High Performing Buildings - Fall 2011 - (Page 10)

e n e r G y at a G l a n c e Annual energy use intensity (site) 29.3 kBtu/ft natural gas 6.8 kBtu/ft2 electricity 22.5 kBtu/ft2 Annual source energy 82.3 kBtu/ft2 Annual energy Cost index (eCi) $0.50 Cdn/ft2 savings vs. mneCB design Building 60% savings vs. AsHrAe standard 90.1-2007 design Building approximately 52% Heating degree days 10,260 (base 65°f) Cooling degree days 326 (base 65°f) W at e r at a G l a n c e Annual Water use 2,660,585 gallons This contradicts the conventional approach to an energy-efficient envelope, which increases opaque areas and insulation on the building exterior. A conservative glazing ratio would compromise two key qualities of a high-quality indoor environment: maximum daylight and outdoor views. By introducing buffer façades on the east-west faces, and by expanding the south façade buffer zones to act as winter gardens, excellent daylighting and views can be maintained while also supporting energy efficiency. The double façades are the most apparent example of the climatically responsive approach used to make Manitoba Hydro Place energy efficient. The east and west façades operate in three main modes. In the winter, the façade is sealed tight and acts as a solar collector. Without the assistance of active heating, the interstitial space regularly reaches 20°C (68°F) — even with outdoor temperatures below –25°C (–13°F). This significantly reduces heat losses through the envelope. In the summer, hundreds of operable windows on the outer (doubleglazed) façade open and allow wind and convective air patterns to ventilate the double façade. Automated louver shades within the curtain wall cavity control glare and heat gain. This ensures that cooling demands are not increased by the façade. © eduard Hueber © Tom Arban Top The double façade curtain wall consists of a double-glazed outer façade and a single-glazed inner wall, which is a reversal of typical installations. It acts as a high-performance thermal buffer in the winter, while maximizing the quality of interior space and protecting motorized shading devices. Below A green roof, made up of natural prairie grasses and ceremonial sweet grass, covers the podium. When necessary, it is irrigated with rainwater collected on site, and condensate from the fan-coils. P e r c e n ta G e o f H o u r s i n n at u r a l V e n t i l at i o n ( 3 5 % A n n u A l ly ) During the shoulder seasons, the outer façade is opened and employees are asked to open the manually operated windows on the inner curtain wall. The outer façade is controlled automatically based on indoor and outdoor conditions, including outside and interstitial air temperature, humidity, light levels, and wind speed. The modulating curtain wall is a visible example of the climatic-responsive 10 HigH Performing Buildings fa l l 2 0 1 1

Table of Contents for the Digital Edition of High Performing Buildings - Fall 2011

High Performing Buildings - Fall 2011
Commentary
Contents
Manitoba Hydro Place
Maplewood Police and Court Building
Omega Center for Sustainable Living
Dockside Synergy at Dockside Green
Golden Hill Office Center
Letters to the Editor
Products
Advertisers Index

High Performing Buildings - Fall 2011