Natural Refrigerants

As Man made climate change are an increasing threat for our future, regulation of the CO2 emissions are on the top of every governments agenda.

Not a Cool Story

The History of Refrigerants

The chemical refrigerants used for air conditioning and refrigeration systems have played a major part in the increased CO2 levels in the atmosphere since the 1930's, and has been regulated more strictly throughout the years. CFC, HFC and HCFC, are already or on its way of being phased out.

This phase out started with CFC, a very strong Ozone layer depletion chemical decided phased out in the Montreal Protocol in 1987. 10 years later the New CFC replacement chemicals, the HFC turns out to be a major contributor to the green house effect due to its properties equivalent of up to 14.800 kg (R-23) of CO2 pr kg HFC. In the Kyoto agreement of 1997 it was then decided also to phase out the HFC chemicals.

For replacing the HFC, yet another chemical cocktail was introduced, the HFO*, that is in basic design a HFC with at least one double binding of the Carbon atoms. Later science reports suggests that some of these new HFO* chemicals like the R1234yz are a potent source of spreading the extremely acidic TFA (Trifluoroacetic acid) as it degenerates in the atmosphere. Others, like the R1234ze seems to be forming a large portion of R23 (GWP of 14.800) in the degeneration process.

Latest findings suggests a future HFO* ban may come faster than we think, as 5 European countries now have suggested restrictions in use of a major chemical component found in HFOs*.

Natures own refrigerants

Ever since the German breweries in the early 1800's needed cooling for their beer brewing processes, Natural refrigerants has been used for evaporating compression cooling systems. From the 1930's and forward, chemical mixtures of various Chlorofluorocarbons was introduced as "safer" refrigerants. At that time the Natural refrigerants like Ammonia (R714), CO2 (R744), Propane (R290), even Ether was used.

The motive for introducing the Chlorofluorocarbons was related to the operational safety of the natural refrigerants systems back then. As all of the above gases was either toxic, flammable, or was operating with a high working pressure - CO2 the latter. As opposed to the new chemical product, that lacked these handling issues.

Back then the technology was far less developed in regards to handle these issues of danger that natural refrigerants posed, and accidents tended to happen frequently.

In the 1980's scientists discovered a major depletion of the Ozone layer, causing large holes in the protective layer around our globe. The sinner was quickly identified, the Chlorofluorocarbons escaping from refrigeration systems due to leakages or from accumulated in the atmosphere.

At that time the Norwegian professor Mr. Gustav F. Lorentzen at NTNU had been looking into the use of natural refrigerants since the early 1950's. His first patent was introduced in 1988, a CO2 based AC system for the automotive market. Gustav's words back then still stands strong: "why risk yet another chemical refrigerant when we have the technology to utilize natural refrigerants in all applications"

Going forward with the HFO's, we are most lightly walking straight into the next disaster and a future ban as the number of science reports on the environmental impact these chemical cocktails represents are piling up. Special attention needs to be payed to what we simply do not know, yet.

As an act of precaution none of Winns's technicians are allowed to preform any work on systems containing HFO's until the gaps in the safety datasheets are filled.

How can CO2 be used to reduce CO2 emissions?

Lets look at the facts that you need to understand about CO2: 

CO2 is a Natural occurring substance contributing to the Global Warming, used as unit of measure for other non-natural substances in regards to the Global Warming Potential GWP. A GWP of 1 equals 1 kg of CO2.

So, if a substance has a GWP of 4000, 1 kg of the substance is equal to 4000 kg of CO2 in global warming  potential, it traps 4000 times more heat energy in the atmosphere than CO2.

Chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs),              perfluorocarbons (PFCs), and sulfur hexafluoride (SF6 used in power breakers) are sometimes called high-GWP gases because, for a given amount of mass, they trap substantially more heat in the atmosphere than CO2.

The GWPs for these gases can be in the thousands or tens of thousands. These are the gases used as refrigerants over the years.

But, CO2 are also a substance with fantastic thermal properties when used as refrigerant. Instead of using a refrigerant with high GWP, Winns use CO2 in our systems.

Lets compare: A typical refrigeration system contains 50 kg of a typical "lower GWP" HFC gas like R134a, this gas has a GWP of 1480, if this is leaking out of the system, the atmosphere have to deal with the equal of 74.000 kg (74 metric tons) of CO2, and this is not a very big refrigeration system.

Imagine that, only 50 kg R134a turns into 74 metric tons of CO2 in worth of damage to our planet. If it was R404a instead of R134a, the figure would be 200 metric tons of CO2.

But, What if we use CO2 as refrigerant in a same size system? Well, 50 kg CO2 is 50 kg, compared to the insane figure 74.000 or even 200.000 kg.   

So, as an owner of a HFC based refrigeration system, what should you do to avoid future bans and phase outs? Looking at the chemicals the scientists are clear: There are no more gas combinations available in the periodic system suitable for the compression refrigeration cycle except for the ones already used in HFC's or HFO's.

There is not going to be a magical drop-in replacement.

Looking at these facts and figures, any excuses for not choosing a natural refrigerant system like CO2 systems should be seriously reconsidered.

Myths and excuses for not choosing CO2
  • It is a virgin technology: No, Since the middle of 2000 CO2 systems has been used in supermarkets, first in the Nordic countries, and are now found world wide. If you walk into a grocery store in Norway today it is a 90% chance that CO2 is the refrigerant keeping your milk cold.
  • Higher investment costs: Yes, due to the higher working pressure ratio of CO2, the components are more expensive, but also more robust and has a substantial lower maintenance cost and longer lifetime. The investment also ensures that you don't have to replace your system in the near future due to phase-out of the refrigerant.
  • It's dangerous: No, CO2 is non-toxic, non-flammable and non-explosive, safety group A1. Although it has a slightly lower detection threshold compered to other refrigerants due to its properties in very high concentrations. Other chemical refrigerants are oxygen displacing, whilst CO2 effects the breathing.
  • To big compressors and pipes: No, in fact the thermal properties of CO2 requires much smaller tubing than a conventional refrigerant like the R134a.
  • It does not fit my application: Yes it probably does, there are few refrigeration or heating application not suited for our systems.
  • Its not as effective: For most offshore installations it will be at least as effective as conventional, pending type of application.
  • To high maintenance cost: No, experience with these systems over the last decade shows the opposite, CO2 systems are more rigid and has stronger constructed components and piping compared to conventional systems due to the higher operating pressure of CO2.
  • Availability is low: No, CO2 systems spares are on the shelf world wide, it is more than 30.000 of these systems running W.W. PT.
  • There is going to be a drop-in replacement refrigerant available soon: No, All the combinations in the periodic system is used, there is no future refrigerant that can replace the HFO's with out the environmental impacts. Only NatRefs, like: Ammonia R717, Water R718, Hydrocarbons R270, R290, R600..., and finally CO2.
*These are HFO's
  • R1233zd (AKA Solstice zd)
  • R1234yf (AKA Opteon YF and SOLSTICE 1234yf)
  • R1234ze (AKA SOLSTICE 1234ze)
  • R448A (AKA Solstice N40)
  • R449A (AKA Opteon XP40)
  • R450A (AKA Solstice N13)
  • R452A (AKA Opteon XP44)
  • R452B (AKA Solstice L41y)
  • R454A (AKA Opteon™ XL40)
  • R454B (AKA Opteon™ XL41)
  • R454C (AKA Opteon XL20)
  • R455A (AKA Solstice L40X)
  • R469A (AKA WT-69)
  • R513A (AKA Opteon XP10)
  • R515B (AKA Solstice N15)

These are HFC's
  • R23
  • R32
  • R134a
  • R152a
  • R227ea
  • R236fa
  • R245fa
  • R404A
  • R407A
  • R407F
  • R407C
  • R410A
  • R413A
  • R417A
  • R422A
  • R422D
  • R427A
  • R437A
  • R438A
  • R507A
  • R508B