White Paper: HFC-134a: An Ideal Refrigerant with Applied Technology

By Jim Parsnow
Environmental Systems Marketing
Carrier Corporation

Solutions to improve the quality of life and sustain the environment often belong to the corporations who have the technology, resources and global reach. A good example of such a solution is the application of refrigerant HFC-134a for refrigeration chillers. As the industry phases out chlorine based refrigerants that destroy the ozone, choices for the future are limited. Basically the industry is left with about six compounds that could be used for fluorocarbon refrigerants. Of these six, HFC-134a is the only compound that is being applied to equipment in singular compound form. The remaining five compounds will be mixed to form zeotropes and azeotrope blends.1

kW/Ton Vs. Year Centrifugal Chillers

HFC-134a has proven to be an optimal refrigerant in chiller application. The compound has no chlorine and does not contribute to ozone depletion. Ozone depletion is the main reason the industry is obsoleting chlorine refrigerants (CFCs, HCFCs).

HFC-134a is a highly efficient thermodynamic refrigerant in application. Current centrifugal chillers using HFC-134a are 21% more efficient than chillers sold just six years ago and 35% more efficient than the chillers installed during the 1970's and 1980's.

These chiller efficiency gains can be attributed to the new technology that has been applied to provide solutions. This applied technology will continue to improve the efficiency of refrigeration equipment for the future. The improved efficiency will have a great environmental affect on climate change as we replace older equipment and lower the consumption of power generated from fossil fuel burning plants. Carbon dioxide and nitrous oxide generated by burning these fuels account for over 55% of the emitted greenhouse gases.

Type Of Equipment

Old Installed Chillers:

New Chillers:

Hermetic
Motor
Driven

Open
Drive
Motors

Hermetic
Motor
Driven

Open
Drive
Motors

Negative Pressure
(operating below atmospheric pressure in cooler)

15%

17%

0.5%

1 - 2%

Positive Pressure
(operating above atmospheric pressure in cooler)

8%

10%

0.1%

1 - 2%

Source: Input discussion with ARI



HFC-134a is a positive pressure refrigerant, which when applied to chiller refrigeration requires that the pressure vessel be built to a national pressure code (ASME Section 8)2 and every step in the construction must be inspected by third party insurance companies. As a result of the stringent testing and applied technology, chiller leak rates can be lowered to less than 0.1%3 annually. Existing chillers have a leak rate of 2 - 15%. HFC-134a also has a small molecular mass than the past CFCs and HCFCs. This is an important feature as it results in an overall product size that is 35 to 40% smaller. This size reduction helps offset the cost of construction and facilitates the use of smaller interconnecting pipes. This advantage has led to adding isolation valves to the chiller piping connection so the HFC-134a can be stored in the chiller during service. This feature allows the end-user the option of never having to remove the refrigerant from the vessels once charged -- A true "no emissions" feature.

The smaller size and ability to design chillers in a bolt together modular form means the equipment has less impact on the building environment when replacing existing equipment. Knocking holes in buildings, digging up parking lots and disposal of the scrap can be eliminated when you can fit the equipment through the standard entrances. The oil used in the chiller is a waste material which is reduced by use of HFC-134a. HFC-134a lacking the chlorine element does not use mineral oils in the system as CFCs and HCFCs do. The oil used is synthetic and has superior properties to the older oils. Where a CFC or HCFC chiller design would require the oil to be changed yearly and dispose the oil as waste, the HFC-134a chiller may run for four to five years before a scheduled oil change. New technology being applied to HFC-134a may eliminate the need for any oils in future equipment, as designs may use the refrigerant (HFC-134a) as the lubricant.4


SAFETY GROUP Per ASHRAE 34
(with examples)

High
Flammability

A3

B3

Low
Flammability

A2
R-406a

B2
R-717

No Flame
Propogation

A1
R-11, R-134a, R-410a

B1
R-123

 

Lower Toxicity

Higher Toxicity

Safety is always a concern with the use of refrigerants5. Some of the commercial refrigerants that are in use have proven to be quite toxic when misapplied6. HFC-134a is probably one of the safest refrigerants in application. With the high quality of containment design and the low toxicity properties, HFC-134a results in a product that service technicians can be exposed at minimized risks. HFC-134a is the leading propellant in respiratory inhalers (metered dose inhalers).7 A person can actually breathe the refrigerant without the body metabolizing the refrigerant.

Is HFC-134a a perfect refrigerant? There are no perfect refrigerants but HFC-134a is definitely an "ideal" refrigerant in application. As we continue to apply technology, HFC-134a will be the refrigerant of choice for chillers.

Jim Parsnow is Director Of Environmental Marketing for Carrier Corporation and can be contacted at 315-433-4376 or by e-mail: jim.parsnow@carrier.utc.com




References:
1. Alternative Refrigerant Choices: Limited But Promising -- J.R. Parsnow, 11/97
2. ASME Pressure Vessel Code Overview, Carrier Catalog Number 819-054
3. Carrier Press Release, Baltimore, June 12, Carrier Positive Pressure Chillers Attain 0.1 Percent Leak Rate
4. May, 1996 ASHRAE Journal -- New Bearing Has HVAC Implications
5. ASHRAE 15-1994: Safety Code For Mechanical Refrigeration -- available from ASHRAE
6. Lancet Medical Journal Epidemic of Liver Disease Caused by Hydrochlorofluorocarbons 23; August, 1997 issue
7. 3M Health Care Announces Use of HFC-134a In Meter Dose Respiratory Devices UNEP IE 	 Ozone Action Newsletter

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