Tackling energy wastage in the food processing sector

The food and beverage industry is one of the UK’s largest manufacturing sectors, both in terms of production and exports. Advances in modern production technology have given manufacturers much greater control over their operations, and temperature control – both in terms of process and facility cooling – is central to achieving consistent output. However, it often comes at a cost.

With the shadow of energy consumption legislation lingering over the food and beverage manufacturing sector, Brent Hall, Technical Manager at ICS Cool Energy, outlines how the efficiency of refrigeration systems could hold the key to achieving the savings mandated by the European Union.

There is often a misconception surrounding refrigeration in food processing applications. While some may view it as a necessary evil, due to the fact it consumes a large amount of energy, it is nonetheless an integral element of nearly all applications across the sector.

Like so many other market sectors of the UK economy, the food processing industry’s level of energy consumption is subject to strict governance by the European Union’s Ecodesign Directive. Given the majority of legislative changes are aligned to specific product groups, be it pumps, fans or compressors, there is a constant stream of updates of which end-users must be aware of in order to ensure their processing plant is operating in line with EU legislation.

While the sheer volume may be intimidating to the end-users, understanding the implications and ensuring any upgrades or investment to processing equipment is undertaken in line with the Ecodesign Directive’s respective legislative mandates will go a long way to reducing a site’s overall energy consumption, and ultimately, their utility bills.

Delving into the detail
Within a refrigeration system – be it a chiller unit or a direct refrigeration system – the compressor is by far the biggest user of energy; and for me, one of the biggest energy consumption challenges facing the food and beverage industry over the next 10 years is how to reduce compressor power consumption without affecting the overall performance of a refrigeration system.

However, achieving this is not an easy process. A compressor’s basic function is to pump a gas from one pressure to another, and that will always expend a certain amount of energy – that’s physics. Therefore, although the principles of vapour compression will remain the same, it is the compressor technology which must change in order to achieve the greater target efficiencies outlined by the Ecodesign Directive (Lot 31).

In order to tackle the issue of compressor efficiency in refrigeration systems, I would say that, collectively, the food and beverage industry needs to look for inspiration from the operating processes of some of the larger compressors. For example, oil-free compressors with magnetic bearings offer improved efficiency levels by reducing moving parts, removing the need for traditional bearings and the associated friction.
Considering the variables

While oil-free compressors represent one potential avenue for inspiration, in reality the technology is not yet widely available in the sizes needed for use in chiller systems. Ultimately one of the most accessible methods of improving energy efficiency in the refrigeration market is the development of compressors which utilise optimised variable speed drives. Variable speed drives have become a go-to retrofit solution for curbing inefficiency in a number of motorised industrial processes, such as pumping systems, and the principal is just as suitable for compressors.

Many compressors currently in operation are running on one fixed speed regardless of demand, and generally achieve a co-efficient of performance (or energy efficiency rating) of 3kw of cooling to 1kw of power. However, applying part-load optimisation through a variable speed drive to Scroll and Screw compressors could allow operators to achieve a ratio of 4.5-5kw of cooling to every 1kw of power: an improvement of circa 50-60 per cent.
Whilst, as with most modern advances in technology, I would expect to see material cost being driven up, this initial capital increase is a nettle the industry needs to grasp.

Doing so will pay dividends given the increased spend on new equipment will be offset by a reduction in energy consumption and, consequently, both carbon emissions and energy bills. Given the integral role of refrigeration within the food processing sector, this saving could easily translate into thousands of pounds in savings for processing plants each year.

Final thoughts
On the whole it appears that the technology is not too far away, as it is currently available as optional extras on larger plant. However for the food and beverage industry to realistically achieve the savings mandated by the EU, such advances must become commonplace across all chiller equipment within the next 10 years, if not sooner.

In short, we need to ensure that advances in larger compressor technology continue to find their way down into smaller compressors, such as those used by chiller systems in the food processing industry. Given the amount of energy it traditionally uses, refrigeration technology is rightly under pressure to contribute to making significant energy savings; after all the planet is not an infinite entity and we have to do our bit to look after it.