Cool, calm, and collected: The benefits of free cooling for the plastics industry

The plastics manufacturing industry is well-known for its incredibly high energy demands, and the subsequent industrial cooling challenges it poses for end-users. For many plastics manufacturers, process cooling is achieved solely via an air or water-cooled chiller or cooling tower. However, these are not the only options.

Here Richard Metcalfe, Director – UK & Ireland Sales & Service at ICS Cool Energy, explains the flexibility of free cooling and how it is ideally suited to the plastics sector.

In its purest form, free cooling works by the unit – usually either a free cooler working in series with a chiller, or a chiller with a built-in free cooling coil – detecting the ambient air temperature and process return temperature.

When the ambient air temperature drops below the process fluid return temperature, a three-way valve diverts the returning process fluid through the free cooling coil. Here, the cooler ambient air removes someof the process heat, and subsequently cools the returning fluid.

As the ambient air temperature continues to fall, the amount of heat taken out of the process fluid by the air increases, progressively reducing the load on the chiller until all the process heat is taken by the ambient air and the free cooling unit. The process fluid is therefore being cooled just by the power used for the fans, rather than by using the compressor, which is traditionally the most energy-intensive element of a chiller.

Ultimately, free cooling is fast, effective and economical; and can result in process cooling energy savings of up to 80 per cent. Given the high-energy demands of the plastics industry, the reduced utility consumption as a result of switching to a free cooling system can equate to tens of thousands of pounds saved a year, compared to a system which relies 100 per cent on electro-mechanical cooling.

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. Both formats can easily be applied to common applications within the plastics manufacturing industry, depending on the site’s location and size.

Lower life-cycle costs

While a free cooling system will still require some electro-mechanical power – and therefore cost – to operate the fans and pumps in a system to physically move the heat transfer fluid, the major energy savings are made when the ambient air temperature is low enough to bypass at least one of the chiller’s compressors.

Further costs can be saved due to the reduced load on the chiller – particularly the compressors and fans – as they are not worked as hard, or at all in some cases. As such, maintenance costs can be lower over the lifetime of the system. During partial free cooling, the compressors are running for less time, so the overall operational life expectancy of the unit is improved.

From a health and safety point of view, unlike cooling towers – which are one of the most commonly-used methods of cooling in the plastics industry – free cooling systems pose no risk of legionella and therefore do not require additional water treatment costs beyond the norm to mitigate the risk of an outbreak.

A helping hand

For those plastics manufacturers where CapEx cost for new equipment may pose a threat, such as SME manufacturers who do not possess the same financial muscle in their facilities and maintenance budget as larger companies or multi-national organisations, free cooling can be accessed via a number of funding incentives.

An SME-specific scheme, which can improve access to energy-saving equipment such as free cooling systems, is the Carbon Trust’s Green Business Fund. Aimed at those SMEs with an annual energy spend in excess of £50,000, the fund allows relevant businesses to apply for up to £5,000 worth of grant funding to contribute towards the capital cost of the equipment.

Final thoughts

Ultimately, free cooling can deliver achievable, long-term energy savings which can translate into a significant reduction in monthly utility costs for industrial end-users in the UK plastics industry. For those end-users keen to explore the potential free cooling has to offer, I would urge you to get in touch with your temperature control provider today to find out more.

About the Author:

Richard Metcalfe is the Director of UK and Ireland Sales and Service at ICS Cool Energy. He has over 20 years experience working with industrial cooling systems and is a fully qualified electrical engineer.