy performance of four passive architectural design alternatives. The results show that using Low-E double glass in addition to applying double wall with polystyrene thermal insulation can enhance the thermal comfort inside the building and reduce the energy performance and CO2 emissions to 17% and 9% respectively. Keywords: Heritage buildings, passive design, energy conservation, and reduction of CO2 emissions. I. INTRODUCTION Heritage buildings are integral parts of modern life, in which they gain their significance from their historical, archeological, and cultural added value [1; 2; 7; 13]. Therefore, improving the energy performance and indoor thermal comfort of an as built building with minimum interventions and preserving its heritage value is a dilemma. This is the role of introducing passive architectural design by precise choice of building materials and additions [9; 14; 18]. Accordingly, this research aims to spotlight on some passive architectural alternatives that can enhance indoor thermal comfort, reduce energy required for cooling and in turn minimize the CO2 emissions. Moreover, heritage buildings inherited from the past are a crucial component of our modern society. Heritage included those buildings, structures, artifacts, and areas that are historically, aesthetically and architecturally significant. Figure 1 below shows the number of world heritage properties inscribed each year per region. As of July 2019, a total of 1,121 World Heritage Sites located in167 States around the globe. Additionally, three key factors determine whether a property worth to be listed as heritage are: historic significance, historic integrity, and historical context. Historic significance is related to how valuable the property to the history, archaeology, engineering or culture of a community. This includes any heritage building that is associated with a past event or an important person in addition to those building that has a distinctive physical characteristic. Historic integrity is relevant to the authenticity of the building identity with existing evidence of its unique physical characteristics during the building's historic period [5]. Figure 1. The number of world heritage properties inscribed each year per region [5]. According to Al-Sakkaf et al. [3; 4] the trends of protection and use of heritage buildings and cultural heritage components testify to increasing attention in the study of heritage and legacy. Studies have shown that project life cycle phases have been developed to evaluate the performance of buildings in general. Nevertheless, heritage buildings and their need were not considered. In heritage buildings projects there are six life cycle phases include: a) planning, b) manufacturing, c) transportation, d) construction, e) operation and f) maintenance phases. In addition, there is a lack of