9 minute read
The Heat Is On But No One's Around
By JENNIFER BRONS
Unlike when lights are left on in vacant spaces, energy waste from operating mechanical systems in vacant spaces may not be as obvious. But some have taken notice and are looking at ways to integrate lighting controls with mechanical systems to save energy and prepare buildings for future energy management needs.
Energy codes for commercial projects in North America require increasingly strict and complex lighting controls. While standalone room-level lighting controls may make sense for small projects, luminaire-level lighting controls (LLLCs) are providing new flexibility for many commercial buildings.
Recently, I spoke with specifiers, facilities managers, energy service personnel, and manufacturers who are successfully working with LLLCs to save energy, both with lighting and HVAC systems. Their projects are using occupancy data from LLLCs to send a signal to the mechanical equipment to automatically adjust thermal setpoints or reduce air flow. LLLCs provide an opportunity for reducing HVAC energy use, especially in spaces with intermittent occupancy patterns like businesses with workfrom-home policies.
In addition to increasingly strict requirements for lighting controls, recent state and model energy codes (e.g., California T24,1 ASHRAE 90.1-20222) also require that mechanical systems in commercial buildings automatically adjust thermostat setpoints when the space is unoccupied. While there is no requirement to use LLLC sensors to control HVAC equipment, Tim Carr, Senior Energy Consultant with Vermont-based VEIC, noted that avoiding the use of separate occupancy sensors for mechanical equipment offers material and labor savings.
Aprille Balangue, electrical engineer at TFNB Engineers in Seattle, pointed out an aesthetic benefit in using wirelessly connected LLLCs to avoid the clutter of additional controls wiring. Reduced conduit looks good, especially with her region’s use of exposed cross laminated timber construction.
Doug White, Energy Services Lighting Product Manager for Trane Commercial, further explained that retrofit customers benefit not only from installation cost savings of wireless LLLCs but can also avoid asbestos abatement issues.
What’s the Holdup? Silos and Uncertainty
Integration case studies,3,4,5 show a wide range of HVAC energy savings, which is part of what makes this integration difficult for utilities to incentivize on a prescriptive basis. Jarad Adams of Alpha Engineers described a 2020 bank project in which his team successfully integrated lighting and mechanical systems. Because the utility did not offer incentives, however, it was not cost effective to use LLLCs.
Using lighting controls to deliver a signal to HVAC equipment represents significant challenges, both in terms of equipment and siloed expertise. Typically, these systems require customized integration with a large building’s BACnet system, variable air volume dampers, thermostats, security firewalls, etc. To spread the fixed costs of integration over a larger area, the U.S. General Services Administration6 recommends integrating these systems on projects greater than 50,000 square feet.
Not all projects are suitable for this type of integration. Constant air volume systems, for example, are less successful than variable air volume systems.7 Particularly successful projects are ones in which occupancy is sporadic and a time clock would not capture savings opportunities. A library (shown above) in Castle Rock, Colorado, is actually not using their integration features; facility manager Dave Meyer explained that, other than a few staff-only spaces, their library is occupied at all hours of the day and night and would not benefit from LLLC controlled temperature setbacks.
The main challenge to integrating these systems is promoting collaboration between lighting and mechanical experts, both in the design stages and during construction. Collaboration should ideally begin early in the project’s design due to the significant equipment coordination required to properly implement these systems.
As for the construction phase, Mark Lane, a controls specialist at nLight, added that because these systems are controlled by two completely different groups (Constructions Specifications Institute8 [CSI] Division 23 vs. 26), a project’s electrical and mechanical contractors need to separately verify their respective systems are working in order to get paid. Any interconnection problems will hamper timely payment.
More recently, integrated cross-functional controls have been defined in CSI Division 25 (“Integrated Automation”). But bridging these systems is not “cookie-cutter” operation; integration requires a rare expert who understands customer intent and who is responsible for carrying the integration through from design to commissioning.
Aprille Balangue pointed out that commissioning these systems can be especially challenging, and contractor programming time is limited, so it is important to write a Sequence of Operation (SOO) in the early design stages that will be understandable and specific to each room. (For more about Sequences of Operations, see Jim Benya’s article9 in the Oct/ Nov 2024 issue.)
Q Gagne of Minnesota’s Center for Energy and Environment agreed that integrating these systems requires an uncommon level of expertise and cited the need for more scalable technology, with an intuitive interface (such as smart phone app) so experts don’t have to fly across the country to commission and troubleshoot. Q predicts integration success led by the HVAC community because they more commonly work with complex SOOs.
Q’s prediction resembles the innovative approach Doug White has been taking at mechanical equipment manufacturer Trane. His group is working with both new buildings and existing clients to specify luminaires and lighting controls that will talk to Trane’s building automation systems. Trane can provide the lighting and controls equipment, and their energy monitoring software can use LLLC sensor data to adjust thermal setpoints after installation by local contractors.
A similarly innovative approach to integration is offered by Jeff Burns of building automation controls manufacturer Magnum First. The company can perform the site audit and system design, pre-program and bundle the material for each room, and work with local energy service companies to perform the installation. Magnum First acts as the controls manufacturer, distributor, and the integrator, returning to the site to commission the systems.
By bridging between lighting and mechanical expertise “silos,” integration service providers can limit the number of people to call when equipment eventually requires updating.
Modularity
Several people advised against installing a lighting control system that will need to be torn out when integrating in the future. Kenny Seeton of California State University, Dominguez Hills recommends choosing lighting controls that work well with BACnet, as well as standardizing across the campus to enable growth over time.
Doug White expressed a similar perspective which he characterized as “crawl-walk-run.” Because many of his clients need to gradually add spaces to a larger building management ecosystem, he favors lighting controls such as LLLCs that enable a modular approach to eventual integration.
Future of Integration
Increasing electric vehicle charging and building electrification will place greater demands, not only on the electrical grid, but also on the building’s electrical infrastructure. Energy management from these types of systems support future building needs.
Greenhouse gas emissions may be limited by the state or municipality, or even the company’s shareholders. More clients have decarbonization goals and will need detailed energy analytics to support accountability for energy use, and integrated systems can enable these types of insights. LLLCs allow flexibility in the future, both in terms of space changes and limiting future costs in labor and material.
By integrating building systems, facilities can use lighting controls to support electrical demand management. Chris Wolgamott of Northwest Energy Efficiency Alliance explained that by using LLLC occupancy data, building owners will be able to predict their needs more precisely, shifting power use away from peak hours to times of lower power demand. Jeff Burns gave an example: during times of peak summer power demand, his firm programmed a large grocery chain to pre-chill the building during low demand periods, then coast through peak demand period. With trends toward increasing electrification, this sort of demand management will help the utility maintain service and reduce customers’ utility bills.
Artificial intelligence with integrated building systems offers opportunities to recognize the occupants’ habits, and preemptively turn up the heat before the occupants typically start arriving, thus overcoming concerns about thermal inertia and occupant comfort. By using weather forecast data, these systems will be able to learn what portions of the building will likely overheat, and preemptively adjust the cooling to maintain occupant comfort. By predicting occupancy patterns, LLLCs will play an increasingly important role in future energy management in our built environment. ■
The author wishes to thank all the interviewees for sharing their insight and unique approaches to integrating these systems. Also thanked are the Lighting Energy Partnership sponsors: Northwest Energy Efficiency Alliance, BC Hydro, and Eversource.
References
1 California Energy Commission. California Building Efficiency Standards. California Energy Commission, Sacramento, 2024. [Available at https://www.energy.ca.gov/ programs-and-topics/programs/building-energy-efficiency-standards].
2 ASHRAE 90.1-2019 and 2022 – Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings. American Society of Heating, Refrigerating and AirConditioning Engineers, Peachtree Corners, GA, 2022. [Available at https://www.ashrae.org/technical-resources/bookstore/standard-90-1].
3 Slipstream Group. Integrated Controls Package for High Performance Interior Retrofit. Report number DOE-Slipstream-EE0008190; DE-FOA-00015182021. Slipstream Group, Madison, WI, 2021. [Available at https://www.osti.gov/servlets/purl/1889908].
4 Pacific Northwest National Labs. Lighting System Integration with HVAC and Plug Loads: Tinker Air Force Base. Pacific Northwest National Labs, Richland, WA, 2021. [Available at https://integratedlightingcampaign.energy.gov/sites/default/files/2021-02/EED_1063_BROCH_ESTCPbrand.pdf].
5 New Buildings Institute. Retrofit Technology Case Study: California State University Dominguez Hills – James L. Welch Hall, Portland, OR. 2021. [Available at https:// newbuildings.org/resource/california-state-university-dominguez-hills-james-l-welch-hall/].
6 Pacific Northwest National Labs. LED Lighting and Controls Guidance for Federal Agencies. Pacific Northwest National Labs, Richland, WA, 2024. [Available at https://www.gsa.gov/climate-action-and-sustainability/center-for-emerging-building-technologies/completed-assessments/lighting/led-and-controls-guidance].
7 Hinkle N, Mead R, Kirlin B. Hot Mess or Cool Tech? Secrets to Success for Advanced Building Controls Integration. In “Proceedings of the 2022 ACEEE Summer Study on Energy Efficiency in Buildings, Panel 3 – Commercial Buildings: Technologies, Design, Operations, and Industry Trends, Asilomar, CA, 21-26 August 2022. American Council for an Energy-Efficient Economy, Washington, DC, 2022. [Available at https://www.aceee.org/2022-buildings-summer-study].
8 Construction Specifications Institute. MasterFormat. Construction Specifications Institute, Alexandria, VA, 2024. [Available at https://www.csiresources.org/ standards/masterformat].
9 Benya JR. About IES Publication LP-16-22; Documenting Control Intent Narratives and Sequences of Operations. designing lighting, October/November, 2024. [Available at https://designinglighting.com/2024/10/15/october-november-2024/].
