Analysis of Operational Energy between Adaptive Reuse Historic Buildings (ARHB) and Modern Office Buildings: A Case Study in Sri Lanka

Adaptive Reuse of Historic Buildings (ARHB) is a new concept in developing countries like Sri Lanka. One of the main concerns for the intendancy of decision makers to ARHB is the operational energy. This paper analyzes the research gap of reusing historical buildings as office spaces by utilizing their structural and architectural designs and preserving the buildings' authenticity for the future. It further aims to protect energy-efficient historical buildings from getting demolished and replaced with new modern buildings. A set of operational energy variables of modern office buildings and the potential historic buildings that can be reused as office spaces was established. During the early 1990s, old Dutch-era buildings in the country were mainly used as government office buildings. Three Dutch-era buildings in Galle Fort and three modern buildings in Colombo City have been selected as the case studies. Design-Builder (DB) software was used to comprehensively analyze sets of operational energy consumption variables. Selected historic buildings in Galle consumed 143.74 kWh/m2, 156.34 kWh/m2, and 209.39 kWh/m2 while modern buildings consumed 337.29 kWh/m2, 210.99 kWh/m2, and 382.57 kWh/m2 as operational energy, respectively. According to the analysis, the operational energy requirement of ARHB is comparatively lesser than that of modern buildings. This study, therefore, mainly concludes that the historical buildings saved more operational energy than the modern building envelopes while considerably reducing environmental impacts and saving the building energy cost.