Data center cooling: Corrosion protection reduces the risk of failure
To prevent corrosion in chilled water systems and ensure smooth processes, plant operators should check the water conditions regularly. They may then need to take measures dealing with, among other things, the pH value, hardness and conductivity of the water.
These days, reliable cooling is indispensable for many technical applications. This is true for process and industrial cooling, medical technology and – above all – server rooms and data centers. When it comes to the air conditioning of IT equipment, in particular, even minimal disturbances in the cooling system can incur expensive consequences. Therefore, for many years the IT sector has made use of defined availability classes and systems with in-built redundancy to reduce the risk of failure.
Besides planning and structural measures, any availability concept should also include a permanent maintenance and service strategy. Leak checks, regular filter replacement and the cleaning of heat exchanger surfaces should all take place as a matter of course. But in addition, continuous monitoring of the water parameters is a vital part of preventive corrosion protection.
The fact is that plant operators who continually keep an eye on water quality – right from the time the system is first filled – improve the general service life of their system and reap the benefits of constantly higher efficiency. Rule 3.003 from the BTGA (German Association of Technical Building Equipment) describes the correct procedure for producing and maintaining ideal water quality. It provides clear specifications on water-borne constituents and, furthermore, on how system maintenance, filling and monitoring should be carried out.
The type of chilling system is also an important factor here. Two different system designs generally predominate in the field of data center cooling: precision air conditioning units with integrated DX refrigerant circuit (Figure 1) and CW indoor units that are connected via heat exchangers to a central chiller (Figure 2).
In both models, the water circuit must be kept free from foreign matter and sediment and rich in oxygen to ensure a long service life and unrestricted function. Current research projects show that closed circuits in chilled water and liquid cooling systems can suffer their first corrosion damage within just one or two years. This is a problem not just because of damaged pipes and eventual leakage, but also because flaked off particles of corrosion can easily clog pumps, filters, and the capillary tubes of heat exchangers