Green Means Go

Water Heater Technology Moves Briskly with Market Trends

By John Vastyan

Engineers in the commercial water heater market are riding the waves of seismic change. Never before has the industry experienced a time of greater pressures and activity--stratospheric fuel prices, price pressures fixated on ROI, universal insistence for green technology and a smaller carbon footprint--all coming together to force an unprecedented shift in the way products are developed and applied.

“Understanding the market and where it’s going is key,” says Mark Taylor, director of commercial and technical sales at Ambler, PA-based Bradford White Corp., a leading manufacturer of commercial and residential water heaters.

For more than 27 years, Taylor has been immersed in the world of water heating at Bradford White. He feels that today’s generation of trade professionals, engineers and installers are becoming more market- and environment-savvy. They are also more compelled to understand and apply new technology than those before them. 

“I think many professionals in the industry--especially design and specifying engineers--would agree that it’s critically important to be attuned to the changes we’re now experiencing,” adds Taylor. “We need to step back, examine the change from a broader perspective and be especially ready to keep in step with those changes tied to green initiatives.”

“But, at times of sudden change and upheaval, and with new technologies being introduced at a rapid pace, it’s best not to react too quickly to every new product or application technique,” he cautions.

What’s the Building Need?

For instance, added Taylor, at the jobsite level where technology meets its need, an engineer must ask: What’s the building want and need? “This is a much better approach than assuming an answer to the challenge posed. Invariably, we all make assumptions about how to apply products to meet a particular need,” continues Taylor. “We tend to move toward what we’re familiar with. That recipe may have worked a lot better just a few years ago, but in today’s market, environmental and technology variables create more challenges.”

Taylor interacts with specifying and system design engineers routinely. He now finds himself saying to these professionals--when faced with the need to make decisions about how and what technology to apply--that the essence of their question should be: “What are you trying to accomplish, based on demand load expectations?”

Tim Rosen, P.E., a partner in the Avon, CO-based mechanical contracting firm, Concept Mechanical, agrees. “The pace of technology, the influence of change in the market and building owner demands are forcing engineers and installing contractors to stay sharper than ever before. To Taylor’s question: ‘What are you trying to accomplish?’ I’ll add: ‘How far can you realistically go?’”

Rosen and Taylor, like many professionals facing this question, will ask about the factors that influence the decision-making process when solving a building’s technology needs.

• Is LEED certification important? To what level can the hot water supply system contribute?
• What are the anticipated use patterns? Will there be varying demand loads?
• Will there be large dump loads requiring stored energy?
• Recovery: how quickly should the system be expected to raise the temperature to set point? 
• What will be required to assure a continuous supply of hot water?

What’s Realistic?

In each scenario, technology is applied. But, the building may not have the space or the funds to meet the engineer’s ideal specification. So, the question becomes: How far can you go to accomplish the goal? What are the constraints? And, the point raised by Rosen: What’s realistic?

“There may be several different ways to get there--to achieve a performance level that meets the need of the building owner, investors and occupants,” adds Taylor. “It’s a greater challenge today to interpret how a product will be used, and how it will interact with other plumbing and mechanical systems within the facility. Another key facet is to know how best to take advantage of the equipment’s capabilities.”

For example, Taylor explains: A solid, medium-efficiency water heater that may operate only a few hours a day may handily beat the overall operating cost (including product and installation cost) of a more expensive condensing system. On the other hand, if it’s determined that the equipment may see long periods of operation or “uptime,” the higher-efficiency condensing system, such as Bradford White’s eF series, would be a wiser choice by taking advantage of the lower fuel use to maintain the same water temperature in the hot water distribution system.

Peachtree, GA-based Rinnai America Corp. confronts the issue of stand-by heat losses with a different approach. With an arsenal of tankless residential and commercial products, they’re one of the leading firms offering this technology. Tim Shellenberge Sr., vice president of Rinnai’s R&D Engineering, says that there are now many applications where tankless systems can be applied, particularly those where stand-by heat loss makes up a considerable portion of the energy consumed by the water heating equipment.

“Total tankless system energy efficiency also plays into the issue of CO2 emissions and green house gases,” says Shel-lenberger. “A high-efficiency tankless water heater can significantly reduce stand-by losses by not storing hot water during non-use periods, which helps to reduce the ‘carbon footprint.’”

Shellenberger points to their commercial models C85i, C98i and C98e. “These high-volume tankless commercial systems can meet water heating capacities from about one-half gpm to nearly 10 gpm. Recently, three C85e outdoor units were installed at a restaurant resulting in space savings along with energy savings. Another example is the installation of 10 indoor units at a hotel with simple sidewall venting. The small, direct-vent, forced combustion natural gas or LP tankless water heaters provide electronic ignition with hot water capacities of up to 8.5 gpm each.

“But there can be a greater perceived notion of energy saved,” adds Taylor. “If an installation calls for 1 million BTUs of peak water heating capacity, five 200 mbh tankless systems, at a higher up-front cost, might be needed to get the flow rates that are required. A simple direct-fired storage unit with less input, but with storage energy in the tank may be a better option.”

Replacements Reign 

Kelly Michel, president of Michel Sales in St. Paul, MN, a manufacturer’s rep firm that specializes in water heating and hydronic technology, says that--even more so now in a flattened commercial market--perhaps 80% of commercial water heating systems are sold as replacements. “By far, it’s the biggest segment of the market,” says Michel. “The key challenge with the commercial business is that, even though much more efficient equipment may be available to the building owner, an urgent call goes out to an installer . . . there’s no hot water, and the need is immediate. The owner may not even consider the options.”

New Equipment, Mistakes + Contractor Training

“With new construction, it’s often a much different picture, with the owner, GC and engineer all involved in the selection of equipment,” says Michel. “And, with state-of-the-art equipment, that’s a good thing because venting, gas pressure and combustion air tolerances are much tighter than they used to be--all are critical to operation of the unit and ongoing performance.”

“Specific minimum running gas pressure and proper venting are also critical to proper performance of the new generation of high efficiency equipment,” continued Michel. “Some systems may need a minimum, steady 8 in. gas pressure . . . and an installer may get that initially at the manifold, but then a boiler is added without considering the consequences. The high-efficiency water heater may be running fine, but then the boiler starts and the 8 in. of gas pressure drops to four, starving the heater for gas. With old equipment, that might’ve worked. Not today.”

Venting new, high-efficiency systems must also be handled differently. “I know of an installation where the manufacturer stated a 90-ft. maximum length for venting,” says Michel. “The installer was confronted by the building owner who stated that he wouldn’t allow the venting out the side of the building and it must go through the roof. Unfortunately, that extended the vent pipe past the manufacturer’s limit and compromised the units. The installer immediately had problems and changed the system’s igniters nine or 10 times--calling the water heater and the manufacturer every name in the book. During a site visit, the vent distances were measured and found to be out of spec. The vent pipe was rerouted out the side of the building and the units perform perfectly.”

Michel is something of an evangelist for training. His interest in improving the quality of installations throughout his sales territory (Minnesota, Wiscon-sin, North and South Dakota and Michigan’s Upper Peninsula) recently led to a substantial investment there. The territory now has one of the finest contractor training facilities in the Midwest, stocked with working heaters and boilers and various operating space and water heating testing tools and equipment, for interactive, hands-on training.

Indoor Air Quality

There may also be IAQ issues. Some appliances are consuming air within the building. That’s fine in some instances, but not in others. The building envelope or other building systems may pose a threat to the water heater’s need for combustion air. Condensing water heaters are especially prone to risk when fumes from chemicals stored nearby (especially chlorines) may be pulled into the combustion chamber. Direct-vent or power-vented appliances were developed, among other reasons, to avoid the pulling of atmospheric air into water heater appliances.

Taylor points to an advanced system that has been one of the more exciting commercial projects at Bradford White in recent years. The manufacturer’s eF Series water heater was developed, with recent refinements and a broadened line, in response to market demand for ultra-high efficiency operation and installation flexibility. The three-pass flue system, low NOx emitting eF water heater offers thermal efficiency up to 99.1%, a 60-gallon tank capacity with 125, 150 and 199 mbh inputs, and 100-gallon tank sizes with 150, 199, 250, 300 and 399 mbh inputs. The system also provides venting flexibility, with power vent (through-the-wall) or power direct-venting options for horizontal, vertical, unbalanced venting with two-pipe or coaxial vent terminations.

Neil Rolph is vice president of engineering for Lochinvar Corp., in Lebanon, TN. Rolph points to their new Armor water heater, a 98% efficient, gas-fired, condensing commercial water heater that’s available in five models ranging from 150 to 500 mbh. The Armor water heater features a 5:1 modulating turndown, enabling it to fire as low as 20% of maximum input and smoothly modulate up to 100%. It includes a built-in cascading sequencer for installations using up to eight water heaters and is designed to be installed with a separate storage tank and can be vented using PVC or CPVC pipe with direct-vent distances up to 100 ft. for both combustion air and vent runs.

“We have a three-fold focus at Lochinvar,” says Rolph. “Energy efficiency; emissions reduction; and we meet or exceed low NOx requirements. And ‘smart controls,’ integrating all appliance functions for optimal operation, such as built-in cascade technology that permits multiple water heaters to communicate and interact in sequence. We always try to achieve the highest turn-down rate possible to prevent short-cycling and to increase efficiency.”

Jay Schechter is president of the New Jersey-based manufacturer’s rep firm, Focus Sales. “Our commercial business is chiefly replacement,” he says. “We’ve been seeing more point-of-use electric installations, but the ultra-high efficiency Bradford White eF has been an answer to dreams. The somewhat higher cost is worth the investment when building owners see a two-, three- or four-year payback on the purchase price because of the energy savings. One of our customers did a Hoboken, NJ, housing project earlier this year with 47 of the water heaters and half a dozed 200-gallon storage tanks installed. The city of Hoboken owns the high-rise multifamily housing projects. The mechanical contractor carefully scrutinized the design spec for the job and chose the eFs. It’s been trouble-free, and there’s an order for more equipment.” 

Without question, market forces are driving the pace for new and innovative commercial water heating solutions. This is chiefly due to the push for higher and higher energy efficiencies, and the demand for equipment to go where no equipment has easily gone before.

The newest generation of commercial equipment--such as condensing technology that purposefully extracts heat from flue gases within the combustion system, volume water heaters, and instantaneous, wall-hung units--have pushed combustion efficiency into the 95% to 99% range. That’s smart use of energy. Add new and sophisticated controls to the picture, and system integration with building automation systems, and you begin to see how quickly this market is moving.

Total System Efficiency

With such high-efficiency performance, building owners are now standing at attention. When the design engineer can calculate a 3- to 4-year payback for new equipment (or perhaps even shorter than that in some instances), there’s real incentive to install new technology. 

“How effectively the boiler relates to the total system is determined by its capacity to deliver heat either quickly, or slowly, depending chiefly on the needs of the system and the ability of the boiler to adjust to changes in the system’s demand for heat,” says Bill Root, a 9-year veteran as vice president of sales and marketing, Laars Heating Systems Co.

The common term is “to size to the load.” Also, total system performance is greatly enhanced when the equipment works at peak performance--with fuel consumption happening at the highest levels of combustion efficiency--at all levels of heat demand.

“And, of course, there’s modulation or staged firing vs. on/off,” adds Root. “This illustrates perfectly the giant strides the industry has made during the past couple of years. Modulating and staged-fired water heaters reduce fuel consumption by ‘sizing to the load’ so that the amount of heat produced by the system precisely matches the need.”

“Condensing water heater technology is one of the key factors for the dramatic increase we see in boiler/water heater system efficiency,” says Root. “Condensing volume water heaters, such as our Rheos+, are built to extract latent heat from the moisture that forms in either the primary or secondary heat exchanger, dramatically enhancing combustion efficiency.”

Still, efficiency is only one of the advantages of installing these systems. Application of the boiler/water heater can play an even more important role. “Their tough resistance to thermal shock and the ability to accept low return water temperatures puts them in a category of their own and opens up many new possibilities for high-volume, cold-start systems. A condensing system takes very low inlet temperatures in stride--in fact, the lower temperature of incoming water, the higher the system’s combustion efficiency.”

Modulation goes hand-in-hand with the ability to operate in a condensing mode. When a volume water heater can operate with low return water temperatures, and lowered firing rates, the relationship of heat transfer surface to fuel consumed, and the combustion efficiency itself combine to deliver maximum efficiency. And, when multiple water heaters are installed, each one handles only a portion of the heating load; that drives system efficiency even higher.

“Some systems that require higher operating temperatures most of the time may still benefit from a “lead water heater” that’s a condensing system,” says Root, “while the remaining water heaters that provide the bulk of the heat are noncondensing.”

But if you want a high-performance system, it only makes sense to start with a high-performance “engine.” Manufacturers today put a lot of engineering effort into maximizing heat transfer to water--and that efficiency is a critical aspect of a water heater’s performance. The only thing to keep in mind is that many applications do not call for the highest levels of combustion efficiency (condensing equipment) because the water temperatures are too high. Designing systems with staged firing, modulation and/or multiple water heaters can often produce higher system efficiency than trying to use a single condensing water heater that claims higher combustion efficiency.

The Greening of Urban Spaces

“Green” boilers/water heaters are another facet to the high-performance equation. “Today, when this topic is discussed at industry roundtables, and looked at here in this region, we examine emissions closely--NOx, CO, CO2--with the real desire to see lower levels of pollutants that endanger our air quality,” says Ron Bradford, a 14-year partner in the manufacturer’s rep firm, Signature Sales, which serves all of Southern California and Nevada. “California’s South Coast Air Quality Management District, the state of Texas and selected projects in almost every other state have set limits for emissions, especially NOx. In addition, requirements for some installations call for 100% of the combustible air to come from outside the building.”

Although system efficiency and emissions tend to steal the commercial equipment spotlight, another interesting issue has risen in areas of high population growth and commercial expansion. “Rather than going into buildings at subterranean levels, our equipment is going in at the ground level and above,” says Bradford. “This is just one facet of the overall effort to get people back into the urban areas by making commercial structures more inviting. The goal is to reduce commuter gas consumption, and ultimately the reduction of fossil fuels. If we can make urban spaces more appealing as living and working environments, we win.”

A water heater on a roof, or outside on a pad somewhere is often out-of-sight and much less a frustration for those whose focus it is to preserve interior space for income-generating purposes. This battle has become more antagonistic over the years. Gone are the days when mechanical room space was provided generously. The use of floor space is guarded fiercely, both in new construction and retrofit applications.

Mechanical equipment must stand up to the scrutiny of space-savers. And must also meet the tougher expectations of a new generation of engineers, installers and building owners. The common denominators all point to smarter, greener solutions.

John Vastyan, a journalist whose work focuses on the plumbing and mechanical and radiant heat industries. He owns Common Ground, a trade communications firm based in Manheim, PA. He can be reached at (717) 664-0535 or via e-mail at cground@ptd.net.