Moving Forward with Natural Refrigerants

Natural refrigerants. We hear this phrase a lot, and many people may not know what this even means. Natural refrigerants are fluids like Ammonia, Carbon Dioxide (R744) or a variety of Hydrocarbons (R290, R600a). Now, these fluids aren't especially 'new', they have been in use since the inception of Vapour-Compression systems were invented.

So, you may ask, "Why do we need these refrigerants when our current refrigerants work completely fine?". I'm glad you asked, many refrigerants currently in use today can have a terrible impact on our environment when either not handled properly, or in the event of a refrigerant leak. Every refrigerant has what is called a GWP (Global Warming Potential) & ODP (Ozone Depleting Potential).

GWP measures the amount of heat trapped in the upper atmosphere relative to CO2, for example, if a refrigerant had a GWP of 1,250, over 100 years 1,250 times more heat would be trapped then the same amount of CO2.

ODP is the ratio of ozone destroyed by a certain mass of refrigerant relative to the same mass of R11, which has a reference of 1. For example, if a refrigerant had a ODP of 10, it would destroy 10 times more of the ozone layer per mass unit.

Luckily for us, refrigerant manufacturers are constantly looking at ways to improve these figures. For decades, most countries involved in the Montreal Protocol have a duty to reduce harmful refrigerant imports every year. In Australia, current refrigerants will be almost entirely phased out within the next decade. This means that the time for retro-fitting older sites needs to be a serious thought in a consumer's mind, or when designing a new system, the equipment selected is future-proofed for this 'phase-out'.

This is where natural refrigerants will come in to play. Apart from the lower environmental numbers, they also rival current refrigerants in terms of performance. For example, Ammonia has a fantastic volumetric cooling effect, resulting in lower mass flow required (less compressor work required to achieve the same cooling result). R744 has a nominal density 4-5 times greater then previous refrigerants (R134a, R404a etc.), resulting in smaller pipework across your site, saving you money.

The forementioned points of performance are great, but I should mention some of the drawbacks. Ammonia is toxic and requires automatic leak detection with stringent safety requirements. R744 is an inert, odourless, non-flammable gas which can be deadly without the right protection methods (Leak detection, automatic system shutdown & isolation). Like anything though, nothing is perfect, but we can control the risks of these natural refrigerants.

Consumers and refrigeration companies alike should be mindful of this push to alternative refrigerants over the next decade. Replacing existing systems sooner will provide a safer, smarter and cleaner way forward for your business and equipment.