Smart HVAC: Smart Commercial Systems Yield a Rich Harvest With Benefits
Today’s smart commercial systems have benefited from several technological improvements that have helped them integrate into existing systems more easily. They also can be used to harvest system performance information that helps keep comfort high and could help reduce service and maintenance costs.
Dick Lemke, portfolio manager for system controls at Trane Commercial Systems, has seen a lot of changes in the 25-plus years he has worked in the HVAC and controls industry. In the early days, “Systems were an add-on to buildings in order to get some kind of energy savings and control,” he said. “That has really grown substantially.”
Tim Wallaert, director of controls product management at Lennox, said the company has seen a continuing theme in the development of smart rooftops. “Years ago, electronics started replacing mechanical controls. Over time, those systems needed calibrations. Then electronics got smarter, providing diagnostics, preventive shutdowns, and monitoring of the system. Now we are making it easy to integrate and install.”
CONTRACTOR PERKSThe biggest change from Lemke’s perspective is the integration of controls into equipment at the time of manufacture. “When we build a package rooftop unit, we build DDC right in at the factory,” he said.
That change doesn’t just affect the manufacturing process. “It enables that piece of equipment to more easily tie the HVAC into the complete building system, gives more access to troubleshooting data and service requirements,” Lemke said. “For example, in the past when we added a controller onto the HVAC unit, we could tell if it was heating, cooling, blowing air, and what the space temperature was relative to the set point. Today we can gather 30 or 40 pieces of data from that equipment - all the internal diagnostic things that we typically look for on the service side.”
This allows whoever is taking care of the equipment, whether an outside contractor or inside staff, to do a better job from the maintenance perspective, Lemke said. “We know the specific run time on the unit for filter changes and coil cleaning, on a preventive basis,” instead of relying on somewhat subjective recommendations. It also gives the maintenance person something to show the customer, that justifies the PM work.
Smart systems “can also allow a servicer to look at the status on the piece of equipment without going out on the job,” Lemke said. “Think of a guy going to the jobsite, going to the equipment, going to the parts house, and going back to make the repair; he can make several assumptions of diagnosis based on data” - and sparing his knees at least one trip to the equipment.
The data gathered by smart systems could also increase system commissioning and retrocommissioning, making sure the building operates the way it’s supposed to. “Having access to so much status information, you can see how the equipment performs for the occupied space.” For first-time commissioning, smart systems allow for access to all HVAC equipment, devices, and controls from a common location. “It is a real timesaver for a commissioning agent when he is on the job.”
Once commissioning has been done, the smart system can provide a full report verifying that the system is functioning as designed. “Trane puts those commissioning report-generation tools right into our support software,” Lemke said.
CONNECTIVITY FOR CONTRACTORS“That’s one of the great things about integrated controls - all of the information that they can give you,” Lemke said. “There is great connectivity to building controls.” Phone dial-up is still one of the most common methods for remote connectivity. Today with Web capabilities and local area networks (LAN), we’ve greatly expanded that connectivity, sending more data to more places.”
What does a contractor need to tap into this wealth of information? That depends on the particular system and its complexity.
Lemke said there are two common methodologies: proprietary software from controls system manufacturers and Web server capability. “No special software is required if you can obtain LAN or Web connectivity; all you need is something like Windows.” This compatibility currently is being built into control devices, he said. “All of the devices we are making and looking at developing have that Web-serving capability. Laptop, cellphone, or PDA, those pages can be served up with the use of a password.”
Web-based access brings an increased emphasis on security. “Security is confronting our systems. It’s important for our industry to make sure we’re a good citizen in the Web environment that makes not only the control system secure, but that we also connect the other part of the LAN, so people can’t use us as a conduit to other parts of system information.”
Looking ahead, “One of the things I see is that our industry is using more industry-standard protocols. Instead of inventing our own protocol, we may use the standard Ethernet Protocol. Embracing the same technology is something that our industry is starting to take hold of.”
INSTALLATION EASEAre these systems really easier to install? For instance, how easily can they be integrated into older technologies already present in the building? “There is some system dependency,” said Lemke, based on whose systems are trying to link up, and the complexity. “One thing we build into our control systems is autoconfiguration and autocommissioning.
“Once the devices are installed and powered, and the communications devices are hooked up, the HVAC controls are capable of sending a message out through the wiring out, detecting devices, gathering data, starting up, and running in an occupied mode.” The contractor needs to make sure the wires have been run to the right place.
Wireless systems help still more. “We have a wireless temperature sensor line available today,” Lemke said. “From the contractor’s perspective, he can order a VAV [variable air volume] box; there are no wires to connect between the sensor and the VAV box. The connection is made by setting the address on the back of the sensor.” Having the one address linking the VAV to the sensor prevents other signals from interfering, he said.
“The other great part about that from a contractor’s position,” Lemke continued, “is that it allows him to put the sensor in the right place to provide occupant comfort.” Think of building turnover and tenant changes; this happens on an average of less than two years per tenant, he said, and it’s often accompanied with changes in how the space is used. “It’s easy to remove those wireless sensors. The contractor doesn’t have to worry about rewiring, and it helps the control system meet the comfort requirement.”
The wireless technology Lemke refers to is designed to work with Trane equipment such as the VAVs, rooftop units, and fan coils typical in commercial environments.
EASIER TO ZONESmarter technology can also help contractors offer better solutions, such as zoning, by making them easier to install.
Wallaert said the company’s Comfort Sensor combines most common sensor types and zone controllers in a single enclosure, with an intuitive interface for daily user functions. The contractor connects two communication wires and the power source. “The product promotes a more modular approach to sensors and zone controllers, reducing installation labor and improving aesthetics.”
The product won a 2007 AHR Expo Innovation Award. “It reinforces that we’re pretty proud of how easy this is to use,” Wallaert said. “Guys are able to correct problems quickly.
“Ease of use has been our watchword,” he continued.” You’ve got pressure and temperature sensors in the rooftop units; all of which gets back to the integrated modular controller (IMC). You can quickly diagnose if you’ve got something out of balance. You’ll also find a problem pretty quickly in commissioning.”
The need to outsource zoning projects has been a deterrent for some contractors to offer them at all, Wallaert said; these contractors simply didn’t feel comfortable doing it themselves. “If one of our good contractors wanted to bid on a job that included zoning, they’ve had to rely on third-party solutions. This resolves that entire situation.”
He drew the following analogy: “If you’ve ever tried to install a device like a camera on your PC, compare it to how you would do that on a Mac.” It’s just easier. “For contractors, they’re easy to install and easy for the building operator to use. Our L Series and S Class rooftop units have the IMC and a simple, two-wire connector. Somebody who is already familiar with the Lennox rooftops is already familiar with this technology.”
OWNER INTERFACEFor the building owner/operator, smarter systems such as the Comfort Sensor, enables that person to have control over the entire enterprise. “They can schedule or program via a laptop. Zones can be overridden; they can set it so occupants can’t change anything, and they can get the status on zones.”
They can also get IAQ information such as humidity and CO2 levels. “For schools, this is becoming more and more important,” Wallaert said.
“The sensors notice that the air is stale and that message goes to the rooftop controls. Another whole raft of other things opens up.”
Occupants can control their comfort via a large digital display with up and down arrows - or not. “The system gives the building owner/operator flexibility over what they give their occupants control over.”
Contractors, on the other hand, know which zones can be overridden. “It will minimize callbacks,” Wallaert said, “and that’s what contractors hate more than anything else. Zoning is the way to maximize comfort and energy efficiency. Customers are happy and life is good.”
Sidebar: A Smaller FootprintBetter start getting used to hearing about carbon footprints. This is how professional HVACR and energy organizations are referring to the amount of carbon a utility company releases to the atmosphere as it meets any particular building’s energy needs. It’s a measure of carbon emissions that contribute to global warming. Reduce a building’s carbon footprint and you lower its contribution to global warming, at least to some extent.
A new, wireless, environmental automation system is said to help hotels cut energy costs and, therefore, carbon output. The WiSuite™ Environmental Management System, invented by Riga Development, uses Ember’s ZigBee networking technology to let property owners have more control of the energy expenditure of every room without compromising occupant comfort. (ZigBee is a global wireless industry standard designed for remote monitoring, control, and sensor networks.)
Westmont Hospitality Group has been evaluating the system in several of its Comfort Inn and Holiday Inn properties in the Toronto area. When a nationwide rollout is completed, Westmont said it expects to save more than $2.2 million in energy costs per year. This equals 14,678 megawatt-hours (MWh) of electricity, eliminating 12,500 metric tons of coal-generated carbon emissions, according to an announcement from ZigBee and Westmont.
The system configures itself into a wireless mesh network of digital thermostats, appliances, and receivers throughout a building. The controls start communicating with the environmental system when occupants check in at the front desk. Unoccupied rooms are kept in setback mode. The entire system, however, is monitored to detect potential problems.
A WiSuite Control Center, securely accessible via Web browser, lets facility managers and front desk staff control the devices, monitor their status, and set up custom schedules. Riga said it plans to expand the products to control power to other in-room appliances, such as TVs, minibars, and lighting.
KEEP TRACK OF USAGE
Being able to measure energy consumption is critical in controlling its use. Echelon Corp. said its Networked Energy Services (NES) smart metering infrastructure is being deployed by the some of world’s most advanced utilities.
Echelon said it plans to bring its production capacity to more than 40,000 smart meters per week by mid-2007. According to Bea Yormark, Echelon’s president and chief operating officer, “In the last eight months we have secured orders and options for more than 1 million meters. After several years of intense research and development, Echelon designed an end-to-end solution which is now being rapidly adopted.”
The meters use digital, intelligent communicating technology “and are not hampered by existing electromechanical designs,” the company said. They feature standard power line communication (PLC) signaling, and are capable of real-time, two-way communication with the utility.
Since they are designed as a network component, the meters will be able to be used in potentially millions of homes with high reliability.
Publication date: 03/05/2007