530 Laurier Case Study
The Queen Elizabeth Towers are a condominium complex located at 530 Laurier Ave in Ottawa. The towers were built 1976-1977. The original fan coil units at 530 Laurier were still providing cooling to the 240 individual suites in year 2019. HVAC mechanical equipment is typically designed for a 15-20-year lifecycle. Therefore, the original fan coils had doubled their service life and were past due for replacement.
Fan coils use water as the energy medium to condition the space. Hot or cold water runs through a hydronic fin-tube coil. A fan blows air over the hydronic coil. The hot or cold air leaving the fan coil provides conditioning for the space.
A typical fan coil system consists of one or two units per suite, and a central water loop that runs through the entire building, connecting each fan coil to a central heating and/or cooling plant. The fan coil system at 530 Laurier was designed for cooling only with heating provided by baseboard electric heaters. Therefore, the water loop in the building provides cold water. The cold water is turned on in the Spring and turned off in the Fall. The fan coils may be used for ventilation in the Winter by turning on the fan to circulate air in the suite.
Inevitably, the aging fan coils at 530 Laurier were breaking down and leaking. Drain pan corrosion was the main issue. When cooling hot humid air, water vapour condenses as the temperature of the air decreases. This condensate is collected and drained. The metal drain pans in the existing 40-year-old fan coils were developing holes from corrosion. This led to water leaking into the suites below.
The operation of the new fan coils is indistinguishable from their predecessors. The same fan and coil assemblies are used to transfer energy between water and air. However, newer fan coils are built differently today than in the 1970s. The existing fan coils at 530 Laurier were blow-through; the fan is positioned before the coil. Newer fan coils are typically draw-through; the fan is positioned after the coil. Unlike older fan coils, newer fan coils use electronics to control their functions and determine if there are errors in operation. Newer fan coils are often larger than older units, a by-product of their design to improve energy efficiency.
The challenge at 530 Laurier is that the existing fan coils were integrated into the walls and structure of the building. Replacing the units with a newer standard fan coil would require major civil work. This would add significant cost to the project and long-term disruption for the tenants.
Mechanical contractor Dilfo HVAC was tasked by Apollo Property Management to provide a replacement option for the 40-year-old fan coil units. Dilfo HVAC approached Longhill Energy to evaluate product options to fit into the existing fan coil wall enclosures. Longhill Energy turned to Aurum Manufacturing. Aurum is a manufacturer of retrofit fan coils; their products are designed to replace fan coils built in the 1970s and 1980s. The Aurum fan coil units fit inside existing wall enclosures. Unlike most fan coil manufacturers, Aurum can provide custom dimension fan coil units to fit into unique locations. The Aurum option was evaluated to be more cost and time effective compared to replacing the individual components of the fan coil unit.
Even though Aurum fan coils are designed as direct replacement to 30-40 year-old products, the Aurum units include the most current technologies. Aurum’s standard fan uses an EC motor. An electronically commutated motor uses considerably less energy and allows adjustability of the motor speed to control the airflow. The Aurum fan coil comes standard with a stainless-steel drain pan. Stainless steel offers higher corrosion resistance than the existing units’ galvanized steel drain pan. The Aurum unit also comes with a high-quality valve and actuator to control the water flow. Lastly, the Aurum unit comes ready to accept hot water in order to use the same fan coil for heating. This offers a tremendous future energy saving opportunity by having the option to remove the electric baseboard heaters and add central natural gas fired boilers to the main water loop.
Dilfo HVAC carefully led and started the project with test installations in two select suites. Both options were documented and presented to the condominium board for review. After selecting the best option, Dilfo HVAC proceeded to audit the building to plan the replacement of each suite. In order eliminate the need for dry-wall work, painting or extra trim pieces, Dilfo HVAC provided dimensions for a custom door to access the fan coil unit. This door was fabricated by Aurum.
The result was an efficient, low time, and minimal cost retrofit of every fan coil unit in the building by the Dilfo HVAC team. From first stepping foot into the suite, the old unit was removed, and the new unit was installed within the same day by the Dilfo HVAC technicians. This included removal of the cabinet’s old fiberglass insulation which was replaced with a new longer lasting foam insulation. On completion, the new unit was completely ready for operation.
Longhill Energy has unparalleled access to many of the world’s leading HVAC manufacturers and their unique technologies.