What is District Energy?
Over the last several decades, it has become common practice in North America to design communities in which each building has its own space heating and space cooling systems. In many cases however these services can be provided more energy-efficiently by systems with centralised heating and cooling plants. These “district energy” systems heat and/or cool a fluid (often water) then pipe the fluid in insulated, underground pipes to each building connected to the district energy system. Heat transfer equipment located in each building then transfers heat either from the district energy fluid into the building (in the case of space heating) or from the building into the district energy fluid (in the case of space cooling). The fluid is then transferred back to the central plant (or in some cases back to one or many of the multiple distributed heat plants) where it is re-heated or re-cooled. The centralisation of these space heating and space cooling services can significantly improve overall energy efficiency. When district energy systems use renewable fuel sources such as wood or solar energy, greenhouse gas emissions for providing the services can be further reduced.
Thirteen buildings on BCIT’s Burnaby Campus have their space heating needs supplied by a natural gas-fired hot water-based district energy system. BCIT’s Downtown Campus is connected to a steam-based district energy system that serves many buildings in Vancouver’s downtown core.
On-Site Renewable Heat Situation Analysis
Because programs located in the Factor Four area produce a large quantity of wood waste and NE01 is connected to the existing district energy system, BCIT expected that developing district energy in the Area could yield significant reductions in energy throughput. To pursue this idea, BCIT commissioned a study that assessed various district energy technologies, designs, and energy sources to identify opportunities best-suited to the BCIT Factor Four context. This study became the foundation of the Factor Four District Energy Situation Analysis. The study confirmed an unused source of renewable energy – approximately 250 tonnes per year of wood waste from the carpentry and joinery shops – that could be burned to displace approximately 4,000 GJ per year of natural gas consumed by the existing district energy system. This represents approximately 20% of the natural gas currently required to heat buildings in the Factor Four Area. In addition to reducing natural gas costs and greenhouse gas emissions associated with burning that natural gas, BCIT would also save more than $20,000 per year in waste disposal fees currently paid to transport the wood for disposal. A second assessment study specific to biomass as part of a district energy system was commissioned. The proposed wood waste-to-energy system will comprise a wood fuel chipping, storage, metering, and handling equipment, a biomass boiler, and state-of-the-art art air emissions filtration and monitoring systems. More details regarding the wood waste-to-energy project can be found here.
District Energy and Biomass approved to be part of the Factor Four Strategic Plan (SEMP)
BCIT’s Board of Governors has approved the wood waste-to-energy project for implementation and the first phase – connecting the system to NE01 – is expected to be operating by December 2014 (pending funding approval from the BC Ministry Advanced Education). The vision is to connect NE08 and NE03 Arch. Ecology during a second phase. NE2 would be retrofitted with radiant floor heating and connected the district energy loop in a third phase. To build the District Energy Strategy, BCIT has estimated the contribution of each phase toward meeting the 75% reduction in energy throughput for the Factor Four Area.
Go to FactorFour Energy Projects Summary – May 2015 Revision – WEB VERSION to learn more about the Factor Four On-Site Renewable Heat Action Items.
Click here to learn more about the situation analysis for Level 4 of the 4Rs framework: Level 4: Renewable Electricity.