Face it, when we talk about a BAS, we typically mean HVAC controls. Providing good control of HVAC has a dramatic impact on the comfort and energy efficiency of a building. However, by only controlling HVAC, we are not addressing the other major energy loads in the building, which include both lighting and plug loads. In fact, lighting is typically the second-largest energy consuming system in most buildings. Lighting systems also share common characteristics with HVAC systems, including the need to be scheduled to match building occupancy, common operations staff, and the ability to connect to future systems including the Smart Grid.
Most BAS have little interaction with lighting control, and when they do, it is often fairly rudimentary (such as switching exterior lights or large zones of lighting within a building). There are many good reasons why a BAS has not typically included more sophisticated or integrated lighting control. This includes a perceived lack of need (and budget), and the technical challenges with lighting controls and protocols. But the real reason has more to do with the division of design disciplines and construction trades. Lighting systems, and therefore their controls, are the responsibility of the electrical engineer and contractor, while HVAC falls to the mechanical engineer and contractor. Therefore the design of an integrated lighting and HVAC control system requires considerably more mechanical/electrical coordination beyond what is traditionally performed.
The movement toward the delivery of high-performance buildings, however, is likely to cause this to change. Providing an efficient building requires good lighting control that includes coordinated scheduling, occupancy sensing, and daylight harvesting. These strategies are quickly becoming requirements in programs such as LEED® and are an expectation in many state energy codes. This is driving the need to design and deliver more sophisticated lighting control systems. It is not an unreasonable stretch to go from these more sophisticated systems to one that allows for integration between HVAC and lighting. There are several benefits that come from integrating BAS and lighting. These include:
- Improved energy efficiency due to coordinated scheduling, occupancy control, and light level optimization.
- Common user interface allows for improved productivity for the operations staff and allows them to more readily respond to occupant’s requests.
- Information from lighting and HVAC can be used to analyze energy usage and to achieve necessary measurement and verification for benchmarking and programs such as LEED.
- The ability to control both lighting and HVAC allows for real-time control options as utilities deploy Smart Grid strategies.
P.S. Integrated lighting control will be one of the main topics at the Engineered Systems Sustainable Solutions Conference next month, which will be a great opportunity to see new products and learn more in lighting sessions and Q&A. ES