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Discussion Starter · #1 · (Edited)
Something to be aware of is the Spark EV is one of the first GM cars to utilize the all-new R1234yf refrigerant in the A/C system replacing the traditional R134a which has been used since the early 90s (it replaced R12 at that time)

According to the EPA, while R134a does not deplete the ozone layer, (as R12 did) it has an extremely high GWP (Global Warming Potential) that is approximately 1,400 times greater than that of CO2.

R1234yf has a GWP of only 4 and reduces global warming impact by 99.7 percent compared with R134a.

R1234yf has been somewhat controversial as some manufacturer's (most notably Mercedes) have claimed it reduces their system effectiveness as well as concerns about the refrigerant's flammability.

GM has found that R1234yf is very suitable for electrically powered variable speed A/C compressors (such as used on the Volt and Spark EV) as it has improved electrical isolation properties.

All GM cars and trucks will be converting to the new refrigerant over the course of the next couple years. Starting with Spark EV dealers, all GM Dealers are receiving all-new A/C recovery, recycling, recharging equipment dedicated to the new more environmentally safe refrigerant.

WOT
 

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How does that compare to R410a? I've never understood why cars use different refrigerant than residential ac units...
 

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Good to know. Thanks for the update, WOT.
 

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You have quite a source of information. I read page 12-2 (Technical Data) of the 2014 Chevrolet Spark EV Owner Manual and the table of Capacities and Specifications has only this:

For the air conditioning system refrigerant type and charge amount, see the refrigerant label under the hood.

The only fluids that the table has are the coolants for the HV battery (6 quarts), power electronics (2.7 quarts) and the heater (2.2 quarts). I expected to see the brake fluid and windshield washer fluids there, too.
 

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R1234yf closely mimics R134a thermodynamically - the evaporating and condensing pressures at normal evaporator and condenser coils operating temperatures are similar - ASHRAE says it has a higher COP than 134a.

R410a is a non-starter for automotive AC units. Automotive AC units can see up to 140 degrees F condensing temperature due to the heating effects under the hood with an engine. This would subject the condenser to over 500 psia pressure. For R1234yf, the pressure at 140 deg. F condensing a little over 200 psia. This is a lot easier on the equipment, especially equipment that shakes and rattles around as much as in a car.

The reason R410a is used in building HVAC is because it is an A1 refrigerant - non-toxic and non-flammable. It also has good efficiency. R1234yf is classified A2L - non-toxic, but with some flammability. Building codes typically don't allow anything other than A1 refrigerants in standard residential/commercial construction.

Edit - also, EU automotive standards have mandated that R134a must be phased out and limited the R134a replacements to CO2, R1234yf, and HFC-152a. If GM is to meet the EU standards, their choices were limited.
 

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It's not really unexpected news when GM announced they would use R1234yf for the Volt in 2010 and that it would be introduced into other vehicles in the future. New product, why would you use the old stuff, especially for another electrically driven AC system?
 

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R1234yf closely mimics R134a thermodynamically - the evaporating and condensing pressures at normal evaporator and condenser coils operating temperatures are similar - ASHRAE says it has a higher COP than 134a.

R410a is a non-starter for automotive AC units. Automotive AC units can see up to 140 degrees F condensing temperature due to the heating effects under the hood with an engine. This would subject the condenser to over 500 psia pressure. For R1234yf, the pressure at 140 deg. F condensing a little over 200 psia. This is a lot easier on the equipment, especially equipment that shakes and rattles around as much as in a car.

The reason R410a is used in building HVAC is because it is an A1 refrigerant - non-toxic and non-flammable. It also has good efficiency. R1234yf is classified A2L - non-toxic, but with some flammability. Building codes typically don't allow anything other than A1 refrigerants in standard residential/commercial construction.

Edit - also, EU automotive standards have mandated that R134a must be phased out and limited the R134a replacements to CO2, R1234yf, and HFC-152a. If GM is to meet the EU standards, their choices were limited.
Wow, thanks! That certainly answers my question :)
 

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the other issue is the original "R22" that was used in home / building A/C units you could reach its critical temperature in a hot under-hood situation.. critical temperature is that with which the substance will not condense to a liquid under any pressure.. an A/C system needs to have that change from gas to liquid and back to gas again to work.. thats the premise of how an A/C works..

as stated the newer R-410a has MUCH highwe working pressures than 134a.. not only is higher working pressures require stronger equipment it also is more prone to leaks, esp in a high vibration environment with removable fittings such as a car..

in a house or building the standard calls for all fittings in an R410a system be Brazed.. compressors are typically sealed so there are no O-rings, moving parts, etc.. the only main failure points are typically the king valves which if not maintained properly can leak.. however they are usually never closed once opened...

flammability in refrigerants has long been a discussion in the "hotrodders" forums.. there are refrigerants which are enviromentally friendly, and VERY efficient, however they are quite flammable... often refferred to as HC refrigerants.. (hydrocarbons)..

this debate goes on and on in respect to the EPA regulations on them.. its almost like putting "propane" into your A/C unit.. not quite but similar.. R134a is also pretty flammable under pressure... however the chances or R134a hitting air and ignition source while under pressure is an extremely unlikely situation.. as the linesets are air-free.. and once the 134a escapes into the air it is no longer under pressure....

HC refrigerants are used in some fixed process refrigeration plants.. (ice making plants).. as is of course ammonia.. many food plant flash freeze systems are still using ammonia refrigeration.. (very dangerous if it leaks)...

I have experimented with HC refrigerants in home and belt-driven auto air conditioners.. and from a cooling and energy use standpoint the results were outstanding... MUCH less energy usage than the EPA approved refrigerant....

though in home A/C use R410a has made the case for HC refrigerant use non applicable as it is an efficient refrigerant.. even though it is a blend it has little to no glide..

ill be interested to see how the numbers come back in practical usage with the new refrigerant R1234yf. it looks good on paper...

-Christopher
 

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Hey ***

In changing refrigerant from 134A to R1234, do any components need to be changed also, or is is just a simple swap?
 

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So, another 10 years and this crap will be a envioro-hazard.

Follow the money...... See who benefits from these contant "discoveries"
 
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