Ene gies 2014, 7, 3282-3303; doi:10.3390/en7053282
ene gies
ISSN 1996-1073
www.mdpi.com/jou nal/ene gies
A icle
A Boile Room in a 600-Bed Hospi al Complex: S udy, Analysis,
and Implemen a ion o Ene gy E iciency Imp o emen s
Juan-Ca los F aile 1, Julio San-José 2,* and Ana González-Alonso 2
1 Ins i u e o Ad anced P oduc ion Technologies, School o Indus ial Enginee ing, Uni e si y o
Valladolid, C/Paseo del Cauce 59, 47011 Valladolid, Spain; E-Mail: jc [email protected] a.es
2 Depa men o Ene gy Enginee ing and Fluid Mechanics, School o Indus ial Enginee ing,
Uni e si y o Valladolid, C/Paseo del Cauce 59, 47011 Valladolid, Spain;
E-Mail: [email p o ec ed]
* Au ho o whom co espondence should be add essed; E-Mail: jul[email p o ec ed];
Tel.: +34-983-423-685, Fax: +34-983-186-462.
Recei ed: 8 Ap il 2014; in e ised o m: 8 May 2014 / Accep ed: 13 May 2014 /
Published: 19 May 2014
Abs ac : The aim o ene gy e iciency is o use less ene gy o p o ide he same se ice.
In hospi als, ene gy e iciency o e s a powe ul and cos -e ec i e ool o educe g eenhouse
gas emissions, uel consump ion, and also unning cos s. O e a six-mon h pe iod, he six
gas- i ed boile s ha p o ide bo h a hospi al’s hea and ho wa e we e moni o ed. Analysis
o he da a ob ained led o se e al ac ions being implemen ed in he hospi al boile oom
con ol sys em o imp o e he e iciency o he hea p oduc ion sys em. Compa a i e
s udies we e conduc ed, du ing simila wea he pe iods, o he pe o mance o he
hospi al’s ho wa e p oduc ion sys em be o e and a e he con ols we e implemen ed.
Resul s indica e ha he con ol ac ions applied p o ed o be e ec i e. Finally; he pape
o e s a inancial; p ima y ene gy sa ing and CO2 educ ion analysis ha poin s o a
3,434.00 €/week sa ings in na u al gas consump ion; and a cu in CO2 emissions o
20.3 ons/week; as compa ed o he e e ence acili y.
Keywo ds: ene gy e iciency; hospi al; boile oom con ol
1. In oduc ion
Hospi als and heal h ca e buildings adi ionally ha e high ene gy demands o bo h mechanical
powe and hea . Mechanical powe in he o m o elec ical ene gy is used o ligh ing as well as
OPEN ACCESS
Ene gies 2014, 7 3283
echnological and medical equipmen . Hea is equi ed o space hea ing needs, sani a y ho wa e , and
s eam p oduc ion.
Inc easing demand o com o in ooms coupled wi h high in e nal loads has led o a signi ican
inc ease in cooling equi emen s o e he las decade. As a esul , hospi al hea ing and cooling sys ems
which ely on con en ional Hea ing, Ven ila ion and Ai -Condi ioning (HVAC) uni s a e bo h ene gy
in ensi e and expensi e. To educe ene gy use and g eenhouse gas emissions by hese acili ies, he
heal h ca e sec o needs ene gy e icien solu ions ope a ing a he lowes cos [1].
This ene gy is o en used ine icien ly and may be due o he con ol/ope a ion o he building [2].
P ope ly unc ioning con ol sys ems (inpu and ou pu de ices, con olle s…), a e a signi ican
con ibu o o ene gy e iciency. P oblems associa ed wi h building con ols and ope a ion a e a
p ima y cause o ine icien ene gy usage. Ha dwa e ailu es, so wa e e o s, and human ac o s
ela ed o he di icul y o use and unde s anding o con ol p oduc s all conspi e o p e en buildings
om achie ing he desi ed ene gy e iciency.
In a 60 building s udy, esea che s a Law ence Be keley Na ional Labo a o ies ound ha 50% o
he buildings e idenced con ol p oblems; 40% e idenced HVAC equipmen p oblems; 25% employed
Ene gy Managemen Con ol Sys ems (EMS) ha did no unc ion p ope ly; and 15% had missing
equipmen [2]. This demons a es ha sol ing con ol ela ed p oblems con ibu es signi ican ly
owa ds p ima y ene gy sa ing.
Acco ding o he USA Depa men o Ene gy [3], o e 50% o he ene gy used in buildings is
consumed by HVAC uni s and ligh ing sys ems. Howe e , esea ch has shown ha up o 40% o his
ene gy can be sa ed by closely moni o ing he s a e o he building and applying sui able con ol
s a egies [4]. The complexi y o he acqui ed senso y da a and he o e whelming amoun o
in o ma ion p esen ed makes such con ol sys ems di icul o adjus o e en unde s and by esponsible
building manage s [5].
The e a e a ound 800 hospi als in Spain, and he heal h sec o is eminen ly public in na u e, o he
ex en ha 108,000 o he coun y’s 160,000 beds a e in public hospi als. Consump ion in he hospi al
sec o in Spain eached 0.6 M ep, accoun ing o 6% o he o al se ice sec o consump ion, and
ep esen ing expendi u e amoun ing o some 600 million eu os. Ene gy consump ion s udies
pe o med in Spanish hospi als a e shown in Table 1, and e lec mean ene gy consump ion pe bed in
one yea o he a ious a eas o consump ion [6].
Table 1. Mean ene gy consump ion pe bed and yea in Spanish hospi als.
Hospi als Elec ici y
(kWh/bed·yea )
Na u al gas
(kWh·HHV/bed·yea )
Diesel
(kWh·HHV/bed·yea )
P opane
(kWh·HHV/bed·yea )
>300 beds
10,043
14,722
6,733
102
<300 beds
8,885
7,987
12,695
229
Hospi als p o ide a wide ange o se ices, each o which has i s own speci ic ene gy equi emen s.
These needs, howe e , a e me h ough cen alized managemen sys ems. The ene gy consumed in a
hospi al is di ec ly p opo ional o demand and in e sely p opo ional o sys em e iciency. Demand
depends p ima ily on: he skin o he building, he use o which he building is pu , en ila ion
equi emen s, p e ailing wea he condi ions in he a ea, and so on [7].
Ene gies 2014, 7 3284
Sys em e iciency equi es p ope ly designed sys em componen s, sui able in e ela ion amongs
componen s and con ol s a egy o each elemen , as well as o he sys em as a whole. This is
e lec ed when conside ing he a ious ac o s in ol ed in a cen alized hea ing sys em (see Figu e 1):
(a) he unc ions o he equipmen (hea p oduc ion, dis ibu ion, and he mal emi ance); (b) he mal
ese oi s (boile s, dis ibu ion, he mal emi ance, p emises, and ou doo en i onmen ); and
(c) communica ion and egula ion (gene a o , dis ibu ion, he mal emi ance, gene al con ol).
Figu e 1. Block diag am o a s anda d hea gene a ing sys em.
The egula ion and con ol o all hese ac o s ha in e ene in a cen al hea ing sys em equi e
Building Au oma ion and Con ol Sys ems (BACS). BACS include in o ma ion conce ning all signals
om he buildings in o de o ge “in elligen buildings”. The sys ems in eg a ed in o he BACS pu sue
di e se and e y di e en pu poses, so in eg a ion issues a e o pa icula impo ance. Compa ed wi h
he ield o indus ial au oma ion, building au oma ion has speci ic and di e en cha ac e is ics [8].
This has c ea ed a la ge quan i y o esea ch o imp o e HVAC ene gy by moni o ing and egula ion
BACS. Vakilo oaya [9] p esen ed he imp o ed ene gy e iciency o an ai cooling plan , in oducing he
model-based g adien p ojec ion op imiza ion me hod. Chung [10] de eloped a communica ion so wa e
ha collec s da a on ene gy consump ion and es ima es consump ion. Bujak [11] imp o es he ene gy
e iciency o a s eam he mal powe plan using ma hema ical modeling; Klein [12] educed ene gy
consump ion by inc easing he numbe o senso s and compu a ional suppo o he Ene gy
Managemen Con ol Sys ems (EMCS). Yoshida [13] pe o med an analysis o ene gy supply in
hospi als, based on a sensi i i y analysis. Ma and Wang [14] imp o ed he con ol s a egy o a
cen alized cooling plan ’s e iciency. Beghi [15] has designed an adap i e con ol o a oile
Ene gies 2014, 7 3285
ai -cooled chille , which has managed o inc ease ene gy e iciency by 3%–7.3%; while Liao [16]
s udied a load p edic ion by occupa ion in comme cial buildings. Wes [17] p esen ed an op imised
supe iso y model p edic i e con ol (MPC) sys em o hea ing, en ila ion and ai condi ioning
(HVAC) in comme cial buildings.
As is clea om hese e iews, imp o ing ene gy e iciency by de eloping new so wa e packages
o BACS is a e y b oad esea ch ield, due o he la ge numbe o a iables and pa ame e s ha ha e
o be conside ed. The EMCS cu en ly ensu es he sa e y and ope a ion o ene gy acili ies, bu he
op imal ene gy e iciency o he ins alla ion s ill equi es wo k and expe imen a ion.
This a icle desc ibes he imp o emen s in ene gy e iciency in a cen alized hea ing acili y in
a 600-bed hospi al complex co e ing a buil -up a ea o 170,000 m2. The implemen ed imp o emen s
educe he pe iods in which he hospi al’s hea p oduc ion sys em is on STANDBY, and he e o e, also
educes he TRANSITION imes. Imp o emen s we e made o e he summe o h ee easons:
(i) es s and adjus men s ha e less impac on he hospi al’s com o le el; (ii) esul s can be ully
ex apola ed o win e , as well as pe iods be ween he ex eme seasons; and (iii) he cos o pe o ming
es s is lowe , since hese a e ca ied ou when he boile s a e wo king a less powe .
2. Ma e ials and Me hods
2.1. Me hodology o Reducing Hospi al Cos s h ough Ene gy E iciency
The ene gy e iciency o an HVAC ins alla ion is imp o ed by a p ocess o ene gy managemen .
Ene gy managemen is a cyclical p ocess (see Figu e 2), wi h he ollowing sec ions: (i) Ini ial s a e;
(ii) Analysis o in o ma ion; (iii) P oposed ac ions and implemen a ion; (i ) Analysis o esul s. Once
hese ou phases a e comple ed, he p ocess o collec ing da a begins again o assess he imp o emen
in ene gy e iciency and con inue he p ocess o con inuous imp o emen [18].
Figu e 2. Me hodology o inc easing he ene gy e iciency o an Hea ing, Ven ila ion and
Ai -Condi ioning (HVAC) ins alla ion.
This me hod is applicable o HVAC acili ies as a whole ( ull sys em) o o sub-sys ems. In bo h
cases, he a iables which he pa icula en i onmen imposes on he sys em o sub-sys em need o be
known. Gi en he complexi y o a 600-bed hospi al’s HVAC acili ies, he bes op ion is o unde ake
he analysis in subsys ems. In his case, wo k began wi h one o he subsys ems which has he g ea es
impac on he hospi al’s ene gy consump ion, he hea ing sys em. Since he case in hand was a ully
Ini ial s a e
Analysis o
in o ma ion
P oposed ac ion
and
implemen a ion
Analysis o esul s
Ene gies 2014, 7 3286
ope a ional hospi al, a s udy was ca ied ou o e he summe , since any p oblems in he HVAC
sys em du ing he win e would p o e o ally unaccep able. BACS is a sys em which allows da a o be
ga he ed and analyzed sys ema ically, and which in many ins ances enables he p oposed ac ions o be
implemen ed, in such a way ha , h oughou he s udy, close a en ion mus be paid o he sys em’s
con igu a ion and unc ioning [19].
The boile oom’s ene gy e iciency may be de e mined di ec ly as a a io be ween use ul powe
and powe consumed. Howe e , i a mo e de ailed analysis is o be pe o med, an indi ec e alua ion
should be ca ied ou in e ms o he sys em’s losses, linked o he use ul ene gy as indica ed in
Equa ion (1):
nconsump ioPowe
Loss - ncomsump ioPowe
=
nconsump ioPowe
powe Use ul
=η ∑
(1)
The hea s a ion e iciency is de e mined in speci ic pe iods o ime, which migh be annual, in
win e , summe , and so on, using powe consump ion and loss o e a pa icula pe iod o s udy.
O e a gi en pe iod o i s unc ioning, he sys em may be in one o h ee modes:
(a) ON: when gene a o s supply ene gy o he sys em. In hese cases, i is assumed ha he
building equi es ene gy. Losses associa ed o his mode a e:
 Hea ing s ack loss (Ph).
 Losses caused by he acili y’s con ec ion and adia ion (Pcd).
 Losses caused by maladjus men s in he con ol sys em (P ).
(b) STANDBY: when gene a o s supply no ene gy o he sys em. In hese cases, i is assumed ha
he building equi es no ene gy. Losses associa ed o his mode a e:
 Hea ing s ack loss caused by chimney d augh (Pi).
 Losses caused by he acili y’s con ec ion and adia ion (Pcd).
 Losses caused by maladjus men s in he con ol sys em (P ).
(c) TRANSITION STAGE: when he sys em gene a o s swi ch om STANDBY o ON. In hese
cases, he building changes om equi ing no ene gy o equi ing ene gy. Losses associa ed o
his mode a e:
 Losses caused by lue gas en (Pp ).
 Losses caused by he acili y’s con ec ion and adia ion (Pcd).
 Losses caused by maladjus men s in he con ol sys em (P ) [20,21].
When de e mining a sys em’s e iciency o e a gi en pe iod, he sys em is checked o see whe he
i has been: in ON mode ( ON), in OFF mode ( STANDBY), o in ansi ion mode ( TRANSITION). The
sys em’s o al ene gy loss is calcula ed as:
ON h cd STANDBY i cd TRANSITION p cd
Loss= ( + + )+ ( + + ) ( + + ) PPP PPP P PP× × +×
∑
(2)
Powe consumed will be he powe o he boile (Pboile ) du ing he ime i was ON and is calcula ed as:
ON boile
Powe consump ion P= ×
(3)
Replacing all hese e ms in he sys em’s e iciency exp ession o a speci ic pe iod gi es:

Ene gies 2014, 7 3287
ON boile ON ON STANDBY STANDBY TRANSITION TRANSITION
ON boile
η= P P P P
P
× −× − × − ×
×
∑∑ ∑
(4)
This exp ession e lec s how losses can be educed by using mo e e icien equipmen and eco e y
sys ems when he sys em is ON, al hough losses canno be o ally elimina ed. Howe e , i is possible
o elimina e losses when he sys em is in STANDBY o TRANSITION mode by sui ably adap ing he
equipmen o demand and by elimina ing ansi ion pe iods. Imp o emen s in he boile oom’s ene gy
e iciency will educe ansi ional pe iods, which will mean ha he boile s ope a e con inuously as
much ime as possible.
2.2. Desc ip ion o he Ho Wa e Dis ibu ion Sys em in he Hospi al
The boile and ho wa e dis ibu ion sys em in he hospi al came in o ope a ion in 2009. The
hospi al comp ises se e al la ge buildings, consis ing o ou loo s, wi h 600 beds, ope a ing hea es,
as well as echnical and consul a ion ooms. I ope a es e e y day o he yea on a 24-hou -a-day basis.
Gas- i ed boile s we e ins alled o mee he hospi al’s hea ing demands. The boile oom comp ises
a g oup o six gas- i ed boile s. These boile s a e he Eu obloc-supe s anda d model, manu ac u ed by
Vulcano-Sadeca [22]. Bu ne s a e he Weishaup RGL (R: modula ing egula ion; G: gas and L: liquid
uel) model, which combines diesel/na u al gas bu ne s. Fou boile s (B1, B2, B3, and B4) a e
equipped wi h a hea powe o 4000 kW each. Boile 5 (B5) has a 2300 kW gene a o , and boile 6
(B6) has an 1100 kW gene a o . Such a a ie y o powe s allows a wide ange o possibili ies o adap
o he hospi al’s ene gy equi emen s. Ho wa e p oduced by boile s is pumped h ough pipes by
means o wo ci cui s:
 P ima y ci cui ( ed in Figu e 3): The gas- i edboile s a e connec ed o his ci cui which is
a closed loop. When ho wa e lea es he boile s, he supply pump uni s d i e i h ough he hea
exchange s, ansmi ing hea o he ai and o he sani a y wa e . The wa e hen e u ns o
he boile by means o e u n pump uni s.
 Seconda y ci cui (blue in Figu e 3): The ho wa e lowing h ough his ci cui is used o supply
hea ing equi emen s in ce ain a eas o he hospi al (pa ien s’ ooms, ope a ing hea es, and
so on) by means o an coils, and o hea sani a y wa e s o ed in anks. In bo h cases, hea
ans e is ca ied ou h ough hea exchange s.
The low in he p ima y ci cui is a iable, while he low in he seconda y ci cui is cons an . The
bypass enables di e ences in wa e low o be compensa ed o . This bypass also helps o aise
he empe a u e o he wa e e u ning o he boile s, making he empe a u e jump in he boile he
bes possible.
Ene gy managemen and con ol sys ems (EMCS) in buildings a e widely used due o hei high
po en ial o sa ing ene gy and cu ing consumed ene gy expenses. The goal o an EMCS is o combine
indoo com o condi ions a he zone/ oom le el o he building wi h an ene gy sa ing s a egy,
moni o ing he pe o mance o he o e all sys em and adap ing he con ol s a egy acco d-ingly [23,24].
Ene gies 2014, 7 3288
Figu e 3. P ima y and seconda y ci cui s o he hospi al’s ho wa e dis ibu ion sys em.
The hospi al EMCS in eg a es senso s, ac ua o s, in e aces, con olle s, local a ea ne wo k (LAN)
and wo PCs o moni o ing. All o hem a e in e connec ed in a cen alized con ol a chi ec u e.
The EMCS con ols and moni o s a wide a ie y o se ices, such as adia o sys ems, an coil uni s,
ai handle s, gas- i ed boile s, sani a y ho wa e , as well as moni o ing medical gases.
All he con ol componen s o p oducing hea and domes ic ho wa e in he hospi al a e
manu ac u ed by T end® (Ho sham, UK) [25,26]. A LON (Local Ope a ion Ne wo k) connec s all he
con olle s T end wi h ade name IQL, and ou Local A ea Ne wo ks (LANs) link up he con olle s
T end wi h ade name IQ2XX. T end 963 so wa e allows da a, con ol se ings, and he de elopmen
o he new con ol s a egy o boile con olle s o be moni o ed.
Figu e 4 shows he a chi ec u e o he EMCS sys ems wi h ou LANs, in e connec ed h ough
an in e ne ne wo k by means o ca ds T end wi h ade name INC2. Two PCs in he hospi al con ol
oom a e linked h ough LAN ne wo ks by means o ca ds T end wi h ade name CNC2.
Figu e 4. The a chi ec u e o he hospi al EMCS.
Ene gies 2014, 7 3289
The con olle s o he six boile s ha make up he hospi al’s hea gene a ing sys em a e linked o
he LAN 4 ne wo k. Boile s 1, 2, 3, and 4 use con olle s T end wi h ade name IQ246, and boile s 5,
and 6 use con olle IQ204. In addi ion, he Weishaup -B eme modula ing bu ne in each o he
boile s allows he PID (P opo ional-In eg al-De i a i e con olle ) con olle pa ame e s o be egula ed.
Imp o emen s in he con ol s a egies we e implemen ed and es ed in he p ima y ci cui o he
hospi al’s ho wa e dis ibu ion sys em (see Figu e 4), and mo e speci ically in he unc ioning o
boile s 5 and 6, which a e esponsible o supplying he hospi al’s hea ing equi emen s.
3. Applica ion o he Me hodology o Ene gy E iciency in he Hospi al
3.1. Hospi al Boile Con ol Sys em: Ini ial S a e
The ini ial basic equi emen s ela ed o boile s 5 and 6 o p o iding he hospi al’s hea ing
equi emen s a e:
 The ho wa e supply empe a u e is con olled o mee he se poin , depending on which
se ices a e equi ed by he hospi al. Se poin empe a u es may be ixed ( he same alue o e
ime) o a iable (based on building loads o ou doo -ai empe a u e).
 The mos e icien g oups o boile s a each momen should be used. Tha is, he g oups o
boile s which bes i he speci ic needs a any gi en momen .
 The numbe o boile s ops and s a s should be minimized, so as o educe bo h consump ion
and mechanical wea .
Regula ing he hea p oduc ion sys em o hea ing and sani a y ho wa e in he hospi al in ol es
h ee pa ame e s which a ec sys em pe o mance:
 Boile ho wa e supply empe a u e.
 Bu ne powe .
 Bu ne con olle PID pa ame e s.
When we s a ed he analysis o he con ol sys em ha egula es boile s 5 and 6 o p o iding
he hospi al wi h hea and ho wa e , he se poin o he ho wa e supply empe a u e was 77 °C.
The bu ne s o hese boile s inco po a e a he mos a which, o sa e y easons, swi ches o when he
wa e empe a u e ises 6 °C abo e he se poin (83 °C). The bu ne s o boile s 5 and 6 we e ini ially
adjus ed so ha hei minimum ope a ing powe was 50%. These bu ne s a e con olled by PID. The
de aul alues (gi en by he manu ac u e ) o hese bu ne s a e:
• Maximumbu ne ope a ingpowe : 100%
• Minimum bu ne ope a ing powe : 50%
• Se poin ho wa e supply empe a u e: 77 °C
• Sa e y s op ho wa e empe a u e: 83 °C
• PID bu ne : Kp = 10
• PID bu ne : Ti = 10 s
• PID bu ne : Td = 10 s
Ene gies 2014, 7 3290
Using hese ini ial egula ion pa ame e s, da a o he hospi al’s hea p oduc ion sys em we e
collec ed o e a six-mon h pe iod. The e olu ion o he “ho wa e supply empe a u e” and “bu ne
powe ” was sa ed. Da a o hese a iables we e aken each wo seconds.
Figu es 5 and 6 show some o he da a collec ed. Speci ically, Figu e 5 shows he e olu ion o
he ho wa e supply empe a u e in boile 5 o one hou (ea ly a e noon: 12 h 50’–13 h 50’). Figu e 6
shows he bu ne ope a ion powe o boile 5 du ing he same pe iod o ime.
Figu e 5. Boile 5: Ho wa e supply empe a u e (°C).
Figu e 6. Boile 5: Bu ne ope a ing powe (%).
3.2. Analysis o In o ma ion
Analysis o Figu e 5 indica es ha he ho wa e supply empe a u e akes a maximum alue o
84 °C and a minimum o 71 °C. The e is a wide oscilla ion o 13 °C o e one pe iod (ea ly a e noon:
12 h 50’–13 h 50’) when he hospi al hea ing equi emen s emain cons an . Ho wa e supply
empe a u e should he e o e e idence “ e y ew” oscilla ions.
Ene gies 2014, 7 3297
4.3. Resul s Analysis wi h Ac ions 1, 2, 3, and 4 Implemen ed
Finally, Figu es 12 and 13 show he esul s achie ed a e implemen ing all he ac ions desc ibed
abo e on boile s 5 and 6.
Figu e 12 shows he empe a u e moni o ing o he ho wa e supply o boile 5 om 19 Augus 2011
o 30 Augus 2011. Tempe a u e se poin is cons an (77 °C) un il 23 Augus 2011. The se poin hen
a ies ollowing he s a egy shown in Figu e 7. This se poin a iable is cha ac e ized by he ollowing
alues: Minimum OT = 17 °C, maximum OT = 26 °C, minimum ST = 75 °C, maximum ST = 79 °C.
This igu e shows ho wa e empe a u e oscilla ions o sui he a iable se poin p og ammed.
Figu e 12. Boile 5: Ho wa e supply empe a u e e olu ion (°C) implemen ing ac ions 1,
2, 3, and 4.
Figu e 13. Boile 5: Ho wa e supply empe a u e e olu ion (°C) and ou doo -ai empe a u e.

Ene gies 2014, 7 3298
Figu e 13 shows empe a u e moni o ing o he ho wa e supply o boile 5 ( ed line) as compa ed o
he ou doo ai empe a u e moni o ing (blue line) om 17 h (30 Augus 2011) o 09 h (31 Augus 2011).
This igu e shows ha he supply empe a u e is lowe du ing he wa mes pa o he day (18 h–23 h).
Du ing he nigh and ea ly hou s o he mo ning (23 h–8 h), when he ou doo ai empe a u e
dec eases and demand is g ea es (due o i ing up machines and equipmen which lies idle o e nigh ,
and hospi al pa ien s using ba h ooms), he supply empe a u e is highe .
The e o e, a e his analysis, we conclude ha he ou ac ions implemen ed on boile s 5 and 6
allow he boile con ol sys em o espond app op ia ely o changes in bo h ou side empe a u e and
hospi al hea ing equi emen s.
4.4. P ima y Ene gy Sa ings, CO2 Reduc ion and Financial Analysis
The hospi al is a majo ene gy consume . The company supplying na u al gas o e s access o
an online applica ion h ough which all kinds o in o ma ion can be ob ained: consump ion, se ice
condi ions, and oubleshoo ing. This applica ion allows us o choose be ween daily o hou ly
consump ion depending on how much de ail we wan .
To de e mine p ima y ene gy sa ing, a compa ison was made be ween he na u al gas consump ion
in he week o 18 o 24 July 2011 (hospi al boile con ol sys em unning in ini ial s a e, wi h no ac ion
o con ol implemen ed), and he week om 12 o 18 Sep embe 2011 (hospi al boile con ol sys em
unning in ini ial s a e, wi h con ol ac ions 1, 2, 3, and 4 implemen ed). As i is summe , only boile s 5
and 6 we e conside ed in he s udy. The o he ou boile s a e no equi ed du ing he summe . We
chose hese wo weeks because, as shown in Table 3, ou side empe a u es (maximum, minimum, and
a e age) a e e y simila , sugges ing e y simila hea ing demands in he hospi al. Figu e 14 shows
empe a u e a ia ions du ing days 18–24 July 2011, and 12–18 Sep embe 2011.
Table 3. Tempe a u e alues du ing he weeks analyzed.
Weekly empe a u es
Maximum °C
Minimum °C
A e age °C
18–24 July 2011
27.7
14.2
20.9
12–18 Sep embe 2011
27.5
14.9
21.2
Figu e 14. Tempe a u e a ia ion du ing 18–24 July 2011 and 12–18 Sep embe 2011.
Tempe a u e °C
Ene gies 2014, 7 3299
Analysis o hospi al gas consump ion o e wo weeks, aken om he na u al gas company’s web
applica ion, has allowed us o calcula e Table 4.
Table 4. Ene gy, cos , and emissions du ing he week.
Days Gas consump ion
(Nm
3
)
Hea ing supply
(kWh)
Gas cos
(€)
CO2 emissions
( on)
18–24 July 2011
24,188.0
289,772
9,283.00
55.2
12–18 Sep embe 2011
15,239.0
182,557
5,849.00
34.8
Reduc ion (37%)
8,949.0
107,215
3,434.00
20.4
The inancial alua ion shown in his able was ob ained conside ing a p ice o 0.032597 €/kWh.
This co esponds o he uni p ice o he a iable e m o he hospi al’s gas bill. Using he p ice
conside ed and he consump ion eco ded, an es ima ed sa ing o 3,434.00 € was made be ween he
wo weeks s udied.
I his esul o one week we e ex ended o he whole o he summe pe iod (June–Sep embe →
16 weeks), he es ima ed sa ing in cos s would be:
3,434.00 €/week × 16 weeks = 54,944.00 €
E en hough, in a la ge acili y such as a 600-bed hospi al, gas consump ion cos s a e eno mous,
being able o cu his amoun by a ound 55,000.00 € ep esen s a conside able sa ing, and one no o
be igno ed.
Figu e 15 shows he cos o gas each hou o e he wo weeks analyzed in he s udy (1 week = 168 h).
A compa ison is made be ween he cos o one week in July (18–24) 2011, and one week in Sep embe
(12–18) 2011.
The impac o he ou ac ions implemen ed in he con ol sys em o boile s 5 and 6 ela ed o CO2
emissions o e he wo-week moni o ing pe iod indica ed abo e was calcula ed, and is shown in Figu e 16.
Figu e 15. Cos o gas consump ion (each hou ).
Ene gies 2014, 7 3300
Figu e 16. CO2 emissions (g).
The CO2 alues indica ed in his igu e a e calcula ed om he combus ion eac ion o na u al gas.
Analysis o his eac ion allows us o es ima e he numbe o g ams o CO2 emi ed o each Nm3 o
na u al gas bu ned:
22 4 4 2
3 3
4 24 4 4
1 mol CO 44 g CO 1 mol CH 830 g CH g CO
2282.2
1 mol CH 1 mol CO 16 g CH 1 m N CH m N CH
××× =
(5)
CO2 emissions a e a di ec unc ion o na u al gas consump ion a he acili y. As a esul , when he
amoun o gas used alls, he numbe o g ams o CO2 emi ed in o he a mosphe e also alls.
Figu e 15 indica es ha emissions co esponding o he week a e con ol ac ions we e aken
(12–18 Sep embe 2011) a e clea ly lowe . CO2 emissions due o he imp o ed con ol sys em o
boile s 5 and 6 a e 37% in he compa a i e s udy pe o med o he wo weeks chosen. This ep esen s
a 20- on educ ion in he CO2 emi ed o he a mosphe e.
5. Conclusions
The ac ions pe o med o egula e and con ol he hospi al boile s allow us o conclude ha :
• The educ ion in he minimum limi o he bu ne powe has managed o p e en he boile om
con inually swi ching on and o , as a esul o eaching high wo king empe a u es a momen s
o low demand.
• App op ia e PID con olle uning o egula e he boile bu ne allows ho wa e supply
empe a u e a ia ions o be smoo hed. Tempe a u e peaks a e smoo hed and a e sho e . When
dealing wi h changes in hospi al hea demand, he boile s a e able o espond apidly o changes
and quickly s abilize.
• Implemen ing a boile con ol sequence leads o a dec ease in he ime in e als in which he
boile is ope a ed a high powe being achie ed. This inc eases boile li espan as well as mo e
e icien unning. Thanks o he suppo boile , dis u bances caused by changes in hospi al hea
demand a e damped mo e quickly, hus educing peak empe a u es in he ho wa e .
Ene gies 2014, 7 3301
• A e implemen ing he a iable se poin , he ho wa e supply empe a u e o he boile inc eases
and dec eases wi h he ou doo ai empe a u e h oughou he day, he eby educing empe a u e
luc ua ions in he p ima y ci cui , so i ope a es mo e in line wi h hospi al hea demand.
We conclude ha he ou well-designed ac ions implemen ed o imp o e he con ol s a egy o he
hospi al boile s a e able o p o ide hea ing in a highly e icien manne . Con ol canno o e come a
acili y’s design aul s, bu can imp o e i s pe o mance, as has been e idenced by he esul s achie ed
in his pape .
Financial analysis poin s o a 55,000 € educ ion in cos s in summe (June–Sep embe ), as compa ed
o he cos s wi h he manu ac u e ’s o iginal con ol sys em. Fu he mo e, he sys em was able o cu CO2
emissions by o e 20 ons be ween June and Sep embe . The e is a o al p ima y ene gy sa ing ha
co esponds o a 37% educ ion in CO2 emissionsas compa ed o he e e ence ins alla ion.
These indings show ha a boile con ol sys em which implemen s he ac ions desc ibed will p o e
an en i onmen ally iendly and inancially easible op ion o hospi al hea ing.
Au ho Con ibu ions
Juan-Ca los F aile and Julio San-José designed he con ol ac ions, p oposed and analyzed he es
esul s, and w o e and e ised he manusc ip . Ana Gonzalez-Alonso de eloped con ol so wa e and
human-machine in e ace o PLC and PC. All au ho s ead and app o ed he inal manusc ip .
Con lic s o In e es
The au ho s decla e no con lic o in e es .
Re e ences
1. Bizza i, G.; Mo ini, G.L. New echnologies o an e ec i e ene gy e o i o hospi als.
Appl. The m. Eng. 2006, 26, 161–169.
2. Ba wig, F.; House, J.M.; Klaassen, C.J.; A dehali, M.M.; Smi h, T.F. The na ional building
con ols in o ma ion p og am. In P oceedings o he ACEEE Summe S udy on Ene gy-E iciency
in Buildings, Washing on, DC, USA, 18–23 Augus 2002; pp. 1–14.
3. Comme cial Buildings Ene gy Consump ion Su ey: Consump ion & E iciency. A ailable
online: h p://www.eia.go /consump ion/comme cial/ (accessed on 30 Augus 2013).
4. Dua e, C.; Acke , B.; G osshans, R.; Manic, M.; an den Wymelenbe g, K.; Riege , C.
P io i izing and isualizing ene gy managemen and con ol sys em da a o p o ide ac ionable
in o ma ion o building ope a o s. In P oceedings o he Wes e n Ene gy Policy Resea ch
Con e ence, Boise, ID, USA, 25–26 Augus 2011.
5. Wijayaseka a, D.; Manic, M.; Riege , C. Compu a ional in elligence based anomaly de ec ion o
Building Ene gy Managemen Sys ems. In P oceeding o he 5 h In e na ional Symposium on
Resilien Con ol Sys ems, Sal Lake Ci y, UT, USA, 14–16 Augus 2012; pp. 77–82.
6. San-José, J.F.; Guija o, A.; Cas o, F.; Villa eula, J.M. Indicado es de ene gía é mica en los
hospi ales de Cas illa y León. Todo Hosp. 2009, 260, 641–648. (In Spanish)
Ene gies 2014, 7 3302
7. Hi s , E.; Clin on, J.; Gelle , H.; K one , W. Ene gy E iciency in Buildings: P og ess and P omise;
Ame ican Council o an Ene gy E icien Economy: Washing on, DC, USA, 2008.
8. G anze , W.; Kas ne , W. Communica ion se ices o secu e building au oma ion ne wo ks.
In P oceedings o he IEEE In e na ional Symposium on Indus ial Elec onics Ba i, Ba i, I aly,
4–7 July 2010; pp. 3380–3385.
9. Vakilo oaya, V. Ene gy-e icien HVAC sys ems-empi ical modelling and g adien op imiza ion.
Au om. Cons . 2013, 31, 176–185.
10. Chung, M.; Pa k, H.C. De elopmen o a so wa e package o communi y ene gy sys em
assessmen —Pa I: Building a load es ima o . Ene gy 2010, 35, 2767–2776.
11. Bujak, J. Ma hema ical modelling o a s eam boile oom esea ch e mal e iciency. Ene gy 2008,
33, 1779–1787.
12. Klein, L.; Kwak, J.Y.; Ka ulya, G.; Jazizadeh, F.; Bece ik-Ge be , B.; Va akan ham, P.; Tambe, M.
Coo dina ing occupan beha io o building ene gy and com o managemen using mul i-agen
sys ems. Au om. Cons . 2012, 22, 525–536.
13. Yoshida, S.; I o, K.; Yokoyama, R. Sensi i i y analysis in s uc u e op imiza ion o ene gy supply
sys ems o a hospi al. Ene gy Con e s. Manag. 2007, 48, 2836–2843.
14. Ma, Z.; Wang, S. Supe iso y and op imal con ol o cen al chille plan s using simpli ied
adap i e models and gene ic algo i hm. Appl. Ene gy 2011, 88, 198–211.
15. Beghi, A.; Cecchina o, I. Modelling and adap i e con ol o smell capaci y chille s o HVAC
applica ions. Appl. The m. Eng. 2011, 31, 1125–1134.
16. Liao, C.; Ba ooah, P. An in eg a ed app oach o occupancy modeling and es ima ion in
comme cial buildings. In P oceedings o he Ame ican Con ol Con e ence, Bal imo e, MD, USA,
30 June–2 July 2010; pp. 3130–3135.
17. Wes , S.R.; Wa d, J.K.; Wall, J. T ial esul s om a model p edic i e con ol and op imisa ion
sys em o comme cial building HVAC. Ene gy Build. 2014, 72, 271–279.
18. Ahmadzadeh ala apeh, M.; Yau, Y.H. The applica ion o hea pipe hea exchange s o imp o e he
ai quali y and educe he ene gy consump ion o he ai condi ioning sys em in a hospi al
wa d—A ull yea model simula ion. Ene gy Build. 2011, 43, 2344–2355.
19. Cong adac, V.; P ebi ce is, B.; Pe o acki, N. Me hods o assessing ene gy sa ing in hospi als
using a ious con ol echniques. Ene gy Build. 2014, 69, 85–92.
20. Diakakia, C.; G igo oudisb, E.; Koloko saa, D. Towa ds a mul i-objec i e op imiza ion app oach
o imp o ing ene gy e iciency in buildings. Ene gy Build. 2008, 40, 1747–1754.
21. Boile s o Cen al Hea ing; Boile s o Wood, S aw and Simila Fuels; Te ms Requi emen s,
Tes ing; DIN 4702–4; Deu sches Ins i u ü No mung e.V. (Ge man Na ional S anda d): Be lin,
Ge many, 1990.
22. Vulcano Sadeca Company. A ailable online: h p://www. ulcanosadeca.es/en/p incipal.h ml
(accessed on 7 May 2014).
23. Dounis, A.I.; Ca aiscos, C. Ad ancedcon olsys ems enginee ing o ene gy and com o
managemen in a building en i onmen —A e iew. Renew. Sus ain. Ene gy Re . 2009, 13,
1246–1261.

Ene gies 2014, 7 3303
24. Koloko sa, D.; S a akakis, G.S.; Kalai zakis, K.; Ago is, D. Gene ic algo i hms op imized uzzy
con olle o he indoo en i onmen al managemen in buildings implemen ed using PLC and
local ope a ing ne wo ks. A i . In ell. 2002, 15, 417–428.
25. TREND Company. Da a Shee 963 Supe iso . A ailable online: h ps://pa ne s. endcon ols.
com/ endp oduc s/cd/i /pd /en- a200636-uk0y 0508.pd (accessed on 27 May 2013).
26. TREND Company. 963 Use Guide. A ailable online: h ps://pa ne s. endcon ols.com/
endp oduc s/cd/ u/pd /en- c200635-uk0y 0308.pd (accessed on 27 May 2013).
27. Kazemian, H.B. Compa a i e S udy o a Lea ning Fuzzy PID Con olle and a Sel -Tuning
Con olle . ISA T ans. 2001, 40, 245–253.
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