By Jill Lori Aronson
Published in the April 2002 issue of Today’s Facility Manager magazine
Four major trends are affecting the design and application of heating, ventilation, and air conditioning (HVAC) and building automation systems in commercial buildings:
- The critical need for energy efficiency, reliability, and flexibility;
- Urgency of indoor environmental quality, including air quality, comfort, and sound levels;
- Demand for open-protocol (and smarter) controls; and
- Importance of maintenance and retrofit options as a difficult economy throttles investment in new capital equipment.
—Bob Russell, vice president of global marketing for the Engineered Systems Group at York, PA-based York International Corp.
“Last year’s experience in California reminded us all of the need for choice and flexibility in energy source, as well as the continuing need for high efficiency systems,” says Russell. “Understanding the pricing concepts employed by electric utilities is crucial to chiller selection for a multiple-chiller facility. Hybrid (and in some cases, tri-fuel) chiller plants employ a mix of electric and absorption or gas-engine drive chillers. This approach substantially cuts operating costs during periods of high electricity demand, while providing the capability to switch quickly to an alternative energy source in the event a primary source is curtailed.
“However,” Russell continues, “when it comes to the energy efficiency of individual chillers, fms and engineers are relying more on chiller-performance ratings developed by the Air-Conditioning and Refrigeration Institute (ARI). The ARI method closely tracks chiller energy performance by accounting for operation at off-design conditions (where chillers operate up to 99% of the time). As a result, engineers can specify energy performance with greater confidence, and fms can anticipate the performance of their equipment over a complete range of conditions.”
According to Syracuse, NY-based Carrier Corp., the ARI standard has limitations because it isn’t representative of any particular project; instead, it is based on one chiller operating alone, and its part-load weighting (efficiency measurement) may or may not have any meaning for central plants with multiple chillers. The pamphlet reads, “ARI, in revising the standard, was trying to define a uniform, industry-wide measuring stick for part-load performance.” It goes on to explain, “Engineers need to recognize the limitations of this standard, use it as a starting point—not an ending point—and recognize that their usefulness as a tool for identifying part-load performance by a single universal figure may be unsatisfactory.”
Russell believes proven energy-saving technologies also come into play. For example, with a constant-speed centrifugal chiller, a variable speed drive (VSD) retrofit can reduce chiller energy costs by as much as 30%. These savings are possible because variable-speed technology works best at off-design conditions.
Energy Saving Technologies
According to Tom Lester, vice president of sales and marketing for Rochester, MI-based Solaronics, Inc., gas infrared heating systems, an energy efficient alternative to conventional warm air heating units, can reap tremendous fuel cost savings of up to 75%.
“With the prices of heating fuels soaring, fms are riding a bucking bronco in their attempt to rein in energy costs. That’s what’s driving the rush to install energy efficient gas infrared heaters in new construction as well as retrofitting older buildings with infrared systems,” says Lester. “Typical fuel cost savings from infrared heaters operating on natural gas or LP propane gas range from 30% to 75% over conventional hot air blowers. Also, it’s not uncommon in retrofits for infrared heaters to pay for themselves within one to two years,” he adds.
Through this process, heat is transferred from a warm object to a cooler one by conduction, convection, and—in the case of infrared heating—radiation. Conduction of heat occurs when faster moving molecules pass on some of their energy to adjacent slower moving molecules within a solid or between a solid and an adjacent fluid such as air. Convection transfers heat by mixing warm and cool molecules. It is the most widely used method of heat transfer because the material being heated, typically air, can be driven by fans and blowers to most areas of a building. Heat transfer by radiation differs from convection and conduction in that a medium such as air is not required to accomplish the transfer. As an example, the sun’s energy warms the earth but doesn’t lose any strength on the way down.
Quiet infrared heaters mounted high overhead work areas direct their energy to the floor, so objects and people below absorb the energy and become warm. Their warmth, transferred by conduction and convection, heats the air inside the building at their working level, providing a comfortable environment. To produce the same comfort level with hot air blowers requires constantly heating all the air space in a building from the floor to the roof when only floor level comfort is needed.
An infrared heater installation at GM’s Inland Division Plant in Euclid, OH slashed energy costs 75% during a single heating season. Prior energy costs were running about $106,000 per year but plummeted to $27,000 with the new infrared heaters. At Magnetic Metals in Camden, NJ, annual heating costs at this industrial electrical products manufacturer went from $130,000 to about $69,000 after 28 ceiling mounted unit heaters were replaced with low intensity gas infrared tube heaters.
In addition to fuel savings, infrared heat also offers fms these benefits:
- Reduced electrical
- Eliminated drafts, dust, and/or dirt blowing around;
- Zoned heat without partitions;
- Lower thermostat settings when outside temperatures drop;
- Prevention of condensation on stored materials; and
- Automatic humidification with high intensity systems—relative humidities will be at 45% to 50% versus the 5% to 10% that is typical of blown heated air.
Although infrared comfort heating technology has been around for over 50 years, the recent surge in fuel costs has provided the stimulus for HVAC professionals to consider this alternative.
Major players in the HVAC equipment manufacturing game are branching into the controls market with renewed enthusiasm. Some companies have been marketing themselves as building integrators for a long time already. HVAC manufacturers are now becoming more competitive in the industry by investing their expertise in this booming market.
Russell says, “The use of open-protocol controls for chiller systems—allowing them to operate compatibly with a variety of building automation systems—has been well established. On-board controls that allow other HVAC equipment, such as AHUs, to operate compatibly with larger control systems have been another matter, until recently.
Jay Behnken, marketing manager of building automation systems at LaCrosse, WI-based Trane Co., says Web-based software suites and systems are another growing part of the HVAC integration industry. “The whole market is driven to provide a usable interface that is easy to use,” says Behnken. To this end, Trane is rebranding itself as a controls company—as well as an air conditioning company.
Companies that market themselves as building integrators primarily do so with proprietary systems. Trane has been integrating systems in existing buildings for as long as those companies have, but they do so in a different way. Trane uses open protocol systems—Lonmark, MODBUS, and BACnet—for flexibility, so their controls can speak to the appliances that already exist in the facility.
According to Behnken, this trend toward integration was driven by the convergence of three technologies: Web-enabled interfaces, high speed networks, and high capacity data storage. If the HVAC system can speak the same language as all of these devices, the result would be a single view into the total facility. This way, fms would not need to switch between systems, software programs, and protocols in order to find faults within the building systems.
“Fms like to keep things clean, simple, and accessible,” says Behnken. “They need to keep doors open; they can’t afford to spend too much time on any one thing. All in one solutions make things run more smoothly, and the technology makes this possible, feasible, and useful.”
In terms of future trends, Behnken speculates, “In some ways, the Web may trump all of the current protocols. The pundits here at Trane think that the protocol doesn’t matter when you get to the bottom of the systems. Web-enabled technology is becoming more of a presence, more accepted, and more useful.”
Another feasible solution is offered by companies with an established reputation in the controls market: energy retrofit services and performance audits conducted in the field by contracted systems technicians.
Technology is driving this solution as well. “Access to information is available to fms through the Web. Remote and predictive monitoring applications (such as vibration analysis) can predict where failures might occur,” says Matt Cole, service marketing leader at Minneapolis, MN-based Honeywell Automation and Controls Solutions (ACS) Services. “Predictive maintenance, as incorporated into a preventive maintenance (PM) program, can reap tremendous savings by eliminating downtime that could have resulted from equipment failure.”
Current remote monitoring capabilities enable fms and their service providers to see mechanical failures as they happen, so that swift action can be taken. Wireless technology is making the connection between the testing/status of the equipment and the service technicians even more fluid. Predictive monitoring and testing will be privy to even further technological advances.
“Now, if equipment goes down, the call is made to the service company, then it is routed to a technician in the area, and then the technician is dispatched to the site to make the necessary repairs,” says Cole. “Remote monitoring automates this process so that the equipment actually, in effect, calls in to the dispatcher, says, ‘I am sick,’ and the technician is dispatched to the site to make the necessary repairs. In the not-so-distant future,” Cole predicts, “technology will allow the equipment to call in to the dispatcher saying, ‘I think I am getting sick,’ and the technician can go out and make the necessary repairs.”
The Atlanta, GA-based American Society of Heating, Refrigeration, and Air-conditioning Engineers (ASHRAE) is in the process of conducting a presidential study entitled, “Risk Management Guidance For Health And Safety Under Extraordinary Incidents.” According to the report of that study, “The public’s expectations for the ability of buildings to keep occupants safe have been raised as a result of the extraordinary incidents that have occurred since September 11, 2001. Building owners and occupants may now be willing to redirect resources to enhance the performance of buildings to further reduce occupant risks associated with extraordinary incidents, while continuing to provide acceptable indoor environments, energy efficiently and cost effectively, during normal conditions.”
One section of this report on the presidential study includes recommendations for owners and managers of existing buildings. As stated in that section, “It is not possible in preparing these recommendations to generalize for all building types, but the recommendations are as universally applicable as possible. Where the building owner or manager has the need for more technical information, this should be obtained from a professional engineer or other qualified practitioner prior to proceeding or at any point along the way where it is deemed necessary.”
The three primary and preliminary recommendations that have resulted from the collaboration of the members of the study group and the lessons they have learned are:
- Understand the capabilities of the building and its systems;
- Assure that the building is performing as it was intended; and
- Do not make changes to building performance unless the consequences of doing so are fully understood and appreciated.
According to Russell, indoor air quality (IAQ) will continue to be a market driver in 2002. Further, Russell claims the growth of raised floor construction as a means of accommodating power, data, and telecommunications cabling is spurring interest in underfloor air. “That’s because the plenum beneath the raised floor is an ideal avenue to deliver conditioned air, eliminating the need for separate ductwork. This air delivery method offers a number of other benefits as well.”
Liana Berberidou-Kallikovka, Ph.D., of Pittsburgh, PA-based KSBA Architects, makes these observations about underfloor air and IAQ:
“The occupants have the ability to control both the volume and the direction of the incoming air, and the fan units can be turned off to accommodate reduced cooling requirements. As a result, personal comfort complaints are virtually eliminated…The upward flow of the supply air draws the pollutants upward rather than letting them swirl around with the room air.”
Russell adds, “Thoughtful design of air-handling units (AHUs) enhances air quality as well. The best designed AHUs incorporate double wall construction to separate the airstream from insulation materials; multi-sloped drain pans to ensure proper draining of condensed water vapor; and built-in airflow measurement controls to assure adequate ventilation at all conditions.”
Outdoor environmental quality is of equal importance to members of the HVAC industry. Chlorofluorocarbons (CFCs) have been used as a refrigerating agent in the industry for approximately 50 years now, but these agents are now considered one of the primary causes of ozone depletion.
According to Trane, CFCs make up approximately 70% of the man-made ozone depleting chemicals in the atmosphere today. Furthermore, CFCs have been found to be powerful global warming gases.
Although CFCs make up only 0.0000001% of the volume of the atmosphere, they contribute 21% of global warming. As a result of this information, the international community has agreed to phase out the use of CFCs in chillers. This agreement was reached years ago, and the world’s chillers are still not even 50% CFC-free.
Fms need to understand that saving money now—even in light of the recent condition of the economy—is not the answer. Proactive spending and preventive steps will save more money over the long term. The bottom line comes at the end of the road…not here and now.
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