Building automation systems (BAS) allow building managers or their service providers to remotely control HVAC, lighting and other applications, in turn maximizing occupant comfort while typically reducing energy consumption by 15% to 30% (it can go as high as 50%). But there has been a traditional split in the BAS industry between lighting and HVAC controls, despite the fact that lighting and HVAC equipment can always be found next to each other in any room of any given building.

The two have been compartmented for many reasons. On the technical side of things, the logistics of wiring and limited number of inputs and outputs (I/O) on every controller have narrowed the industry focus on application-specific products – either lighting or HVAC. On the organizational side of things, HVAC and lighting controls have emerged as comfort, safety and energy efficiency solutions at different times, and are often manufactured by different companies. They are also frequently installed and maintained by different servicers specialized in one or the other.

A costly split
The separation, for which there was no alternative until now, has had a steep cost for system integrators, building owners and facility managers. Having separate lighting and HVAC systems means that each application requires its own set of controllers and gateways, in turn doubling the number of boxes (hardware) required to fully manage every zone in a building. In some cases, the management software or dedicated server for each application might even be different. Overall, the lighting/HVAC split has inflated the cost of building automation systems for most stakeholders.

Considering all of the above, it’s no surprise that some buildings have centralized HVAC control without lighting control, and vice versa. This is a testament to the difficulty of scaling from one application-specific system to the next. To be more precise, the penetration ratio of HVAC to lighting energy management systems is approximately 4 to 1. Building automation systems in general are only found in about half of large buildings and less than 10% of small and medium size buildings (under 100,000 sq. ft.).

For the uninitiated, the distinction between HVAC and lighting might seem a bit odd. If a smartphone enables you to talk, exchange emails, surf the web and command your home appliances at the same time; how is it that one controller cannot manage HVAC and lighting simultaneously? That is a good question, which has been answered.

Leveraging the power of IT
When looking at innovations, our reaction is often admirative surprise: “What a great idea!” But in many cases, it should be inquisitive reprimand: “What took so long?” In this particular case, it really should be the latter. To understand how this innovation came about, it is important to understand what delayed its arrival.

On the manufacturing front, several hurdles had prevented the emergence of a combined HVAC/lighting line of controllers. First, within industry giants, the departments and subsidiaries that make HVAC products are separate from the ones focused on lighting products. Second, their respective R&D efforts were always limited within 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. Fortunately, it was achieved.

The advantages of combining wired, wireless, HVAC and lighting control
First, combining HVAC and lighting in one controller cuts expenses for both controllers and gateways. Because the controllers are fully programmable, instead of application-specific, there is no longer a need to have one controller for each application. This reduces the number of controllers per room to one, instead of two (HVAC & lighting) or more. The same rule applies to gateways. Since the integration is made in-node (inside the controller), extra gateways are no longer required. This also simplifies network architecture and installation logistics.

Diagram of Merged HVAC and Lighting Controls

Regarding labor costs, having both physical and wireless inputs and outputs on a single device means being able to wire what needs to be wired, while going wireless for everything else. Since opening and closing walls to connect controllers and end-devices is costly, wireless control and networking reduces labor and downtime on system installation – in turn making the payback period much shorter for the end-user.

The nature of wireless is what allows a cost-effective bridge between HVAC and lighting controls. Unlike their physical counterparts, wireless I/Os are not limited by a fixed number of connectors or points. They can take as many ins-and-outs as their communication range and processing power can handle. Instead of being limited to control one, two or three end-devices, a wireless enabled controller can easily manage five, ten or even fifteen end-devices… at no extra cost.

Taking scalability to a whole new level
In terms of scalability, the expression “the whole is greater than the sum of its parts” suits this development well.  Combining HVAC and lighting control with wireless capabilities dramatically decreases the cost of adding new control and sensing points to existing systems. Let’s take the example of an office building where the manager wanted to improve energy efficiency. First, he wanted to control an existing variable air volume (VAV) duct system and install new thermostats. Second, he wanted to prepare the upcoming expansion of his BAS – adding lighting control, occupancy sensors and other similar end-devices – over time and based on his initial ROI.

The project was made with CAN2GO VAV controllers (they support HVAC & lighting control via wired and wireless communication) from manufacturer SCL Elements. Each unit and their pressure sensors were physically wired to a VAV box. Instead of wiring all the controllers together, they networked wirelessly using their ZigBee transceivers. The thermostats chosen were based on the EnOcean technology; a standard for wireless, battery-less energy harvesting devices. CAN2GO controllers also having embedded EnOcean wireless transceivers, no wiring was required there either. Overall, the installation cost had been greatly reduced. No walls had been opened and downtime was minimal. The manager could expect a fast payback. But what about his upcoming expansion? Was he ready?

When the time will come to add more end-devices, there won’t be any headaches. Because the already installed CAN2GO VAV controllers can manage both lighting and HVAC, with wired and wireless inputs and outputs, the only work necessary will be to select the proper wireless devices, place them in each room, and let the existing controllers do the rest. For the manager, it means minimal hardware, labor and downtime costs, which enables him to scale up much faster.

The scenario would be quite different with a traditional, wired only, set of VAV controllers. The initial setup would require wiring between controllers and to each thermostat – adding labor and renovation costs. With regards to expansion, it would be tedious and pricey. First, new sets of application-specific controllers and gateways would be purchased and wired together in parallel networks. Second, all new devices, whether for control or sensing, would be wired back to each controller. These constraints would be great for all dry-wall contractors out there, but not so great for building owners and managers.

There is simply no comparison between the payback periods of the two solutions. The less a system costs on installation, the faster the return on investment will be. And the faster the ROI, the sooner more investments can be made to save even more energy.

Building automation’s missing link
The demand has been growing rapidly for cost-effective energy management solutions. But the industry was stuck offering technology that was 10, 20, or even 30 years old. Accordingly, the penetration rate of these products is half of what it should be. New technology was needed to close this gap and provide payback periods that match today’s fast ROI expectations.

Photo of a connected office space

Building automation controllers that offer simultaneous wired and wireless control for lighting and HVAC applications are the new face of the industry. They support multiple communication standards and protocols, such as BACnet, IP/Ethernet, CANbus, Modbus, EnOcean and ZigBee – allowing managers to reduce labor and downtime expenses while increasing scalability. It is not a stretch to say that they are building automation’s missing link.

About the Author
Mr. Hamer is a registered professional engineer and an accredited LEED professional. He graduated in electrical engineering from the University of Sherbrooke’s coop program and has also completed technology product management and entrepreneurship training by the MIT. He is a frequent contributor to various local and international conferences and publications on the subjects of energy efficiency, greenhouse gas reduction, wireless technologies and network reliability and security. Before joining SCL Elements, he co-founded Eco2Max, an engineering firm specializing in energy efficiency and building automation. He has also worked for larger groups such as Nortel and Verint.