Mechanical boiler upgrade to reduce future carbon emissions by optimizing the heating system for Brooksbank Elementary

Compared to other elementary and high schools in North Vancouver, Brooksbank Elementary was one of the highest fuel-using schools based on area. North Vancouver School District (SD#44) decided to upgrade the boiler plant, and use this opportunity to reduce future carbon emissions by optimizing the heating system for the school.

Challenge

Upon the initial review in the fall of 2012, clear issues with the boiler plant operations were observed, including the system controls, the equipment condition, and the undersized heating capacity. Working with Prism Engineering, the team expedited design and construction in order to capitalize on funding opportunities available through the Carbon Neutral Capital Program. Meeting the funding deadlines required a plant upgrade in the midst of the heating season, requiring detailed construction coordination using a phased approach.

Solutions

Prism carried out a boiler system upgrade that included the following:

  • A low loss header was installed to ensure independence between the primary and secondary loops of the heating system
  • ​Matching the variable flow rates between both loops effectively eliminates mixing between the supply and return, which optimizes the potential for condensing in the variable-flow, low- mass boiler system
  • The latest technologies were used in the upgrade including condensing boilers and Electronically Commutated Motor (ECM) pumps
  • An upgrade to the building’s DDC controls allowed for heating demand feedback from each system zone
  • The critical zones within the school are identified and the system flow and temperature are reset based on the building heating demand. This control strategy drives the supply and return water temperature  as low as possible, increasing the condensing boiler efficiency.

Results

The boiler upgrade concluded in February 2013, and the savings were immediately apparent:

  • a 40% or 896 GJ of annual natural gas savings
  • an estimated 45 tonnes of CO2e, equivalent to $1,117 in BC carbon charges
  • an annual reduction in natural gas payments by approximately $9,300 

Not only has the boiler upgrade led to significant energy savings, the operational issues initially observed are no longer a concern, and occupant heating complaints have been greatly reduced.