March 2019

Richard Metcalfe, director (UK & Ireland sales & service) at ICS Cool Energy, breaks down the pros and cons of the two most popular types of free cooling systems. 24 | Plant & Works Engineering www.pwemag.co.uk March 2019 Process, Controls & Plant Focus on: Process Heating & Cooling Standalone Vs integrated: How to decide on the best free cooling route F ree cooling is a fast, effective and economical way for industrial end-users to reduce their process cooling energy costs, in some cases by up to 80%. However, accurate specification is key to unlocking its true potential – get it right and the system can pay for itself within 18 months, but get it wrong and the investment may fail to live up to expectations. Suitable for all industrial applications with a water leaving temperature of 10°C or more, free coolingcan be achieved as soon as the ambient air temperature drops below the process fluid return temperature. When this happens, a 3-way valve diverts the returning process fluid through the free cooling unit, where the cooler ambient air removes some of the process heat, subsequently cooling the returning fluid. As such, free cooling is a tangible, sustainable and cost-effective way of reducing a site’s process cooling operation costs. However, maximum efficiency can only be achieved by accurate specification. Free cooling systems are typically available in two forms, either as a standalone unit where the chiller works in series with an independent free cooling unit, or by integrating a free cooling coil into an existing chiller installation. However, they are by no means interchangeable and opting for the wrong solution can significantly impact system efficiency and long-term ROI. Standalone free cooling A standalone free cooling system sees an independent free cooling unit working alongside a chiller. From a cap-ex perspective, the start-up costs are comparatively lower for a standalone system as end-users can partner the free cooling unit with their existing chiller. One of the key requirements to maximise the ROI of a standalone system is ability for it to be externally-sited. As the system comprises of at least two units, it requires a greater amount of space given the footprint of the equipment, and the subsequent need to allow air to circulate around the units. However, the increased footprint means a larger surface area, which

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