What the potential holds for automotive refrigerants is uncertain, but adjustments are coming. At some point down the road, R-134a refrigerant will most likely be replaced by one or even more alternative refrigerants. The query now is which one?

The Europeans have chose to phase out R-134a in new automobiles starting in 2011, by using a comprehensive phase-out by 2017. The European guidelines involve any new refrigerants will need to have a world wide warming prospective of less than 150.

Though R-134a poses no danger to the ozone layer if it escapes in to the environment, this is a “greenhouse gas” that has a fairly higher worldwide warming prospective of 1300 (compared to 1 for carbon dioxide, which can be nature’s personal greenhouse fuel). A leak that permits only an ounce or two of R-134a to escape in to the environment may not look like a large offer, but in excess of time it all adds up, especially when you multiply compact leaks occasions the numerous countless cars that now share planet Earth with humanity.

According to November 2006 report from the Power Data Administration, automobiles while in the U.S. leaked 50.8 thousand a lot of R-134a in to the environment, equivalent to to over 66 million plenty of greenhouse gases. The emissions are 7% higher than in 2004, and up 273 percent given that 1995.

As of 2008, the North American and Japanese auto markers haven’t decided to change R-134a with any other refrigerant. However the auto makers are redesigning their A/C programs together with the following goals in thoughts:

* To implement much less refrigerant. Some newer A/C systems now use only 12 to 14 oz. of refrigerant, that’s considerably less than the 24 to 60 oz. expenses that most older A/C techniques use. As time goes on, we will see much more and much more of these low capacity A/C systems in new autos.

* To reduce refrigerant leakage 50% in excess of the existence from the motor vehicle. This involves working with improved seal patterns, hoses and o-ring connections.

* To improve cooling efficiency 30% with more effective condensers, compressors and operating tactics (points like variable displacement compressors that run every one of the time as an alternative to cycle on and off). Mercedes has this now.

* To cut back the cooling specifications inside the passenger compartment 30% by utilizing reflective coatings on glass, heat reflective paint, and venting the interior during hot weather.

Alterations are also being produced to scale back refrigerant losses if the A/C system on a automobile is serviced. The latest generation of refrigerant recovery machines do a greater task of removing all the refrigerant from your system. Older machines can leave as substantially as 20 to 30 percent with the outdated refrigerant charge within the system. The residual refrigerant can escape into the environment if the A/C system is opened to replace parts. A number of the newest machines can pull as much as 95% of your refrigerant from the system to cut back the quantity of R-134a that escapes to the atmosphere.

Auto makers have also been including leak detection dye on the refrigerant to create it less complicated for technicians to detect refrigerant leaks. A leak will leave a telltale stain that glows greenish-yellow or greenish-blue when illuminated by having an UV light supply. Leaks as little as 1/8 oz. of refrigerant annually might be detected by doing this.

The Europeans auto makers are taking a unique approach. They want long term A/C systems to become as environmentally benign as you possibly can. That suggests no chlorine-containing CFCs for instance R-12 or R-22 that trigger ozone depletion, an no refrigerants that could add for the international warming challenge (which consists of R-134a). Any new refrigerants will have to also be nontoxic and safe, even though that does not always mean nonflammable.

In an energy to address these issues, the Alliance for Accountable Atmospheric Policy (ARAP) plus the U.S. Environmental Protection Agency (EPA) have held a number of annual meetings to discuss and evaluate alternatives to R-134a. The first of those meetings was held in 2003 from the European Commission in Brussels. As a result of that meeting, the European Commission chose to let carbon dioxide, HFC-152a as well as other refrigerants as is possible replacements for R-134a.

CO2 as an Choice Refrigerant?

When used being a refrigerant, CO2 (that is referred to as R-744) involves really large operating pressures (up to 1,800 psi about the substantial side, and 350 to 400 psi on the reduced side), as compared to 300 to 400 psi about the higher side for R-134a. The main reason the pressures are so large is mainly because CO2 will not condense within the refrigeration circuit. It remains inside the gaseous state. As a result, the front warmth exchanger is called a “cooler” as opposed to a condenser.

CO2’s major attribute is always that it has nearly no impact on international warming or ozone depletion. CO2 is also nontoxic in little doses but concentrations over 5% is often lethal. Additionally it is low cost (about $10 for a 20-lb. cylinder) and nonflammable. Many test motor vehicles with CO2 A/C programs hae proven that CO2 does offer cooling effectiveness comparable to R-134a.

SAE is developing service fitting specifications for R-744. Leak detection presents a challenge due to the fact purely natural amounts of CO2 from the environment may be larger than the quantity emitted by a leak from an A/C system. Some sort of ultrasound or infrared equipment might be needed to uncover R-744 leaks, but dyes might also do the job or plain old soap bubbles.

HFC-152a

HFC-152a is almost a straight drop-in substitute for R-134a. The molecule is equivalent to R-134a except that two hydrogen atoms are substituted for two fluorine atoms. It has related operating characteristics to R-134a but cools even greater. One check in an otherwise unmodified Saturn Ion located that A/C duct outlet temperatures have been a number of degrees C reduced with HFC-152a. Fuel effectiveness was also up 10% at idle, and 20% at highway speeds. The system generally necessitates only about two-thirds with the regular charge with HFC-152a and may be employed with existing desiccants.

An environmental benefit of HFC-152a is the fact it’s a world-wide warming rating of 120, which can be 10 times much less than R-134a, but nevertheless a whole lot greater than CO2. That may be why HFC-152a is presently used in many aerosol items as being a propellant. Its principal downside is always that it is actually slightly flammable (Class 2A), nonetheless it isn’t as flammable as propane or most other hydrocarbon-based refrigerants.

The first mobile A/C system to utilize HFC-152a was unveiled on the Mobile Air Conditioning Society (MACS) Throughout the world tradeshow in January 2004; a self-contained unit for off-road development equipment that featured an oil-driven compressor. Produced by Red Dot, the unit can be the forerunner of future HFC-152a A/C programs to come.

Red Dot workers explained the HFC-152a refrigerant employed inside the self-contained unit improves cooling capacity, decreases fuel use and helps secure the climate. The brand new technology also satisfies stringent new regulations proposed by the European Commission. Red Dot personnel also said the HFC-152a system utilizes new technology that can use hydraulic-driven compressors and secondary loop technologies to improve reliability, security and reduce the amount of refrigerant expected.

HFO-1234yf

One more new refrigerant that is certainly becoming regarded is HFO-1234yf. Designed jointly by Honeywell and DuPont, it really is becoming promoted as being a feasible drop-in replacement for R-134a in the two new cars and older automobiles, really should that become necessary in the future. HFO-1234yf has thermal qualities that are very comparable to R-134a, so no main modifications to the A/C system are necessary. Much better still, HFO-1234yf features a world wide warming probable of only 4, in comparison with 1200 for R-134a, permitting it to meet the European requirements for a GWP of much less than 150. Present refrigerant leak detectors could also detect HFO-1234yf if it leaks. But HFO-1234yf is mildly flammable (however significantly less so than HFC-152a), and long term toxicology tests are nonetheless underway.

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