A Study of Mechanical Systems in Canadian High-rise Multi-unit Residential Buildings

Abstract

Mechanical systems providing indoor environmental control and domestic hot water functions generally represent the largest consumer of energy in Canadian high-rise multi-unit residential buildings. Many different systems exist, but limited literature is available to guide the selection process. This thesis seeks to identify current available technologies, define the driving factors behind system selection, and to determine if there are specific systems or technologies which are advantageous with respect to economic, environmental, and practical characteristics. Research was divided into four categories. A literature review was conducted to identify both similar high level research projects as well as specific details associated with the design and operation of mechanical systems. A model of an existing high-rise MURB was built and calibrated from extensive real world data. This model was used to construct six reference buildings – 3 code-based, and 3 low-energy – located in Vancouver, Toronto, and Edmonton. Using these reference models, a series of simulations were conducted to evaluate the relative performance of a wide variety of mechanical systems and equipment. Analysis and discussion of system characteristics revealed no mechanical systems which were advantageous in all scenarios, though there are systems which are clearly advantageous to specific stakeholder groups. Location and climate were found to influence ventilation loads more than any other building load. The carbon intensity of the electric grid was found to be the determining factor of greenhouse gas emissions for systems using electricity as their primary fuel source. Heat pump technology was identified as providing the lowest site energy consumption. Air-to-air heat recovery was found to be the most effective in reducing ventilation energy consumption and emissions. Recommendations for future work include expansion of scope to low- and mid-rise buildings with different form factors. Targeted studies could also be performed to evaluate the impact of internal distribution losses as well as to help refine the cost-to-performance relationship of heat pump technology in order to identify cost competitive applications.