This can be a big challenge but it can preserve the lifespan of the system and minimise carbon footprint.
Interview with Emilie Kugener, Corporate & Web Communication Manager with Pierre Emmanuel Danet, Technical Support Manager at Climalife.
Indirect cooling systems are on the rise, why are they an interesting solution for the manufacturing and preservation of food products ?
P-E. D. : Heat transfer fluids (HTFs) provide a solution to the requirements of F-Gas. The design of an installation with a secondary circuit makes it possible to reduce the refrigerant charge, contain it and be able to use fluids with very low environmental impact, such as ammonia in the food industry, for which use is regulated.
Is there a heat transfer fluid for each application and how should it be selected ?
P-E. D. : The heat transfer fluid is formulated based on glycols (MEG, MPG), 1.3 propanediol, betaine, etc. to which corrosion inhibitors are added. The coolant is diluted according to the desired freezing point. Each application is unique and it is important to analyse all the possible solutions before making a selection, which is why Climalife offers an all round offer. The choice of a coolant depends on the temperature required for the process. Ice cream production, freezing tunnels, meat production, packaged food, etc. can be affected by heat transfer fluids at low or very low temperatures.
In order to meet these needs, we have developed Greenway® Neo, based on bio-sourced 1,3-propanediol, which combines performance and sustainable development. We also offer Temper, based on potassium acetate and formate, which covers very low temperature applications (down to -60°C at freezing point) due to its low viscosity. Finally Friogel® Neo (MPG based) which is commonly used by the big names in the food industry.
Can the heat transfer fluid be considered as a food additive ?
P-E. D. :No, a heat transfer fluid is not a food product. Where food is being produced, we recommend an installation is designed to avoid contamination of the production by the HTF. Because the precautionary principle is necessary, and even if the process does not bring the food into direct contact with the fluid, it is dangerous to use Mono Ethylene Glycol (MEG) heat transfer fluids in food because they are harmful if ingested. Indeed, some manufacturers believe that there is no proven danger and choose MEG-based solutions at about 40% less cost than other non-hazardous heat transfer fluid bases. However, we know that the heat transfer system can suffer undetected leaks related to corrosion or other causes with serious consequences in this sector of activity.
In the event of leakage, contamination or contact of a coolant with a food product, even if the product is not classifed as toxic under the regulations, any contamination of a food product renders it unfit for consumption.
The contaminated food product must be withdrawn from the market and destroyed regardless of the approval of the coolant.
Do heat transfer fluids contribute to reducing environmental impact ?
P-E. D. : Yes, the nature and characteristics of the HTF will have an impact on production efficiency. This is particularly true for those that combine low viscosity and non-fossil origin. The size of the pumps is reduced, electricity consumption is reduced, so they contribute to improving the energy efficiency of an installation.
For example, Greenway® Neo can be used for temperatures down to -50°C its lower viscosity than MPG increases efficiency and reduces energy consumption. In addition, for ISO 14000 certified companies, the Greenway® Neo vegetable based HTF is ideal. The main ingredient of this fluid, bio-sourced 1,3-propanediol, shows a 42% reduction in greenhouse gas emissions and a 38% reduction in energy consumption during its manufacture compared to a conventional HTF.
And for refrigerants, is there also a fluid for each application? How do you make the right choice?
P-E. D. : There are different types of molecules on the market. There is no single solution that covers all food production and preservation needs. However, when designing a new refrigeration installation, the refrigerant must be selected taking into account the technical, economic and environmental parameters according to the cooling production needs. Contained facilities reduce environmental impact.
Several criteria must be considered when choosing the most suitable fluid, in particular :
- the GWP of the fluid,
- refrigeration production,
- energy efficiency,
- the use of the chosen fluid,
- safety,
- the return on investment.
Can you give us some examples of fluids and applications ?
P-E. D. : Of course. Solstice® N40 (R-448A) is the alternative for existing installations using R-404A / R-507A refrigerants widely used in the food industry. With a GWP of 1387, it is suitable for medium and low temperature refrigeration installations in cold stores, for deep-freezing, for preparation areas and for the preservation of frozen products.
For new systems in medium and low temperature refrigeration, we recommend Solstice® L40X (R-455A) which is the solution with the lowest GWP (<150) on the market. This fluid has a better coefficient of performance. Several studies in the sector have shown that this refrigerant allows efficiency gains of at least 6% for low temperature refrigeration applications. From a safety point of view, the R-455A is classified as having very low flammability. Its flammability range is only 1.1% and it is non-toxic, which is an interesting advantage over B2L ammonia, which is frequently used in food processing applications.
Finally, to replace R-134a in new installations in chill refrigeration and air conditioning applications, Solstice® ze (R-1234ze) is a very low GWP (<1) HFO.
It offers good performance for a reduced environmental impact. The temperature range covered by R-1234ze is much wider than that of R-134a (it covers a spectrum from -20°C to +110°C), which makes it possible to consider new applications in the food industry such as vegetable bleaching, for example, by heating water above 85°C.
In conclusion, what solutions do you recommend to optimise the energy efficiency of food processing installations ?
P-E. D. : From a pure energy point of view, direct expansion circuits, equipped with an efficient leakage and energy monitoring system, will be the most efficient. The choice of fluid should be made according to its volumetric refrigeration capacity, operating regime, ambient conditions, production, or storage. Working pressures will also be considered (lower pressure will result in lower consumption and reduce the risk of leakage). From this perspective, HFO-based mixtures are interesting.
Indirect systems will consume more energy due to losses related to intermediate exchange and pump consumption. This is why it is important to choose the coolant with the best thermal capacities and the lowest viscosities. And just as for fluids, the safety/toxicity aspect of the heat transfer fluid used must be taken into account in compliance with regulations and implementation recommendations.
Find our case studies on our website :
Heat Transfer Fluid Greenway® Neo saves energy: a demonstration.
Danone reduces its carbon footprint with Greenway® Neo heat transfer fluid.