HVAC and BAS Approach Peak Efficiency

Nov. 2, 2013

Worldwide, the consumption of energy to provide buildings with heating, cooling, and lighting outstrips all other energy uses on the planet. And within buildings, HVAC boilers and especially chillers typically consume more power than anything else.

Given incessant growth in energy demand, the power generation industry can barely keep pace. There have been multiple initiatives to reign-in excessive energy demand by every means. A new one reportedly looming in 2016 is an effort by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to develop standards for measuring building energy use so that higher efficiency targets under ASHRAE 90.1 can become effective that year.

The past couple of decades have brought steady improvement to building automation system (BAS) components, operational practices, and dashboard or automated smart controls, “to the point,” says HVAC industry executive Bob Gray of Schneider Electric, “that we’ve pretty much done everything we can do to eke-out as much energy savings as possible.”

So the question building owners and HVAC managers have been asking is: What, if anything, are the options for investing in building energy savings that can be recouped in a reasonable timeframe?

Gray, who is an OEM segment manager for Schneider’s HVAC business, points out that a well-maintained HVAC system “that’s still in good shape after a decade or so, typically won’t be consuming any more energy than when it was new. Yet, during its years of service, energy costs have kept creeping up.” Schneider Electric is a multinational corporation headquartered in Rueil-Malmaison, ÃŽle-de-France, that specializes in electricity distribution and automation management, and related products.

Nevertheless, he says, tech advances are in the pipeline constantly. The question, “What’s left to do?” is really only rhetorical. In fact, there are plenty of cost-effective energy efficiencies to accomplish if you know how to find them. The following brief discussion merely introduces a few representative products and larger trends now influencing many systems and technologies offered by scores of businesses.

And markets are clamoring for it all, too. Gray notes that, especially given the current cachet for green buildings and optimized facilities à la the increasingly sought-for LEED (Leadership in Energy and Environmental Design) building certificate, there’s a holistic dynamism occurring between demand for efficiency and eager vendor suppliers.

Historically, the two prime building energy users could be delineated as HVAC and lighting. But some degree of convergence in their operational management has come to pass, due to cheaper and easier networking and shared system resources. To a large degree, both HVAC and lighting work more efficiently if they’re powered on for occupied rooms, then muted or off for vacant ones. Moreover, this common strategy enables all-in-one performance monitoring and integration. Decisions can be fine-tuned at one remote dashboard or console, or, even increasingly, via a mobile smartphone app. Powerful, and very affordable, hosted cloud solutions integrate the systems, thereby enabling collaborative energy management with service vendors.

The cost of ownership is also tending to decline to the point that surprisingly small facilities can gain BAS benefit.

To start with, Gray suggests, a site owner can apply HVAC-related retrofit solutions “that dig deeper into the control of the machine.” One good example is what Gray calls “floating high-pressure control,” or what’s more commonly known as building high pressure control (BHPC). This method, he says, “will enable you to take advantage of cooler outdoor air temperatures to reduce your intake temperature . . . and, under part-load conditions inside, to reduce your high pressure.” He explains: “Any time you can do this on your refrigerant circuit, you’re able to reduce the lift, or the amount of work that the compressor is actually doing,” and thus save energy on, say, a building’s air-cooled chiller.

This “floating” or flexible pressure is accomplished with a control upgrade, he notes. It can potentially save up to about 25% of the power load on that particular piece of equipment. Almost two decades ago, ASHRAE independently validated this impressive figure, he points out.

Complementing this on the compressor side is an energy innovation that Gray and Schneider Electric call “superheat control.” This is accomplished by adding a new component in a tweaked setting.

Gray explains: First, “You have to make sure you have an electronic expansion valve meeting your low-pressure side” to accommodate this control. This enables accessing “the high-pressure control on the high-pressure side by utilizing VFDs [variable frequency drives] on your condenser bands, plus a pressure-control algorithm.” This arrangement takes advantage of colder outside air temperatures and part-load conditions, he says. In the bargain, “you get quite a bit more energy savings,” he adds.

Gray also points out the reality that, although such HVAC retrofit and control concepts have been around for two decades or so, there’s a gap between what’s theoretically doable and what’s been brought to market in practical terms. Accomplishing floating operational control, he says, “takes more than a device and software with an algorithm,” as, ultimately, success requires alterations in architecture to make the savings happen.

“So,” he continues, “you have to have VFDs, appropriate electrical distribution components, sensors, control panels, disconnects, fuses, and everything that goes with that particular solution, to monitor modify that machine to make that work.”

Paradoxically, then, although a BHPC makeover brings potent savings and isn’t exactly new, few facilities managers have actually ever seen one implemented. This, says Gray, is primarily because nobody has come up with an effective turnkey solution to make it happen without costly customized design. “Although you have any number of manufacturers of controllers out there,” he says, “they’ve not put the architectures together.” They might slap on a smart device, but the energy-saving legwork is left undone.

There’s plenty of inherent need, though, he notes: In the past two decades about 180,000 air-cooled chillers have been installed domestically. Their average lifespan runs 15 to 18 years, ASHRAE has found. Even so, few sites have put together complete solutions, again due to the need for specialized remodeling.

With that thought in view, Schneider Electric recently set about designing a relatively easy “bolt-on” retrofit package that’s “a plug-and-play type solution,” says Gray. It is comparatively “very quick” and easy to install and commission, and can be had for less than one-tenth the cost of a full HVAC system replacement. If applied to, say, a 10-year-old machine, it can raise efficiency to rough parity with that of the best new equipment. The retrofit offers a two- or three-year payback, and can potentially extend equipment life because it decreases the short cycling of compressors, which are the HVAC components most likely to go bad.

VFDs, Mobile Monitoring, Continuous Commissioning
Gray continues his overview of HVAC efficiency suggestions by again mentioning the ubiquitous and ever-increasing role of VFDs. They’ve been around for years now. They remain an unbeatable value, he says, both when specified in new HVAC systems and for retrofits.

In terms of impact, typically, by replacing a fixed-speed fan with a VFD and controller, he says, “You can reduce fan speed 20%, and that will yield you 50% energy reduction.”

However, reducing or varying fan speed will add a need for monitoring the resulting indoor air quality (e.g., levels of CO2 and VOC), which in turn determines the number of air exchanges needed per hour in a building, under ASHRAE code 90.1. “So,” he continues, “VFDs have to be coupled with a more sophisticated control and monitoring system” to assure compliance. Special controls are needed whenever installing VFDs on rooftop and/or water-cooled HVAC units.

That said, trending strongly these days with HVAC design is a capability for built-in monitoring of the new systems. On such machines, says Gray, it’s critical to understand and evaluate your specific need for networkability, given the babel of protocols (BACnet, LonWorks, SNMP, Internet IP, Modbus, ZigBee, etc.)

Surging beyond even this well-established networking expectation is a market demand for smart phone apps, especially to monitor kilowatt-hour usage and voltage conditions. He comments: “It’s not enough anymore just to be able to operate the machine effectively, without being able to check in on it” periodically. “The maintenance staff, performance contracting parties, and building owners,” are all now toting smart phones. They naturally expect to be able to on amps and volts from time to time. This kind of doting attention is also increasingly mandated by the high performance standards set by LEED ongoing certification, he adds.

Another fairly new and expanding trend in HVAC is the notion of continuous commissioning. This could be defined, he says, as “better machine control, as compared to what we had even just five years ago.” The controller that provides continuous commissioning, he adds, “is going to be one that’s specifically designed for the HVAC equipment and provides that very in-depth machine control,” alluded to above.

In this context, continuous commissioning means that, “At any given time when you check on a piece of equipment, it is able to “˜self-correct,’ you could say, to be able to provide the most efficient operation at any given time.” For example, as condenser coils get dirty, the adaptive control would be able to compensate for dirty coils by increasing the condenser speed appropriately-“while still being able to get the maximum BTU transfer across the coils,” he explains.

“Seven Steps to Maximizing Central Plant Efficiency”
Johnson Controls (Corporate headquarters in Milwaukee, WI) is, of course, a major supplier of BAS components. In 2011, the company published a helpful whitepaper that neatly sums up the current state of HVAC and its optimization. The “seven steps” are described by David Klee, Johnson Controls’ director of HVAC channel marketing and strategy, and Gary Gigot, who at the time of authorship was vice president of business development for Optimum Energy, LLC (Seattle, WA).

In essence, Klee and Gigot echo a point made by Gray: impressive continuous improvement in HVAC products has been going on for decades-but the future potential curve is leveling off. So, “What’s left to do?”

Second, they write, it’s very common to find that, over time, even the best components “fail to maintain their promised efficiency.” This is because historical maintenance practices have focused on parts replacement and assessing potential failures. In place of this mindset, they suggest, it’s time to think more holistically of central plant optimization, being a resource that is networked and interconnected.

The term is new and fashionable, but there’s imprecision about what CPO means. Basically, say the authors, optimization consists of combined solutions: hardware, software, third-party add-ons, and operational and maintenance practices as well. There needs to be a shift in thinking. It’s not enough simply to specify best-in-class hardware and assume that optimization is done. Components alone “cannot deliver the levels of energy and operational savings” that are being demanded. Thus Klee and Gigot offer seven steps which, skillfully applied, “can deliver sustained energy savings of up to 60%.”

  • First comes system design (Basically, use VFDs).
  • Second, component selection (Right-size these for typical working conditions, not for extremes.)
  • Third, component application (Be precise in complying with a component’s operating specs, e.g., use exact water flow-rates and chilled temperatures, not ballpark figures.)
  • Fourth, apply building automation systems. High-end BAS can perform amazing functions, like continually turning on systems in proper sequence, developing self-adjusting algorithms, and recalculating set-points.
  • Fifth, use of networking software. Increasingly, this is Web-accessible for convenience and is cloud-based.
  • Sixth, revamp maintenance to make it more predictive rather than too reactive.
  • Lastly, apply copious energy-performance measurement and verification tools. For example, systems can now offer profuse Web-delivered performance stats and diagnostics.

A Self-Powered-Building “Enlightenment”
To wrap up, here’s a look at some emerging products and practices within the ongoing boom in lower-cost building control technologies.

They’re not just for HVAC, but offer integration of wireless networking of thermostats; addressable dampers for zoned climates; all manner of smart switches, sensors, and such; and control of room lighting and, even, plug outlets.

Globalized production has spawned dizzying lineups of OEMs, system integrators, software developers, and providers of wireless networking. It would be difficult to catalog more than a few of the “coolest” innovations.

What’s probably trending most are products and strategies aimed at bringing costs down to rock-bottom; this assures would-be adopters that their investments will be easily recouped, and also enables expansion into hitherto unripe markets. Now even small commercial and residential sites can install sophisticated, integrated automated control networks affordably, and with the prospect of a payback.

As a starting-point to illustrate: a half-dozen years ago something called the EnOcean Alliance (San Ramon, CA) came forth. It’s an international consortium organized to partner with the game-changing technology of the firm called EnOcean (Oberhaching, Germany). Among the Alliance aims was to standardize and internationalize EnOcean’s “energy harvesting” wireless tech. Indeed, in March 2012, the EnOcean wireless standard was ratified as the international standard ISO/IEC 14543-3-10. This is optimized for wireless solutions with ultra-low power consumption and energy harvesting. Perhaps more than any other recent innovation, this one promises to make buildings green, sustainable, and “intelligent” on a vastly expanded scale.

To date, dozens of partners are participating, mainly in North American and Europe. Primarily, EnOcean sells a patented control chip to utilize in BAS devices; the resulting fruits of integrators are then openly shared.

One remarkable set of EnOcean-enabled devices illustrate what’s become doable here: wireless self-powered switches and occupancy and motion sensors. As explained by one innovative EnOcean Alliance partner, Walt Dowling of Autani Corporation (Columbia, MD), these devices run themselves “and have no electrical connections,” he says. Some get power from harvesting light, either indoors or outside solar (supported with a 10-year battery in case there’s ever extended darkness). Others get power from nifty micro-distributed energy.

Dowling explains: “When you push the “˜on’ button, they’ll make a click. There’s a little tiny generator inside that switch, and the action of pushing it carries just enough electricity to send a little tiny radio message, with are range of 100 feet, to turn [a system or appliance] on.”

Needing no external power naturally brings tremendous savings, both in avoidance of paying electricians to hook up systems, and in operation. (More on that below.)

What EnOcean has done with its low-powered, self-powered components really sets the keynote for what a whole BAS industry is up to.

A similar case in point comes from the wireless networked thermostats and dampers, etc., made by a company called Insteon (Irvine, CA; see also, Smarthome.com ). These enable remotely controlled and programmed thermostats for heating and cooling, including advanced two-stage systems. They’re especially valuable wherever room usage varies a lot.

The value proposition here is to minimize wastage of heating or cooling for empty rooms. Duct dampers are addressable and can close or open to shunt air streams selectively as required. Operation is automated by a central controller. Motion sensors can be integrated and linked for on/off functions. Using certain compatible central control products, like HouseLinc or Perceptive Automation’s Indigo, individual room temperature can be monitored and controlled. Versatile Insteon components can be used as controllers to also activate and direct other devices, such as when ambient temperature changes.

As Wi-Fi networking has grown ever-cheaper and ubiquitous, such control becomes cost-justifiable all over the place.

Lighting Controls
Opportunities for energy savings with lamp fixtures may not be as huge as with HVAC, but when lighting retrofits are artfully designed, they’re enough to be reasonable attractive. They’re also easily networked together with HVAC controls, sharing occupancy sensors, switch technologies, and wireless infrastructure.

Here, a representative product is that of Osram Sylvania’s (Munich, Germany) ELogic. It’s a wireless, battery-free dimming technology for fluorescent ballast controls and LED power supplies. According to the product website, ELogic uses the EnOcean chip and is equipped with circuits that enable flexible reconfiguration; in other words, switches may be re-directed or relocated without the rerouting of wires.

Similarly, Insteon manufactures an extremely low-cost lighting dimmer that plugs into a wall outlet. A fixture of, say, 300 watts can be dimmed to 32 different brightness levels via remote control.

Founded in 2000, nLIGHT (Vancouver, WA) “integrates time-based, daylight-based, sensor-based, and manual lighting controls,” as the company website states. Elements can stand alone in a room or be networked across a facility or campus. Wirelessly communicating together are occupancy sensors, photocells, power/relay packs, wall switches, dimmers, panels, timers, and, even, luminaires. Collectively, they yield a kind of “distributed lighting intelligence,” as the company puts it. Time-based and sensor-based controls are integrated. Key components are both addressable and smart, meaning they can make switching and dimming decisions. Relays and dimming outputs can be located within sensors, photocells, and wall stations, for cost-effective efficient designs. The network can be controlled locally or remotely with mobile software.

Another lighting firm, Dowling’s employer Autani, similarly touts the benefits of low overall equipment costs, dramatically reduced installation labor, plug-and-play ease, and scalability. Autani’s approach takes EnOcean’s self-powered components and supplements them with powered smart switches and sensors. As Dowling explains, smart elements can be set to perform variably, depending on time of day or night, then shut off after a period of room vacancy. By mixing both EnOcean and Autani elements, Autani has effectively creating a hybrid dual network, says Dowling. Under this concept, there are times when a room needs only low-power EnOcean service; at other times activity or loads are high, and thus a longer-range, higher-bandwidth, bi-directional Zigbee-based network is called for. In the latter mode, full control is powerful.

Dowling says, “We’re able to display the status of every device on the network at any time,” tracking its behavior and energy consumption.

When a room quiets down, Zigbee networking becomes overkill; the network reverts to EnOcean self-powering mode.

Autani also uses this hybrid network with a low-voltage LED lighting control system. Perhaps inspired by the easy appeal of wireless networking, Autani recently developed a way to eliminate the need to run line voltage to every light fixture. Starting with only an idea in October 2012, the company (partnering with Enterprise Electric of Nashville) developed its “e>pod” product line, which distributes low voltage to LED lights. This scratches much of the power-supply cost and wiring for LED.

Says Dowling: “We use absolutely no switch wires,” thanks to the EnOcean chip. Multiplied across a facility with hundreds of rooms, the savings add up. Payback within about three years are realistic, says Dowling.

Also, rather sophisticated BAS for even a small commercial site like a gas station might be doable for under $1,000, he estimates.

After just nine months in development, Autani rolled out the e>pod lighting package in May 2013. Quickly its first two orders arrive. As of late summer, installations in all patient rooms at two San Antonio hospitals is expected to be completed by year end, says Dowling.

Another Autani product, EnergyCenter, melds lighting control with HVAC fans, etc., as well as plug loads. The respective functions share occupancy sensors and metering in a wireless energy management system.

Like seemingly all of the networked BAS coming into in the market, Autani’s can be run, or at least watched, in action via a smartphone, tablet, or PC, “with real-time energy monitoring,” says Dowling.

Smart Power Outlets
Along with HVAC and lighting efficiency, a third focus of energy zealots is wall outlets (where some energy-hogging computers are plugged in). According to EPA’s Energy Star program, something called “vampire power” is sucking out billions of dollars in electrical “juice” from out circuits; energy is depleted whenever something’s plugged in, even if “off.”

In response, ASHRAE standard 90.1 as of 2010 requires that half of all outlets in open offices, computer rooms, and classrooms be controlled by occupancy sensors, scheduling, or both (as Dowling notes). This mandate has launched a scramble of innovations, ranging from redesigned power strips, to low-cost, but increasingly sophisticated, plug controls.

In one typical model, a plug outlet is equipped with a timer; sockets turn off after-hours. Dynamic scheduling ensures that outlets are available whenever a room is occupied, but turned off when vacant, “and not easily circumvented or disabled, so as to be ineffective,” adds Dowling, describing Autani’s outlet.

Assorted outlets are able to track, control, log, and report specific types of plug usage. Appliances like big copiers, water coolers, desktop computers with printers, etc., are able to hibernate, and the hibernation can be coordinated with the outlet’s on-off schedule. Once the “vampire” gets a stake plugged into its heart by the insertion of a smart outlet, the saving, in what was once-lost, energy can pay back in surprisingly quick order. In any case, outlets are ASHRAE-compliant.

This concludes a brief product survey, but a final word comes from an OEM that is also in the thick of new product development. Like Autani’s mere nine-month-long LED product genesis, this account gives the flavor of how speedily the industry is at work, advancing innovation constantly.

Cell-Phone HVAC Monitoring for a Few Bucks a Month
When telephoned last summer and asked to comment on BAS and HVAC controls for this article, Ryan Fetgatter, general manager at Davidge Controls (Santa Ynez, CA), replied with note of mild amazement. “It’s interesting that you’re writing on that,” he said, “because we’ve spend the last couple of months developing a new product to do this. And, we’re specifically targeting HVAC systems,” adds Fetgatter, who is also managing partner of the startup firm, OEM Integration, pursuing this enterprise.

He explains that, although multiple manufacturers out there are already doing a good job with BAS controls, including some who offer retrofit packages with software that can operate system breakers, he sees a unique appeal in his particular concept.

Basically, what Fetgatter plans to offer for sale by late 2013 is an HVAC monitoring service at extremely low cost. The fee will be so low that he believes the HVAC marketplace will find it almost impossible to resist. One of the hurdles in HVAC retrofits, he points out, is the sometimes high up-front cost; he echoes Gray above. In theory, “things sounds easy to do. But it really turns out to be a little more difficult,” says Fetgatter.

Good vendors and products exist; Fetgatter mentions the Benjamin Electric Company (Los Angeles), for example, for its system that will open-up electrical panels and the breakers to wire-in retrofitted controls. “But building automation is not cheap” to do, using something like this, he adds.

What Fetgatter has done is simply cherry-pick a key and desirable element of HVAC management. By far the biggest energy hogs in buildings are rooftop HVAC units, so Fetgatter designed, and will soon make, “a cell modem-based software platform that monitors these HVAC units,” he says.

At first all it will do is sample and report energy usage-but at an almost token cost of less than five dollars per month.

Modems will be built into OEM heating and chilling plants, for both 220- and 480-V sizes; Fetgatter has talked to several major ones who are interested. Once the newly equipped units come out the factory door with his device in place, “You’ll be able to get critical energy usage reading over a smartphone app,” he envisions.

Cell phone data plans have plummeted in cost; Fetgatter has partnered with a Verizon reseller to sell time. Modems, too, are suddenly cheap. “We’re making it so affordable, that it’s a no-brainer,” he says. “It’s ridiculous not to do it.”

What’s the value of mere data?

Initially, his unit, linked to cloud-hosted software, will detect dangerous voltage irregularities that indicate a need for maintenance. “When you start seeing high amps or a power factor way off-or volts spiking or unbalanced-you know you have issues that you have to look at before something breaks down completely,” he says.

The cloud-based software is also extensible and should enable diagnostic data mining of HVAC historical load profiles. Fetgatter plans to have everything tested and lab-certified, ready to ship by November. 
About the Author

David Engle

David Engle specializes in construction-related topics.

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