Case study: HVAC and lighting control integration

Energy efficiency was a key driver when designing the fit-out of a company’s North American headquarters. Working as an integrated design team, we implemented several strategies that combined lighting and HVAC controls.

The building consists of two floors of research and development laboratories with three floors of office space above them. The upper office floors are large, open-concept perimeter office spaces with private offices and breakout spaces aligned at the core. The layout provides access to daylight and views deep into the building footprint. The lighting systems at the perimeter open-office spaces have daylight and occupancy control in addition to code-required manual control.

HVAC for the perimeter areas is based on a timed occupancy schedule and not integrated into the lighting controls. The inboard offices, conference spaces, and breakout rooms aligned at the core are all provided with integrated occupancy controls that control the lighting, HVAC, and switched receptacles in the room. The base-building HVAC for these spaces is a traditional variable air volume (VAV) air system. When rooms are vacant, the lighting and receptacles shut off and the HVAC systems reset temperature and airflow setpoints. The occupancy/vacancy signal from the lighting controls system communicate to the HVAC controls through a BACNet interface. Below is a control diagram for this type of installation.

The facility laboratories have sequences that allow the HVAC systems to lower to minimum air-change rates when the labs are unoccupied. This is mainly based on a time schedule—some of the labs cannot take advantage of this type of control due to the activities in them. The lighting in the spaces is also on vacancy control. The occupancy/vacancy signal originates in the lighting controls system and is communicated over a BACNet interface between the lighting controls system and the building management system that controls the HVAC.

Applicable lesson learned from the project include:

• Involve the client’s information technology personnel early and continuously throughout the design process to help determine if control systems can operate on the building data network, or if they need to be separated. A common network is needed to facilitate integrated control system communication.

• If applying lighting and HVAC control in the laboratory context, carefully coordinate with the facility’s environmental health and safety staff to determine when setback of ventilation rates is appropriate and safe for the occupants. Leave the system flexible so that if a lab has ventilation-rate setback, but the function of that lab changes in the future, the sequences can be easily adjusted by facilities staff.

• Make sure that default programming of controllers is setup so that if a power bump or other failure causes the controller to reset, those default values are what you need to properly operate the systems connected to it.

Don’t fear the future, embrace it. There are tremendous benefits that can come from the integration of networked controls. HVAC and lighting integration is just the beginning of the journey.

Paul Kondrat is an engineering leader in CannonDesign’s Boston office. Throughout his career, he has worked to integrate controls systems in health care, science and tech, and other large institutional projects for more than 2 decades.

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