Merging HVAC and lighting controls

Manage both HVAC and lighting from a single controller for a more cost-effective and scalable BAS.

By Louis-Nicolas Hamer, PE, LEED AP, SCL Elements Inc./CAN2GO, Montreal June 29, 2011

HVAC and lighting controllers are different products based on different technologies, which is why they are distinct. Combining both applications within a single system requires specific hardware, software, and a lot of integration labor—the long-standing assumptions of the industry.

Because controllers have a limited number of physical inputs and outputs (I/O), and because wiring to and from them is affected by building constraints, the industry has kept the focus on application-specific products—leaving HVAC and lighting apart.

The ROI of combining

Working with separate controllers means two controllers will be installed for each room where HVAC and lighting management is required. Doubling the controller count for every room is not a cost-efficient business practice and also implies using several application-specific gateways to bridge both applications to the central BAS.

These costs to “scale-up” explain why many buildings have only an HVAC management system without lighting control, and vice versa. These financial hurdles are an important factor behind the asymmetrical penetration rate of both systems.

The alternative—using single, multipurpose controllers—would significantly reduce controller and gateway count, which translates into savings on hardware, making the return on investment (ROI) more attractive. It would also dramatically increase scalability from HVAC to lighting and vice versa, providing more buildings with an affordable way to add control points to increase energy savings via building automation.

Of course, this would work well if it were not for the I/O and wiring conundrums. In the pay-per-input/output world it can be a hard sell to install a controller loaded with extra I/O just in case the building manager wants to expand his system. Even with such an expansion, wiring every control point back to a smaller number of controllers might add to the burden of wiring logistics within building walls and ceilings. In other words, we needed an alternate method to merge HVAC and lighting control in a sensible way.

Breaking the barriers

Like in all industries, paradigms change over time, often at the pace of innovation. Today, we are provided a workaround to break the I/O limit and wiring barriers. Both hurdles are being eliminated by the adaptation of mature wireless standards to building automation.

How does wireless communication change I/O count limitations? The answer is where it gets really interesting.

Physical, wired connections are limited by the number of connectors available. But when the connection is wireless, there are no connectors. The I/O limit is determined by the controller’s communication range and processing power.

Accordingly, a fully programmable controller, capable of managing both HVAC and lighting, will be able to integrate a variable and a significantly higher number of I/O by supporting wireless communication. This is precisely the kind of controller that is available today.

The wiring logistics barrier is eliminated by the same controller feature: wireless communication.

To sum it all up, the controller that provides the hardware savings and scalability benefits of combining HVAC and lighting to contractors and end users is a controller that:

  • Is fully programmable
  • Is equipped with basic wired I/O for what needs to be wired
  • Is equipped with one or several wireless transceivers to manage wireless end-devices
  • Has an embedded gateway for in-node multiprotocol integration.

Scaling up

The advantages of fully programmable controllers are permanent in that they can evolve and adapt—via line-by-line coding—to advances in energy management techniques and programming. The advantages of using controllers with wireless I/O are also permanent in that they allow continuous scaling.

In an upgraded facility, the controllers that are now in place have the capability to take in even more control points. If the manager wants to add occupancy sensors, light sensors, or access and security oriented end-devices, the existing controllers will be able to manage them. The only constraint is wireless compatibility. In the aforementioned case, the communication standards used are EnOcean for end-devices and ZigBee for controller networking, both resting on broad adoption.

Whether a system integrator is called upon to install a lighting or HVAC control system, putting in place multipurpose wired and wireless controllers will allow long-term scalability without incurring further controller or gateway expenses while minimizing wiring labor costs. This effectively converts any HVAC project into an easily upgradable installation for lighting control, and vice versa.

Planning for change

This method is well suited for retrofits and renovation projects, without discounting applicability for new constructions too. Very few new construction projects come with a pre-installed BAS; those decisions usually are reserved for the incoming building managers, not the main construction contractor.

In a majority of cases, new buildings have to deal with the same situations as older buildings: configuration changes that come with new tenants, scaling from HVAC BAS to lighting BAS, adding sensors over time to improve control and efficiency as building use evolves, and upgrading systems to comply with new regulations.

Whether the building is old or new, system integrators and building managers who rely on good planning are destined to plan for change. Within this context, a multipurpose architecture that can easily scale, expand, and be easily repositioned due to strong wireless capabilities is a cost-efficient way to start a new building.

Energy codes compliance

The merged HVAC and lighting control solution can play a significant role to achieve the U.S Dept. of Energy-recognized ASHRAE Standard 90.1-2007 and U.S. Green Building Council LEED certification.

For Standard 90.1-2007, the merged solution provides compliance for several lighting and HVAC control items (see code sections 6.4, 6.5, 6.7, and 9.4). For LEED, it provides points for minimum and optimized energy efficiency performance, performance measurement, and the lighting and thermal comfort controllability of systems.

In relation to such codes, the difference between an application-specific architecture and a multipurpose control architecture is twofold. First, you’re not limited to points for HVAC or lighting applications; you get both. Second, because the use of wireless reduces downtime, repair, and labor costs, compliance is obtained with a faster payback period and better ROI. This, in turn, can accelerate BAS adoption as a whole.

Right now, the penetration rate of BAS is approximately 45% for large buildings (over 100,000 sq ft) and only 5% for small and medium buildings (less than 100,000 sq ft). The main deterrent is the payback period—the more cost-efficient merged control solution can increase penetration in larger buildings and unlock the smaller buildings market.

Trans-disciplinary technology development

We often react to innovation with admirative surprise: “What a great idea!” But in many cases, we should react with inquisitive reprimand: “What took so long?” In this case, I really believe it should be the latter because even though the factors that have delayed this innovation are tangible, they should have been circumvented earlier.

These factors are twofold. First, for a number of manufacturers, the departments and subsidiaries that develop HVAC products are separate from the ones focused on lighting products. Second, their respective research and development efforts were always limited to the confines of automation technology, foregoing all the opportunities presented by the IT and networking side of the technological spectrum. Creating a line of HVAC and lighting, wired and wireless controllers, required taking the opposite route: combining automation, IT, and networking know-how through an innovation process that leveraged multiple fields of expertise.

The juxtaposition of expertise can be summarized as follows: Automation know-how is the base of the pyramid, providing reliability, interoperability, and accuracy in execution. IT technology powers this base via electronic components that boost controller random-access memory, storage, processing capabilities, and multiprotocol integration. Networking standards, namely established wireless ones, add flexibility and reduce the labor cost of system installations.

By finally opting for a transversal research and development philosophy, the building automation industry is now able to offer more flexible and powerful solutions to contractors and end users. Contractors gain competitive advantages by offering systems with shorter payback periods and reduced invasiveness and downtime on installation. End users gain by harnessing the maximum amount of energy savings at a lower cost of ownership.

The smartphone you have in your pocket right now probably enables you to talk, exchange e-mail, surf the Web, and take pictures at the same time. What has your BAS controller done for you lately?

Hamer is the vice president of Product Strategy at SCL Elements Inc. He is the co-founder of the engineering consulting firm Eco2Max and has worked for Nortel and Verint. His expertise covers energy efficiency, greenhouse gas reduction, wireless technologies, and network reliability and security.