Trends in HVAC

Jan. 9, 2006
Changes to standards and evolutions in equipment shape HVAC

Lately, the HVAC industry seems to move in a state of constant flux. And, this movement focuses around the quality of the built environment.

Changes to ASHRAE standards, the new federal Energy Policy Act, and the ongoing evolution of equipment and controls continue to shape the way facilities managers select, maintain, and operate HVAC equipment in commercial buildings. While energy efficiency and sustainability remain in the forefront of today’s HVAC-related trends, the overall environment plays a strong supporting role.

“In the past, we focused so much on energy conservation at the expense of comfort and ventilation,” says Terry Townsend, president of Townsend Engineering, Chattanooga, TN, and president-elect at Atlanta-based American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). “We have to remain serious about overall resource conservation, but we also have to have a comfortable and healthy built environment so occupants can perform as intended and be comfortable. That’s our mantra. That’s what it needs to be.”

Standards Drive Change
As a result, two of ASHRAE’s dogmatic standards affecting HVAC systems in commercial facilities underwent changes.

ASHRAE 90.1 was updated as of 2004. Mechanical requirements of the standard now offer more stringent energy-efficiency requirements for controls and equipment, as well as building construction and operation. The equivalent Intl. Energy Conservation Code (IECC) also underwent similar updates in its most recent release, published in 2001.

The ASHRAE 62.1 standard for ventilation has also been updated and includes new requirements for ventilation requirements. Some of the changes include the need to base ventilation rates in multi-room buildings on the ventilation requirements of each room and requirements on spaces and the recirculation of air. This standard also specifies requirements for exhaust separation and inlet air locations.

Such changes in standards are creating a more prominent focus on how equipment operates, industry leaders say.

“There is also growing interest in commissioning and operation of the unit equipment and facilities,” notes Richard Lord, manager of Packaged Platform Engineering at Carrier Corp.’s Farmington, CT, location. “New efforts are under way for technician certification through the North American Technician Excellence Inc. (NATE) program, as well as procedures for commission and operation of units through Air-Conditioning Contractors of America (ACCA) and other organizations.”

The NATE certification program for technicians involved in heating, ventilation, air-conditioning, and refrigeration is the only independent, third-party test supported by the entire industry. Testing validates a technician’s knowledge and a training program’s instruction. NATE-approved testing organizations throughout the United States and Canada offer NATE tests. Candidates can earn installation and/or service certification in five specialty areas: air-conditioning, air distribution, heat pumps, gas heating, and oil heating.

To become certified, a technician must pass both core and specialty exams. The core test covers basic math, customer relations, and the fundamentals of electricity, heat transfer, and comfort. The specialty tests cover system components, applied knowledge, diagnostics, troubleshooting, and service and installation topics. Certification lasts for 5 years, after which a technician must re-certify.

Feds Set Energy Mandate
Changes affecting commercial heating and cooling are occurring beyond the boundaries of the HVAC and facilities industries. The federal government continues its movement into the realm of energy efficiency. “The federal government has been a bit of an early adopter with technologies that relate to energy efficiency,” says Robert L. Johnson, Arlington, VA-based director of institutional markets for Trane.

In August, President George W. Bush signed the Energy Policy Act of 2005 into enactment. The act, which goes into effect on Jan. 1, 2010, provides incentives for traditional energy production as well as newer, more efficient energy technologies and conservation. More than 1,700 pages long, the act has hundreds of provisions that affect the commercial, industrial, and residential sectors.

Most notably for the facilities industry, the act sets minimum efficiency standards for 16 consumer and commercial products, including commercial unit heaters and large commercial air-conditioners. It also directs the U.S. Department of Energy to set efficiency standards for external power supplies, battery chargers, and refrigerated vending machines.

The act also includes requirements for government building upgrades, as well as several rebate and tax credit initiatives to encourage energy-saving design.

Sustainability Drives Total Building Operation
According to Townsend, ASHRAE is striving to assist in the creation of net zero energy use facilities. In such a facility, for a year’s operation, the building would produce as much energy as it consumes, he explains.

“That is an ultimate goal. We’re not sure how we’re going to get there yet, but it is something to strive for in new and existing facilities,” notes Townsend.

One possible step in achieving this is the use of energy recovery ventilators, says Mark Menzer, vice president of engineering and research at the Arlington, VA-based Air-Conditioning and Refrigeration Institute (ARI). “You bring in outdoor air [and] precondition it,” he explains. “You recover some of the cooling energy you’ve already paid for as you exhaust some of the cooler air and bring in the warmer, more humid air. You’re saving on energy by preconditioning the warmer air.”

Sustainability and the quest for efficiency in heating and cooling are driving the way commercial facilities operate, Townsend notes. “What you’re going to be seeing coming up in HVAC from ASHRAE in particular is performance evaluation methods for facilities in relation to resource conservation, indoor environmental quality, and comfort,” he says. “The industry needs that in order to quantify and qualify what they claim.”

Townsend says ASHRAE is taking the lead in developing tools to look at new and existing facilities to see if they are performing as intended - not just from the HVAC standpoint, but from total building operation. “The critical question from a building owner’s perspective is, ‘What is the right thing to do?’,” Trane’s Johnson notes. “You need to step back and look at the building to determine how much it costs to build it and how much it costs to run down the road to get the best possible building over the life-cycle.”

For example, most HVAC system design is based on what happens at peak load. In most cases, however, a building will only see that load for about 80 hours per year. In reality, many of the other assumptions made in determining the design load do not occur simultaneously, so the actual hours are even less.

ARI has found that typical commercial buildings in the United States operate 1 percent or less of the time at full-load tonnage. The rest of the time is spent at 25- to 75-percent full load. “You have a lot more operating values at part load than full load,” notes Daryl Showalter, director of chiller marketing for McQuay Intl., Staunton, VA. “The chance of running at your full-load tonnage is rare.”

Load requirements, as affected by the building envelope, the equipment, and even the building itself, can be tracked. The availability of more sophisticated building analysis software allows design firms to look at all the options available and to better understand the long-term implications for system sustainability, Menzer says.

“It has been a long process to get building owners and architects to recognize the long-term operating costs and not just the first cost of equipment,” he points out. Menzer adds that ARI standards for larger air-conditioning equipment do have part-load considerations covered under a term known as integrated part load value (IPLV). The IPLV measures the efficiency of air-conditioners when the unit is operating at 25, 50, 75, and 100 percent of capacity and at different temperatures. IPLV is calculated only for commercial cooling systems.

“Chiller manufacturers would like to see ASHRAE 90.1 give more attention to part-load efficiencies,” Menzer says. “The question is how much weight will these standards give them? [Full- and part-load efficiencies] should both be considered.”

Equipment Efficiency Evolves
The question as to whether standards are driving technology or whether technology is driving standards is like asking whether the chicken or egg came first, according to Johnson. “Are standards catching up, maybe because technology is moving?” he asks, noting that there are also standards out there to which technology still needs to reach.

Standards aside, the biggest drivers behind technology are the end-users - customers who are seeking greater energy efficiency.

“The opportunities to improve existing facilities with energy-saving improvements are tremendous,” says Colleen Julian, area manager for Carrier Commercial Service’s Upstate New York region, East Syracuse, NY. “There are both products and services to assist in saving.”

Consider variable frequency drives (VFDs), also known as variable speed drives. They’re gaining in popularity. Menzer says the price point on such drives has dropped enough that it now makes sense to use them on smaller applications.

As Julian notes, the traditional motors on these smaller applications consume a great deal of energy. “Many facilities have hundreds, even thousands, of small motors in their facilities, fan-coil units, unit ventilators, and packaged terminal air-conditioners (PTACs),” she says.

Variable speed drives can be retrofitted to existing equipment and can, in some cases, save up to 40-percent more in energy. Some newer equipment comes with built-in VFDs. “It gives you more opportunities to operate the equipment at its highest efficiency. It’s not just an on/off operation,” says Menzer. “You can really optimize it. It makes a big difference in efficiency and comfort.”

Another recent development in HVAC equipment is variable air volumes. In such systems, anyone who has an air-handler blowing in, on, or around them can control the temperature in their own personal space. “If another employee and I are on the same system and he wants a different temperature, the system can heat his space and cool mine. It can change the volume of air delivered to the space. It’s possible to have a controller in every space,” says Bill Rau, senior vice president and general manager of Mitsubishi Electric HVAC, Suwanee, GA.

With variable air volume systems, it also is possible to damper off a space that is not occupied. “What’s the efficiency of air-conditioning a space that is not occupied?” Rau asks.

Even chillers themselves continue to evolve, both from sustainability and maintenance standpoints. Consider frictionless chillers that operate with oil-free magnetic bearing technology. Some models are operating at 0.345 kW per ton at the IPLV level, in comparison to traditional chillers that operate at an average of 0.53 kW per hour. With the magnetic bearing technology, these chillers do not require oil to run. Thus, the system does not have an oil cooler, oil pump, or an oil heater.

“We’ve seen as much as a 50-percent reduction in maintenance over typical centrifugal or screw machines because there is no oil in the system,” says McQuay’s Showalter. “By taking away those components, you make the machine much simpler to understand. You don’t have pumps and heaters to break down or control.”

Controls Grab Attention
HVAC systems are also becoming more complex in terms of control strategies - an area important for facilities professionals to understand if they want to achieve maximum efficiency benefits. “If the facility manager is not cognizant of what is required, there might be a tendency to revert to what is most comfortable, and then the system doesn’t operate as intended,” Townsend says.

The complicated world of controls has been simplified a bit by emerging control protocols and standards such as the Open Building Information Exchange (oBIX) and BACnet.

“It’s making life simple for the facility manager,” Townsend says. “You have four or five different types of systems that are now compatible. You can have different vendors who have their different systems in different buildings. The facility manager has the ability to have the common communication and interlinking of the systems throughout all facilities.”

Robin Suttell ([email protected]), based in Cleveland, is contributing editor at Buildings magazine.

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