RBC Waterpark Place

Set for completion in 2014, the 930,000-square foot RBC WaterPark Place is intended to be the first new speculative office tower in Toronto to achieve the highest green building rating — LEED Core & Shell Platinum.

The developers and the design team want to demonstrate that achieving the highest level of sustainability is not only possible today, but also is cost-effective and feasible for a developer’s bottom line.

The 50-storey complex extends for a block along the north side of Queen’s Quay Boulevard between York and Bay Streets, just south of the business district and close to the busy Toronto waterfront. The building, which incorporates a seven storey podium, is being developed by Oxford Properties and designed by WZMH Architects. Sustainable design facilitation, LEED consulting, and energy efficiency modeling were provided by Enermodal.

The construction cost is $400 million. Oxford expects about 1% to be the incremental cost of going from LEED Gold, which was the developer’s initial goal, to LEED Platinum. Given that the expected operating cost savings are $150,000 annually, the developer expects a four-year payback. Enermodal conducted a comprehensive engineering study and energy model that examined the cost benefits of a wide range of technologies to determine which would yield the highest energy savings at the lowest cost.

Vision glazing used strategically

A careful configuration of the building envelope is one strategy used for achieving energy savings. The tower will have a high-performance building envelope by ensuring that vision glazing is only used where it provides the most benefit. As a result, vision glazing accounts for a little over half the exterior walls, compared to most new office buildings, which have 70%-80% vision glazing. Insulated glazed panels are used in areas near the floor, above the ceiling, and in front of obstructions like pillars. The envelope provides energy efficiency and occupant comfort improvements.

Dedicated outdoor air system

The building will use a dedicated outdoor air system (DOAS) for ventilation and an independent variable air volume system (VAV) for delivering the heating and cooling.

A DOAS is a well tested and relatively simple system to design and operate. The systems are often paired with innovative, high-performance heating and cooling systems like variable refrigerant flow, chilled beams, or radiant slabs. In this way, a DOAS based strategy can deliver a superior indoor environment with low operating costs and excellent long-term performance.

But design teams also need not venture too far from their technical comfort zone to implement a DOAS strategy. In a system such as is being installed at RBC Waterpark Place, a DOAS running in parallel with a standard VAV system providing thermal control will provide significant savings relative to a traditional office mechanical system. In this configuration, ventilation air from the DOAS, which is provided to match occupancy needs, is delivered to the space independently of heating and cooling and is controlled by CO2 sensors. The VAV system has a more or less traditional design and is controlled by thermostats in each zone.

True, there is a little more ductwork in the ceiling space but the control strategy is simple and allows each zone to receive what it actually needs — fresh air, heating or cooling, without one compromising the other. Plus, because most building operators are already well versed in traditional VAV systems, the learning curve to manage a DOAS+VAV system is fairly gentle.

Enwave’s deep lake water cooling and dedicated natural gas high-efficiency boilers will supply the energy required by the systems at RBC Waterpark Place.

This project will demonstrate that designers can achieve the same level of energy savings as other advanced HVAC systems with something as simple as added ductwork and VAV boxes with added controls. This reliable, well understood, and easy-to-maintain design is also less expensive and more reliable than underfloor systems that are often considered a default for high-performance office towers. It serves as an example for other big city high rises to shoot for.

Ongoing measurement and improvement

Enermodal will be installing a sub-metering system in the building to monitor energy and water use for the first year of operation to determine the actual energy efficiency levels of this office. cce

Michael Pires, P.Eng, is the Manager for Sustainability at Enermodal Engineering/MMM Group, in Toronto.

Owner/Developer: Oxford Properties

Sustainable design facilitation,

LEED, energy modelling: Enermodal,

a member of MMM Group (Michael

Pires, P.Eng., Marlene Waters, P.Eng.)

Architect: WZMH

Structural: Read Jones Christoffersen

Mechanical: Hidi Rae

Electrical: MMM Group