Technoeconomic assessment of a solar-driven adsorption-based space conditioning system for low-energy multi-unit residential buildings in canada

Abstract

Building energy demands and associated greenhouse gas emissions are increasing in Canada. A potential pathway to counteract this trend involves moving away from carbon intensive fossil fuel and electricity driven space conditioning technologies like furnaces and vapour compression air conditioners towards more sustainable solar heating and cooling technologies. This study evaluates the technoeconomic and environmental performance of a solar-driven adsorption-based system used to meet the space conditioning and domestic hot water demands of a low-energy multi-unit residential building in Canada. A transient numerical model of the building and proposed system is developed in the TRNSYS environment. The following two reference systems are also modeled for comparison: 1) a modern system that uses unit-level mini-split heat pumps for space heating and cooling, and a centralized electric domestic hot water tank for water heating; and 2) a centralized system that uses natural gas for space and water heating, and a vapour compression chiller for space cooling. Results from annual simulations in 12 Canadian locations show that the proposed system can achieve solar fractions greater than 0.8 in certain areas (e.g., the cities of Winnipeg and Ottawa) and can reduce annual greenhouse gas emissions by up to 62.7% and 99.8% (in the city of Winnipeg) relative to the all-electric unit-level heat pump and centralized natural gas reference systems, respectively. While the levelized cost of energy for the proposed system is high, a compelling economic argument can be made in jurisdictions with fossil fuel dependent electrical grids.