The change to sustainable temperature control

The change to sustainable temperature control?

In everyday life, hydrocarbon gases are in commonly used in houshold environments. Just think about gas powered central heating, water heaters and cooking stoves.Or propane gas bottles, used in caravans and barbecues. In temperature control technology, natural hydrocarbons are also used as climate friendly refrigerants.

Which refrigerant?

The decision on which refrigerant to use in a temperature control unit is a complex engineering decision. It is a compromise between different factors: it must be compatible with the other materials used in the refrigeration circuit such as the copper piping or lubricant in the compressor, be energy efficient and have the properties required for it to function as an effective refrigerant over the required temperature range.
Previously, refrigerants used met all of these criteria but were shown to be harmful to the ozone layer and contributed to global warming. The EU F-Gas Regulation limits the use of these environmentally harmful refrigerants. Modern refrigerants need to have the same energy efficiency while respecting the environment. Natural refrigerants are the answer. Peter Huber Kältemaschinenbau, an innovator in the refrigeration technology, has tried to and succesfully implemented the use of hydrocarbons in their temperature control systems for many years.

Eu F-Gas Regulation

‘Older’ refrigerants contained Chlorofluocarbons (CFC’s) and Hydrochlorofluorocarbons (HFC’s), which are non-flammable and possess excellent thermodynamic properties. Yet these fluorinated gases were shown to be harmful in that they have high ‘Ozone Depletion Potential‘ and high ‘Global Warming Potential’.
The objective of the Eu F-Gas Regulation is to drastically decrease the amount of refrigerant released every year to 21% in 2030, with 2015 serving as baseline (100%). Parallel to the phase down, additional GWP (Global Warming Potential) limits are set for various applications, such as stationary refrigeration systems, with an exception for devices working below -50°C.

Alternative refrigerants

Already in the early 1970s, company founder Mr. Peter Huber started researching and using natural refrigerants. In the following years, Propane R290 and Propene R1270 have been used as a standard refrigerant in many units. These refrigerants have zero ODP and a low GWP. Some users are a little sceptical about natural refrigerants due to their flammability but Huber AG can look to historical records that involve (literally) thousands of units sold over a period spanning almost 40-years with not a single incident to confidently state that the use of the environmentally friendly natural refrigerants is safe.
The compact chillers (Unichiller, Minichiller), process circulators (Petite Fleur, Tango) and cooling circulators (KISS, Ministat, etc.) have been filled as standard with Propane R290 or Propene R1270 for many years. The refrigerant filling level on these models is less than 150 g, which usually requires no safety precautions. Even larger temperature control systems, such as the Unistat 610w with a capacity of 2.2 kg, are available on request with natural refrigerant. In this case, measures on the part of the operator to comply with standard laboratory safety regulations are necessary.

In the current climate, there are no real alternatives to natural refrigerants. While new Hydrofluoroolefins may have a lower impact on the global warming potential, they are also combustible, meaning the same risk assessment must be made. Overall, the refrigeration industry has little option but to increase the use of flammable refrigerants in order to achieve the climate protection goals.
With the uncertainty of synthetic refrigerants’ future, it becomes essential to think about the long term when purchasing a temperature control unit. Bearing in mind possible availability problems and price peaks, natural refrigerants will probably ensure that your systems can still be operated and maintained in the future.

Refrigerant R290 in practical use

In practice, natural refrigerants have significant advantages over their synthetic derivatives. The refrigerant R290 has very good thermodynamic properties. Advantages include low pressure losses in pipelines and heat exchangers, low energy consumption during compression, lower amounts of refrigerant required and good material compatibility. The operating performance is even better than that of R507A, R404A and the replacement refrigerant R449A. The disposal of R290 is also easier than that of synthetic materials. Since propane is a natural substance, it can be discharged into the atmosphere in a controlled manner.
Using a Petit Fleur process circulator on a 2 litre glass reactor, Huber conducted a research on the performance of R290. With its 0,48kW cooling capacity, the circulator covered a +100 °C to -20°C of the mantle within 70 minutes, showing stable and precise curves.

The next step: CO2 as a refrigerant

With the presentation of the new Unichiller CO2 model range in 2018, Huber took the next step in the development of environmentally friendly temperature control solutions. The new chillers use CO2 (carbon dioxide, also R744) as refrigerant. This colourless gas liquefies under pressure, has a neutral ozone depletion potential and a negligible global warming potential. A disadvantage is the high operating pressure but this has been addressed through the engineering expertise of Huber AG.

The component prices are currently higher than for conventional refrigeration systems owing to the unavoidable increased thickness of components to operate under the pressures required to use CO2. The market share of CO2 refrigeration systems has been growing rapidly for years, which bodes well for availability and competitive pricing. The thermodynamic benefits of CO2 as well as the good availability and safety speak for themselves and enable future-proof planning.

Conclusion

Natural refrigerants are the future. No matter what needs to be temperature controlled or cooled in the laboratory: from distillation apparatus through the analyser to the research reactor, natural refrigerants contribute to a positive environmental balance. There are no limitations in terms of performance and the safety concerns are unfounded as can be seen in the common domestic use of these gases as well as the historical record.
When choosing a temperature control unit, users should keep in mind that the unit will be in use for many years. During this time, the refrigerant has a significant impact on energy consumption. A choice of refrigerant based on sustainability eliminates the need for subsequent, costly retrofits and protects against additional investment due to new regulations and laws.

So, if you want to invest in your future, both environmentally and economically: