Technical
CORROSION :
A CLEAR AND PRESENT DANGER
By Tobias Wolf , deputy head of product management at Stulz GmbH
Data centre free cooling system components such as air to water heat exchangers are subject to the possibility of corrosion , which can lead to significant efficiency and availability issues . Precautionary measures are therefore vital . This article explains how to minimise the risk of failure and save costs along the way .
Free cooling has become firmly established as a highly effective way to reduce the energy consumed by chillers through the use of outside air or water . Free cooling systems can save data centre owners and operators massive amounts of electricity and money , significantly improving a facility ’ s overall energy efficiency . However , for a free cooling system to operate as effectively as possible , its air to water heat exchangers must be maintained to a high standard .
INSIDE OUT Air cooled heat exchangers , such as condensers , dry coolers , or those used in free cooling systems , are often exposed to elements such as pollution and salty air , which can accelerate corrosion . Data centre operators should therefore address the issue of preventive corrosion protection as soon as possible after installation . Since all cooling and refrigeration components are exposed to certain corrosive processes , depending on specific environmental factors it is only a matter of time before measurable material changes occur in individual components .
Put simply , the right choice of corrosion protection can help to significantly extend the operational life of a cooling system . Understanding the various corrosion protection measures for air cooled exchangers , as well as the corrosive processes that take place in a chilled water circuit , serve as the basis for a proactive maintenance strategy . If a heat exchanger leaks due to corrosive processes , it can lead to a failure of the installation , so corrosion therefore has a significant , as well as negative , impact on efficiency and availability .
DEFINING MOMENT Corrosion is defined as the reaction of a metal with its environment – a gradual process which , over time , can lead to impairment of the function of a component or even a complete system . Corrosive processes are triggered by chemical or electrochemical substances in the ambient air or by contact between two different metals . Under particularly unfavourable environmental conditions , air to
All images : STULZ GmbH
Corroded V4A pressure switch due to acid corrosion in a deionized water circuit .
Corrosion damage to finned tube heat exchanger .
water heat exchangers can be damaged to such an extent that they become deformed or lead to individual fins breaking . Damage to the material structure is usually irreversible and requires expensive repairs or even replacement .
Oxygen corrosion is caused by a metal reacting with oxygen to form oxides . In the case of copper and aluminium the resulting natural oxide layer protects the interior of the metal , so oxidation can even be
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