Gas vs Electric Cooling

7/31/2019 Gas vs Electric Cooling

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GAS COOLINGVS.

ELECTRIC COOLINGCO MPARING THE COSTS

John Cerisano

Four Seasons Controlled Climates Ltd.February 26, 2001

10 0 Car lauren Rd. , Woo db r idge , O ntar io L4L 8A8

Tel: (41 6) 73 6-8 42 4 FAX: (41 6) 73 6-7 16 5

www.fscc-online .com e-mail: [email protected]


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IntroductionNo t so lon g ago wh en som eo ne ne ed ed to p urcha se a chi ller for the i r faci lity, in a l l likel iho od , it wa s

taken for granted that the chi ller w ou ld be an elect r ical ly-po we red, c om pressor-dr iven un it . Tod ay, a

growing number of manufacturers are of fer ing chi l lers that are powered by natural gas. Many claim

natural gas chi l lers can have lower operat ing costs than elect r ic chi l lers and may therefore be more

eco no m ical . The m ain po int sup po r ting this argume nt i s that , p er u ni t of en ergy, na tural gas costs lessthan electricity.

In m any p ar ts of the w or ld elect r ic i ty is so e xpen sive that gas coo ling is wi thout q ue stion m ore eco -

no m ical . In the se region s, favourab le e con om ics for na tural gas has m ad e gas coo ling m ore p revalen t .

In Japan , for e xam ple, gas cool ing acco un ts for ab ou t 70 % of total installed coo ling ton nage. In N or th

Ame rica, w he re e lec tricity is st ill relatively ch ea p, gas co oling cu rrently acc ou nts for o nly abo ut 8 % of

the space cool ing market . However , energy pr ices are r is ing rapidly , prompting more and more peo-

ple to look at a l ternat ive tech no logies, such as gas cool ing, for the ir spa ce c oo ling ne ed s. The pu rpose

of this s tud y is to p rovide pe op le w ho are co nside r ing a na tural gas po we red ch i ller for a co m m ercial

or indu str ia l faci lity with the informat ion to he lp them m ake an inform ed de cision .

Comparison OverviewIn our s tudy we compare three chi l lers: an electric chiller, a gas engine chi l ler a n d a gas absorpt ion

chiller. The com par ison i s based on p r im ary en ergy cos t s , m a in t e n a n c e c o s ts a n d e q u i p m e n t co s t s.

S ince the operat ing condi t ions are exact ly the same for each chi l ler in our compar ison, the energy

costs dep en d o n tw o factors: the cost of the en ergy used (elect r ic i ty or natu ral gas) an d th e e ffic iency

of e ach ch iller .

In o rder to t ruly und erstand the co st of e lect r ic ity or natural gas, we m ust und erstand exact ly wha t

we are paying for. To that end we take a fair ly detailed look at the rates for electricity and natural gas

an d re vie w th e various ch arges that co m p rise an electric bill or a gas bill. The electricity rate s we u sed

com e from Toron to H ydro . The r a tes took e f fec t on De cem be r 1 , 200 0 . The n a tu ra l gas r a tes com e

from Enbr idge Consumers Gas, and took ef fect on January 1 , 2001.The e ffic iency rat ings for e ach chi ller are ba sed on figures taken f rom m anu facturers pu bl ished da ta .

The maintenance costs come f rom a study conducted by the Georgia Inst i tu te of Technology.

Equ ipm en t costs are d er ived from the average co st per ton of cool ing for ea ch type of chi ller.

Operating

ConditionsThe chi l lers in our compar ison are

used for coo ling a co m m ercial bu i ld-

ing of ap proximate ly 40 0,00 0 squa refeet . The chi l lers operate 24 hours

per day for the months of Apr i l

through O ctobe r. The coo ling loa ds

used in ou r calculat ion s are the m ax-

i m u m a v e r a g e a n d m i n i m u m a v e r -

age cool ing loads for each month

and were ca lcu la t ed us ing wea ther

data for the city of Toronto.

AVERAGE MONTHLY MAXIMUM AND MINIMUM COOLING LOADS

1000

900

800

700

600500

400

300

200

100

APRIL MAY JUNE JULY AUG. SEPT. OCT.

COOLINGL

O

AD

(TONS)

Min. Cooling LoadsMax. Cooling Loads

Figure 1 : Average m axim um and m inim um cool ing load s for the m onths of

April throu gh O ctob er . No te: Average minim um tem pe ratures for Apri l and

O ctober resu lt ed in no average m inimum cool ing load s for those m onths .


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The ChillersThe e lec tric ch iller an d th e gas e ngine chiller are essen tially the sam e typ e o f ce ntrifugal chiller , which

o p e r a te o n t h e vapo ur com pression p rocess. The elect r ic ch iller e m ploys an e lect r ic m otor to dr ive the

compressor whi le the gas engine chi l ler employs a natural gas-powered internal combust ion engine

to d r ive the com pressor. Both c hi llers use an H FC (H ydrofluo rocarbo n) refr igerant .

The ab sorpt ion c hi ller is unique am on g the ch illers in th is com pa r ison. Rather than u sing a com -pressor , the absorpt ion chi l ler uses the heat f rom natural gas combust ion to dr ive a thermal-ef fect

refrigeration process called the absorp t ion cyc le , in which water is the refrigerant. All three chillers

ha ve a m axim um de sign load of 100 0 ton s of coo ling, w hich is eq uivalent to 1 2 m illion BTU/h (Brit ish

Therm al Un its/hou r) or 3 ,51 4kW (kilow at ts).

Chiller Particulars

Electric Chiller

The e lect r ic ch i ller i s equ ipp ed wi th a variable frequency drive (VFD ). A VFD ad justs the spe ed of the

elect r ic m otor in prop or t ion to ch anges to the coo ling load , m aking the chi ller m ore e ffic ient a t pa r tloa ds tha n a c hiller tha t is not e q uipp ed with a VFD. An e lec tric ch iller w itho ut a VFD is m ost efficien t

wh en op erat ing at o r ne ar ful l load cap aci ty (in this case, 1 00 0 tons). H ow ever, chi llers rarely ope rate

at ful l loads; they typical ly spend most of thei r operat ing t ime between 50% and 75% (500 to 750

tons) of full load capacity. The VFD raises average efficiency of the chiller by almost 19%. It also

increases the equipment cost of the chi l ler by about 22%.

The efficiency of an electric chiller is also directly effected by its p o w e r fa c to r. Power factor is a

m ea sure of ho w effic ient ly an elect r ic m otor u t ilizes e lect r ic ity. No t a l l of the p ow er d rawn by an elec-

t r ic motor i s used to produce actual work ( i .e . turn the motor shaf t ) . Some power , cal led reactive

p o w e r, is nee de d just to m aintain th e n ece ssary magne t ic f ie ld inside the m otor. Powe r factor i s the

ra tio o f the ac tua l pow er used to tu rn the m otor shaf t t o the to t a l po we r the m otor d raws . The e l ec -

t r ic chi l ler in our compar ison has a power factor of .95. This means that 95% of the elect r ic i ty sup-pl ied to the motor i s turned into useful work.

Gas Engine Chil ler and Heat Recovery

O f all the en ergy gen erated by the en gine of our gas engine chi ller, abo ut 30 % actual ly goe s to dr iv-

ing the compressor . The rest remains as waste heat . A por t ion of the waste heat generated by the

en g ine can b e r ecovered a nd used fo r o ther pu rposes. In o ur com par ison , the r ecovered hea t is used

to supplement the heat generated by a boi ler that suppl ies the bui ldings hot water . By applying the

en ergy savings gained through h ea t recovery against the e ne rgy used by the chi ller w e c an ef fect ive-

ly low er th e ch iller 's ene rgy costs.

Coe f fic ien t o f Per form ance (CO P)

CO P is an overal l m ea sure of a ch iller s cool ing ef fic ien cy and is expressed a s the rat io o f ou tpu t en er-

gy in cool ing (heat removal) to input energy. In other words, COP measures how much energy the

chi ller requ ires to rem ove a given am ou nt of heat . The m ore u ni ts of heat e ne rgy a chi ller can rem ove

for every un it of ene rgy pu t in , the highe r the CO P an d th erefore the highe r the e ffic ien cy. The e lec-

t ric chi ller h as a CO P of 6 .0 at ful l load . This me ans tha t the en ergy rem oval (the ou tput) is 6 t ime s

grea ter than the en ergy inp ut f rom the elect r ic m otor. The full loa d CO P for the gas engine chi ller i s

1 .9 4. The CO P for the a bsorpt ion chi ller -heate r is 1 .0 . As you can see, the elect r ic chi ller is abou t

three t im es m ore e ffic ient than the gas engine chi ller an d six t im es m ore ef fic ien t than the absorpt ion

chiller at full (design) load.


4/18

Altho ugh C O P i s typ ica l ly

m ea sured a t ful l load , CO P val-

ue s can vary at pa rt loa ds. All of

the chi l lers in our compar ison

have h igher C O Ps a t pa r t load s

(see Figure 2) . The elect r ic

chiller is up to 50% more effi-

c ient a t par t loads than at ful l

load. The gas engine chiller is

up to 13% more ef f ic ient , and

the absorpt ion chi l ler i s up to

17 % m ore e ffic ient .

The Cost of EnergyO ne of the m ain argum en ts for gas cool ing is that e lect r ic ity rate s tructures m ake the cost of e lect r ic-

i ty very high for commercial customers wi th high elect r ical demands. In order to understand howm uch a ch iller wi ll cost to op erate , o ne m ust know wh at they are b eing charged for. In the fol low ing

sect ion we will take a c lose look at bo th elect r ic ity rates and natu ral gas rates to un de rstand wh y each

on e co sts what i t doe s and ho w the costs for e lect r ic ity com pa re to the costs for na tural gas.

Understanding Electricity RatesFor our com pa r ison, we used the rates from Toron to H ydro. It mu st be no ted tha t ra tes and rate s truc-

tures can vary from util i ty to uti l i ty, and region to region. Lets take a look at the various charges that

m ake u p a n e lect r ic bi ll.

C u s t o m e r C h a rg eThe Customer Charge is what the ut i l i ty charges

in order to pay for f ixed costs , such as the costs

of maintaining generators , power l ines, t rans-

fo rmer s , and fo r cus tomer se rv ices such as

bi lling, m eter ing and 2 4-ho ur em ergency service.

D is trib u t io n Ch arge an d Tran sm issio n Ch arge

C u s t o m e r s w h o s e d e m a n d e x c e e d s 5 0 k W a r e

c h a r g e d f o r m a x i m u m d e m a n d . M a x i m u m

demand is the fastest ra te a t which elect r ic i ty is

consumed at any t ime dur ing the bi l l ing per iod.The r eason tha t cus tome rs a r e charged fo r max-

im um de m and is tha t e l ec t ric ity is an on -dem and

service. Util i t ies cannot store electricity; i t must

be genera ted the minu te i t i s needed . However ,

a cu s tom er s max im um de m and typ ica lly occur s

for only very shor t per iods dur ing each day ( for

example , a t t he beg inn ing o f the day when equ ipment i s s t a r t ed up) . Hav ing the capac i ty to mee t

shor t per iods of high de m and pu ts extra burde n a nd cost on the ut i li ty, wh ich the ut i lity pa sses on to

those custom ers respon sible for it .

Customer Charge...................................................

Distribution Charge (per max kVA).........................

Transmission Charge (per peak kW).......................

Energy Charge

Peak/Shoulder (per kWh)..........................

O ff-pe ak (per kWh )..................................

Transformer Allowance (per max kVA)...................

Winter

$ 2 3 . 0 6

$ 3 . 9 1

$ 3 . 2 9

$ 0 . 0 8 8 2

$ 0 . 0 3 4 6

$ 0 . 6 3 0 0

Summer

$ 2 3 . 0 6

$ 3 . 9 1

$ 3 . 2 4

$ 0 . 0 7 3 2

$ 0 . 0 2 3 8

$ 0 . 6 3 0 0

TORONTO HYDRO ELECTRICITY RATESTime-of-use rates for custome rs with

monthly demnads of 501000kW

(Effect ive December 1 , 2000)

P eak : 0900 to 2000 Monday th rough F riday, excep t pub l ic ho l idays

S hou lde rs : 0700 to 9000 and 2000 to 2300

O ff-Peak: All other times

Figure 3: Electricity rate schedule.

CHILLER COEFFICIENT OF PERFORMANCE (@TONS / kW)

1,000 / 3,514 750 / 2,635 500 / 1,757 250 / 879

Electric 6.0 7.2 8.8 9.0

Gas Engine 1.94 2.19 1.97 1.20Absorption 1.0 1.097 1.167 1.089

Figure 2: Coefficient of performance figures for the three chillers.


5/18

Under Toronto Hydros la test ra te s t ructure , the demand charge is broken up into a Dist r ibut ion

Cha rge a nd a Transmission Cha rge. The Distr ibu t ion Cha rge is wha t Toron to H ydro ch arges to get the

electricity, which is measured in kVA (kilovolt-amperes), from a distr ibution centre to the customer.

The Transm ission Ch arge is the ch arge for transm itting the e lec tricity, wh ich is me asure d in kW, from

O ntar io Pow er Ge ne rat ions gen erat ing plants to a Toron to H ydro distr ibu t ion cen tre . U nd er the o ld

D em and Cha rge the ut i lity charged for e i ther 10 0% of the kW or for 90 % of the kVA, which e ver was

grea ter. This schem e w as based on the ide a that a good po we r factor was at lea st 0 .9 ; that is , a t lea st

90 % of the sup pl ied kVA was turned into useful kW.

En ergy Ch arge

The Energy Cha rge is wha t you p ay for the actual am ou nt o f e lect r ical ene rgy used du r ing the bi lling

per iod, and is measured in ki lowat t -hours (kWh) . For example, a 1 kW motor operat ing for 1 hour

will consume 1kWh of electricity.

Trans form er Allow ance

Some custom ers choose to bu y the ir own t ransform ers. Since this redu ces the cost burde n on the u t il-

i ty , Toronto Hydro compensates these customers wi th a pay-back in the form of a t ransformer

allowance. For our study, a Transformer Allowance is not applicable.

Tim e-o f -Use R a tes

C ustom ers wi th d em and s be twee n 5 0kW and 100 0kW can o p t fo r tim e o f use b illing which has d if-

feren t ra tes for pe ak an d o ff-pe ak t im es. This cou ld b e very be ne ficial if the custom er runs eq uipm en t

dur ing the of f -peak hours when energy charges are lower . Customers wi th demands greater than

100 0kW are au tom at ica lly p laced on a t im e-of -use schedu le .

The e lect r ic chi ller in ou r com pa r ison falls wi thin the 50 to 10 00 kW rate sched ule . Since the chi ller

is running 24 hours per day, we wi l l use the t ime-of-use rate schedule and calculate the elect r ic i ty

costs using a combinat ion of peak and off -peak rates . Opt ing for the t ime-of-use schedule should

result in slightly lower electricity costs than if we chose the standard schedule.

Understanding

Natural Gas RatesThe rate structures for natural gas are

m uch s im ple r than the r a te s truc tu res

for e lec tricity. The m ain re ason for th is

is that, unlike electricity, the energy

from natural gas does not have to be

genera ted on demand by the u t i l i t y .

Rather, the energy from natural gas isstored in the na tural gas, wh ich itself is

s to red ins ide p ipe l ines un t i l i t i s

burne d by cus tom ers eq u ipme nt . Gas

util i t ies also maintain reserves of natu-

ral gas, so short- term fluctuations in

natural gas consumption is less of an

issue for gas uti li ties. N atu ral gas prices

a re made up o f severa l componen t s ,

wh ich a r e de sc ribe d be low.

C u s to m er C h a rg e p e r m o n t h (p e r m e t e r )

Delivery Charge (for m 3 p e r m o n t h )

For the first 30 m 3 ........................................................

Fo r the nex t 55 m 3.......................................................

Fo r the nex t 1 ,315 m 3..................................................

Fo r the nex t 1 ,400 m 3..................................................Fo r the nex t 2 ,800 m 3..................................................

Fo r al l over 5 ,600 m 3....................................................

System Sales Gas Supply Charge (if applicable*)........

Buy/Sell Sales Gas Supply Charge (if applicable*).......

$ 1 8 . 0 0

Price (per m 3)

1 4 . 3 7 7 9

1 3 . 8 5 5 4

1 3 . 2 8 0 5

1 2 . 6 5 5 4 1 2 . 0 3 0 4

1 1 . 0 9 0 9

2 4 . 4 4 4 5

2 4 . 4 2 6 7

Price (per kWh)

1 . 3 6 9 3

1 . 3 1 9 5

1 . 2 6 4 8

1 . 2 0 5 3 1 . 1 4 5 8

1 . 0 5 6 3

2 . 3 2 8 0

2 . 3 2 6 3

ENBRIDGE CONSUMERS GASCOMMERCIAL & INDUSTRIAL RATES

For the m on ths o f Apr i l throu gh No vem be r inclusive(Effect ive January 1 , 20 01 )

*The System Sales Gas Supp ly Charge is app l icab le i f the c ustomer p urchases i ts natu ral gas

requirement from Enbridge (system sales). The Buy/Sell Gas Supply Charge is applicable if the

custome r is unde r a buy /sel l p rogram.

O n e m 3 of natu ral gas has an ene rgy con ten t o f 37 .8 MJ (Mega-jou les) , wh ich equa ls

10 .5kWh , o r 35 ,842 .5 Btu .

Figure 4: Natural gas rates.


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C u s t o m e r C h a rg e

Similarly to the electricity Customer Charge, this charge is for f ixed costs (such as meters) and admin-

istration.

D e liv e ry Ch arge

The Delivery Charge covers the costs associated with getting the natural gas to your facil i ty (via the

pipelines).

Sup p ly Ch arge

The Supply Charge is the cost for the natural gas i tself . I t is analogous to the Energy Charge on your

e lectric b ill.

Comparing the Costs of Electricity to Natural GasIn order to have a di rect compar ison between the energy costs of natural gas and elect r ic i ty we must

f i r s t use the same uni t of energy wi th which to measure them. In this compar ison we wil l use kWh.

No rma lly the en ergy conten t of natural gas is me asured in Btu (Br it ish Therm al Uni ts). O ne cub icm eter of Canad ian n atural gas has an en ergy content of abo ut 36,00 0 Btu which equ ates to 10 .5 kWh .

To calculate the p er kW h cost of na tural gas we ad de d the average De livery Cha rge an d the Supp ly

Charge. We then factored in the Customer Charge, which had a negl igible af fect . The resul t : natural

gas costs 3 .40/kWh.

Calculat ing the per kWh cost of e lect r ic i ty is more complex due to the more complex rate s t ruc-

tu re . To ca lcu la t e the per kWh cos t , we must t ake in to accoun t the demand charges , which vary

de pe nd ing on th e d em and . The refore the pe r kW h co st calculat ion of e lect r ic i ty is spe cific to the elec-

tric chiller in our study.

To calculate the per kWh cost of electricity, we took the total of all the associated costs: Energy

Charges, Dist r ibut ion Charges, Transmission Charges, and Customer Charges. We then divided that

figure into the total num be r of kW hs used . The p er kW h c ost of e lect r ic i ty for the elect r ic ch iller w as

7.96. Therefore, kWh for kWh, elect r ic i ty costs about 2 .3 t imes more than natural gas.

Why is natural gas a cheaper source of energy than electricity?The answe r to tha t q ues t ion has to do wi th a conce p t ca lled the fu e l cyc le . The fuel cycle examines

the costs ( in terms of energy efficiency) associated with getting the energy from natural gas or elec-

tr icity from the source to the end user. Invariably, i t is impossible to capitalize on 100% of the avail-

ab le en ergy con ten t b ecau se en ergy mu st be expe nd ed to ex t rac t , re fine , genera te , t ranspor t and d i s-

t r ibute the energy or energy source. Natural gas must be extracted f rom the ground, compressed,

t ran spor ted through pipe line s, and dist ribu ted to the en d user. To gene rate e lect r ic ity, fue ls such a s oi l,

coal and natural gas must be extracted, processed and t ranspor ted. When elect r ic i ty is generatedusing nu clea r po we r or the kine t ic e ne rgy in f low ing w ater (hydroe lect r ic i ty) it m ust be con ver ted from

one source of energy (nuclear or kinetic) into electricity.

According to the U.S. Department of Energy, the conversion efficiency of natural gas from source to

en d u se r is abou t 91%. W hich me ans 91 % of the to t a l ava ilab le en ergy reach es the e nd use r. The con-

version ef fic ien cy of e lect r ic ity is betwe en 29 % and 40 %, dep en ding on w hat e ne rgy sou rce wa s used

to gene rate the e lect r ic i ty, wh ich m ea ns that no m ore tha n 4 0% of the avai lab le e ne rgy actual ly rea ch-

es the en d user. O f cou rse i t is the e nd user wh o p ays for a l l the costs associated wi th the fue l cycle .


7/18

Chiller Cost ComparisonWe have seen that e lect r ic i ty costs much more than natural gas per uni t of energy. Does this neces-

sar ily me an that an elect r ic chi ller i s m ore e xpen sive to o pe rate than a ch iller p ow ered by na tural gas?

Lets factor in the othe r costs and find ou t . It should b e n oted that the en ergy cost calculat ion s take

into accou nt on ly the en ergy used to dr ive the com pressors (in the case o f the e lect r ic chi ller an d th e

gas engine chi ller ) and the he at supp lied by the gas burne rs (in the case o f the absorpt ion c hi ller ). Inthe case of a l l three chi l lers , some elect r ic i ty is a lso needed to power equipment such as pumps and

control systems. All cost f igures were rounded to the nearest dollar .

Electric Chiller Cost Calculations

D is trib u t io n Ch arge s

The D ist ribut ion Cha rge is for the m axim um po we r draw, m ea sured in kVA for eac h m on th. Beca use

the m axim um average coo ling load var ies from m on th to m on th, the m axim um kVA also var ied from

a h igh o f 55 6 kVA in July to a low o f 93 kVA in April. The total am ou nt p aid in d istr ibu tion ch arges

fo r the seven m onth p er iod is $8 ,416 .

Transm iss ion Ch arges

The t ransmission cha rge is for the m axim um po we r draw in kW for ea ch m on th. This var ies in d irect

prop or t ion to the the kVA draw. The total am ou nt of t ransm ission cha rges is $6,62 6.

Energy Charges

The to ta l amount o f energy used by the ch i l l e r over the seven month per iod i s 956 ,265 kWh. The

m axim um m onth ly ene rgy consump t ion was in Ju ly (258 ,577 kWh ). The m in imum ene rgy consump -

t ion occu rred in Apr il (32 ,296 kW h) . The total cost of the en ergy used is $60 ,917 . ($4 ,366 in o ff-pea k

cha rges an d $5 6,55 1 in p ea k charges). The lowe r off-pea k cost reflects the lowe r pr ice of e lect r ic ity

du r ing off-pea k (night- t im e) hou rs an d th e low er coo ling load placed on the chi ller d ur ing those ho urs.

C u s t o m e r C h a rg e :

The total in Customer Charges is $161.

Electric Ch iller Electricity Co st Sum m ary

D ist rib u tio n Ch arge .. . . . . . . . . . . . . . . . . . . . . . . .$ 8 , 4 1 6

Transm ission Ch arge.. . . . . . . . . . . . . . . . . . . . . . . $ 6 , 6 2 6

Energy charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$ 6 0 , 9 1 7

Custom er Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$ 1 6 1

Total Electricity Costs......... ..........$76,120

Gas Engine Chiller Cost CalculationThe to ta l am oun t o f na tu ra l gas consum ed by the ch i lle r was 3 85 ,23 3 m 3 . The m onth w ith the h igh-

est consum ption of course wa s July (84 ,047 m 3) and the low est was Apr i l (26 ,948 m 3). Wh en w e ca l -

culate the var iou s charges we get the follow ing.

Delivery Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$43,282

Supply Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$94,168

Customer Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$126

Total Gas Cost................................$137,576 (wi thou t hea t recovery)


8/18

The He a t R ecovery Fac tor

We are ab le to r ecover 65% of the was te hea t genera ted by the gas eng ine which supp lement s the

he at gen erate d b y a bo iler . After factoring in th e b oilers efficien cy of 90%, the total volum e o f na tural

gas saved w orks ou t to 15 9 ,005 m 3. The savings is $57 ,059 . W he n w e ap ply this savings against the

cost of the gas consumed by the chi l ler we get a to tal energy cost of $137,576 - $57,059= $80,517

Absorption Chiller Cost CalculationThe total amount of natural gas consumed by the absorpt ion chi l ler i s 640,137 m 3. The m onth w ith

the h ighest consum ption of course wa s July (15 6,10 1 m 3) an d th e low est was Apr il (29 ,695 m 3). Whe n

we calculate th e var iou s charges we get the follow ing.

Delivery Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$71,949

Supply Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$156,478

Customer Charge.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .$126

Total Gas Cost...............................$228,553

Maintenance CostsThe annual maintenance cost for a 1000 ton elect r ic chi l ler i s est imated to be $22,320. The est imate

for the 10 00 ton gas engine chi ller i s $3 4,55 0. The highe r cost for the gas engine chi ller i s du e to the

com plexity of a gas en gine wh ich h as m ore m oving pa r ts that an e lect r ic m otor. The absorpt ion ch i ller -

he ater wh ich ha s very few m oving par ts has m aintena nce costs eq ua l to the e lect r ic chi ller a t $22 ,320 .

Equipment CostsBased on operating costs alone it is clear that the electric chiller has the lowest operating costs of the

three chi llers . The closest com pe t itor is the gas en gine chi ller w ith h ea t recovery, wh ich cost $1 6,62 8

m ore to op era te . How ever to ge t the wh ole p ic tu re w e n ee d to co ns ide r a t leas t one o ther cos t: t he

cost of the equipment . Here is where the picture gets blown total ly out of propor t ion.

Equipment costs were calculated based on the average cost per ton of cool ing. An elect r ic cen-

t ri fugal chi ller co sts abo ut $ 27 5 pe r ton. So a 10 00 ton elect r ic ce ntr ifugal chi ller w ill cost $27 5,00 0.

The e lect r ic chi ller in o ur com pa r ison wa s equ ippe d w ith a var iable frequ en cy dr ive wh ich ad ds abo ut

$6 0,0 00 to the cost . So th e elect r ic ch iller co sts app roxim ately $33 5,00 0. A gas engine chi ller w i ll cost

are you re ad y$90 0 p er ton! You do the m ath. Thats right , a 100 0 ton gas en gine cen tri fugal

chi l ler wi l l cost you a whopping $900,000! The di f ference in cost between a 1000 ton elect r ic cen-

tr ifugal chiller and a 1000 ton gas engine centrifugal chiller is $565,000. An absorption chiller costs

a round $750 per ton which works ou t to $750 ,000 fo r a 1000 ton un i t .

CHILLER ANNUAL ANNUAL TOTAL ANNUAL EQUIPMENTENERGY COSTS MAINTENANCE OPERATING COSTS COST

Electric $76,120 $22,320 $ 98,440 $335,000

Gas Engine $137,576 $34,551 $172,127 $900,000

with HR $80,517 $115,068

Absorption $228,553 $22,320 $250,873 $750,000

Figure 5: Operating costs and equipment costs of the three chillers.


9/18

ConclusionWe star ted out by compar ing the uni t for uni t energy costs of natural gas and elect r ic i ty; we found

that currently, natural gas costs less than half what electricity costs. This suggested a clear advantage,

at f ir st , for the gas chi llers . The n we ap pl ied the rate inform at ion to ca lculate the actua l ope rat ing co sts

of the three chi llers . Du e to the supe r ior e ffic iency o f the elect r ic ch iller, the pr ice ad vantage o f nat -

ural gas wa s not grea t en ou gh to t ranslate in to low er o pe rat ing co sts . In shor t , a t current e lect r ic i ty andna tural gas pr ices, e lect ric co ol ing is mo re e con om ical.

It ma y surpr ise som e to learn tha t gas cool ing costs m ore tha n e lect r ic coo ling, g iven the com m on

knowledge that gas heat ing is so much more economical than elect r ic heat ing. As we have just

proved , th is is not the case. W hy is th is so?

H ea t ing u sing n atural gas is very effic ient b eca use the pr imary en ergy der ived from natu ral gas is

heat . Transfer r ing the heat energy f rom the natural gas to the water or a i r being heated is a very

straight-forward , an d there fore, inh eren t ly ef fic ient p rocess. W he n you factor in the supe r ior fuel cycle

conversion efficiency of natural gas over electricity, we can easily see why gas heating is more eco-

nomical than elect r ic heat ing.

H ow eve r, con verting h ea t into oth er form s of en ergy is intr insically ine fficien t. In a gas en gine ch iller

for exam ple, the p rocess of con ver ting the h ea t from the co m bu stion of natural gas into kinet ic ene r-gy to turn the com pressor is only abou t 30 % effic ient . In a n elect r ic ch iller the proce ss of conver t ing

elec tricity to kinetic e ne rgy is 95 % e fficien t.

Can gas cool ing ever co m pe te w ith e lect r ic coo ling on an eco no m ic b asis? Lets say that a p erson

was will ing to install a more expensive gas engine chiller over an electric chiller if the pay-back peri-

od wa s reasonab le , say five yea rs. In o rder to ach ieve a f ive-year pa y-ba ck, the overal l cost of e lec-

tr icity wo uld h ave to be ab ou t five t im es the ove rall co st of na tural gas. As electricity is cu rrently abo ut

2.3 t ime more expensive than natural gas, that means the cost of e lect r ic i ty would have to increase

by m ore tha n 2 00 % wh ile the cost of natu ral gas rem ained stat ic . The likel iho od of th is hap pe ning is

low, e spe cially given the fact tha t natu ral gas prices are increa sing, an d at a m uch faster ra te than e lec-

tricity prices.

O ne caveat : e ne rgy pr ices are current ly very unstable . All of ou r m ain sources o f en ergyoi l, nat -

ural gas, e lect r ic i tyare becoming more expensive. Deregulat ion of e lect r ic i ty markets , which is

being considered in many regions, adds an element of unpredictabi l i ty to the future pr ices of e lec-

t r ic i ty . Fur thermore, g iven the uncer tain future of nuclear power as a means to generate e lect r ic i ty

very cost effect ively, i t is not u nreason able to pred ict that w e m ay see increa ses in the pr ices of e lec-

tr icity on a similar scale as we are currently seeing in the prices of oil and natural gas. So, if you have

gathered fact sheets and brochures on gas chi l lers , i t might make sense to keep them in your f i l ing

cabinet , i f not on your desk.


10/18

Air Conditioning

Ventilation

Refrigeration

Process Heating

Process Cooling

Heating

Sheet Metal

Energy Management

Controls

Humidity Control

Industrial

Commercial

Institutional

Trust us to do it right.Every time.


11/18

We helpbusinesses

succeedWe a ll have t he s ame co nce rns when wene ed some on es services : W ill they do a good

jo b ? D o th e y re a lly ca re ab o u t m y n e e d s o ra r e t h e y o n ly in t e r e s t e d in m a k in g a sa le ?Do they s tan d b eh ind the ir work? W ill they bethe re when I need them ? Can I trust them?

H aving these sam e con cerns ou rse lves , wecreated a com pany mad e u p of honest peo ple,dedicated to serving t h e b e s t in t e re s ts o f o u r c u s to m e rs . We take personal in teres t inh e l p i n g p e o p l e s o l v e t h e i r p r o b l e m s a n dimprove their everyday operat ions. In short ,we help businesses succeed .

We do th is in 4 m ain w ays:

1) We lower operating costs by redu cing thenum ber o f eq u i pme n t b r eakdow n s, op t im iz -ing performance, maximizing eff iciency and

extend ing eq uipm en t life .

2) We lower production costs by imp rovingthe pro du ct ivity, e fficiency an d safety o f pro-duct ion l ines; minimizing cost ly down t ime,and; improving bui lding comfort for higheremployee product ivi ty.

3) We solve problems. We offer co st-effec tivesolut ion s for indo or e nvironm en tal prob lem sand p rodu c tion p rob lem s.

4) We expand capab ilities with cus tom-d e sig n e d , s p e c ia l e q u i p m e n t t h a t c a nim prove an exis ting o pe ra tion or p er forma ne w func t ion .

H un d red s of bu sine sses, large an d sma ll, ha vetrusted Fou r Sea sons Co ntrol led Clim ates tolower their costs while improving their opera-t ions. Allow us the opportuni ty to help yo u rbu sine ss succe ed .


12/18

We look after your best interests

At Four Seasons Controlled Climatesou r be st inte res ts are your b e st inte r -es ts. O ur goal is to h elp you im p roveyour b us ine ss, no t jus t m ake a sale .We care fully con sid e r you r sp e cificneeds and offer the solut ions that

will best look after them.

A higher standard of service

We judge our level of service in avery simple way: We ask ourselves if w e w e r e th e c u s to m e r h o w w ewo uld like to b e served and then tryto serve ou r custom ers even be tter.Fur the rmo re, we con t inu ally loo k forwa ys to im pro ve ou r service in o rde r

to m axim ize the be ne fits of d ea lingwith us.

A higher standard of workmanship

The operat ion of your bus inessde pe nd s on the q ua lity of ou r work.We take this very seriously, so wecontinually strive for higher qualityworkmanship that i s above indus trys tandards .

A higher standard for employees

The m ain w ay we ach ieve a h ighe rstanda rd in ou r service and wo rk-m an ship is wi th a highe r calibe r of people. All Four Seasons ControlledClimates employees , f rom the techni-

Why Four SeasonsControlled Climates is

better for your businesscians to the office staff, are carefullyse le cted for th e ir pro fe ssion alism,in te grity, skills an d d e d ication toserving our custom ers. We p rovid eou r em ployee s a co m for tab le worken viron m en t, the latest tec hn ology,an d on -going training so th e y are

eq uippe d to loo k afte r your nee ds .

A greater variety of services

W ith exp er t ise in so m an y type s of m ech anica l system s we are ab le tooffe r a variety of se rvice s th at m o stof ou r com pe t itors cant tou ch.

Respect for the environment

Fee l com for table kn ow ing you re

de a ling with a co m pa ny tha t caresfo r the env ironm en t. W e cond uc tproper recycling, reclamation and

disposal of materials and chemicals.We kee p ou r service veh ic les tune dand running well to reduce emissions.W e recom m en d t he m os t e ffic ien teq uipm en t and op t ions , and we offerso lu t ion s for e ne rgy m ana gem en tan d e ne rgy reco very. Its ou r pa rt tohe lp en sure a clean er future for u s all.


13/18

YourInstallationThe qual i ty of your mechanical system star tswith the quality of its installation.

Fou r Seasons Co ntrolled Clim ates ha s thee x p e rtise , th e p e o p le a n d t h e t e c h n o l o gy t op rovid e sup e rior-qu al ity installat ion s of al ltypes o f bu ilding m ec ha nical system s, fromrooftop uni ts to ent i re product ion l ines.

W he n p lann ing an ins ta lla t ion we take in to

accou nt en vironm en ta l con di tion s, sit e co nd i-t ions, s t ructural concerns, future considera-t ions , and ease o f ma i n tenan ce . We t hen e ng i-ne er the system , se lec t the m ost app ropr ia teeq uipme nt , fabr ica te the ne cessary pa r ts andm ake the ne cessary prepa ra tion s . The e ffor t s of al l people involved, from technicians to suppli-ers, a re careful ly coo rdina te d to e nsure asmooth, efficient installation from startto finish.


14/18

Engineering Services

U sin g the late st CAD softwa re, w ecan properly design/engineer installa-tions to ach ieve op t im um systempe r form ance , grea te r eq uipm entreliabi lity, an d m axim um en ergyefficiency. With engineering donein-ho use, get t ing pro jec ts from pa p erto m e tal is faster an d co sts le ss.

Complete Fabrication Services

W e m a ke custom components,build specialized equipment a n drefurbish older equipment. O u rfabrication facil i t ies are equippedwith the la tes t te chn ology an d a rewe ll-stocked with q ua lity pa rts an dm ater ia ls. We pe r form as m uchin stallat ion p rep wo rk as po ssib lein -ho use for t ighter q ua lity control

and for smoother, more efficientwo rk on site .

Fleet of Mobile Shops

We ha nd le on -site w ork with ful ly-eq uipp ed and stocked m obi le shops .W e keep ou r m ob i le shop s c lean ,organized and running wel l to helpus d o o ur w o rk we ll an d e fficien tly.

Complete Installation ServicesO ur co m p lete range o f ins talla t ionse rvice s in clud e structural work,crane service, roofing, electrical,control work, piping (gas, stea m , a ir,wa ter, refrigeratio n, e tc) an d sheetmetal work(duct work).

Quality. Installed.

Team of Skilled Technicians

All installat ions are p e rform e d bylicensed technicians w ho w or k a sa t eam un de r the sup ervision of ah ighly expe rien ced Forem an. O urtech nician s are specially-trained forthe type of equipment they ins tal l ,and they take grea t p r ide in thew or k they d o .

Suppliers of Quality Equipment

Fou r Sea son s Con trol led Clim atesh as w e ll-estab lishe d relation shipswith repu table supp liers wh o o fferfas t , dependable del ivery. Whenavailab le , we pre fer to use e qu ip-m en t from local m anu facturers tohe lp sup po r t the loca l econ om y.W hiche ver supp lie r s we use , theequipment must meet our high

standards for durability, reliability,p erform an ce an d efficien cy.

The Most For Your Investment

W ith a prop er ly en gine ered system ,qu a lit y com po ne n t s and unb ea t ab lewo rkm anship , you can re ly on aFou r Sea son s Con trol led Clim atesinstallat ion to give you the mostreturn o n your investm e nt . It s one

of the w ays we can he lp you r bus i-ne ss succe ed .


15/18

Compute rized Plasma CutterComputerized Plasma CutterIn-House EngineeringIn-House Engineering Sheet Metal ShopSheet Metal Shop

Machine ShopMachine Shop WWelding Shopelding Shop

Proces s LineProces s Line

Structural WStructural Workork

Heavy Equ ipme ntHeavy Equ ipme nt

Rooftop SystemsRooftop Systems

Mobile ShopMobile Shop

Crane ServiceCrane Service Equipment TEquipment Transpor terranspor ter


16/18

Protect yourinvestment:Certified Service Plan

To get the m ost for you r investm en t in you rmechanica l sys tems you need to keep themop era t ing prope r ly a t minim um cos t for aslong as possible. To do that , you needp r o p e r m a in t e n a n c e .

The p rob lem is, a good m a in t enan ce

program is hard to find . Service com pa niesare of fer ing cheap er and cheap er program sin o rder to com pe te for your bu s ine ss .As a resul t, you m ay en d up wi thinad eq ua t e m a in t enan ce t ha t ac t ua llyincreases your operat ing costs becauseyoure no t pa ying an y less in rep airs ,p lus you h ave to p ay for the p rogram .

We be l ieve t ha t a m a in t enan ce p rogramsho uld save you m on ey, not cost you extra.

Thats why we created the Cert i f ied ServicePlan.

The Certified Service Plan is a customized,wo rry-free pro gram , carefully de signed tokeep your equ ipm en t runn i ng p rop e r ly andefficiently. We dont cut corners,om it step s, or set loss lea de r price s andthe n t ry to find wa ys to reco ver the loss.Fur thermore , we record a l l maintenance ,so you ll know your eq uipm en t is

receiving the care i t needs.

W ith low er op erat ing costs and m axim izedeq uipm en t life , a Ce rtified Service Plangives you the most for your investment .


17/18

Service so goodits Certified

Custom-Tailored Maintenance

W e c rea t e a n o p t im ized sched u lethat provide s the right maintenanceat the right time b a se d o n y o u rspe c ific eq uipm en t and o pe ra tingcondi t ions .

Your Technician for the Durat ion

A licensed, specially-trained techni-cian is ass igned to your equipment .Yo u r te ch n ician o ffe rs on-going rec-ommendations to im prove the p er -form an ce of you r system s andreduce operating costs. Two b ack-up technicians are assigne d toen sure you are a lways covered .

Taking the Time to do it Right

We al low technicians the correctam ou nt of tim e to p rope r ly pe r formdocumented, step-by-step mainte-

nance procedures that are specificallyde signe d for each piece of equ ipm en tyou m ay have .

ISO/QAS Service Reports

After e ac h visit from you r tech n icianyou rece ive a complete report tha tlists the eq uipm en t service d , thew or k pe rfo r me d an d an y recom -m en da t ion s from your tech nic ian .Rep or ts a re do cum en t ed acco r d ingto ISO/QAS standards so re gistere dbusinesses can maintain therequ ired reco rds.

Computerized Records

We use specially-developed softwareto create your cu stom ized servicesche du le , up da te in form at ion onyour eq uipm en t , and t rack servicehistory.

If Repairs or Upgrades are Needed

You m ay cho ose to give ap pro valfor repairs while your technician isat you r site , or you r tec hn ician orTe ch nical Sales Ad visor can p resen ta n action plan com ple te wi th co st sand risk analysis.

24/7 Emergency Service

A technician is available to respondto you r ne ed s any t im e o f the d ay

or n ight . After -ho urs em ergenc yca lls a re han dled by ou r automatedattendant which will dispatch atech nician to you r site w ithin m inu tes.

Helping Maintain Your Cash Flow

The co st of inve stin g in the Plan isspread throughout the t e rm.

Return on Investment

W ith low e r en ergy cos ts, few erb r eakdow n s and le s s do w n t im e ,you r Ce rtifie d Se rvice Plan will n otonly pay for itself but it will alsopay big dividend s.


18/18

Our la rge team of dedica tedOur la rge team of dedica ted

l icensed technic ians are spec ia l lyl icensed technic ians are spec ia l ly

t ra ined for each type of equ ipmen tt ra ined for each type of eq uipme nt

they serthey ser vice. Tvice. Trr us t them to do i t r ight .us t them to do i t r ight .

Gas vs Electric Cooling

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