HVAC/R – When the City of Westmount, Que., decided to build a recreation centre in Westmount Park with two NHL-sized ice hockey rinks, local residents were concerned that their view of the landscape would be obstructed by bricks and mortar.
“If the recreation centre was above ground, they would be looking directly at walls,” explains Carolyne Van Der Meer, director of communications for Pomerleau, the construction company awarded the $33.5-million dollar design-build contract.
To counter residents’ concerns, the city decided to build the recreation centre underground – 8.5 metres below grade – with a 65,000-square-foot green roof covering the top.
Although building the Westmount Recreation Centre (WRC) underground presented many challenges for both Pomerleau and Beaudoin Hurens, the lead mechanical contracting firm on the project, it offered significant advantages and savings for the city.
“The building is like a large geothermal system because at this level the temperature of the ground is always around 15 degrees Celsius,” explains Pomerleau’s Louis-Philip Bolduc, LEED AP and project manager for the WRC project. This will have a significant impact on the energy consumption levels.
• 1 outdoor pool, 20 metres x 25 metres
• 2 NHL-sized rinks
• 13 locker rooms
• 3 exercise rooms
• 1 youth lounge
• 1 lounge area in the pavilion at roof level
• Administrative offices
Feeling the Heat
Most of the heat supplied to the building is provided by the waste heat generated by the refrigeration system. A 240 kW electrical heating coil is available for backup, but despite the colder-than-usual temperatures experienced this year, and hitting the system’s design condition at -24˚C, the backup system was never activated over the entire winter.
“The heat rejected by the compressor can go up to 1,173 kW,” explains Maxime Boisclair, mechanical engineer for Beaudoin Hurens, and lead engineer for the WRC project.
The heat rejected from the refrigeration system is used for under slab heating to avoid permafrost, radiant floor heating for the spectators’ area, heating of the fresh air, heating of the tempered water for water-to-air heat pumps, to pre-heat domestic hot water, and for heating the pool.
The heat from the refrigeration system is also used to heat the snowmelt pit.
“This is very important since there is no other way to remove the snow,” says Boisclair.
The WRC is also equipped with 20 heat pumps throughout the building that can provide up to 50 tons of cooling.
“The whole building has a tempered water network to supply heating or cooling to decentralized water-to-air heat pumps,” says Boisclair. “It was the most affordable way to bring energy to a wide building. Instead of bringing air ducts to all rooms, we only have to bring small piping and hook it up to the heat pumps.”
Making a big splash
The heating system for the outdoor pool allows the WRC to open its pool at the beginning of June instead of late June, and close in late September instead of the last week of August, which is typical of outdoor pool operations in Montreal, says Boisclair.
“It adds almost two full months of operation,” he says. “It doubles the season. A total of 630 kW can be supplied to the pool through the heat rejection system.”
Venting for the underground ice rinks was set up in a similar manner to an underground building.
“All ventilation for the mechanicals is located at the centre of the building and we have built a small pavilion on the roof for fresh air entering and outdoor exhaust,” says Bolduc.
One challenge experienced during the installation of the venting involved the transferring of air into the locker rooms.
“There are many locker rooms for both the ice rinks and the pool,” explains Boisclair.
“All those locker rooms need to be exhausted as per ASHRAE standard 62.1. When we finalized our calculation, we found out that we needed to transfer air from everywhere in the building – even through the mezzanine – to be able to have enough exhaust for the locker rooms.”
As a result, a fan was installed to bring air down to the locker room.
No pumping allowed
The owners of the WRC did not want a sewer pump inside the building. This created additional challenges for the design-build team.
“Underneath the lower level we have an important sewer network for showers, toilets and lavatories,” explains Boisclair. “We had to find a way to hook up to the municipal sewer system even if our network was very low below grade.”
By going with larger sewer piping his team was able to reduce the slope, and thus avoid the pump.
Pomerleau’s Bolduc says the biggest challenge in the WRC project was the coordination involved in ensuring all materials, such as the refrigeration units, were sized correctly and installed at the right time.
“The units had to be sized exactly according to plans, otherwise the units wouldn’t have fit between the steel beams already erected in the facility,” he says.
WRC project manager Louis- Philip Bolduc says one of the objectives in the construction of the recreation centre is to obtain LEED Gold certification in the new construction category, which he expects the facility to receive from the Canada Green Building Council (CaGBC) in the near future.
“This building is an example of green building with a high level of energy efficiency that will represent real savings for the City of Westmount, based on the electricity consumption,” says Bolduc.
The overall cost of the WRC project was approximately $38 million, which included a $33.5-million design-build contract that was awarded to Pomerleau. Funding for the project stemmed from $20 million in government infrastructure grants, with the remaining costs coming from a combination of donations and Westmount taxpayer dollars.
Written by Andrew Snook