Glycols and Brines

The application thresholds of water can be expanded to -50 °C up to 170 °C using glycol or brine (pressure compensation is required from approx. 110 °C depending on the water content). The excellent thermal properties of water are only slightly compromised. In addition, a modern additive technology leads to good corrosion protection and improved thermal stability.


Variants of cooling brines and glycols

There are two types of glycols: monoethylene and monopropylene glycol (MEG and MPG). Both are miscible with water in any ratio, i.e. water glycol mixtures do not separate. Frost protection can be achieved down to -50 °C depending on the water concentration. The inhibitors protect any commonly used metallic materials. However, zinc-plated parts should be avoided, as zinc particles can be released and cause damage in the system.

All FRAGOL glycols are free from silicates, nitrites, nitrates, phosphates, borates and amines. They are readily biodegradable and classified as water hazard class 1 (slightly hazardous to water).

When talking about industrial frost protection, the most common one is MEG. MEG is classified as a hazardous substance and may not be used in systems where the medium may come into contact with the drinking water circuit or any foods. All required precautionary and safety measures in the Safety Data Sheet must be observed when handling.

MPG is used in the food industry as frost protection in heating and cooling systems as well as in solar and heat pump systems.

For the high requirements in the food industry, FRAGOL offers FRAGOLTHERM® W-PGF and Zitrec® F, two clear, colourless and almost odourless heat transfer fluids based on propylene glycol in USP/EP quality.

FRAGOLTHERM® W-PGF and Zitrec® F are HT-1 approved by NSF. In addition, FRAGOLTHERM® W-PGF is certified Halal and Kosher. HT-1 classification means, that the product may be used in applications with possible unintentional food contact. It does not mean, however, that it may be used as a food component or as an additive.

The frost protection of a water glycol mixture may be checked with a commercially available antifreeze tester, but ensure that the tester is only used for MEG or MPG respectively.



Salts such as potassium formate or calcium chloride can be mixed with water instead of glycols. These mixtures have better low temperature viscosities than glycol blends. The application range may be extended down to -60 °C.

FRAGOLTHERM® W-KFA is a heat transfer fluid based on potassium formate. Its specific thermal capacity is significantly higher than that of other organic fluids. This characteristic, along with the low viscosity, leads to good heat transfer characteristics and a good pumpability at low temperatures.

However, in spite of the additives used, there is still a corrosion issue with some materials. We therefore do not recommend FRAGOLTHERM® W-KFA for equipment containing aluminium, zinc or zinc-plated steel. In addition, the maximum operational temperature is restricted to 60 °C.

Applications include heat pumps, cooling and heating systems for industrial processes and indirect cooling systems for artificial skiing or ice rinks. Climate chambers, wind tunnels and hydrogen filling stations also use the beneficial thermodynamic properties of these products.

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