Lessons learned about zero-net-energy buildings

Designed by Hughes Condon Marler Architects (working with Fast + Epp, Integral Group, MMM Group, space2place Design, AECOM, and Ledcor), Burnaby’s UniverCity Childcare Centre at Simon Fraser University (SFU) was examined in the CABA study.
Photo courtesy SFU Community Trust

Major takeaways
The CABA study notes daylighting controls are an integral part of high-performance buildings, but glare control and shading must be done properly to realize the benefits of daylighting. Most designers used fixed elements (e.g. overhands or louvres) or manual shades. Interior shades or blinds were used in more than half the projects (i.e. 12 of the CABA buildings) toward their energy reduction and occupant comfort goals, and 34 per cent (i.e. four projects) applied automation to the shades or blinds.

These buildings are designed to energy-use levels 
50 per cent less than most new buildings today and over 75 per cent less than the average existing buildings, with renewables making up the small balance of energy needs. The majority of design firms attributed HVAC, lighting, and plug loads each having a greater than 15 per cent impact on the energy savings—therefore, the success of the control of these systems means the success of the energy goals.

From both the design team and the operators’ perspective, the solutions lie in an increased need for the controls contractor and the building operator to be more actively engaged with the design early, during commissioning, and after occupancy.

The study also suggests the role of occupants on energy outcomes has never been greater. Seventy-four per cent of the buildings rely on the occupant for some part of the controls success, from roles with operable windows and blinds to plug load controls and energy awareness campaigns.

Health and economy
When properly specified, building controls like shading assemblies also have positive impacts on aspects beyond energy efficiency. Much is now known about the health importance of maintaining circadian rhythm, day/night cycles, and having a view to the outside. Research has confirmed people have evolved to a 24-hour cycle that includes a sleep (rest) time and an alert time, with light providing the catalyst for the body to respond accordingly. Combatting Seasonal Affective Disorder (SAD) is primarily done by light, too. Exposure to light at the right intensity is critical. Restful sleep is best done with a darkened environment as light stimulates the body into its wake/alert cycle. Besides the circadian maintenance aspect, access to daylight offers psychological benefits resulting in less absenteeism, improved job satisfaction, attentiveness, and faster recovery time/need for less medicine in healthcare settings.

Roger S. Ulrich, PhD, EDAC, is one of the pioneering researchers of evidence-based design. He specifically researched the effect of window views on recovery time, reduced stress, and reduced healthcare costs of patients in hospitals and the effect of visual surroundings of patients in intensive care units (ICUs) and psychiatric facilities. He was co-founding director of the Center for Health Systems and Design at Texas A&M University and is now an architecture professor at the Center for Healthcare Building Research at Chalmers University of Technology in Sweden. His work frequently notes the preference for views encompassing natural scenes and the sky in contrast to other buildings.

Satisfaction with daylighting system and characteristic.

Another frequently cited report is Windowscapes: The Role of Nature in the View from the Window, authored by Judith Heerwagen of the Pacific National Laboratory in Seattle. She thoroughly explains the role of daylight and time cures such as alertness during the day and calmness for promoting sleep at night. Co-editor of Biophilic Design: The Theory, Science, and Practice of Bringing Buildings to Life, Heerwagen discusses how research is moving very quickly on circadian rhythm and how the brain responds to light. As light-emitting diode (LED) sources replace incandescent and fluorescent lighting to reduce energy consumption, there is opportunity for light-tuning or manipulation of colour to mimic natural day/night cycles. However, additional research must be done in order to establish exact parameters of colour and intensity—a feature that dynamic daylight does from sunrise to sunset.

Certainly, Leadership in Energy and Environmental Design (LEED), the venerable green building rating system, recognizes a view to the outside and many other ratings standards note the importance of views and proximity to a window. In the LEED 2009 program, Indoor Environmental Quality (EQ) Credit 8.1, Daylight, requires daylight integration via controls for saving energy.

Another important standard is ASHRAE 189.1-2011, Standard for the Design of High Performance Green Buildings, which offers peer-reviewed definitions, guidance, clarifications, narratives, and prescriptions/rules on systems and concepts being used in 
the built environment. This standard 
can be used as a companion to green rating systems.

From an energy perspective, energy codes value daylighting—especially when used along with controls for turning off or dimming nearby electrical lighting that is made redundant by abundant daylight. In the United States, California’s Title 24 has a goal of reducing energy consumption; this state rule has spurred design changes throughout the built environment and fosters usage of control systems. A key element is use of sensors for dimming or turning-off electrical lighting when daylight is present.

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