UBC Theses and Dissertations

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UBC Theses and Dissertations

A life cycle thinking-based energy retrofits planning approach for existing residential buildings Hewa Godella Waththage, Tharindu Prabatha


Curbing greenhouse gas (GHG) emissions has become a global need with the raising concerns about climate change. Buildings account for 32-40% of the global energy use and thereby are responsible for a significant portion of GHG emissions. Therefore, the federal and provincial governments in Canada are looking to reduce the emissions associated with buildings. Policy initiatives such as British Columbia Energy Step Code have been launched to reduce the operational emissions of the new constructions. However, embodied emissions associated with energy upgrades are being overlooked in these initiatives. Moreover, initiatives focussing on existing buildings are minimal. Therefore, this research aimed to develop a life cycle thinking-based energy retrofits decision-making approach under uncertain conditions for existing buildings. According to the recent literature, low investor confidence, predicting the performance uncertainties, performance gaps in the design and post-retrofit periods, capital investment barriers, and ensuring the quality of retrofit implementation are critical challenges faced by building energy retrofit projects. Performance gaps during the post-retrofit period are mainly caused by uncertainties associated with the building operations, which inevitably results in low investor confidence. A fuzzy-based performance prediction and retrofit selection approach was used to identify the best retrofit strategies for a given building while accounting for the performance uncertainties. Poor workmanship can also result in lower energy savings in the post-retrofit period. Therefore, the potential of employing energy performance contracts (EPC) to ensure the quality of implementation and deliver guaranteed cost and energy savings were investigated. An optimization algorithm was developed to identify the optimal financial parameters to meet the expectations of all stakeholders involved in an EPC. It was observed that the retrofit solution that produces the highest cost-savings does not necessarily produce the highest emissions savings in provinces with a greener electricity grid. An optimization algorithm was developed to assist in financial incentive strategy planning to promote eco-friendly retrofit solutions. The findings from this thesis will benefit multiple stakeholders including, building owners and managers, utility providers, and governmental bodies. In conclusion, this thesis lays the foundation for developing a comprehensive retrofit strategy for Canadian residences.

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