Advanced energy retrofit projects: cross-case analysis of integrated system design

Built environment researchers and practitioners are addressing the current sustainability and energy challenges facing the industry. The shift in building energy and sustainability expectations has led project teams to develop new practices and processes. Owners, project managers, designers and contractors now actively seek opportunities to improve the energy performance of existing buildings through retrofitting. Given that integrated system upgrades result in more significant energy reduction rates than traditional approaches, this study adopted a case-study approach to understand the integrated system design process and its effects on energy-efficiency performance measures in retrofit projects compared to traditional retrofit processes. Within this scope, three retrofit projects with different processes and rate of energy consumption reduction were purposefully selected to meet certain project delivery and system design characteristics. This paper focuses on effects of these characteristics on the collaborative decision-making process and integrated system design. Its main contribution lies in the analysis of critical decisions related to process and performance modelling practices in the delivery of retrofit projects. As a consequence, it was found that while collaborative energy benchmarking and performance goal setting provided a transparent decision-making environment, the review of existing conditions prior to design and the use of historical operational performance data made the iterative energy modelling of an integrated building system design realistic.