compression systems for refrigeration, a/c, heat pumps, chillers and similar systems. There are four levels of flammability classification. Materials such as R134A and R410A are non-flammable and fall into the first category. Mildly flammable material is classified as A2L and this includes such materials as R1243yf and R1234ze. R1234ze has a GWP of 7, is non-toxic but some special conditions apply. It is only flammable above 30°C.

Moderately flammable is classified as A2 and includes R152a. The A3 classification includes many of the natural refrigerants such as isobutane and propane. There are further classifications, B2L, which combine flammability and toxicity – ammonia is a very efficient, high performing refrigerant with a zero GWP falls into this category as it is mildly flammable and toxic. There are no B3

The search for altern refrigerants.

ative refrigerants is at

different stages across the globe. One of the most talked about refrigerants is R32, a mildly flammable material offering a replacement for R410A in new equipment. Its GWP rating is much lower than R410A with a GWP of 675

as opposed to 2088, and it is more energy efficient.

R32 is suitable for air conditioning and

heat pump applications but already it is being regarded as an interim material such is the pace of development. Last summer, Honeywell announced a non-flammable alternative, Solstice N41 or R466A. But even this is being regarded as a medium-term solution. Other refrigerants include the A2L-rated

R1234ze and A1-rated R448A (Solstice N40) which have low GWPs and were developed to replace the HFCs R134A (popular in small equipment such as foams, aerosols and refrigeration) and R404A (used in new installations) respectively. Due to their efficiencies, some of these refrigerantss require a larger footprint – so there needs to be some consideration given to the design of the system when replacing equipment, as larger chillers may be required.

But does a lower GWP refrigerant means increased flammability? Pavel Makhnatch of Stockholm’s Department of Energy Technology explains: “For many refrigerants, GWP and flammability levels are inversely related. Lowering the GWP intrinsically means that the substance is less stable and its reactivity

increases. The physical characteristics of the chemicals make this unavoidable.” As the industry invests in lower GWP refrigerants, more equipment will come onto the market that relies on the use of flammables. A2L refrigerants are the most likely replacements for A1 refrigerants which are currently used in the majority of commercial and residential applications. Flammables that are already in use include, ammonia (both flammable and toxic) and high-pressure CO2 systems. The former is used in industrial and commercial refrigeration, a/c chillers as well as leisure centres (ice rinks in particular) and sited primarily in machine rooms or outdoors.

CO2 has been embraced by the supermarket sector as well as commercial refrigeration systems and industrial applications.

All refrigerants can be safe if standards and the safety guidelines are followed.

Every type of refrigerant comes with its own set of challenges. To stay at the forefront of greener cooling, product and component manufacturers must continue to innovate as refrigerants are going to be an essential part of the HVAC landscape for quite some time.



Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72