O
`
`CI-I-95--Ig—.<I
`
`'
`
`INNOVATIONS [N DISTRICT HEATING
`AND COOLING 1934-1994 AND
`
`A
`
`THEIR ECONOMIC IMPACT
`
`Graran Momhed
`
`ABSTRACT
`
`Thomas R. Casten
`
`7791! periadfram 1934 20 I994 Jaw flu.’ cancep-i‘ afd"I.r-
`!'I'I'c: Jaearfng and c.*ooII‘.r:_g'revI"IIe:i M229: new dumrr .-zmz;-gy
`systems were erfabfirixed and existing 53.9-rams ;:rp::I':'rded'_
`The expansion 1:41-'1' Em affrifiufed to technical irznavarforls m
`we?! :2: t'I:I.m':nI':I'Ona.u’. znvframmenxal. and economic chm-::ge.r,'
`no one event can be srlrtgie;-a’ out as a main reasonjbr the I'm.-
`proved climate: The rfisrricr coofing industry in parlicrdan
`fi-‘I21-<21‘-7
`grcrwing demand and technical i.I1wo1w1.I'0.=r.. experi-
`emeaf 42 period :3! wgarrcedemed exparavion. On the srrrfaae.
`the conazp: of Iii-:m'¢:.I coding would appear Ia be uneco-
`Homfcal Although economic IN:ne;I'it.s' can be achieved 1.I.:.r'.*rg
`1’radirEr.>I1rI'l dfsrricf cooling Iec}rI'Io!ag;_v aver .fmf'n-:'rfua1 b::i.i'a'-
`fag .r_v.s1‘e:n.r, fire I'J£.*rzr.;i"'I’r.s firam technical innmratiom dun‘.-rg
`the !a.rr 19 years. such as Iowlangperafwe cJ:.I'J'!ea'—wal.9:'
`storage. trigencrafiarr 'Par1'I:'bF2-speed-drhra :9:-Jan-IaJ‘og].v,. and
`alrtomatforr, Irave made disfrfcr cooling more competitive
`and Plans conrrfbmed to 1'na':Is!I'3r growth. On the district
`heudfirrg 512523 I'n.-rmvariorzr :1.rch as low-cost disrriburfan rec}:-
`noI’o_g;P and cast-\=.5fi?éc£3*ve cageneralion .‘Ie1'pea' cram‘: a re-
`naI'.$.sI:'.-Ic.9_ Tke improved camperiiivauass qfdirrrfcr hearing
`aria’ cooling has mrlde rha cambirzedservfce arrracrivefor us-
`ers who now do not need to rafy on either in-Jzonse heating
`or cooling _pi'rJ:1J'.£. 0:JgcII'2:g :'rmovarI'o.I-1-.-.' in the Jhdzuny set
`the stage for corufnued expansion as district heaiirarg and
`r:9oII‘ng—-disrrici energy-—move into {.512 next cenmry and
`help improve our r.-I-brm arm‘;-anmem‘ more than ever.
`
`INTRODUCTION
`
`Duzillg the last decade, the cancepl. of district heating
`and con-Iingwas revitalized and district energy became an In-
`crcasingly vital bancfactur to cry: major urban centers. This
`growth from 1984 tn 1994 can be a11:rib-uted :rI 1I:Ch.ni|:aI in-
`novations as well as institlltinaaaj, vimmnental, arid accr-
`ncrmic changes. It was during this parfud that Cornpanics
`decided to focus. on their core business. Devoting ‘time and
`rcsuurces In the nperatiun of healing and cooling :q'u'1pme.:I11:
`unrelated to a company’; I:Iu5iJ-1:55 made less and lass 51:11::
`in innreasizagly difficulr and competitive times. I\.:1.h¢ sarm:
`timc. mare nnviranmental regulations, including ‘Eh-C phase-
`out of chlutrnfiuorucarbcrns (CI-'-Cs), made mdividxnl bufld-—
`
`Eng Owners take a hardfir look at the costs associated with
`self-gmcratim. Wlnm 111::
`factors are added to the
`trchnala-gical innovations of district hcatlng and cooling, a
`synergy developed that propelled the popularity of‘ distrir:I
`_h.eati.I-lg and cuoling to a-new high.
`This papa‘ focuses on the irmuvations in the technology
`the: formed One pan in the revival. Exisfing distri-:1 energy
`systems were able to improve their economic feasihility, and
`new systems wen: built using ncw -:os1—eEfeCtive distribuiic-fl
`technology. Di.sl:riIc‘I cooling, which had bean largr.-Iy Iirniled
`to campus systems, experienced an unprecedented cxpansian
`in downtown I.I.rban CIHS.
`
`TJ: this new mvircmnerrt, the term :fr'.s-:1-Ea: Energy came
`into use to dcst:r1'bL': utilization of tI:II-_-III: innovations in the
`combination of heating and cooling services, and it became
`clear that the fiJI!‘IIJ-I: of £115 business was in providing, “mm;
`fm't,."' not s=I]‘Ing']1I:at.
`
`INNOVATIONS IN DISTRICT
`HEATING AND COOLING
`
`hrcreasingiy duflng the last few decades and espctially
`during the last IO }-ram, tI:I:l:InJ'::a] innovations have bean a.
`driving force. behind the conrirluing expansion of districlt
`heating and cooling. These innmrations have improved. the
`I:::cmom1':s Ofexisting systems and rrnde the develapmznr I:If
`new ans feasible.
`in
`The district heating and cooling industry is small
`comparison to other tcclillilfllflgy-l'I:}3ItBd industries, such as
`power gen.-.ratiOn. Although there cenabdy have been dc-.-el~
`Opmenss made by the district haafing and cooling industry, in
`many cases tcdlnolngy developed for other fields has been
`successfirlly applied. Innovations such as Eargz-scale chilled-
`watcr storage and low-cost dist:-ibution piping are examples
`Of the former, while efiiciem cogenexation technology and
`process automation arc c:I:an1pIes of 1111: Janet. Applications
`of these i11:I1a1.|'at:'IoI:1s and thl: beneficial rasuhs from them, are
`borne out by the cxperfertctt in district energy sysrcuas oper-
`ated by the authors and Othus in, for ex,ampIe_ Tulsa, OK.
`Chicago, IL, 51. Paul, MN. and elsewhere.
`Diilficl heating and cooling is capital intensive and on
`[he surf'aI:I: appeal’: to 05¢: few operational oust. savings
`cumpamd to invhousc heating and dealing. However. Ihe
`
`Carat: Mornhed is prcjact marmgar and Thomas R. C1.-ten is presidl.-.I'I.t arid CEO a1 Trigcn Em-:rg;.r Cm-pOra.ticIn, White Plains, NY.
`nus pagpmm .5 son mscussme PUFI‘PI'_‘lSES_Oh|LY. FOFI INCLLI-.sJON_ra II-SI-{RAE rn.IIN.5_AC‘nOI_I9 1995, II. 1:11, 5-1. 1. No: In be l'%P'in1ed _|n_.1\rPI'.I|a at
`in pan wi111ouIwr'IIIIarI pennissinn nf lha Janertszan sou:-etv ul Healing. Halngmhnn and Air-Good?!‘-orw\sI Engineers. In. 1:91 Tome Circle. HE. Mlmra.-GA 30329.
`C:q:IinII;ma_ rrnu‘.-ngs-_ I:o.v1g:|usI'ons_ nrmanmmendalions axprassed In this paperam Lrn:-ee ol ma audnnjS',I anddcl not necessarily rel'rec| um flew: d‘ .ASHEInPIE\"I'2!1'lIeI1v
`quasliuns and D:||'nI'I'IEI'1ls regarding His paper SIIDI-W-‘l bfl f|=0=1VI=d GIASHPME I'M‘-I Ialar Elan February 3. I595.
`
`PAGE 1 of 6
`
`PETITIONER'S EXHIBIT 1226
`
`

`
`teclmoiergy offers much flexibility in selecting, the most eco-
`nomic method of supplying a large pooled heating and cool-
`ing demand.
`'
`'
`An isolated building is limited to the use of installed
`equipment, normally sized on a rarely seen peak load. A
`pooled energy d.eI:n.and can be met from multiple plants using
`different technologies. Difiuent technologies are used to
`meet base load and peak demand, witltthe selection basedon
`maximizing the efficiency of each piece of equipment and
`miriirnizing fuel costs. Cogeneration of healing and cooling
`or hearing and power fimlter enhances efficiency. Thermal
`storage systems are employed to reduce electric peak de-
`mand As a technology, dish-iet energy offers unlimited flex-
`ibility For optimizing the efliciency of both beefing and
`cooling.
`.
`The innovations made during the last decade have sig-
`trlficantly improved the technology by
`
`0
`
`increasing the efficiency of chilled-water production
`(using turbine~dz-lven red-igeratioo,
`t:hilled—wate:r stor-
`age, and so forth),
`increasing the efficicnqr ofstearn and hot water produc-
`tion {improved efficiency in boilers and hot water gen-
`craters},
`improving the efficiency of combined heating and cool-
`ing (cogeneratiou and trigeneracion), and
`reducing the cost of distribution systems (iinproved
`prefabricated piping for direct burial, more effective
`variable pumping, etc).
`
`As a result, district energy can today be developed at a lower
`specific cost, with a higher efficiency, and with more flexi-
`bility than ever before.
`
`Cogeneration
`
`Ct:-generation as a concept hardly counts as an innova-
`tion after a century or more or" use. However, after decades
`of limited potential, cogenerntlon has been revived through
`tedmical inatovntions.
`_
`I
`lznprovernents in gas turbine technology have greatly
`enhtmced their mechanical ttfilcifitlclf all-1. Wh-‘lffl III-Bil-1I‘£|-l gas
`fiuel is available, gas turbines are today increasingly replac-
`ing
`steam turbines
`in
`cogencration
`applications.
`Traditionally, the seasonal heatittg, loads in district heating
`systems limited the economical size of die back-pressure
`steam turbine; the turbine had to be sized based on a fi-action
`cfthe winter peak steam flow to allow economical operation
`cloning most oftlte year. The relatively small turbines im-
`posed a practical litnitation on system steam data and tuflriue
`emcicncy. As a result, most ha-cl-tqaressure steam turbines in
`district heating systems were relatively small and inefficient.
`Alternatively, irnemal combustion engines provided a higher
`mechanical efficiency but, in most cases, a lower thermal ef-
`ficiency and limited steam production.
`
`The innovations in gas tur|:Iine technology have pro-
`duced a tuecltirte that combines small size and light weight
`with high mechanical efliciency and high exhaust tempera
`rune. In cogent.-ration applications, producing both steam and
`elecuicity, they combine the desirable characteristics of high
`mechanical efficiency (30% to 40%) with high thermal effi-
`ciency (70% to 80%}. lldore-over, efficient gas turbines are
`today available, as evidenced by current manufacturer litera-
`ture, in a wide size 1-arige-fiomless than 1,000 horsepower
`Clip} (750 law] to more than ltlllI,tl[)0hp (75,000 kw).
`Large gas tltrbines can be sized based on steam load,
`maximizing electric production for the grid. while smaller
`gas turbines can be advantageously used as chiller d.n'ves or
`pinup drives, with recovered steam used to supplement
`boiler steam in the distribution system. In meclranical drive
`applications, steam from the turbine exlianst can nialte a sig-
`nificant contribution to the steam production throughout the
`summer season. Excess steam not required for distribution
`can be used for producing chilled water in absorption or
`steam turbine chillers.
`_
`'
`Additional
`inpmvements in gas turbine technology,
`such as combustion air cooling and duct firing, can easily be
`incorporated into a dish-ict energy facility, and help to fur-
`ther irnprnrve the cost-effectiveness ofthe installation. Com-.
`bustion air cooling, which can be provided fisr through a
`chilled-water ‘or refrigerant coil in the cunbustion air intake,
`will alleviate the problem of gas l‘I.u‘b-ine deratirig at high am-
`bient temperatures when the gas turbine electric power is
`most valuable. Duct fi.n'.t1g allows the warm mrbine EXl1E.|.l5t
`to be used as preheated ctnnbustitrn air to generate additional
`steam at a very high efficiency.
`
`Trigeneraiion
`
`“Trigenera.tion” is an extension of cogeneration technol-
`ogy that
`involves the simultaneous generation of heat,
`chilled water, and electricity. The trigeneration machines de-
`veloped for district energy systems in the last few years fee-
`nm: a prime mover connected to an indncnon generated
`motor and a chfller screw compressor on time same shaft [Fig-
`ure 1). In this way, any combination o-fatatuml gas and elec-
`tricity can be used to drive the
`screw compressor.
`Conversely, l:'ht': shaft power produced by the prime mover
`can be used to generate electricity and chilled wetctf ifl 3113'
`proportion. The third product, heat,
`is generated at?‘ the
`prime mover exhaust.
`Trigeneration technology can be advantageously applied
`to ttistrlct energy facilities that produce both hearing and
`cooling, Specially if a thermal storage tank is incorporated
`in the system and the machines can operate 24 hours per day.
`The relatively high initial cost of the ttigenetation technol-
`ogy in such a plant is more t.ha.n offset by the machines high
`utilization: gas-fiseled cooling, nu)-tilinzry power genefittion.
`and electric peak shaving, all at a high thermal cfiiciency of
`70% to 80%. Finuicnnore, since a combination of these uses
`
`PAGE 2 of 6
`
`PETITIONER'S EXHIBIT 1226
`
`

`
`Figure I Concepl a_ffrI'genera:':'o-rt
`
`e:-clsts year-round, the rnachi.ne'5 load factors are typically
`high. Existing installations typically operate at full load for
`5,GO0 to 7,005 hours per year.
`Compared rt) ‘tmdiciunzl healing and cooling plants, zlw
`pmpcrly applied trigenenizion machine will produce chflled
`water at a net cocflici-ent ofpuformance (COP) cfbcrween 3
`and 4, a higher nu: efficiency than any o1i1er commercially
`available ga5icl:|i1Ied—wat'er technology {Figure 2) (Casten
`19941 Note: In Figure 2, the COP is based on 1,000 awe?
`of natural gas. These chta have I:|:e:n validated by disuict en—
`ergy plant operatian in Tulsa and Oklahoma City, OK.
`
`Large-Scale Chilled-Water Storage
`
`The period 1934-1994 saw me clewrelupment of 1arge+
`scale thermal storage. Earlier, small-sI:ale therrrlal storage fa-
`cilities, such as it: slang: and meznbrane tanb, were used
`in limited applications.
`111 the 19l!Ds, however, larg-e—sca]I:
`stratified chilled-water tanks were beginning to be used (An-
`rkepnnl I992).
`-
`Cl:1ilIE'.1:l-waier slung: I;a.11.l4:s provide a nI.lJ11b-er of bene-
`fits to district cooling systems, i.m:luding thefollnwing.
`
`I. Expensive base-load chiller capacity can be fully uti-
`lized 24ll:curs per day, efiecfively doubling in capacity
`for most applications.
`I
`Electric chillers can be up-eraied “ofl'peak" and elettlrlc
`demand charges minirrljzed (load shifting).
`The chillfls am he upttratecl at optimum efiicimcy to
`charge tl1e1ank, and the tank can then be discharged on
`an as-required basis.
`The: storage tan]: provides an ahsmnmneous ::l'1llled—
`water backup.
`'
`
`fliighest density of water}. In stratifietl storage tanks, mid‘
`wateris stared inthc bottom of the ta.-11:. As it is used for
`cI:-I:-ling, it is returned warm to the top of the ‘tank. The water
`is charged and discharged as laminar flow at very low flow
`rates. Because of the higher density of the colder water and
`the low charging, velocity, the water strarifies in the tnnlc and
`only a. 2- to 3-foot {lJ.fil— to 0.9l—metr.-r) disturbed laycr—a_
`I.harmocli;n1e%epm-ates the warm and cold water (AS!-ERAE
`1993; CB&lC 1989).
`The dim-vbau.'.k with these tanks is mat 1:5.-.:r3 with in-
`creaszingly common 34*}-' [1 .]“C) chilled-water systems an-
`not be served than the tank A recent development
`(inexpensive fitczillg-point depressant} has solved the prob-
`lem and pmduced tanks that stntlify to 25"!‘-' {-3.9“C) or less
`(Figule 3). The 1ow—:empe1-atlire strar1'ficcl sic rage offers
`many iinprovcments over the traditional sh-atified tank:
`
`*
`
`doubling of the lhennal capacity tlunugh an i.ncrease in
`the leanpcrature difi'e:n.-ntiaI—3{l"Ff54"F instead of
`42"F."54"F [—fl.'l°CJ'l2.2"C instead 0-l'5.6°CJ'1.'Z.'}."C),
`
`
`
`
`
`Halural(inC-Dl‘II.lJn1.p‘I|al'I.1'JF.."lnn-hr
`
`Hlal Fllcmfllry
`
`In the mid-19805, tan]~'.°. were developed in which chilled-
`waxer would stmfify down to a temperature of 39°F (3.9°C)
`
`Figure 2
`
`Chifler energy canmmplfan.
`
`CH-95-I D-4
`
`PAGE 3 of 6
`
`PETITIONER'S EXHIBIT 1226
`
`

`
`i
`
`.F':'_gore.'1-'
`
`Temperature profile of cl _par1:'a-L5: chm-gent
`Io-ware.-nperatm-e stratified rank.
`
`no atlditional water lIeal:In=en.t required that will incrnse
`C-051.
`no corrosion inhibitor Iequiredto protect the tan:-:,
`can be used with conventional as well as Iow-tempera-
`ture chillers, and
`less expensive per tori-houn than other thermal storage
`systems.
`
`Series Chilling
`
`Series chilling is an operating technique that increases
`the capacity ofdisoict cooling networks (Figure 4]. Most ex-
`isting district cooling systems are designed for traditional
`supply tcruperatttrec in the 40°F to <$2"F (4.-4°C lo 5.-5°C)
`range and typically experience return temperatures in die
`52°F to 56°F {1],.i"C no l3.3°C} range. In saris chfllittg,
`]ow—teropcran.I.r¢ chillers operate in series with conventional
`chiilers, decreasing the supply temperature to 34°F (].1°C]
`or less iffreezin g-point depressants are used. The increase in
`the chillccl—wa.tcr tecoperanxre diflbretttial from 12°F-14°F
`{_c:~c—7.3°c) to 20°F-25°F (11.1-c-1 33°C} will almost
`double the capacity of existing tlistributioli piping or, alter-
`natively, reduce pumping power to I fraction. In addition.
`service can be pro-videcl to new customers who need chilled
`were: at lemperatures less than 40°F (4.4°C}. The economic
`benefits of series chilling can be sigrnifiounfly enhanced by
`Lhe irtstallation oflow-tempetanrre chilled-water storage.
`
`Ammonia Refrigeration
`
`Most older district cooling systerns and individual
`buildings are based on commercial h£._fi'l:ing, ventilating, and
`air-conditioning 1'_]-WAC‘) technology and use packaged cen-
`trifugal chill-:.n with CFC refrigerants. By contrast, most in-
`dustries relying on refii geration, such as food processing and
`cold storage warehouses, have been using a.n:u'nonia refi-iger-
`ation For decades.
`
`The growth of the district cooiing induslry, combined
`with the phasing out of CFC refrigerants, has resulted in the
`
`surf (113)
`
`Figure 4'
`
`Typical sen‘ chflifng concept.
`
`increased use of industrial ammonia refrigeration. for district
`cooling.
`Compared to other refrigerants, arnruonia stands out as
`not only one -of the most effioicnt rcfiigcrants, but also the
`most acceptable from an environmental point of view. An".-
`monia has no impact on the ozone layer and no gneenhousac
`efiecr. In IEEICI, vast amounts ofammonia are used as agricul-
`tural fertilizer. Ammonia is generally arvailable at a tenth or
`less ofthe cost of otherrefrigesnnts.
`Ammonia vapor has a low density and therefore is d.il‘fi-
`eult to use in centrifugal compressors. However, modem
`screw r::I:unp1‘cssm‘s that feature variable compression are ide-
`ally suited to district cooling. Using ammonia screw com-
`pressors,
`the cooling tower wet-bulb approach can be
`maintained in a wide temp-er.1tI.1re range and the resulting
`colder condenser water advantageously used in the cooling
`plant, with the lower condenser water temperature, a lower
`coinprcssiori
`is required and loss compressor power can-
`‘.i-|JII1¢d— Anunooia screw compressors compare in efficiency
`to modern cen.1:rifi.Ig3l chillem at design conditions and can
`be operated at full capacity at less than 0.3 ltwfton using
`40°F (4.4-°C) condenser water teruperature (Figure 5). Note:
`In Figure 5, the wflues are based on manufacturers’ published
`
`
`
`
`
`Erma}Cnnsumrlliorl.I:Wi'I.on
`
`0.?
`
`I16
`
`5.5
`
`IF. -I
`
`IIL3
`
`u_2
`
`,
`51:
`
`70
`El!
`Cori-dII'l:o¢I' Wilnl Temperature
`
`ll!
`
`91:! ‘F
`
`o ~c
`lb
`fill
`an
`
`Screw compressor energy cortsumprion.
`
`CH—95—'lIIl-4
`
`PAGE 4 of 6
`
`PETITIONER'S EXHIBIT 1226
`
`

`
`4
`
`Im
`
`data. The high part-compression and part-load cfficiencies
`become increasingly valuable as buildings‘ cooling loads inr
`ctr.-asingiy become a fimclinn of intcmal heat gains rather
`than warm ambient weather, and their cooling requixttuenls
`extend into periods of cold weather.
`
`Variable-Speed Drives
`
`Variable-speed drives are not new, but their universal
`and economic applitations in district energy systems are.
`Whether using clcclzricity, steam, or natural gas, variable-
`speed drives have contributed to greatly enhance efficiencies
`in district energy systems, where the energy demands are
`seasonal and also very front day to day. Variable-speed
`drives are toda3r'co1'nn::only_used in the form ofvariable-freu
`ttuency drives for electric motors and speed controls for
`steam turbines and engines.
`The eflicicncy ofchiliedewater systems in particular-can
`be edhattoed by the use oft-ariable-med drives. Substantial
`sltafl. power
`is
`involved in chilled-water production-
`ehilied-water pumping, compressor power, condenser pump-
`htg—b-rrl the cooling dtnnands vary widely fi-orn hour to
`hour. Significant energy savings can be realized with vari-
`ab-I‘I:-speed drives shtc-e the eoerg'y consumed is geometri-
`cally pro-p0I'lit:e:Ia.I to the flow rate.
`The savings associated with var-iab]e—speod drives are
`realized by autoinatiually and instantaneously optimizing the
`drive speed to meet the production requireroenr ofthe driven
`device. The compressor speed is optirnized to meet the
`chilled-water production requirements, and pump drives are
`operated to maintain a minimum remote differential pres-
`sure. The continuous adjusnnents will ensure that the opera-
`tion is always optimized and that the consumed sltafi power
`is minimized.
`
`Process Automation
`
`District energy systems have benefited much from the
`hoorn in computer and controls technology in recent yesrrs.
`Controls and automation have been employed to improve en-
`ergy efE.cienc}r as well as system: productivity. Today, fewer
`operators are producing more district energy at higher efii~
`cicncy. Automation has many applications in district ensign’
`systems, sotne of which are outlined below.
`
`Automation for remote opclalion is of special interest‘,
`since it has the potential to allow the txilization of existing
`equipment without incretncntal labor additions and thus re-
`duces the capital costs of district: energy systetn develop-
`ment.
`
`Wherne allowed by code, district energy systems served
`by multiple production facilities have been able toopcmle
`peaking and ba.t.'.5t—up plants remotely and in die process isn-
`ptove both efficiency and ;lfOClIJl.'.'fi_Vit}'. Conversely, controls
`teclntology has enabled other systems on incorporate larger
`ctntomer plants and thus reduce Capital cost expendituns.
`
`Low-cost Distribution Piping
`
`oflht: cost t:-fa new district energy
`A substantial
`cost of distribution piping.
`system is related to the
`Costsavings resulting from new distribution 5'_V'SI|:Il11 technol-
`ogy will significantly improve the competitive advantage of
`district energy.
`.
`The gntdual -change to direct buried piping has helped
`reduce the costs of distribution piping. even fltough the pre-
`dominm use of steam as the distribution medium in the U3.
`has limited the cost savings here. Dealing with large thermal
`expansion and the rcqII1'J'emeut for steam naps and other me»
`chanical devices in the distribution system continues to keep
`the cost of st dislIil:tutiotn high. In Europe, when: men
`dium-tcmp-emlure hot water is a commonly used distril:-u't:iot:t
`me-diurn, high—qua]ity, inexpensive, mas 5~prot.’tuoed piping
`has been predorninarttly used since the 19805.
`
`THE ECONOMIC IMPACT OF INNOVATIONS
`
`As outlined above, a large number of tocltnical and op-
`erational irtnotcations have cnrttribrrted to irnprovs the corn-
`petitiveness ofdistrict heating and cooling during the last 10
`years. These innovations have coincided with instiuttional,
`em-irontnentnl, and economic changes in societ}-—cl‘l.aIlgB5
`that by and large have. been favorable for the expansion of
`district heating and cooling.
`issues 113.5
`An increased awareness -of environrnenlal
`opened the public’: eye: to the benefits of district enetgy and
`has improved the acceptability of district energy as 2 con-
`cept. At the same tttnc, stricter regulations have increased
`
`ltarametet
`
`Combustion
`Process
`Speed conh-ol
`Spccdconlrol
`Pro-cc.-In
`Pressure. Flow
`Teletnetrics
`Total process
`
`Rumpus:
`
`lt:I'tp'ro-vcd efl-‘rcinncy, decreased emissions, monitoring, redttmtl labor
`Improved cfficicncy, monitoring, redrmccd labor
`T1"|'l]:I'l't1'r' ed efiiciency
`improved efficicney
`Decreasctfi complexity. rnunitor-ing
`Marti to ring. rcdtl ccd labor
`ivlonitoring, aecmacy
`Remote operation. rnorrir.oring,reduce:i labor
`
`PAGE 5 of 6
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`PETITIONER'S EXHIBIT 1226
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`

`
`Irtterestingly, technological advances in district energy
`have often come Erorn other industries. District heating, for
`example, has benefitted
`from the
`developmertt
`of
`cogenet-arion; this was made possible, in ‘part, by deveEop-
`merits in combustion turbine technology. The defense indus-
`try‘: need for ligtmveight but powerful jet: engines was the
`impetus behind this progres 3.
`District cooling has bcncfitlzed frctrn innovations in other
`industries as well. The computer industry has produced so-
`phisticated monitoring devices that have allowed plant oper-
`ators to optimize plant performance and achieve efl-iciencies
`never before possible.
`Regardless of the source, iiniovetion has made district
`heating and cooling economical. with the industry‘: abiiiry
`to provide total comfort service, and with growirtg environ-
`mental contents, the stage has been set for a renaissance in
`the district energy industry.
`'
`
`REFERENCES
`
`Andrcpoot. LS. 1992. Central chilled water plant expansions
`and the CFC refiigerant :issoe—Case studies of chilled
`water storage. Proceedings oftiaz Association a_-fl-i'1‘gi'ner
`.E.'ducr:fr'arr Facilflies Ofiicers, T9111 Annual Meeting.
`Washington. DC: APPA.
`ASHRAE. 1993. Desigrr gurkiefor cool thermal storage. AI-
`Ianta: American Society of Hearing, Refi-ig-crating and
`Air-Conditioning Engineers, Inc.
`.
`Costco, T_R. 1994. District cooling with rrigenerated ammo-
`nia cooling. .-[.SHRA_E' Ilransncti-ores 100(1).
`CBELIC. 1939. Dantfcn! temperance profile: r.'.fNort.'t Mer-
`qnite High School. Pieinflcict. 11.: Chicago Bridge 3:
`Iron Co.
`
`the enviromnenral performance 1‘e=qI.ti1'ed of district ergy
`systems. New technical innovtrtions have helped to make
`district heating and cooling more effi-cient than before. and
`have significantly reduced the potential economic impact. of
`stricter environmental regulations. Using recent technology.
`district energy systems use less fuel, electricity, water, and
`other commodities than before. They also produce less emis-
`sions than any comparable technology.
`_
`Thelow interest rates during the latter-part afrhe decade
`provided the means by which to increase spending on capi-
`tal-intensive technology, such as district energy. The con: i-
`nation of rising electricity rates and failing, interest rates
`provided a powerful incentive to develop new cooling tech-
`nology ‘that, even though capital
`inuensive, would prove
`competitive through its high efficiency.
`oisirsct heating and cooling was reinvigorated in the last
`few decades and is today accepted as an vironrncntaliy
`sound and economically attractive comfort service. The in-
`troduction of inJ1ova.t'ivc technology and the development of
`clistrict cooling has made district energy the "right" choice
`for building owners. it is more cnnvenienlz. less expensive.
`and cleaner than the alternatives. District hearing service
`alone leaves the building owner with the task of spending
`much human and capital resources on cooling; resources that
`in many cases are significantly greatcrtharl the ones spent on
`heating. A combined district l1cati:ng and cooling service is
`the logical choice for a building owner, who can now coo—
`center: on his or her business and avoid operating energy
`production equipment.
`No "one innovation or change can be said to have caused
`the new vitality in the district energy industry. All innova-
`tions, especially in the district cooling field, have contributed
`to the 'tudu51:I'_y‘s improved perforrnance and competitiveness.
`in some cases, where district cooling was developed as
`an aftnrfliought to an misting district heatizrig system, the dis-
`trict cooling met some time became the main business. Be-
`cause of the marry innovations in district cooling and the
`almost unlimited growth potential, the district energy indus-
`try is today increasingly focused on the development of dis-
`trict cooling. Yet, district co-ol'n1g works best, technically and
`as at service, in cornhiriation with district heating.
`
`CO NCLUSION S
`
`Technological innovation has been a. prime cool:t1'b1.Itot
`to the renewed interest in district heating and cooling. It has
`improved the efficiency and consequently reduced the cost
`of district energy, making it the energy of choice fiorn an
`economic as well as environmental perspective.
`innmrarion has occurred to the largest -esttent in district
`cooling, which has, relatively speaking, only recently he-
`comc the focus of attention. Trigeneration, chilled-water
`storage, and other iruiovations have reduced operating costs
`significantly, making district cooling. and consequently dis-
`trict energy, highly desirable for the building owner.
`
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`PETITIONER'S EXHIBIT 1226