# T he r e f r ige r at io n a nd ai r c o ndi tio n in g indu s t r ie s hav e un de r go ne s ig nif ic an t c h ang e s s i nc e t h e f ir s t day s o f t he Mo n t re a l P r o to c o l and C l e an Air Ac t

. H o w e v e r

, o u r in dus tr y

c o nt in ue s to c ha nge t o day

, be c aus e s o m e o f th e r e gu l at io n s r e l at e d to t he r e f r i g e r a n t pha s e o ut h av e no t y e t ta ke n e f f e c t .
O t h er r eg ul a ti o ns , s uc h as t he m inim um SE E R r a tin g fo r air co n dit io n e rs , whic h h ad u nde r go n e l e ng t hy l it iga

ti on , h av e j u s t n o w f in al l y s e tt l e d s o we c an be g in t o s e e wha t it s ef f ec t s wil l b e . T he fa c t is

, ou r i ndu s tr y

ha s be en , and wi l l c o nt in ue to be in fl u x fo r s o m e t im e to c o m e. I n t he U

. S.

, t h e m an uf

a ct u re o f C FC s was r e q u i r e d by l aw to be dis c o nt in ue d by th e b eg in nin g o f 1 99 6, an d H C F C - 1 4 1 b 1 by t h e be g inn ing o f 20 0 3. W e a re no w
p r ep ar in g fo r th e n e x t big s t e p in t he pha s e o ut t im e t ab l e: Ja

n

. 1

, 2 0 1 0

. F r o m t h a t d a t e o n , U

. S

. s y s t e m m a n u f a c t u r e r s wi l l

s t o p p r o du c t io n o f n e w e q u ip m e n t u s i n g H C F C

- 2 2

. Gi

v en h o w ex te n s iv e t he us e o f R- 2 2 is in bo t h r e f r i g e r a



# Peering Into the Pr esent and Futur e of Refrigerants Peering Into the Pr esent and Futur e of Refrigerants

H e r e ’ s a n o v e r v i e w o f w h a t ’ s h a p p e n e d t h u s f a r

w i t h re f r i g e r a n t s a n d a l o o k a t c u rr e n t a n d p r o j e c t e d
d e v e l op m e n t s , i n c l u d i n g a c o up l e t h a t m a y s u r p r i s e y ou H e r e ’ s a n o v e r v i ew o f w h a t ’ s h a p p e n e d t h u s f a r

w i t h re f r i g e r a n t s a n d a l o o k a t c u rren t a n d p r o j e c t e d
d e v e l op m e n t s , i n c l u d i n g a c o up l e t h a t m a y s u r p r i s e y ou

B Y G U S R O L O T T I B Y G U S R O L O T T Iti o n an d a ir c o n dit io nin g, th is wil l h av e a m aj o r i m pac t

. L e t ’ s l o o k a t wh at th e in du s tr y

ha s d o ne s o f ar

in t er m s

o f r e fr ig e ra nt de v el o p m en t . T he gr e at e s t po r t io n o f t h e hv a cr ind us t r y h as us ed R- 1 1, R-1 2 , R- 50 2 a nd R- 22

. So m e o f t he o th e r r e f ri ge r an ts
, s uc h as R- 5 00 o r R- 11 4

,
w e r e de s ig ne d m o r e f o r s pe c if ic

appl i ca t io ns an d, t he r e

f o r e , we r e us e d in m u ch s m al l e r q ua nt it ie s c o m par e d to
R- 12

, R- 5 02 a nd R- 2 2.
E q uip m en t o e m s e x te n s iv e l y a na l y z e d t he dif f e re n t

r ef r ig er a nt a l t er n at iv e s a v ail a bl e t o t h e m a nd s e tt l e d o n a

nu m be r o f p ro d uc t s . O nc e a ne w re f r ige r a nt h ad be e n

s e l e ct e d, t h ey r e - e n g i n e e r e d t he ir eq u ipm e n t ( no t a tr iv ia

l

p r o c es s by an y

m e ans ) an d be ga n m an uf

ac t ur in g ne w

e q

uipm e n t f o r u s e wit h t he ne w r e fr ig e ra nt s

. I n th e s e

c as e s , s o m e c l ea r wi nn er s e m e r g e d . P re v i o u s l y

, R -1 1 wa s u s e d m o s t l y in l o w- pr e s s u r e

c hil l e r s

. T h e o n ly s u bs t it ut e c u rr e n tl y av a il abl e is HC F C12 3 , t ho u gh it s us e has n o t be e n wide l y

e m br ac e d by th e i n d u s t r y i n s pit e o f its c l e ar be ne f it s r e g a r ding r e d u c e d

e m is s io n s a nd s up e ri or e f f ic ie n cy an d pe r f o rm a n c e .
C o n c e r n

s f o r R -1 23 ar e i ts l o w le v e l o f t ox ic it y ( m e a s

u r e d as ti m e we ig ht e d av e r age o r T W A) an d t h e f ac t t ha t
, be ing a n H CF C, it m ig ht be s c h ed ul e d fo r pha s e o ut
, al t ho u gh a t a l at e r da t e t ha n R-2 2 . W h il e t he ind us t r y

c o nt inu e s t o l o bby l eg is l a to r s to al l o w t he u s e of R- 12 3 i n d e f i n i t e l y

, s o m e o t he r s h av e be gun m anu f ac t ur in g s y s

te m s us ing R -1 34 a. Fo r m o s t o f t he ap pl ic at io ns u s ing R -1 2, HF C -1 34 a be c am e th e c l e ar do m ina t ing c h o ic e. Al l a ut o air co n diti o nin g an d m e di um

- t o h ig h-t e m pe r at u re r e f r i g e r a t i o n ,

e s pe c ial l y in t he app li an ce s e c to r , ha v e be e n us i ng R- 1 34 a. Fo r m e dium

- a nd l o w- te m pe r a tu r e r e fr ig e r at io n app l ic at io ns pr e v io us l y u s ing R -5 02

, e q u ipm e nt o em s f o r t he

m o s t pa rt

s e l e ct e d R- 40 4 A o r R- 50 7 A 2

. S o m e d ec id e d t o

us e R- 22 a s a t e m po r ar y

s o l ut io n d ue t o it s c o s t a nd t he

av ai l abil i ty o f s y s t e m c om p o ne nt s

. T his is ir o nic s in c e R- 50 2 wa s or ig in al l y de s ign e d t o

r ep l ac e R -2 2 in l o w- te m p er a tu r e r e fr ig e r at io n. In additi o n, R -4 10 A, whic h s o f ar h as o nl y be e n c o ns i de re d in a ir

c o ndit io n ing

, is no w be in g t es t e d as a po t e nt ial r e f r i g e r a

ti o n fl u id as we l l

. F r o

m a te c h nic a l po in t o f v ie w , R -4 1 0A wo r k s we l l in th e r e f r ige r at io n r an ge o f t e m pe ra t ur e s , an d it c o u ld e v e n ha v e be t te r c apa ci ty an d e f f ic ie nc y

t ha n R-4 0 4A . H ow e ve r ,
e q

uipm e n t r e de s ig n wil l b e ne c e s s a ry t o c o m pe n s at e f o r th e h igh e r c o m pr e s s o r d is c ha rg e t e m pe r at ur e s an d t h e hig he r op e ra ti ng pr e s s u r e s

. W ha t wo ul d it ta ke f o r R- 41 0 A to be c o m e a v ia bl e

o pt io n f or

r e fr ig e ra ti o n? I t c o ul d be a c o m bi na tio n o f fa c to r s : Re gu l at io ns in t he U .S

. o r i n th e E u r o pe an U nio n ( E U) m ak in g t he u s e o f R-4 0 4A m o r e d if f ic u l t due t o g l ob

al war m in g; m a r ke t in g s tr a te g y f r o m a c o m pr e s s o r o r s y s

te m o e m ; o r a m a rk e t d em a nd f o r o ne f l uid in s t ea d o f

tw o . At t h is p o int

, R -4 10 A is ge t ti ng a ha r d l o o k

, a nd if

an y c o m pa ny be l ie v e s t h at it wil l gai n an a dv ant a ge o v e r th e c o m pe t it io n by us ing it

, i t m ay ha ppe n

. T he c ho ic e o f R-4 0 4A v s

. R -5 0 7A h as no t b ee n y e t s e tt l ed . R- 40 4 A i s a t hr e e -c o m po n e nt bl e nd de r iv e d f r o m t h e
t wo -c o m po n en t R -5 07 A. T he m a in dif f e r e n c e in c o m po s it io n is th e a ddit io n o f a s m a l l a m o un t o f R -1 34 a t o R- 40 4 A t o re d uc e i ts o pe r at in g pr e s s u r e . O v e ra l l , s al e s o f
R- 40 4 A a r e ab o ut f o u r t o f iv e t im e s t ho s e of R- 50 7 A. Mo s t m aj o r r e f ri ge r an t m an uf

ac t u re r s an d w ho l e s al e r s o f

f e r bo t h r e fr ig e r ant s an d m os t c o m po ne n ts ar e no w

r at e d f o r b o th r e f r ige r an ts a s we l l

. T h e r e is no t ec h nic a l

ne e d f or

t he s e t wo r e fr ig e ra nt s be c aus e e it he r o n e c o u l d

r ep l ac e t h e o t he r q u it e e as il y

. T h e m a r ke t , o e m s and c o nt ra c to r s ul t im a te l y wil l hav e t o s e l e c t o nl y o ne

. 

# R e t r o f i t r e f r i g e r a n t s e m e r g e

W hi l e t he o em s de c ide d wh at w ou l d be t he ne x t ge ne r a

t io n r ef r ig er a nt f o r t h e ir n ew e q ui pm e nt
, t he y c o ul d no t

e as il y

c o nt r o l wh at re f r ige r a nt we n t in t o e q ui pm e nt a l r e ady in u s e . T h is c r e at e d a who l e ne w m ar k et in t he f o r m

o f t he r e t ro f i t s .
R e t r o f it

r e f r ig e r a nt s a r e “ in t e r im ” r e f r ig e r an t s u s e d i n

e q

u ip m e n t d e s i gn e d f o r

o t h e r r e f r ig e r a nt s ( t he o e m r e f r i g

e r a nt )

, b ut s t i l l al l o w t h e e q u ipm e nt t o o p e r at e

. W h il e o e m Mark Sullivan of Atofina’s Calver t City , Ky ., plant labels fr eshly painted R-22 cylinders. In time, the number of r efrig

erants should begin to consolidate to a select few

.r e f r ig e r a nt s w e r e f e w , r e t r o f

it

r e f r ig e r a nt s w e r e m a ny

. Co n tr a ct o r s and s e r v ic e t e c hs be c am e an no y e d an d

c o nf us e d wit h t he “ r e f r i g e r a n t - o f - t h e - d a y

, ” an d c o m

pl ain e d abo u t t he nu m be r o f c y l in de r s t h ey h ad t o c ar r y in t he ir v ans t o s e r v ic e r e t r o fit t e d un its . Af t er th e d us t s et

tl e d, j us t a han df ul o f r e t r o f it r e f r ige r an t s , s uc h a s R -4 0 9A

an d R -4 0 8A, th at had be e n pr o v e n t o wo r k we l l an d w er e o f

f e r ed by a n um be r o f re p ut abl e c o m pan ie s , m ai nt ain e d

a c o ns ide r a bl e po s i tio n i n th e m a r ke t pl ac e

. I n an y c a s e, th e h e y day f o r r e t r o f it s fr o m R- 12 a nd R- 5 02 h as pa s s e d, al t ho u gh a h e al t hy m ar k e t s t il l r e m a i n s .
T he ne x t r e f r ige r an t t o be ph as e d o ut i n th e U

. S. is
R- 22

. B e c au s e o f R-2 2 ’ s us e in bo t h t he r e f r i g e r a t i o n

an d a ir -c o n dit io nin g s e c to r s , m or e th an o n e r e p l a c e m e n t

r ef r ig er a nt w il l be ne e de d t o r e pl ac e it e n tir e l y

. In t he re f r ige r a tio n m a r ke t
, R- 2 2 is be ing s u bs t it ut e d
wit h R- 40 4 A/ R-5 0 7A . In t he air

- c on dit io n ing m a r ke t
,
m o s t ly in t h e r e s ide n tia l a nd l ig ht c o m m e r c ial s e c to r s , R- 41 0 A i s t he l e adin g c an dida te

. K e e p in m in d th at w hil e th e s e n e w r e f r ige r an t s u bs t it ut e s a r e c ur r e nt l y

av ai l abl e ,
an d m a ny c o m pan ie s ar e m a ki ng

e q

uipm e n t an d c o m po ne n ts f o r th e m , R- 2 2 c an be us e d f o r e q uip

m e nt s er v ic e inde f in it el y

. It wo u l d s ee m l o gic a l t o a s s um e th at a ne e d to r e t r o f it R -2 2 e q uip

m e nt w o ul d no t d ev e l o p un t il 2 0 10

o r l at e r , e s p ec i al l y co n s ide r in g th at R- 22 w il l c o n tin ue t o be pr o d u c e d fo r s e r vi ce un t il 2 0 20

. H o we v e r , in th e h v ac r m a r ke t
, l o gi c m ay h av e

no t hi ng t o do wit h r e a l i t y , s in ce a

s m al l m ar k et f

or

r e t r o f it s a ppe ar s
to ha v e be g un r e c e n t l y

. T h e r e a re s e v e ra l r e as o n s fo r th is de v e l o pm e nt . F ir s t is t he n e e d o f s o m e in du s t r y

s e c t o r s
t o

b e m o r e “ g r e e n ” d u e t o i n t e r n a t i o n a

l p r e s s u r e f

r o m e n v

i

r o n m e n t a

l g r o u p s

. N e x t a r e d o o m s da y

p r e d i c t i o n s a bo u t R

- 2 2 s h o r

t a g e s a n d p r i c e i n c r e a s e s

. T h ir d is t h e U. S

. E n v i r o n m e n t a l P r o t e c t io n Ag e n c y ’

s ( E P A) in t e n t io n t o

r e di s t r ib u te a l l o c at i o ns fo r t h e pr o d u c t i o n / i m p o r t a

t io n o f
H CF C s i n 2 0 0 9

, c r e at i ng un c e r t a i n t y

. F i n a l l y

, E P A

’ s h e av y

re f r ige r a nt e m is s io n f ine s c o upl e d
wit h an o f fe r to r e duc e o r e l im in at e s o m e fi ne s if o z o ne

de pl e t ing s u bs t an c es ( O D S) we r e c o m pl e t e l y e l im in at e d ah e ad o f s c he du l e

– s uc h a s in t h e ba ke r y

an d s upe r m a r

ke t indu s t r ie s

– ar e a ddit io n al re a s o ns f o r an e m e r g i n g
R- 22 r e t r o fi t m ar k e t. T h e r e a re a nu m be r o f re f r ige r an t s t h at c an be u s e d a s

r e t r o f it s f o r R -2 2, de pe ndi ng in p ar t o n t he appl i ca t io n. I n

r ef r ig er a ti o n, r e f ri ge r an ts s u ch a s R-4 0 4A /R -5 07 A, R-4 0 7C

an d R -4 1 7A ar e be ing m e n ti o ne d, w ith t h e l as t o ne pr o

m o te d as a dr o p- in. Fo r air c on dit io n ing , o nl y R- 4 07 C o r R- 41 7 A a r e m e nt io n e d.
O ur l a b d at a, a s we ll as t ha t o f s e v e r al o th e r in de pe nd

e nt t e s t ing f a ci l it ie s , s h ow t ha t wh il e t h e f l uids wil l wo r k a d e q u a t e l y

, no ne wil l m at c h th e p er f o r m an c e o f R -2 2.
R- 40 4 A and R -4 07 C is t he cl o s e s t in pe r f o r m

a nc e , bu t

r e q u i r e s an o il c han ge to a po l y o l es te r ( PO E ) o il

. R- 41 7 A m a k er s c l aim t he re f r ige r an t wo r k s w ith th e

c u r r e nt oi l in t h e s y s t e m , bu t a t t he co s t o f a pe r f o rm a n c e l o s s

. I n al l c a s e s , r e t r o f it

t ing wi ll f o rc e th e e n d us e r t o
c o m p r o m is e

. No t e t h at R -4 10 A, th e l e ad ing o e m r e f r i g e r

an t , is no t a r e t r of it

c and idat e be c aus e it s m uc h hi gh er

o pe r at in g pr e s s u r e s a r e n ot c o m pat ibl e wit h t he d e s ign o f
R- 22 s y s t e m s

. 

# W h a t a b o u t t h e o t h e r s ?

T h r e e ot h e r r e fr ig e ra nt s ar e w or t hy o f d is c us s i o n: h y dr o

c ar bo n s ( H C ) , am m o n ia ( NH 3) an d ca r bo n dio x i de ( C O 2 ) .
T he y ha v e a l l be e n u s ed , o r a re c ur r e nt l y

in us e , i n hv ac r

. T h e s e r e f r i g e r a n t s a r e v i e w e d a s “ g r e e n ” o r a

t l e a s t “ g r e e n e r ”

t ha n cu r r en t H F C c ho ic e s , e s pe c ia l l y w ith r

e g a r d to gl o ba l

w a r m

i ng. Addit io n al l y , r e ce n t ly pr o po s e d l e gis l a t io n in t he
E U m a y m a ke s o m e o f th e m m o r e p o pul a r t he r e . H y d r o ca r bo ns ha v e be e n u s e d f o r a f e w y e ar s in r e f r i g

e r at o r s , c o m pe t ing f o r m a r ke t s h ar e wit h R -1 34 a in s o m e E U m e m be r

s t at e s

. H o we v e r , t he y ha v e n ot be e n

u s e d i n th e U

. S. H y dr o c ar bo n s ar e

r e l at iv e l y i ne x pe n s iv e , c o m pat ibl e wit h m in e r al oi l a nd ha v e a l o w d i r e c t g l o bal war m in g po t e nt ial

. O n t he do wn s ide

, th e y a re hi ghl y f l am m a bl e a nd t he ir us e is s e v e r e l y

r e s t ri ct e d by bui l ding a nd f ir e c o de s

a c r o s s t he U. S . Addi ti on al l y , t he ir us e i n c r e a s e s e q u ipm e nt c o s t ( t o e l im in at e a l l po s s i bl e ig nit io n s o u r c e s )

a nd t he ir o v e r al l gl o ba l wa r m i n g in de x ( dir e c t an d i ndi r e c t ) 4 is c o m p ar abl e an d, in m a ny c as e s , w o rs e t han th at o f appl i c abl e H FC s

. H y dr o c ar bo n s w il l pr o ba bl

y

ge t v e r y l it t l e u s e , if

a n y , in t he U

. S.
Am m o n ia ha s be e n u s e d f o r m any y e ar s

. It is be s t s uit

e d fo r re l a ti

ve l y l ar g e ap pl ic at io n s s u c h as ind us t r ial

p r o c e s s c o o l in g whe r e i t ap pe ar s t o ha ve s e e n s m al l

g r

o

wt h. Am m o ni a ex hibi ts go o d t he r m o dy n am ic pr o p e r

t ie s a nd l o w dir e c t gl o ba l wa r m ing p ot e n tia l

. It s us e is l im ite d by it s inc o m pa ti bil it y

wit h c op pe r , a

c o m m o n m at e r ial us e d in r e f ri ge r an t l ine s an d he at

e x c ha ng er s , and by it s fl a m m abi l ity a nd t o x ic it y r a tin g

o f B 2 by A S H RA E ’ s S t a nd ar d 3 4

. It s u s e a l s o i s l im it e d by b u il d in g a nd f

ir e c o d e s , s o it is

be s t a

pp l ie d i n r e l a t i v e l y

r e m o t e l o c at i o n s wh e r e it c a n be c o nt a in e d e a s i l y o r wh e r e it s r e l e as e wo u l d n o t af f e c t s u r r o u n din g

po p ul a t io ns

. Ca r bo n dio x id e ( C O 2 ) i s n o t us ed m u c h in c o m m er c i a l

ap pl ic at io n s t o day

, a

l th o ug h it wa s u s e d m any y e a rs ag o b e f o r e be in g dis pl a c ed by r e fr ig e r ant s s uc h a s C F Cs

. CO 2 ha s s ee n a s t r o ng r e s u r g e nc e d ue to s e v e ra l E u r o pe an c ar m a n u f a c t u r e r s ’ in t e re s t in us i ng it to r ep l ac e R -1 34 a in

m o bil e air c on dit io n ing ( M AC ) , m o s t l y f o r e n v ir o n m e n t a lr ea s o ns l in ke d t o g lo b al war m i n g . C O 2 o f f e r s a v e r y

l ow di re c t g l o bal war m in g po t e nt ial

an d c o m pa r abl e pe r f o r m an c e t o R -1 3 4a s y s t e m s

. I t pe r

f o r m

s be t te r th an R -1 34 a in t h e he a ti ng m o de o f he a t
pum p a ppl ic at io n s

. T he do wns i de s f o r C O 2 a r e t h e e x t re m e l y hi gh o pe r at

ing p r e s s u r e s ( a ppr o x im a te l y 10 ti m es t ho s e o f R- 1 34 a)

, g r

e at e r s y s te m we igh t a nd c o s t t ha n a co m p ar abl e R- 13 4 a

s y s t e m a nd po o r p er f o r m an ce at hig he r a m bie n t t em p e ra

t u r e s ( g r ea t er t han 9 0 ° F )

. O v e r al l

, C O 2 i s t ho u gh t t o be

s l igh t l y in f e ri or o r c o m pa ra

bl e t o en ha nc e d R- 13 4 a aut o

m o bil e a / c s y s t e m s bas e d o n T E W I. T h e r e is l e gi s l at io n pe nd ing be f o r e t he E ur o p e a n Co m m is s io n par l ia m e nt t h at p ro p os es t he ban nin g o f
R- 13 4 a in au to a/ c s y s te m s be gi nn ing wi th s o m e ne w 2 00 9

m o de l s a nd al l m o de l s in 20 1 1. T his l e gis l a t io n, w hic h

app ea r s t o be ba s e d o n l y on th e r e f r i g e r a n t ’ s d ir e ct gl o ba l

w a r m

in g v al ue , wo ul d o nl y al l o w t he us e of CO 2 in a ut o a/ c s y s te m s af t e r R- 13 4 a. T h e c u rr e n t dr af t o f th e l e gi s l ati o n al s o ex cl u de s R-1 5 2a , a f l am m a bl e H F C.
At t hi s po i nt , e v e n th o ug h m uc h wi de r pr o po s e d l e gis

l at io n af f ec t in g R- 13 4 a w as de fe a t ed in E u r o pe , t he fu t ur e

o f R- 13 4 a in au t o a /c

is s til l un c l e ar

. A ut o m ak e r s s e e m to be b al k ing a t t he hig h c o s t t o c o nv e r t pr o du c t io n to CO 2 ,
e s pe c ial l y af t e r t he es tim a t e d $ 5 bi ll i o n- pl us ( in U .S

. do l

l ar s ) pr ic e t ag o f c on v e rt in g f ro m R- 12 to R- 13 4 a j us t a f e w y e a rs a go

.

Af

t er e igh t y e ar s o f t he CF C ph as e o u t an d wit h o nl y s ix

y e ar s un t il t he H CF C ph as e o ut
, i t is s t il l n o t c l e ar o r c er

t ain wh ic h r e fr ig e r ant s ar e h e r e t o s t a y

. F o r t h e U .S

. a t l e as t
, it l o o ks l ik e R- 1 34 a, R-4 0 4A /R -5 07 A an d R -4 1 0A ar e
p r e t ty s u re be t s

. ◆

G u s R o l ot ti is te c hn ic al a nd a pp l ica ti on s l ab ma na ge r , K ing

o

f P ru s s ia T e c hni ca l Ce n te r , A t o

fina C he m ic al s I nc

. F or

m o r e i n f o rm a ti o n , v is i t f o r

a n e

. c o m o r a t o

f i n ac h e m ic al

s

. c o m

.

F o o t n o t e s 1 . W hi l e R- 14 1 b had l im i te d us e as a r e fr ig e ra nt
, it s e ar l ie r ph as e o ut av o ide d a dr as t ic re du c t io n in R- 22 pr o d u c

t io n, whic h wo u l d hav e dir e c tl y im pa c te d t he hv ac r s e c to r

m o r e di r e c t l y

. 2 . T he AS HR AE St a nda rd 3 4 de s ig na ti o n fo r th is r e f r i g e r

an t is R- 50 7 A; R -5 07 al s o is a c c ep te d an d us e d.
3 . T hi s is m e as u r e d a s t o t al e q uiv al e n t wa rm i ng in de x ( T E W I) o r l if e cy cl e c l im at e p e r f o r m an c e ( L C CP )

. B o t h
T E W I an d L CC P t ak e in t o a cc o u nt t h e di re c t a nd t he indir e ct po r ti o n o f a r e fr ig e ra nt by c o n s ide r in g fa c to r s s uc h a s e f

f i c i e n c y

, e n er g y u s e d and e n d-o f -l i fe dis po s a l

.