Challenge
A review of water consumption data for 2007 indicated that water use intensity at Park Place was approximately 63% higher than average, when compared to similar buildings in the Lower Mainland. The main cause was the building’s “once through” water-cooled condensers in air conditioning units which were primary used to cool the tenants’ server rooms. “Once through” systems circulate city cooling water to remove heat absorbed from spaces. This water is then inefficiently sent to the drain.
Solutions
Prism recommended the installation of a dedicated closed-loop cooling system to eliminate the use of “once through” water. Two options were presented: a fluid cooler and a cooling tower combined with a plate heat exchanger.
Although the fluid cooler option was more efficient, the costs associated with physically lifting the fluid cooler coil to the roof were found to be prohibitive. Several alternative methods for hoisting the coil were considered including the use of external cranes, the existing window washer crane and even a helicopter. In the end, since the cooling tower and plate heat exchanger could be disassembled and their parts easily taken to the roof by service elevator, it was deemed the most financially and logistically sound option.
After the project was approved by the building owner, Prism completed the mechanical engineering design. The installation of the cooling tower commenced in August 2008 and was completed in February 2009 by mechanical contractors, Fred Welsh Ltd.
Results
As part of project follow-up for GWL Realty Advisors, Prism analyzed the water savings. In 2011, Prism’s audit indicated that annual water consumption for 2010 (52,000 m3) had fallen nearly 60% from 2007 levels (127,000 m3).
The water use intensity for the building in 2010 was 37% below average compared to similar buildings – an impressive improvement from three years earlier!
$86,000 in water utility costs were avoided from the project in 2010. In 2011, this figure is expected to exceed $95,000 and will increase annually as water and sewage rates continue to rise in Vancouver.
