Heat transfer fluids

I want to add treatment chemicals into my facility.

The anti-freeze you use has undergone a series of development studies designed by manufacturer.  Its corrosion inhibitors have been assessed and validated in the course of a number of corrosion tests.  There is therefore no need to add other products.  Furthermore, the addition of other products could destabilise the formulation of the glycolated water and reduce the effectiveness of the corrosion inhibitors in the anti-freeze.
Feb 13, 2013

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I would like to know the lifespan of the glycolated water in my installation

Unfortunately, it is impossible to give a specific duration. This is because the corrosion inhibitors will be "consumed" at varying speeds over time according to operational constraints, the kinds of materials, the extent of galvanic coupling and so on.  Only an analysis of the glycolated water can determine whether you need to renew it.
Feb 13, 2013

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I put blue anti-freeze in my system and the liquid is now a yellowish colour

The dyes used in anti-freeze are organic molecules.  The coloration can change under the influence of the temperature or the metal oxides present in the circuit.  This colour change does not neccessarily mean that the product is no longer effective.
Feb 13, 2013

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I want to use a pure glycol because it is cheaper than anti-freeze

A word of caution: pure glycol contains no corrosion inhibitors.  Using this kind of product in aqueous solution may cause severe corrosion to your circuits.

Even if the pipes are made of stainless steel, if you have a different alloy somewhere in the system (eg copper in a heat exchanger), you will have galvanic coupling and we do not know in this case which allow will act as the shield to the other.

Feb 13, 2013

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I want to buy the anti-freeze as a concentrate and dilute it myself

We recommend using treated water (demineralised) in order to limit the introduction of compounds (chlorides, sulphates, carbonates) that can jeopardise corrosion resistance.  All the standardised corrosion tests are carried out with concentrations of 33% by volume of anti-freeze.  Below this concentration, the amount of corrosion inhibitor in the circuit is too low and may not provide adequate protection against corrosion.

That is why we recommend, not just because of the protection provided against freezing, using a minimum concentration of 33% by volume of anti-freeze.  This concentration, depending on the anti-freeze gives  freezing point of 12 - 18C.

Feb 13, 2013

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