Green HVAC: Flattening the

Learning CurveTtie future of tiie H\/AC industry isgreen, but buiiding owners want energysavings and emission reductions now

By CLYDE FORD and SHANE STANFIELD, LEED BD+C

Southland Industries

Garden Grove. Calif.

The HVAC industry is evolving as the demand for greenIIVAC (- hanges the way mechanical engineers conductbusiness. As building owners and operators seek oppor-tunities to reduce energy costs and their buildings' emis-sions, green presents a very strong growth opportunitylor the industry.

Federal agencies, municipalities, and utilities offerthe economic incentives that make investments in greenHVAC attractive. These incentives typically are linked tocertain levels of reduction in energy and water consump-tion. In many cases, HVAC is one of the largest consumersof both in a building, and, therefore, often is one of thefirst areas in which a building owner will invest.

Rebates, tax credits, energy codes, industry standards,and energy costs are driving the adoption ofgreen HVAC technologies. These factorshave ushered in a wave of innovationin the industry that requires a true un-derstanding of available technologiesand the business acumen to identifycost-effective solutions across multiplebuilding sectors. As we will examine

later, the return-on-investment (ROI) tolerance for eachsector varies. Nevertheless, green HVAC plays a role inthe design and construction of most new and renovatedstructures.

This article will explore the learning curve in innovationand the challenges of green HVAC systems in both newconstruction and renovation. When correctly designedand constructed, green HVAC systems provide manybenefits for a building owner, not the least of which is asmaller utility bill. Owners also can expect an improve-ment in indoor-air quality, a quieter building, reducedmaintenance costs, and extended life of installed equip-ment with a properly designed system and maintenanceplan.

Soiutions Influence DesignGreen HVAC systems, such as underfloor air distribu-

tion, displacement ventilation, and active chilled beams,have widely different design and operating characteris-tics, and each one offers a solution to a building ownerthat may have a significant influence on building design.Natural ventilation is another option, but one in which thebuilding occupants should be willing to accept a widerrange of temperatures. Although the temperatures willbe within the American Society of Heating, Refrigerat-ing, and Air-Conditioning Engineers (ASHRAE) comfortrange, they are not as predictable or controllable as tra-ditional systems. In addition, some owners might prefersolutions that are highly visible to build a reputation as aforward-thinking owner.

Collaborating with owners and architects to under-stand their required ROI timeline enables contractors toidentify cost-effective strategies and win support of in-novative solutions. Few owners are interested in spendingfor spending's sake, but if there are logical, well-plannedopportunities to reduce the cost of ownership, they are

more likely to recognize the value.Designing for energy efficiency is not the sole re-

sponsibility of one contractor, subcontractor, or con-sultant. Rather, it should be the combined effort of

Clyde Ford is a project manager for Southland Industries. He has more than 22 years of experience in mechanical engineering. Hehas worked in many different market sectors, with an emphasis on educational facilities. Shane Stanfield is a project engineer forSouthland Industries and a LEED BD+C accredited professional. He graduated from the University of Nevada-Reno with a bach-elor's degree in civil engineering and currently is pursuing an MBA from the University of California-lfvine.

34 HPAC ENGINEERING DECEIVIBER 2011

a collaborative design team that in-cludes architects, mechanical andelectrical engineers, consultants, andowners. Collaboration throughoutthe process helps eliminate unneces-sary change orders and delays be-cause the mechanical engineer canright-size the system with a broader

understanding of the energy-perfor-mance and occupancy goals.

Big-ticket improvements and solu-tions might garner most of the atten-tion, but it is important to design andconstruct what is right for a project.Once again, collaboration is critical.Engineers and construction teams

should look for opportunities toachieve the same energy goals withthe most cost-effective solutions.

Designing Green in anExisting Structure

Your green modifications in anexisting building may be limited by

SOLAR-THERMAL STORAGE BENEFITS PIERCE COLLEGE

No owner specifications were provided when implementinggreen HVAC technologies for the near-net-zero central-

plant upgrades at Pierce College in Woodland Hills, Calif.This project was developed while a new maintenance andoperations building also was being designed. This put theresponsibility of the design and construction of the project onthe design-build team.

The owner asked the design team to improve an existingsystem at a nearby campus. This required the implemen-tation of a single underground solar-thermal hot-waterstorage tank. Keeping the tank insulated and protected fromcorrosive soils presented a challenge. The design-build teamcollaborated with an independent tank-fabrication companyto fabricate the tank and a separate insulation company toinsulate the tank off site and then set about the task of in-

Building-information-modeling Screenshot of the near-net-zero

central utility plant at Pierce College.

stalling one of the first underground solar hot-water storagetanks used for green HVAC.

After consulting with a chemical-corrosion specialist, thesolution to designing the underground hot-water storagetank was to insulate the 42,000-gal. tank with high-temper-ature spray foam sealed with abrasion-resistant elastomerand perform an intensive design review.The tank was successfully fabricated,insulated, and installed to providehot-water storage. The design team alsoinstalled a solar hot-water system thatused gas-fired boilers to heat the waterduring periods of low sunlight.

Another challenge involved thehigh-temperature valves, seals, andpipe joints. Because the water fromevacuated solar-thermal tubes canreach temperatures above 250°F, all of

Installation of the 42,000 gal. insiiL: m ;

hot-water storage tank at Pierce College.

Photovoltaic panels installed above parking spaces provide power to

the college s central plant and mainteance and operations building.

the solar-thermal system's components needed to be ableto withstand those temperatures.

The design of the system also required a way to dissipateheat in the event the water stored in the solar storage tankwas saturated to the designed temperature of 23O''F. Thesystem design also included the ability to reject excessstored heat if the tank reaches the maximum design tem-perature of 230°F. As long as the sun is out, the systemwill produce hot water. If there is low or no demand for thechillers to operate (perhaps in economizer mode), the heatfrom the solar tubes is rejected through a heat exchangerand cooling tower. On the other hand, on cloudy or overcastdays, if the storage-tank water temperature is below theminimum operating temperature required by the absorptionchillers (185°F), the implementation of a back-up systemusing natural-gas boilers has to be incorporated to fire thechillers for space cooling or heating hot water for spaceheating.

Our design-build team reviewed the solar-thermal watertemperatures to develop the most effective solutions.Welded pipe systems were used inside the central plant,while high-temperature sealing elements were used on

the distribution piping systemsand all of the valves, accesso-ries, etc., including high-temper-ature flouroelastomer sealingelements. Gas-fired boilers wereused as the back-up system forbuilding heating and cooling. Thissolution has lower energy con-sumption when compared withcentrifugal chillers, which wereused on previous projects of thisnature.

DECEMBER 2011 HPAC ENGINEERING 35

GREEN HVAC: FLATTENING THE LEARNING CURVE

The trench for

instaiiation of

the chiiied-water

ioop at Golden

West Coliege.

PLANNING NETS REBATES FOR GOLDEN WEST COLLEGE

Golden West College in Huntington Beach, Calif., usedCalifornia Legislature Government Code 4217 to conducta campuswide energy-savings project. A new central plantneeded to be built with 1,400 tons of cooling and 400 mbhof heating, with room for future expansion. A campuswidecentralized energy-management system and controls systemwas essential. Eighteen existing buildings needed HVACretrofits and lighting upgrades. Furthermore, 6,400 linear

feet of trenching needed tobe dug and 26,000 linear feetof heating and chilled-waterpiping needed to be installedto interconnect existingbuildings and the central plant.

The chilled-water loop for theretrofit at Golden West Collegeprovided more than just a wayto connect the 18 existing buildings to the newcentral utility plant; it also provided a source ofthermal energy storage. Because of the amountof underground chilled-water piping installed,approximately 30,000 gal. of chilled water wasdesignated to provide cooling upon start-up inthe morning. A bypass loop that allowed thepumps to run in the morning without goingthrough the chillers was installed in the centralpiant. Water was circulated in the loop until thereturn to the central plant reached 60°F. Thisprovided the owner with two to four hours ofcooling, depending on the time of year, beforethe chillers were required to start. In doingso, the owner was granted additional energysavings. The chillers were required only whenthe system had depleted the cooling of under-ground chilled water in the loop.

Thanks to extensive pre-planning and greatcommunication with Golden West College, theproject was completed on schedule, underbudget, and with minimal impact to the school.Directly relating to the goal of the project.Golden West College received $500,000 in

Boiler room in the new central energy rebates through California Edison andutility piant at Golden West will save thousands in monthly electricity costs.

College.

Chiller water pumps in the new

central utility piant at Goiden

West Coiiege.

the building's structural integrity.For example, although a rainwater-harvesting system may be beneficialfor reducing water consumption, theroof of the building might not sup-port the necessary infrastructure forsuch a system. Therefore, changesto the structure could alter the es-timated ROI to a point where it no

longer is cost-effective.Ceiling height is another potential

limitation. For example, if the ceilingis opened for a renovation project,adjusting the ceiling height can addan unrecoverable construction cost.A simpler solution that does not al-ter the ceiling height might have ashorter payback analysis.

It is possible that necessaryHVAC equipment may need tobe placed on the side of a build-ing, rather than in the legacyequipment's location, because ofweight or vibration differences.

Working in OperatingBuiidings

Be prepared to work withthe building owner to developan accurate and safe schedule

and communicate with all stakehold-ers throughout the process. Thisexchange needs to be coordinated,discussed, and documented early inthe project to mitigate any interrup-tion to the building's operations andits core business. Changes will oc-cur, but a documented schedule willprovide the framework within whichthe project takes place. Short-termchanges will be more easily accom-modated if there are open channelsof communication.

Safety and comfort are primaryconcerns for an owner and con-struction team. Anything that couldjeopardize safety must be scheduledat a time that minimizes the risk tooccupants and construction teams.Plans should be in place for tempo-rary mechanical accommodationsand continuity for mission-criticalHVAC needs, such as those of datacenters and hospital operat ingrooms.

Depending on the sector (healthcare, education, government, etc.),the choreography could be a chal-lenge. Education projects offer a briefwindow in the summer when the siteis nearly vacant, but deadlines stillare critical for the safe return of stu-dents in the fall.

Consider the iViaintenanceRequirements

Green HVAC success is not onlydetermined by the design and con-struction of a system, but also main-tenance. ROI and payback analysisare based on the assumption that asystem is maintained properly. Inmany cases, however, systems are

36 HPAC ENGINEERING DECEMBER 2011

GREEN HVAC: FLATTENING THE LEARNING CURVE

not maintained properly and ineffi-ciencies result.

Inefficiencies in a system cancause the owner to undershoot theestimated ROI. Unfortunately, thisoften goes unnoticed until it is toolate. As the systems installed in to-day's buildings increase in complex-ity, it is critical that maintenancepersonnel have the expertise andbackground knowledge of the in-stalled systems to operate them atpeak efficiency. Engaging the main-tenance departments of a mechani-cal design-build partner can alleviatethis learning curve, as there is priorknowledge of the installed systems.In a design-build-maintain model,there is a single source of account-ability for the green HVAC system,providing greater assurance that en-ergy goals will be realized.

Owners must be involved in thedecision-making, as realizing their vi-sion requires a whole-building designprocess. The whole-building designprocess requires the responsible teammembers to work together to set andunderstand the energy-performancegoals. The purpose of the holistic de-sign approach is to enable the entiredesign team to interact throughoutthe process and understand system¡nterdependencies. A systematic anal-ysis of these interdependencies canhelp ensure that an efficient and cost-effective building is produced.

The design-build method alsospurs innovation and collaborationamong the design team to identifypreviously unrecognized synergiesand solutions, leading to an efficientconstruction project that saves theowner time and money.

Where is the Industry Headed?Future demand and innovation

in green HVAC will continue to beone of the most important aspectsfor new building and renovation.Ihe innovative solutions generatedby design teams also will influencethe energy-consumption standardslor future construction while rais-ing the bar for the next generation

of buildings, as the prospect of net-zero buildings becomes more preva-lent. New innovation in software fordirect digital controls could unlockeven more flexibility and scalabilitythat can change the way energy isconsumed. By virtually any criteria.

the future of the HVAC industry is agreen one.

Did you find this article useful? Sendcomments and suggestions to Se-nior Editor Ron Rajecki at ron.rajecki©penton.com.

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