Manitoba 1 Final

Civil Engineering DepartmentCivil Engineering Project 2 ( H22A12)

Coursework 2: Case study on sustainable design of a civil engineering project

Title: Sustainable designs of Manitoba Hydro Place, Winnipeg, Canada

Group leader: CHIN SHENG JI (UNIMKL-008808)Team members:YASHNA HEMASHREE SEEBUN (UNIMKL-011473)LIP YIH HERNG (UNIMKL-008783)Group: 9Personal Tutor: KOK SIEN TI

While many towers claim to be the “greenest” building in the world, one building stands apart as the first in the new generation of energy-efficient, climate responsive buildings. Awarded the most energy-saving tower in North America, Manitoba Hydro Place (MHP) in Winnipeg, is among the rare projects which met challenging goals in terms of energy savings, urban revival, and a supportive workplace without the expense of cost and design. In this paper we will explain how the design and construction of the office building contributes to its sustainability.

MHP is the headquarters tower owned by the company, Manitoba Hydro-. Integrating time-tested environmental concepts along with advanced technologies, it achieved a “living building” that responds dynamically to the local climate. Its goal is to mobilise 2000 employees from the suburbs under one roof in an open, collaborative environment. Moreover, the formal Integrated Design Process (IDP) was mandated by the client such that the design team was to commit a year to develop the building concept and using another year. This ensured the concept integrated the key elements to achieve the objectives of 60% energy savings, supportive workplace, urban revitalization, signature architecture and cost effectiveness.

Encapsulated in the street 360 Portage Avenue, the site was strategically selected because over 95% of the bus routes pass this address, including routes to suburban Winnipeg where 80% of Manitoba Hydro employees live.

The architectural design of the building was designed by Kuwabara Payne McKenna Blumberg Architects (KPMB) (design architect) and Smith Carter Architects & Engineers (executive architect). The organisation of engineers involved is Halcrow Yolles, Crosier Kilgour & Partners as the structural engineers and AECOM as the mechanical and electrical engineers. As for the main contractor involved in this project is PCL Construction Canada. The total cost for the whole project is $271 million dollars.

In 2005, a previous building occupying the site was destroyed and undertaken with a commitment to reduce waste, with 95% of the materials recycled or re-used, such as the “Douglas Fir lumber” was milled and reused as soffit cladding for the 22 story office tower. A containment pond was built onsite by re-using precast traffic barriers for groundwater and run-off filtration.

Initially, based on the project charter goals, four design charrettes were concluded to design sixteen alternatives which were evaluated by the energy consultant, Transsolar; three options were selected (Figure 1). During the last design session, “Comfort Tower” had been selected and after several solar, massing and wind modeling, the model was rotated so that its atria faced due south to capture Winnipeg’s abundant winter sunlight and strong winds.

Figure 1

The two 18-storey “vertical neighbourhood” towers splays out on the southern façade and “fuses” at the north end by the solar chimney, bringing about a capital “A” shape (Figure 2).

Oriented along the building’s North South axis is its ventilation tower know as “the solar chimney”. The 15.5m long, 2.85m wide and 119.0m tall shalf was built at parking level and extends to 115.5m above the grade. Composite cladding of 500mm wide x 2000mm high conceals a thick layer of mineral fibre insulation that surronds the exterior to reduce heat loss. Windows on the east and west facades consist a double curtain-wall that insulate against heat and cold. The system is made of single-glazed inner wall spaced one meter inside a double-glazed outer wall, creating a energy efficient buffer zone. (Figure 3).

Figure 2

Figure 2

MHP also has the largest closed loop geothermal system in the province with 280 boreholes, each 150mm in diameter; penetrate the site 125m underground. Initially bored 50 to 300 feet deep, a pair of pipes with a U-bend assembly at the bottom was inserted into the bored hole vertically to maximise the use of land area. Grout seals the boreholes and the pipes connect to the heat pump furnace units inside the building to pump glycol which extracts or rejects heat depending on the seasons. Water is circulated through the heat exchanger and distributed through thermal mass of the concrete structure which in turn heats or cools the space consistently. (Figure 3) In 2006, the foundation work construction faced the problem of

too high water level, forcing the elimination of one underground level. Many basement features were relocated and the foundation was redesigned. However, these problems were immediately solved with the IDP implemented by the design team.

Coldest city in the world as well as the sunniest location in Canada, Winnipeg endures extreme temperatures which vary around 70°C over a year, plummeting below -35°C in winter, and soaring above 35°C in summer. This supports the highest air conditioning use per capita, and in view of Canada’s delayed commitment to the Kyoto Protocol, MHP demonstrates an exemplar

of the Integrated Design Process for achieving energy efficient, human-centered design. The unusual floor plate configuration and the advanced

façade system of MHP ensure light reaches all the way to the core of the building, resulting in a total day-lit building area of 85% (Figure 6). Computer models in combination with data from the building’s weather station control a fully automated louver shading system and determine how the angle of 100mm deep louver shade should be deployed to suit sun location and angle. When fully deployed, the aluminium louver blades feature a finely perforated surface, stopping solar glare, but still allowing views to the outside. Areas of

the building with higher amounts of sun receive a permanent ceramic frit pattern to reduce solar glare and gain.

In 1999, the California Board of Energy Efficiency found that increased productivity, increased wellness, and reduced energy costs resulted from companies using natural lighting instead of artificial light. This reflects the owner’s commitment to the health and wellbeing of its greatest asset—its employees.

The building is filled with 100% fresh air, 24 hours a day, year round, regardless of outside temperatures. The solar chimney is a key element in the passive ventilation system which relies on the natural stack effect. It draws used air out of the building during the hot seasons. In winter, exhaust air is drawn to the bottom of the solar chimney by fans, and heat recovered from this exhaust air is used to warm incoming cold air (Figure 7). The air is preconditioned by tensioned mylar ribbons whereby conditioned water run down each strand to humidify ambient fresh air in winter and dehumidify it in summer. (Figure 8)

Figure 8

In spring and fall, the mechanical ventilation systems of the building are turned off and the building is ventilated by opening window vents (Figure 9

and 10).

Figure 9

Figure 10

This type of system achieves much higher air quality, lowers energy use, eliminates conventional ductwork and a hung ceiling altogether since air enters below the floor and moves through occupied space in an orderly, stratified manner. The results are shown below.

Green roofs cover a majority of the low roof surfaces and they mitigate the urban heat effect by minimising heat absorption at the roof surface. The green roof aids in storm water retention, reducing strain on the city infrastructure. Water from the condensate from fan coils in the building and collection tanks are used for the non-potable irrigation system of the green roof and the landscaping.

Performance data and occupant surveys conclude the human health and a sustainable design can considerably rise productivity, trigger employee retention and reduce absenteeism. Brent Bellamy, a senior design architect

says. “Even small percentage gains in employee productivity, when multiplied by the annual payroll; result in considerable savings that can redefine the net economic model for green buildings.” In the base building, rent is limited to stimulate the support of local businesses and to encourage staff to experience their city. Due to the influx of 2000 employees, rising sales and development in the surrounding area have been observed by the downtown business group.

Indeed other buildings have also realised advanced sustainability standards. The Jim Pattison Centre fulfilled an estimated energy reduction of 96% compared that of MHP which is 77%. It is the largest building to date to do so. However, the extent of human centeredness remains unknown. In MHP, the objective of creating a highly supportive, comfortable and healthy work place was critical to its success. Column free loft spaces are stacked and organized into vertical neighbourhoods with interconnecting stairs for face to face communication and improved culture of teamwork. Everyone has access to the façade and can control their personal environments, using operable windows, task lighting, and shading devices. Displacement ventilation is deployed via a series of occupant controlled floor grills, allowing users to have individual control airflow and temperatures of their immediate work environment.

Manitoba Hydro office tower is a state of the art building committed to energy conservation, quality and comfort at the workplace. Through all the collaborative design charettes and workshops, architects were able to draw out innovative designs that contain clear vision, understanding and objectives. With the aid of Integrated Design Process, these objectives were achieved and have set a new standard for sustainable buildings design and construction. Their annual energy usage is 85kWh/m2, first office building to do so in North America, earning them the Leadership in Energy and Environmental Design (LEED) Platinum certificate. (Figure 9).

Figure 9