### Secondary*Loop*Motor*Vehicle*Air* Condi5oning*Systems*(SL:MACs)* Using*Low:Global*Warming*Poten5al*(GWP)*Refrigerants*in*Leak:Tight*Systems* In*Climates*with*High*Fuel*Prices*and*Long,*Hot*and*Humid*Cooling*Seasons* Building*on*the*Previous*Success*of*Delphi,*Fiat,*General*Motors,*Volvo,*Red* Dot,*SAE*Coopera5ve*Research*Projects,*and*Other*Engineering*Groups* 

### Orlando*MACS*Briefing* 6*February*2015* Stephen*O.*Andersen*&*Nancy*J.*Sherman,*IGSD* Timothy*Craig,*Delphi* James*Baker,*JAB*Consul5ng

## Protocol*&*Market*Drivers* of*HFC:134a*Phase:Down*in*MACS* • Protocol*Drivers*

– The*Kyoto*Protocol*already*controls* hydrofluorocarbon*(HFC)* emissions'

– The*Montreal*Protocol*will*likely*soon*control*HFC* produc-on'and'consump-on''' • Market*Drivers*

– EC*MAC*Direc5ve*requires*GWP*<150*aaer*2017*for* new*automobiles*sold*in*the*European*Union*

– US*EPA*offers*credit*toward*fuel*mileage*standards* and*may*prohibit*HFC:134a*in*new*cars*aaer*~2022*

## SL:MAC*Demonstra5on* Project

• Design,*build,*test*and*demonstrate*an*energy: efficient*SL:MAC*for*high*ambient*temperature* climates*using*R:1234yf*(GWP*<1)*or*R:152a* (GWP*=*138);*both*SNAP*and*REACH*approved** • Financed*by*the*Climate*and*Clean*Air*Coali5on* to*Reduce*Short:Lived*Climate*Pollutants*(CCAC)* • Principal*Inves5gators:*Stephen*O.*Andersen,* IGSD;*James*Baker,*JAB*Consul5ng;*Timothy*Craig* &*Mark*Zima,*Delphi;*and*Sangeet*H.*Kapoor*&* Nagarhalli*Prasanna,*TATA*

## Why*Secondary*Loop?****************** • **Safe*use*of*mildly*flammable*refrigerants* • **Lower*charge*reduces*refrigerant*emissions/costs* • **Reduced*A/C*system*noise* • **Lower*cost*for*mul5:point*cooling*point*systems* • **Cold*storage*comfort,*economy*&*environment* • **“Regenera5ve*cooling”*during*decelera5on;* reduced*compressor*load*during*accelera5on* • *A/C*comfort*during*longer*stop/start*(idle:stop)* • *Uniform*air*temperature*across*cooling*coil* • *Fewer*compressor*oil*starva5on*issues

## Why*a*First*Demonstra5on*in*India?*

• Longer,*hooer,*and*oaen*humid*cooling*season* with*rela5vely*high*fuel*prices*in*India*shortens* the*payback*for*energy*efficiency*improvements* • Low*risk*of*freezing*allows*choice*of*secondary* loop*coolant*that*op5mizes*energy*efficiency* • India*and*other*developing*countries*will*qualify* for*Montreal*Protocol*financing*once*the*HFC* phase:down*Amendment*is*agreed*

## Technical*&*Cost*Performance**

• Cooling*Performance*

– Cooling*capacity*(Bench*and*wind*tunnel*tests)*

– Cooling*comfort*(ride*tes ts )*

– Op5mized*engine*loading*by*interac5on*of*secondary* loop*coolant*buffer*with*engine*management*system* • Cost*Performance*

– Reduced*refrigerant*charge*and*refrigerant*cost,*but* added*cost*of*chiller,*pump,*and*reservoir*

– Less*frequent*and*lower*cost*recharge*from*leaks,* accidents*or*component*failure*

– Lower*cost*for*addi5onal*cooling*points***

## Environmental*Performance*

• Direct*Refrigerant*Greenhouse*Gas*(GHG)* Climate*Performance*

– Reduced*refrigerant*charge*and*life:cycle*leak*rate* with*shorter* hoses,*fewer*fiqngs* and*integrated* components*(calculated*using*SAE*J:2727)* • Indirect*Energy*GHG*Climate*Performance*

– Higher*energy*efficiency*with*engine*management* system*(EMS)*integra5on*and*cooling*on*decelera5on* (regenera5ve*cooling)**

– Higher*fuel*savings*from*stop/start*by*reducing*the* 5me*stop/start*is*deac5vated*because*it*is*too*hot

## Safety*&*Economy:*HFO:1234yf*
• Cost*of*addi5onal*secondary*loop*components* offset*by*savings*from*reduced*system*charge* • Reduced*charge*encourages*proper*service*using* HFC:1234yf*rather*than*lower*cost*HFC:134a* • Lower*life:cycle*emissions*reduce*trifluoroace5c* acid*(TFA)*forma5on*from*HFO:1234yf*refrigerant* degrada5on*

## Safety*&*Economy:*HFC:152a*
• Cost*of*addi5onal*secondary*loop*components* offset*by*refrigerant*cost*savings*compared*to* HFO:1234yf* • Proper*service*using*HFC:152a*because*HFC:134a* costs*more* • HFC:152a*has*no*TFA*degrada5on*byproducts* • Use*of*HFC:152a*refrigerant*in*leak:5ght* secondary*loop*systems*is*safe*and*approved* under*the*US*EPA*Significant*New*Alterna5ves* Policy*(SNAP)*Program*and*the*EC*F:Gas*Direc5ve**

## Poten5al*Challenges:* Risk*Mi5ga5on*

• Small*Charge* • Charged*components*in*wind*stream** • Refrigerant*isolated*from*igni5on*sources* • Loca5on*and*control*of*refrigerant*pressure* relief*valve* • Ac5ve*safety*systems?* A company considering HFO-1234yf unsafe for their cars in direct expansion systems could declare secondary-loop as the design solution

## Poten5al*Challenges:*Design*

• Managing*weight*and*spa5al*impact*of*addi5onal* components*in*the*engine*compartment*and* vehicle*cabin* • Sizing*to*sa5sfy*cooling*performance*and*ride* comfort,*par5cularly*for*ini5al*cool:down*from* hot:soak* • Developing*compressor*on/off*strategies*that* balance*fast*thermal*pull*down*in*high*ambient* temperatures*with*fuel*efficiency***

## Poten5al*Challenges:*Service*

• Safety*in*servicing*pressurized*systems*with* flammable*refrigerants* • Best*prac5ces*in*refrigerant*iden5fica5on,* recovery,*recycle,*etc.* • Maintaining*coolant*quality*and*freeze* protec5on*and*avoiding*and*resolving*air*in* the*coolant*circuit*

## The*Importance*of*Advisors*

• Help*make*the*design*and*demonstra5on*as* good*as*it*can*be* • An5cipate*and*help*answer*important*ques5ons* about*technical,*environmental,*and*cost* performance* • Communicate*the*findings*to*the*mobile*air* condi5oning*community*and*to*policy*makers* • Head*start*on*how*to*contribute*to*the* commercializa5on*of*SL:MACs**