Too Pure?
Can water be too pure for use in PC water-coolant systems? It may sound counter-intuitive, but yes, water can be too pure. As we discussed in Part 1, both distilled and de-ionized (DI) water have a very low dissolved solids content. This means there is a very low concentration of ions in solution, as indicated by high conductivity. It takes a lot of effort and energy (various purification processes) to remove the majority of ions from water. Water desires these ions back to maintain equilibrium and will aggressively take them from any available source.
Using 100% distilled water or DI water in a PC water-cooling system is not recommended, as it may slowly attack metallic surfaces, especially aluminum!
Several of the coolant additives specifically designed for race cars and water-cooled motorcycles have warnings stating not to use distilled or DI water with their products unless automotive antifreeze is also used in the mix. The reason for this is that the thin walls of lightweight aluminum radiators used on racing cars and motorcycles may form pinhole leaks as the aluminum is attacked by the hot, pure water. Adding a little antifreeze (or other additives) to the mix puts enough ions back into the water to re-establish equilibrium and help neutralize pure water's corrosive properties. It is worth noting that this affect is greatly accelerated by the higher temperatures found in racing coolant systems.
So why use distilled water at all? Another good question! The two main reasons I recommend using distilled water as the primary component of the coolant are:
- Distilled water is naturally low in dissolved minerals and other contaminants
- Steam distilled water (especially if it has been treated with ozone or uV light prior to bottling) will be virtually free of microorganisms
- And, because the corrosive nature of distilled (or DI) water can be effectively neutralized by adding small amounts of various additives
Using water that is low in mineral and other contaminants is important for two reasons:
First, having a low mineral content will help prevent any mineral deposits from forming on heat transfer surfaces. This is the same scaly buildup commonly associated with hard water. The
second reason for using water with minimal contaminants is that this removes one of the main food sources that microorganisms need to live on. Without a food source they can not grow and multiply.
As in Part I, I still recommend using distilled water as the primary coolant. The key is to use a proper mix of additives to minimize corrosion, keep microorganisms from growing and decrease surface tension. We will discuss various coolant additives in more detail later.
é preferível aconselhar os novatos com as coisas pelas regras correctas. Usar só agua destilada porque:
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acho k finalmente o pessoal chegou todo a um consenso
fixe