Weighing up energy efficient chillers
May 1st 2008

Steve Warnock, managing director of cooling specialist Coolmation, exclusive UK distributor for the low energy Rhoss Micro Powercool range of chillers, advises how works engineers can best select an energy efficient chiller

With energy prices continuing to accelerate and the credit crunch starting to bite, plant and works engineers and factory management are under increasing pressure to reduce plant operating costs.

On many manufacturing sites, the industrial water chiller is one of the biggest energy consumers, and also represents a significant capital investment for many companies. As a result, specifying energy efficient chillers either for new installations or to replace antiquated or energy wasteful ones must, when it is done, be done right.

However, selecting the most energy efficient chiller for the job is not that simple.

When comparing new chillers, it is important to look at each unit's EER (Energy Efficiency Ratio), the ratio of cooling output compared to power input. Eurovent, the European Committee of Air Handling and Refrigeration Equipment Manufacturers, has set its own formulae to calculate EERs, making it easier to compare the performance of chillers manufactured by Eurovent accredited companies. Eurovent has also established its own classification for full load EER. This classification follows a similar A to G approach to the Energy Labelling Directive (although the directive is restricted to household appliances and is only mandatory for Room Air Conditioners with a capacity equal to or lower than 12kW).

Eurovent's classification is a voluntary initiative, unrelated to any directive and no label is used. Instead the energy efficiency of chillers is designated by Eurovent A or Eurovent B in catalogues and the Eurovent Directory of Certified products.

However, it's worth at this point sounding a word of caution. A chiller's EER should not be considered in isolation since most units rarely operate at full capacity throughout their life cycle. That's why it's also vital to take a look at a chiller's ESEER (European Seasonal Energy Efficiency Ratio), as set out by Eurovent. The ESEER is the chiller's performance ratio which compares power input to cooling power output at partial loads, therefore giving a more realistic view of the chiller's life-cycle performance.

As well as considering a chiller's EER and ESEER specifiers should also ensure they establish the integrity of the energy efficiency data published in manufacturers' literature. Although some energy efficiency data is validated by independent testing organisations, such as Eurovent, some manufacturers' literature simply presents a theoretical calculation of the performance of individual components, such as compressors and heat exchangers which when put together affect the performance of the other.

Another key resource for finding energy efficient chillers is the Carbon Trust's Energy Technology List (www.eca.gov.uk). Only chillers meeting the Carbon Trust's performance criteria are included on the list.

It is very easy to identify these products since the ETL symbol is used to endorse qualifying products. Chillers on this list guarantee both reduced capital investment through significant tax benefits (Enhanced Capital Allowances) and lower energy costs, leading to climate change levy savings.

Chiller manufacturers, like Rhoss, one of the leaders in European chiller design and the company behind our new Micro PowerCool range, recognise the demand from heavy users in the industrial and process sector to reduce fuel consumption and meet EER and ECA compliance requirements. The result is increasingly innovative component design and application to create low energy chillers.

For example, the new breed of energy efficient chillers, like the Micro PowerCool range, use low energy scroll compressor technology and incorporates special, plate type evaporators designed to improve energy efficiency, especially at partial loads.

However, what is really innovative about this type of chiller is that it is the first industrial chiller to use green energy efficient R410a refrigerant. The largest units, from this unique breed of chillers, also feature two small compressors of different capacity installed in the same refrigerant circuit to provide three cooling capacity steps and further increase the chillers' efficiency. Coupled with R410a this new range operates at a significantly higher energy efficiency ratio than previous chillers. At the same time, chiller operation is managed by an intuitive, multi-function microprocessor controller offering both highly precise stability and energy efficient compressor operation.

As fuel prices continue to escalate, it will become essential for engineers to be able to easily recognise efficient chillers in order to specify the most efficient unit for an industrial cooling process. It will be equally important to ensure installed chillers run to their optimum efficiency and that every possible method of enhancing this is employed.

The latest Micro Powercool series from Coolmation has been developed to provide the best EER (European Efficiency Ratio) performance available in its range, (15kW up to 70 kW cooling capacities). The Micro Powercool is the first industrial chiller to use the green energy efficient refrigerant R410 with scroll compressors and comes with a 3-year warranty. In addition the Micro Powercool chiller range features a unique patented control system, Adaptive Function Plus, which has been developed jointly by Rhoss and the Physics and IT Department at the University of Padua. The Adaptive Function Plus has the capability to reduce energy consumption by up to 36% in winter months and 18% in the summer. It also allows significantly reduced water volumes to as little as 2 litres/kW, which results in smaller tank sizes and footprint, allowing easier chiller installation. Like the majority of chillers now available from Coolmation, the Micro Powercool chillers are also approved and listed under the Government's ECA scheme and when part of an installed system, can be retrofitted with free cooling units to lower energy costs still further.

Coolmation is the exclusive distributor for low energy ECA approved and Eurovent certified Rhoss chillers.

More articles from Coolmation Limited: