April 2006

www.pmengineer.com

5

FiveTime Winner

2005 APEX Awards

0406cover.qxd 3/29/06 1:42 PM Page 1

30 PMEngineer April 2006

If you’d dial your transporterbeam back to, say, 1991, and aimyour arrival for the hydronicsindustry, you’d quickly find a sadand forlorn marketplace. Just 15

years ago, manufacturers were barelytreading water, cranking out replacementboilers at a slower pace each year. Theburgeoning new construction marketwouldn’t have anything to do withhydronics. It was a pretty dismal scene.

Today, the hydronics industry hasemerged with an extreme makeover—moving at warp speed with confidenceand clear direction. New equipmentand market conditions have drivenmanufacturers to new levels of engi-neering excellence.

Without question, market forces—chiefly, the push for higher and higherenergy efficiencies, and demand forequipment to go where no equipmenthas easily gone before—are drivingthe pace for new and innovativehydronic solutions.

The newest generation of equip-ment—such as condensing technology

that extracts heat from condensatewithin the system—has pushed com-bustion efficiency into the 95% to 99%range. That’s smart use of energy. Addnew and sophisticated commercial con-trols to the picture, as well as systemintegration with building automationsystems, and you begin to see howquickly this market is moving.

With performance like that, buildingowners are now at attention. When thedesign engineer can calculate a three- tofour-year payback for new equipment(or perhaps even shorter than that in

some instances), there’s real incentive toinstall new technology.

To help explain this phenomenon,we’ve tapped the experience and expert-ise of several industry experts, including:

• Bill Root, vice president of sales andmarketing, Laars Heating Systems Co.

• Mike Chiles, president and generalmanager, Watts Radiant.

• Tony Radcliff, building servicesproduct segment manager, GrundfosPumps Corp.

• Tim Rosen, P.E., ConceptMechanical.

• Mark Olson, CEO and general man-ager, Caleffi Hydronic Solutions.

• Joan Mishou, manager of applica-tions engineering, Laars Heating Sys-tems Co.

You’ll learn that high-performancehydronic heating and volume waterheating depend on the interrelation-ship of the following six key facets ofthe boiler system.

1. System EfficiencyHow effectively the boiler relates to

An industryemerges,

from bust torobust.

By John Vastyan

(Grundfos photo)

feat10406.qxd 3/31/06 1:31 PM Page 30

the total system is determined by itscapacity to deliver heat either quickly, orslowly, depending chiefly on the needs ofthe system and the ability of the boiler toadjust to changes in the system’sdemand for heat. The common term is“to size to the load.” Also, total systemperformance is greatly enhanced whenthe equipment works at peak perform-ance—with fuel consumption happen-ing at the highest levels of combustionefficiency—at all levels of heat demand.

According to Joan Mishou of Laars,another important factor is the use ofmore sophisticated controls that samplechanges over time and “learn” theresponses of the system to changes inconditions, such as heating load, out-

door air temperatures, and firing stagesof the boiler(s).

“And there’s modulation or stagedfiring vs. on-off,” said Mishou. “Modu-lating and staged fired boilers reducefuel consumption by ‘sizing to the load,’so that the amount of heat produced bythe system precisely matches the need.”

Piping and pumping are also keyfactors in building an efficient system.The most efficient boiler in the worldcan’t make an entire system efficientif the system is not piped andpumped correctly.

And, there’s response to outdoor tem-peratures, water storage temperatures,and system loop temperatures. These,too, are very important contributors to

overall system performance. Controlsystems should take these key variablesinto consideration.

“Condensing boiler technology is oneof the key factors for the dramaticincrease we see in boiler/water heatersystem efficiency,” added Bill Root, alsoof Laars. “Our condensing commercialboilers, such as the Rheos+, are built toencourage the formation of condensatewithin the system and to withstand thecorrosive nature of the liquids that formthere. Latent heat is extracted from themoisture that forms in either the pri-mary or secondary heat exchanger, dra-matically enhancing combustion effi-ciency,” he said.

But efficiency is only one of theadvantages of installing these systems.Application of the boiler can play aneven more important role. “Their resist-ance to thermal shock and the ability toaccept low return water temperaturesputs condensing systems in a category oftheir own, ideally suited for high-vol-ume, cold-start systems,” he said.

Modulation goes hand-in-hand withthe ability to operate in a condensingmode. When boilers can operate withlow return water temperatures and low-ered firing rates, the relationship of heattransfer surface to fuel consumed, andthe combustion efficiency itself, com-bine to deliver maximum efficiency.And, when multiple boilers are installed,each one handles only a portion of theheating load; that drives system efficien-cy even higher.

“Some systems that require higheroperating temperatures most of the timemay still benefit from a ‘lead boiler’that’s a condensing boiler,” continuedMishou, “while the remaining boilersthat provide the bulk of the heat arenon-condensing.”

2. Combustion Efficiency & Thermal Efficiency

Just a few years ago, many of us in theindustry considered combustion effi-ciency and thermal efficiency to be themost important factors in determiningoverall system performance. That’s notthe case today.

According to Root, transferring heatfrom a boiler into a total system—and

New Age Hydronics

32 PMEngineer April 2006

Pennant boilers by Laars

permit easy diagnostics

during pre-fire.

feat10406.qxd 3/31/06 1:31 PM Page 32

34 PMEngineer April 2006

in just the right amount and at just theright time—is a truer measure of sys-tem performance.

Manufacturers today put a lot of engi-neering effort into maximizing heattransfer to water—and that efficiency is acritical aspect of a boiler’s performance.The only thing to keep in mind is thatmany applications do not call for thehighest levels of combustion efficiency(condensing equipment) because thewater temperatures are too high. Design-ing systems with staged firing, modula-tion, and/or multiple boilers can oftenproduce higher system efficiency thantrying to use a single condensing boilerthat claims higher combustion efficiency.

“Green”Boilers“Green” boilers are another facet to

the high-performance equation.“Today, when this topic is discussed atindustry round tables, we look atemissions—NOx, CO, CO2—with thereal desire see lower levels of pollu-tants that endanger our atmosphereand indoor air quality,” said Mishou.“California’s South Coast Air QualityManagement District (SCAQMD), thestates of Nevada and Texas, and select-ed projects in almost every other statehave set limits for emissions, especial-ly NOx. And, being able to take 100%of the air for combustion from out-

side the building is also required inmany installations.”

3. Information ExchangeHow well does the boiler act as part of a

system in terms of both accepting andresponding to external sources of informa-tion? “Information exchange,” if we reallyput it to the test, refers to the boiler’s abili-ty to both receive external information—such as outdoor air temperature, newinstructions from a BAS, and system zoneinformation—and to send informationback to the BAS—such as inlet and outletwater temperatures, operating cycles, fuelconsumed, pump operation, etc.

According to Root, these functionsplay an important role in the exchange ofinformation to and from the system,such as the…

• Ability to accept communication sig-nals from BAS (BACNET, LON, Metasys,Echelon);

• Ability to report information back tothe BAS;

• Collection of data that providemanagement information about oper-ating statistics and efficiency, such asinlet and outlet temperatures, runtime, percent load, domestic tank tem-peratures, system loop temperatures,etc.; and

• User interfaces—how well, and howeasily the user can change operationalsettings, is important. Consider how easyis it to learn the boiler’s command sys-tem. This also includes function andusability of keypads, displays, and con-venience of access.

4. Installation and ServiceabilityHigh on a field technician’s or build-

ing maintenance supervisor’s wish listwill be:

• Easy access to all components;• Easily accomplished field wiring of

New Age Hydronics

Installer Hot Rod Rohr

prepares several three-speed

circulators for connection to

a Caleffi HydroLink low-loss

hydronic header.

(Grundfos photo)

(Grundfos photo)

feat10406.qxd 3/31/06 1:31 PM Page 34

36 PMEngineer April 2006

thermostats, field interlocks, accessoryequipment and BAS control;

• Convenient access to water, gas andelectric at different sides of the boiler;

• Combustion air that’s filtered, withfilters that can be washed and reused;and

• Options that include sidewall andvertical venting, as well as a boiler’sinstallation outdoors.

5. Multi-Speed CirculationOne of the most important facets to

optimal circulation for hydronic sys-tems is for design engineers andinstalling contractors to match apump’s performance or flow character-istics to the specific job that it needs toperform within the system.

According to Radcliff, a single-speedpump has one performance curve. Butnew multi-speed circulators, such asGrundfos’ SuperBrute, and the larger

VersaFlo, offer a much broader range ofperformance. With the flick of a switch,various speeds can be chosen, easilychanging head and flow to meet the spe-cific needs of the system.

“We’ve standardized on multi-speedcirculators because we feel they do the

best job,” said Tim Rosen, P.E., a partnerin the plumbing and mechanical con-tracting firm, Concept Mechanical.“Three-speed circulators give us greatercontrol and versatility.”

Rosen said that he always does themath, calculating heat loss, flow rate,and pressure drop for each pump.

“I use this information and the statedpump curve to select the proper pumpfor each load,” he continued. “In thepast, we might have three or four differ-ent pump models on one job, all selectedto match the exact needs that we’vedetermined. With multi-speed pumps, Ican use one pump and select the speedto match the flow and head that wewant. And, the use of multi-speedpumps allows for future expansions,changes and retrofits in stride.”

Enhanced Piping SolutionsAnother advanced device combines a

hydronic separator and distributionmanifold. Called the HydroLink, fromCaleffi, the unit is attached to hydronicheating or air conditioning systems topermit different heat adjustments formultiple zones when there is only oneboiler or chiller.

Its configurations are compact andcan easily be designed into any type ofhydronic circuit. According to MarkOlson of Caleffi, the key operatingprinciple is that when a single systemcontains a primary generating circuitwith its own circulator and a second-ary circuit with one or more distribu-tion pumps, conditions may permitinteraction between the circulators,

New Age Hydronics

Watts Radiant's Onix tubing is

easily stapled up without plates,

offering superb heat transfer.

(Laars photo)

feat10406.qxd 3/31/06 1:31 PM Page 36

creating unwanted flow rate and pres-sure abnormalities.

The device provides a low-pressureloss zone, enabling both primary andsecondary circuits to be hydraulicallyindependent of one another. Yet the unitcombines both a low loss header and adistribution manifold. A low loss headeris critical for high-flow-resistant low-mass boiler installations because itmoves the point of lowest pressure dropfrom the boiler to the unit’s low-pres-sure chamber. The distribution manifoldhas closely spaced tees that connect thesecondary circuit to the primary loopinternally, so that flow in the primaryloop has very little tendency to induceflow in the secondary circuit.

“Because the unit’s openings are soclose together, there is almost no pres-sure difference between them, thus thepressure differential across the internalheaders is close to zero,” added Olson.“The pressure increase created by a giv-en zone circulator is almost entirelydepleted by the time the flow returnsback to the distribution manifold. Thisarrangement prevents interferencebetween the boiler circulator and what-ever zone circulators are operating.”

6. Heat DistributionThe hydronic industry’s renaissance is,

in part, due to the reemergence of theradiant heat industry. In the commercialsector, large radiant heat systems placeunique demands on a boiler, or series ofboilers. According to Mike Chiles ofWatts Radiant, these systems were histori-

cally character-ized by cold startswith long boilerrun times, highwater volume,high mass, coolerrequired supplywater tempera-tures, and shortboiler cycle-timeswhen the mass isat temperature.

Of course,large radiantsystems requirea boiler or boil-ers with high

output. A key advantage is that whenthe thermal mass of a floor or heatedsurface has reached temperature,shorter and less frequent boiler cycle-times are required. Better yet, a boilersystem with modulation permits theheating, and later, heat-maintenanceof the heated surface. Either a fullymodulating burner, or the lead-lagstaging of boilers, would allow a sys-tem to meet ever-changing loadrequirements for optimal system effi-ciency. Another option is to add massto the piping system to increase boilerrun times during periods of lowdemand. For this, water tanks can easi-ly add mass to a piping system.

“Snowmelting systems pose a differ-ent challenge: high demand and highmass with extremely cold water/glycoltemperatures,” added Chiles. “Here, thechallenge is not short-cycling of theboiler. Thermal shock happens whenfreezing return-water temperaturescome crashing into the heat exchangerin a long, hard, cold start.”

Fortunately, the new generation ofcondensing boilers takes this brutal jabin stride. Many modern boilers aren’tsusceptible to thermal shock, due to thematerials of their waterways and heatexchangers. Others can be easily protect-ed from thermal shock with the use of aboiler bypass, which can be built tooperate automatically with the additionof a control system, or they can be man-ual, fixed temperature systems.

Quite a difference in just 15 years. Wenow have smart technology that’s gettingsmarter, inspired professionals respond-ing to market needs, and customers whosee the value of contemporary hydronicsolutions. Anyone for a spin in the trans-porter to the year 2021?

John Vastyan, a journalist whose workfocuses on the plumbing and mechanicaland radiant heat industries, owns CommonGround, a trade communications firmbased in Manheim, PA. He can be reachedat (717) 664-0535, or cground@ptd.net.

38 PMEngineer April 2006

New Age Hydronics

Modern

equipment

includes

conveniences

such as slide-out

diagnostic

control panels.

(Laars photo)

Three-speed, wet rotor circulators

are an ideal choice for many retrofit

applications. (Grundfos photo)

feat10406.qxd 3/31/06 1:31 PM Page 38