Leveraging embedded technology to empower building automation
Embedding gateway and Web server functionalities at the controller level allows building automation systems to offer better solutions encompassing more applications to a wider variety of building types, including the large underserviced market of light commercial and mid-market buildings.
We live in a world of networks. Your car’s navigation system, your smartphone, your baby monitor, your PC and router – all are part of networks. As we function within these networks, we forget about them, as it should be.
Surprisingly, even though building automation is a landmark networking industry, and despite the constant emergence of new communication and processor technologies, the Building Automation System (BAS) industry’s technological portfolio has progressed at a snail’s pace. During the past three decades, our society has gone from rotary phones to omnipotent satellite-linked devices combining phone, camera, and computer functionalities with Web browsing and augmented reality capabilities. In that same period of time, the building automation industry has barely been able to adopt a limited number of standards, sticking with the same basic hardware and software models. However, that intransigence is changing.
Tower of Babel no more
Many BAS parts aren’t interoperable because they use different protocols. At the integration level, BACnet and Lon are the two dominant standards. But at the control level, several interesting pieces of hardware use other protocols. For example, many inexpensive products for lighting and metering use Modbus. And more and more game-changing wireless products for lighting, HVAC, and access applications are using the EnOcean and ZigBee standards.
Bringing all those different components into one system is sometimes difficult and costly, if not downright impossible. This is where embedded technology comes in. The BAS gateways that try to combine these pieces have traditionally been quite expensive and most often found near the top of BAS architecture, preventing the use of intelligence at the local level. The solution to this conundrum is to embed gateway functionality at the controller level. This not only allows a single controller to manage multiple end devices using various protocols, it also allows the use of intelligence and programming at the local level in each controller.
With such a solution, system integrators – the people who install BAS – can choose the best combination of end devices to meet their clients’ needs.
All systems in one box
Controller-embedded gateways also address a second pain point of BAS: They tend to be application-specific. Looking at the number of buildings equipped with HVAC and lighting BAS in the United States reveals a huge discrepancy. There are 5x more HVAC systems than lighting systems. This divide between the two applications is decades old and remains today because expanding from one system to add the other is costly. They each use their own different controllers and gateways, so the installation of one system provides absolutely no financial advantages leading to the installation of the complementary system.
Fortunately, controllers that provide their own gateway functionalities as well as support local intelligence and programming are bridging this historical divide between applications.
A single controller with an embedded gateway can manage HVAC, lighting, and other applications such as access, occupancy, and metering. Thus, instead of installing two, three, or four parallel systems, an engineer can use a single controller for everything. This drastically cuts installation time and hardware costs, making system expansion easy and cost-effective.
This begs the question: How can a single controller with a limited number of I/O manage all these applications? That’s where wireless communication comes into play. There’s no I/O count limit with wireless; the only factor that matters is range.
A practical example of this is the wired and wireless CAN2GO controller (Figure 1), which comes with an embedded gateway and Web server. Thanks to its wireless support, a single CAN2GO can manage a quasi-unlimited number of wireless I/O from EnOcean and ZigBee end devices. In a K-12 school installation, one of the units manages five thermostats, five actuators, seven lighting relays, and seven light switches, all without a single wire.
The controller is the server
Besides the gateway, another component of traditional BAS can be embedded directly into controllers to expand the appeal of control-based energy efficiency: the server.
In a traditional BAS, the interface from which everything is programmed and monitored is the Building Management System (BMS), which is often based on a dedicated server or software package with license fees. The dedicated hardware and software license cost of the BMS effectively excludes 65 percent of the commercial market from building automation solutions.
Buildings with less than 100,000 square feet represent 98 percent of buildings and 65 percent of the floor space of the commercial real estate market in the United States. But according to a U.S. Energy Information Administration nationwide survey, the penetration rate of HVAC energy management and control systems in this market is 5 percent, and it’s even worse for lighting energy management and control systems.
The main reason for the lack of BAS penetration in this market is that a BMS does not scale well and tends to cost proportionally more in small and medium buildings than in larger constructions. These fixed costs lengthen the payback period and cannot be absorbed by light commercial and mid-market facilities.
A controller with an embedded Web server solves this problem by providing an affordable alternative to this huge underserviced market (see Figure 2). Wi-Fi routers have embedded servers and it doesn’t make them bulky or expensive. Putting Web servers inside controllers offers a viable user interface, with all the necessary programming options including scripting, schedules, events, trend logs, and more without the costs that accompany dedicated servers and large software suites.
Case study: Cardboard box factory
In Montreal, Canada, a 427,000-square-foot factory has 25 gas-fired unit heaters originally controlled by mechanical thermostats. The challenge was to integrate the heaters within the existing BACnet IP system used in the office section of the factory. Because installing miles of conduits and wires throughout the factory would be costly and cause downtime, wireless was the only option offering a short payback period.
The optimal system architecture was to use wireless EnOcean relays to control the heaters, as well as ZigBee wireless mesh communication for networking because of the better wireless range. The contractor chose to use CAN2GO controllers because their embedded gateways allowed each controller to tackle both EnOcean and ZigBee communication at the same time. The controller’s embedded servers provided seamless integration to BACnet IP, along with the Web BMS necessary for configuration. Only 25 controllers were needed to cover the entire facility, without any gateways or dedicated server and with minimal wiring.
Using this embedded solution, installation time was reduced by 40 percent and caused no downtime for the factory. Overall, $45,000 was saved on labor and materials during installation.
Ready for the future in wireless and IP
Looking at the global trends shaping the future of the building automation industry, the use of wireless technology and IP integration are the two dominant forces at work. Using embedded gateways and Web servers at the controller level is a sensible way to meet the needs presented by those trends.
As we go forward, more and more systems – HVAC, lighting, metering, access, and others – will converge to a single point of integration. Wireless communication is the most cost-effective way to install and control the end devices in these systems. An embedded solution provides the local intelligence and multiprotocol integration necessary to interact with all of these components and flip everything over to IP.
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