Assessment of Passive Retrofitting Scenarios in Heritage Residential Buildings in Hot, Dry Climates

Abstract

Retrofitting heritage buildings for energy efficiency is not always easy where cultural values are highly concerned, which requires an integrated approach. This paper aims to assess the potential of applying passive retrofitting scenarios to enhance indoor thermal comfort of heritage buildings in North Africa, as a hot climate, a little attention has been paid to retrofit built heritage in that climate. A mixed-mode ventilation residential building in Cairo, Egypt, was selected as a case study. The study combines field measurements and observations with energy simulations. A simulation model was created and calibrated on the basis of monitored data in the reference building, and the thermal comfort range was evaluated. Sets of passive retrofitting scenarios were proposed. The results (based on the ASHRAE-55-2020 adaptive comfort model at 90% acceptability limits) showed that the annual thermal comfort in the reference building is very low, i.e., 31.4%. The application of hybrid passive retrofitting scenarios significantly impacts indoor thermal comfort in the reference building, where annual comfort hours of up to 66% can be achieved. The originality of this work lies in identifying the most effective energy measures to improve indoor thermal comfort that are optimal from a conservation point of view. The findings contribute to set a comprehensive retrofitting tool that avoids potential risks for the conservation of residential heritage buildings in hot climates.

Towards Nearly-Zero Energy in Heritage Residential Buildings Retrofitting in Hot, Dry Climates

“…These buildings are located in downtown Cairo, in the part well known as Khedivial Cairo. This part acts as a 'buffer zone' for the UNESCO Heritage Site of 'Historic Cairo' [12,24].…”

“…The annual total radiation was extracted from the Typical Meteorological Year (TMY) weather file of Cairo [12,43]. As a result, we found that the global solar radiation in Cairo reaches up to 2409 kWh/m 2 annually, with approximately 3300 h of full sunshine.…”

“…Accordingly, conservation-compatible energy retrofitting strategies and scenarios that integrate renewable energy resources (RES) utilization in those strategies [9,10] need to be developed. Martínez-Molina et al (2016) revealed that several energy retrofitting projects and studies in heritage buildings were carried out in cold zones, e.g., the UK and USA, while hot zones, e.g., Libya and Morocco, had few initiatives in this field [11], although climate is an important factor in such contexts since it influences energy use in the achievement of comfort [12]. Accordingly, retrofitting heritage buildings for energy efficiency became a top priority in such severe climates.…”

“…This article contributes to fill the gap in this field. Thus, this work is a part of a wider-scale research project comprising a series of published articles [12,24,25]. The research process has multiple stages that start with developing a classification method to select reference buildings of a heritage building stock [24], proposing a retrofitting checklist based on in-depth analysis of cultural values [24,25], and assessing the potential of applying passive retrofitting scenarios to enhance indoor thermal comfort [12].…”

“…Thus, this work is a part of a wider-scale research project comprising a series of published articles [12,24,25]. The research process has multiple stages that start with developing a classification method to select reference buildings of a heritage building stock [24], proposing a retrofitting checklist based on in-depth analysis of cultural values [24,25], and assessing the potential of applying passive retrofitting scenarios to enhance indoor thermal comfort [12]. Lastly, in this article, we assess the potential of transforming the heritage residential building stock towards "nearly-zero energy" and apply the entire methodology developed through the previous stages.…”