ASHRAE Journal - December 2011 - 54

models knows that they are to actual buildings what lifelike mannequins are to humans. When buildings are operating, they tend to take on a life of their own. Building structure, systems, occupant habits, schedules, the weather and even building surroundings become part of a complex organism that never behaves quite as expected. For example, simulation software uses average standardized climatic conditions (contrary to reality, which tends to surprise us) and occupant habits can be erratic. However, even after taking varying weather conditions and differing occupant schedules into account, the building was still underperforming. And so the commissioning team set out to ﬁne-tune the sequence of operations and work out a few kinks and quirks along the way. It was discovered, for example, that during winter, room temperature setbacks triggered heat pumps to enter cooling mode. Since this glitch took place during unoccupied hours, without the energy consumption benchmark, this aberration might have gone unnoticed for quite some time. The commissioning team monitored energy bills throughout the following year and were pleased to discover that energy consumption was on target. With an average 3% variation between the simulation model and actual energy consumption (Figure 4

and Table 2), the building’s HVAC systems now clearly meet speciﬁed performance criteria. By optimizing the sequence of operations, energy consumption was cut back by more than 10%, which illustrates how essential it is to remember that commissioning is not just the start-up of HVAC systems, it is a continuing process by which the quality of the project is maintained to a high standard. Today, behind its elegantly restored 19th century façade, the Cowansville Courthouse conceals HVAC systems worthy of cutting-edge 21st century construction. With its efﬁcient renewable energy systems and the latest technologies, the courthouse is now recognized as one of the most modern courthouses in Québec. In its reacquired functional role, the heritage building has regained its status as a symbol of Cowansville’s history and legacy. With a LEED certiﬁcation on the way, the project is a reminder of how important it is for HVAC designers to harmonize sustainable development with economic feasibility, because energy-efﬁcient systems really are the heart of any green building design.

Cowansville Courthouse Today

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The Design, Construction, and Operation of Sustainable Buildings
Third Edition

The Design, Construction, and Operation of Sustainable Buildings
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American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

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ASHRAE Journal - December 2011

Table of Contents for the Digital Edition of ASHRAE Journal - December 2011
