Track 1: Effects of Climate Change in Warm Weather Coastal Regions
APT Student Scholar Abstract and Application
Existing buildings consume a large proportion of total energy usage in developed countries and are responsible for an equally significant amount of associated greenhouse gas emissions, contributing to the severity of potential climate change impacts. To achieve ambitious targets of greenhouse gas reductions to mitigate climate change impacts, large energy reductions need to be achieved in existing buildings. Currently, many important existing buildings are being considered for historic listing which means these buildings hold cultural values (tangible and intangible) and significant embodied energy within their structures, making them worth conserving for present and future generations. Historic and traditional buildings can be more unique in their construction and materials and may have additional issues due to poor maintenance over decades. These differences between historic buildings and modern buildings pose challenges in how a deep energy retrofit analysis should be conducted and how to select the best retrofit options that achieve both conservation and sustainability objectives.
An historic house in Ottawa, Ontario, Canada, built in 1889 is studied and modelled in building performance simulation software to create a detailed energy model for an energy retrofit analysis. Based on this study, a methodology and decision-framework are presented for balancing heritage and sustainability objectives. The model is used to conduct a parametric analysis to maximize reduction in energy use, and as a result reduce the carbon footprint of the building, while conserving the heritage values of the house. The results of the analysis show that of the individual energy retrofit measures explored for improving the building envelope and HVAC efficiency, an air-source heat pump achieves the greatest energy savings of 27%. Other measures that produced substantial energy savings were a significant increase in insulation and a significant decrease in air infiltration. When the best retrofit options that also respect the heritage values of the building are combined, an overall energy savings of 46% can be achieved. The best measures combined included increased insulation from about 2.2 m2-K/W to 4.6 m2-K/W on the interior of the building envelope, a 70% reduction in air infiltration to 4.2 ACH at 50 Pa, window rehabilitation from double pane to triple pane low-E windows using storm windows, and an air-source heat pump to supplement the existing gas boiler. This case study demonstrates that it is feasible to achieve deep energy retrofits in historic and traditional buildings in a cold climate.