Tag: hcfc

 

Graphic Courtesy of Danfoss

The week of 9/18/2017 Danfoss put out a lot of great information on global changes to refrigerants and the impact this will have on equipment and the industry.

This a quick overview of the different types of refrigerants, the reasons for the changes and some things to watch out for.

ODP & GWP 

When I went to trade school in the 90’s, all the talk about refrigerant regulation stemmed around the destruction of the Ozone layer by CFC (Chlorine, Fluorine, Carbon) refrigerants like R12 and HCFC (Hydrogen, Chlorine, Fluorine, Carbon) refrigerants like R22. The likelihood that a particular chemical would break down Ozone in the stratosphere was designated by an ODP (Ozone depletion potential) number. The worst offender was R11 and it was the benchmark for ODP with a rating of 1. Other refrigerants like R12 and R22 had a lower ODP than R11 but still had the potential for Ozone depletion.

Over time these CFC and HCFC  refrigerants have slowly been phased out in the developed world, starting with Europe and moving on to the USA and many other countries.

The attention of the scientific and regulatory world has now shifted to considering the emission of greenhouse gases like methane and carbon. Scientists have studied the effects these gases have on global climate and have concluded that they contribute to global warming.

The term used to identify how much a particular gas contributes to global warming is GWP (Global Warming Potential). The number starts at 1 with Carbon Dioxide (CO2) and goes up from there with common modern HFC (Hydrogen, Fluorine, Carbon) refrigerants like R410a and R404a both having zero ODP but high GWP numbers.

Because of this, manufacturers like Danfoss have looked carefully at alternative refrigerants by looking at new technologies as well as some refrigerants that have been around for a very long time.

HC (Hydrocarbons)

The hydrocarbon category contains FANTASTIC refrigerants with excellent heat transfer, pressure/temperature, and oil miscibility. The only problem is they are all flammable. These include R290 (Propane), R600a (Isobutane), R1270 (Propylene) and even some uses of butane and ethane in refrigerant blends. These refrigerants are already being used in some small, self-contained units like soda machines and water fountains. They have zero ODP and very low GWP. Read more from Danfoss on HC refrigerants.

Naturals

Natural refrigerants were the earliest refrigerants used. Starting with Air and Water and then moving on to Ammonia and Carbon Dioxide.  All of these refrigerants are inexpensive with little to no GWP and they all can be used as a refrigerant.

Water and Air have never been economically viable when compared to other refrigerants based on the power input to BTU output.

Carbon Dioxide has a low critical point making it fairly well suited for colder climates and low-temperature equipment but posing some challenges in areas with higher outdoor temperatures.

Ammonia is arguably the best refrigerant available but it is highly corrosive and toxic, making it a real safety risk.

HFO ( Hydrofluoroolefin)

HFO refrigerants have a similar makeup to HFC’s but they are formulated to break down more quickly, greatly reducing their chances of making it to the upper atmosphere. Because these refrigerants are new and, still contain Fluorine (a limited natural resource) the production costs are high. Currently, R1234YF is the most commercially available HFO and is being used as a replacement for R134a (HFC) in refrigeration and automotive applications.

Recent Changes

Just last month on 8/8/17  the United States court of appeals struck down an EPA phaseout of HFC refrigerants under the Clean Air Act on the basis that the Clean Air Act only gave the EPA the right to regulate Ozone depleting substances. This decision is likely to be appealed further. This case could have a wide ranging impact on HFC regulations for the next several years, but those in the know suggest proceeding as planned due to the likelihood that HFC phaseout is still on the horizon.

Danfoss did some excellent interviews with Zack and Ralph from the HVAC Shop Talk podcast that you can hear below

 

In this episode of the podcast Jeremy Arling from the EPA comes on and answers some common questions about the new rule changes that affect recovery, leak repair, record keeping and evacuation on HVAC and refrigeration systems. You can find the complete rule update HERE
a
s well as Jeremy’s presentation slides HERE as well as a quick sheet for technicians HERE

If you want an app to help you keep record of recovered refrigerant I would suggest looking at the R-Log app HERE

If you have an iPhone subscribe to the podcast HERE and if you have an Android phone subscribe HERE

graph

There are all sorts of complicated refrigerant acronyms.. HFC, HCFC, CFC and well as the mythical Zeotropic, Azeotropic and near Azeotropic… Let’s simplify

CFC = Refrigerant that is really bad for the Ozone. They are almost all gone. R-12 and R-11 are examples

HCFC – Refrigerants that are bad for the Ozone but not as bad as CFCs. Most common is R22.

HFC – Refrigerants that aren’t bad for the Ozone but they do add to global warming through the greenhouse effect. Most common is R410a.

When it comes to the whole zeotropic, azeotropic thing the main thing you need to know is that older refrigerants were often just one type of molecule. That meant that they condensed and evaporated consistently and it didn’t matter if you added them to the system via vapor or liquid. These simple refrigerants were known as PURE refrigerants.

Today we mostly work with HFC and HCFC blends. These blends can be Azeotropic, which means they blend together and act as one refrigerant or Zeotropic which means they have “glide” resulting in different boiling and condensing temperatures of the refrigerants mixed in. Rubber meets the road in a refrigerant with high glide when you need a separate “condensing” and “boiling” termperatures on the PT chart. R407C is an example of a high glide zeotropic refrigerant where R410a has nearly 0 glide. While R410a is TECHNICALLY zeotropic is is so close to being Azeotropic that the industry coined the phrase near-azeotropic.

In all blends you must charge the refrigerant as a liquid to prevent the refrigerants from separating in the vapor state. As always, when charging liquid in the suction line, add it slowly and carefully, allowing all the liquid to boil off before entering the compressor to prevent flooding / slugging.

— Bryan

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