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Feature
RACA Journal
Adriaan Hofmann , technical sales manager at ACS at Frigair . water can seep through , and corrosion builds up in the pipe . Corrosion will inevitably reduce the flow area of the water . This corrosion issue is more predominant in small systems .
The diameter of the pipe is a crucial factor to consider in the design of a cooling system . The size of the pipe must be calculated correctly to ensure that it fits with the overall system , with the calculations of the pipe diameter accurate so that the velocity of the system is optimised and efficient . If the velocity is minimised throughout the system , then the water will be able to freely run and cool areas . Additionally , there will be less corrosion if the velocity is kept to a minimum .
The introduction of chemicals in the water is the last element to consider when looking at piping . In an open-atmosphere system , chemicals are typically introduced to control the pH level of the water . If chemicals are not introduced and the pH levels are not monitored , corrosion is likely in the piping system , causing a slow flow of water . In closed systems , there tend to be fewer minerals in the water . Consequently , closed systems can use aggressive fluids such as de-ionised water , requiring the use of plastic piping or stainless steels rather than iron or steel .
CHOOSING THE RIGHT VALVE TYPE FOR A COOLING SYSTEM When it comes to cooling systems , the valves that are selected are typically going to be flow control valves and shutoff or bypass isolation valves . There are a number of points to consider before picking the valve for the cooling system :
• The flow capacity , for which it is important to remember in valve selection the pipe size .
• What flow capacity is needed for the cooling system ?
• What size piping will be used ?
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Automated Control Solutions
A DN250 Danfoss AB-QM PICV valve and actuator – one of six installed at a local data centre .
RACA Journal I January 2024
The valve pressure / temperature rating must be within the system design parameters . The initial factor to be considered is the maximum pressure that the cooling system will have to hold , to determine the valve rating . Regarding the capacity of the system , consideration should be given to choosing whether a small-diameter pipe ( globe control valve ); mid-diameter pipe ( segmented ball valve ); or large-diameter pipe ( high performance butterfly valve ).
Different types of isolation valves also are considered based on pressure and related capacity :
• Small-diameter pipe : two- or three-piece ball valve
• Mid-diameter pipe : three-piece or flanged ball valve
• Large-diameter pipe : butterfly valve
The capacity of the overall cooling system is something that should be considered – the smaller the system size , the more accurate it will likely need to be . The cooling system in a CPU liquid cooler is one that should be accurate as there is a finite amount of space the water works with to cool the variables along the piping system . www . refrigerationandaircon . co . za