secondary refrigernt additives

[afeef]

please inform me about the kind of additives and its percentage we must add to the cooling water in the centeral a/c system,

[US Iceman]

When you select a secondary refrigerant (glycol) make sure it is a heat transfer grade of glycol. The inhibitors will be included in the glycol when you purchase them.

A heat transfer additive to depress the freezing point of a water mixture is different from anti-freeze. Do not use an automotive grade of glycol in a water circulation system.

The percentage of solution for the mixture should be based on the lowest expected temperature that can be seen at your location, or, at least 3-5C below the refrigerant evaporating temperature. Whichever is the lower temperature (cold ambient or 3-5C below the evaporating temperature).

The glycol manufacturer/supplier can provide you with sample bottles for periodic testing to verify the additives and inhibitors.

Here is a link to find additional information.

http://www.dow.com/heattrans/

Best wishes on your project,

US Iceman