In our last post on the subject of the 2019 EPA changes to refrigerants, we pointed out that the HVAC and refrigeration industries faced three specific design challenges as traditional refrigerants are phased out starting in 2019: efficiency, chemical compatibility with seals, and reducing leaks. Fortunately, there are seal solutions and polymer materials that can address all three of these issues -- which happens to the topic of this blog post.
Impact of Seals of Efficiency and Leaks
Seals are the primary factor that controls leaks in any kind of system that involves fluids and gasses. In addition, seals have a major impact on the efficiency of HVAC and refrigeration: if the refrigerant leaks and levels begin to run low, the system will not be able to maintain the desired temperatures effectively.
Chemical Compatibility and Seals
The materials used for seals in refrigeration systems must be compatible with the more chemically aggressive refrigerants that will be used in order for the seals to support maximum efficiency while minimizing leaks. There are polymeric materials which are compatible with some of the more aggressive refrigerants that will be used more in the coming years.
Polyketone is not one of the more commonly used seal materials, but it has been making a comeback in recent years. As a high-performance polymer, it offers excellent chemical resistance, high-temperature performance, outstanding wear resistance, and improved impact strength. The fact that it is eco-friendly is yet another plus for polyketone.
Polyvinylidene Fluoride (PVDF)
PVDF (perhaps better known by its trade name Kynar®) is another polymer that is not often associated with seals but offers many of the characteristics that engineers look for in refrigerant seals. For example, it performs extremely well with some of the most chemically aggressive refrigerant materials on the market right now. PVF is considered an engineering polymer and its outstanding properties include:
- resistance to creep and cracking
- good impact strength
- excellent overall strength
Note that PVDF is also recyclable, making it another eco-friendly option.
Fluorosint® 500 PTFE
Another excellent material option is Fluorosint® 500 PTFE, which retains the basic properties that have made PTFE such a popular choice while improving on other aspects. These improvements include:
- greater resistance to deformation under load
- better wear characteristics
- a lower thermal coefficient of expansion
It remains extremely resistant to a wide variety of chemicals, including many of the more aggressive refrigerants.
Fluorolon 1065 is another strong option that competes with those above in terms of quality, compatibility and price. A modified PTFE compound, Fluorolon 1065 is offered by Advanced EMC Technologies.
Changes the EPA is making to refrigerant requirements will result in the use of alternative refrigerants that can make it challenging to minimize leaks and maximize efficiency. A well-designed seal, on the other hand, can help solve both those problems. However, because these refrigerants may not be compatible with standard traditional HVAC seal materials, new material options such as PK, PVDF, Fluorosint® 500 PTFE and Fluorolon 1065 need to be considered.
Did you miss Part 1 of this series? Read it here: