Which hydrocarbon refrigerant is approved for retrofit into existing household refrigerators?
a) HC R-600A 2 ounces or less
b) blended HC R-441A
c) HC R-290 1 lb. or less
d) Hydrocarbons are not approved for retrofit applications
Answer: The correct answer is option a) HC R-600A 2 ounces or less.
Explanation for HC R-600A (Isobutane) – 2 Ounces or Less
a. HC R-600A (isobutane) is a hydrocarbon refrigerant widely recognized for its high efficiency, low environmental impact, and excellent thermodynamic properties. It is commonly used in small, sealed refrigeration systems, particularly in household refrigerators and freezers.
b. When it comes to retrofitting existing household refrigerators, R-600A is approved in some cases under strict guidelines:
1. Safety Limit (2 Ounces or Less):
R-600A is highly flammable, so its use is restricted to small quantities—typically 2 ounces or less. This small charge ensures the refrigerant remains within safe operational limits to mitigate the risk of fire or explosion.
2. Retrofitting Considerations:
a. Compatible Equipment: The existing system must be evaluated for compatibility with R-600A. It requires modifications to handle the refrigerant’s pressure and flammability.
b. Lubricant Compatibility: Mineral oil or synthetic lubricants compatible with hydrocarbons are necessary.
c. Regulatory Compliance: Retrofitting must comply with regulations, like those of the EPA in the U.S., which may impose restrictions.
3. Environmental Benefits:
a. R-600A has an ultra-low Global Warming Potential (GWP) of 3.
b. It is ozone-friendly, with zero Ozone Depletion Potential (ODP).
4. Common Applications:
While retrofitting with R-600A is less common, it is prevalent in new refrigeration systems designed to safely use hydrocarbons.
Note: Always follow local laws and manufacturer guidelines when using or retrofitting with hydrocarbon refrigerants, as improper handling poses safety hazards.
