Dunwood Place in New Westminster saves big with energy retrofit
Source: case study informed by energy study by Impact Engineering
August 7, 2020
BCNPHA’s Retrofit Coach conducted the initial walk-through audit and helped Dunwood Place contract an engineer for further study. The energy study identified opportunities to upgrade the heating boilers and Domestic Hot Water (DHW) system as well as reductions in high airflow and temperatures of the Make-up Air (MUA) systems.
Building Name: Dunwood Place
Building Type: MURB
Location: New Westminster, BC
Square Footage: 120,000 sq ft (11,150 m2)
Year built: 1977
Number of suites: 193
Retrofit: Boiler replacement and ventilation measures
Completed: 2018
Engineer: Impact Engineering
Gas savings: 2,441 GJ
GHG savings: 135 tons CO2e/year
Annual cost savings: ~$18,000/year (not including reduced maintenance costs)
Winner of the 2019 FortisBC Efficiency in Action Awards
Dunwood Place is an independent senior living facility located in New Westminster, BC. This facility provides studio and one-bedroom suites as well as multiple amenities for its occupants, housed in an 11-storey tower, 5-story building, and 1-storey connector, originally built in 1977.
BCNPHA’s Retrofit Coach did the initial walk through audit and helped the society contract an engineer for further study. The energy study identified opportunities to upgrade the heating boilers and Domestic Hot Water (DHW) system as well as reductions in high airflow and temperatures of the Make-up Air (MUA) systems.
The engineers and BCNPHA Retrofit Coach sought supplemental funding for the study and upgrades through the Commercial Custom Design Program. This building also had an Operating Agreement with BC Housing, which made them eligible for additional provincial funds.
Boilers
The existing boilers installed in 2009 were oversized, causing them to cycle on and off frequently, especially while heating requirements were low. The boilers were producing domestic hot water through instantaneous coils, which required very hot water and caused additional run-time through boiler cycling.
The recommended solution was to replace the standard efficiency boilers with more efficient condensing boilers and replace the instantaneous DHW coils with a storage tank system for greater efficiency. Both these measures would eliminate the cycling issue and allow for much more effective boiler staging.
Energy savings were estimated at 30%, given the amount of cycling, oversizing and inefficient DHW production. Boiler operating efficiencies would yield about 15-20% savings and good boiler staging, controls and eliminating boiler cycling would provide the remainder of the savings.
Ventilation and energy
It is common for buildings in the same vintage as Dunwood Place to provide higher ventilation air rates than needed, sometimes providing over double what’s required by building code. Heating all that outdoor air is a very real cost and was a significant portion of natural gas use at Dunwood Place.
A newer existing Make-up Air unit was simply modified rather than replaced, reducing its cubic feet per minute (CFM) of air from 2,750 down to near 1,000 CFM. Air balancing was performed at each of the supply grilles after the retrofit (pictured below). The supply air temperature was also reduced for greater energy savings.
Results
The reductions in greenhouse gases from replacing the boilers was equal to planting approximately 916 mature trees or removing 26 cars from the road. Maintenance costs were greatly reduced and the total energy savings was estimated at $18,000 per year.
FortisBC provided $86,784 in custom energy study and HVAC rebates and BC Housing’s Energy Efficiency Retrofit Program provided $139,809 funds, the sum of which covered the entire project cost!
Testimonial
The retrofit project was very exciting for Dunwood Place and we were very happy with the whole project and the results. The experience was very positive because of the hands-on approach from BCNPHA. Working with the Asset Management Coordinator from BCNPHA was the best as she was totally there for us from beginning to end and we had a great engineering consulting company at the helm. BCNPHA made it such an easy process. The result from the retrofit is an annual savings of about $18,000 in gas costs with maintenance costs down considerably!
– Linda Bilinski, Administrator, The Presbyterian Senior Citizens’ Housing Society
