Energy efficient chillers

Coolmation, exclusive UK distributor for the low energy Rhoss Powercool range of chillers, advise how works engineers can best select an energy efficient chiller.

Wasted energy has cost UK business an estimated GBP570m this summer and this, in combination with ever escalating fuel prices and the climate change levy, is putting plant and works engineers and factory management 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 whys 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 manufacturer's 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/etl/).

Only chillers meeting the Carbon Trust' 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 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 PowerCool, use low energy scroll compressor technology and incorporate special, multi-circuit, plate type evaporators with two refrigerant circuits and one water circuit in a design that improves energy efficiency, especially at partial loads.

At the same time, chiller operation is managed by an intuitive, multi-functional microprocessor controller, which amongst other critical functions, automatically regulates fan speed to optimize efficiency and maintain constant condensing temperatures in ambient conditions down to -10.

Another way to reduce a chiller's operating costs is by incorporating a free cooling system.

This takes advantage of low ambient temperatures to pre-cool the water returning to the chiller, reducing the load on the compressors and therefore the energy consumed.

When the ambient temperature falls 1oC below the temperature of the water returning to the chiller, for example, the.

water return temperature is 15oC and the ambient is 14oC, free cooling can be activated.

Free cooling is particularly effective in the UK where the ambient temperature is below 15oC for almost 75 per cent of the year.

Typically, with an ambient temperature between 3oC and 5oC below the set point temperature, the compressors will completely switch off and the only energy consumed will be by the small fans on the free cooler.

A free cooling system operates by the return water being automatically diverted through the free cooler before going to the chiller.

The free cooler pre-cools the water, reducing the load on the chiller and the energy being consumed by the compressors.

The lower the ambient temperature compared to the return water temperature, the greater the free cooling effect.

Free coolers can be retrofitted to existing chilled water systems as well as incorporated in new ones.

The pay back is fast and energy savings year-on-year are considerable.

Where space is an issue in a new system, free coolers can often be incorporated within an air-cooled chiller.

Here the air-cooled condenser is double banked rather than being a single coil.

The system works by one coil becoming the condenser, the second and outer coil, the free cooler.

Free cooling systems and chillers can often be funded through a government backed, interest free unsecured loan of up to GBP100,000.00.

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 Powercool series from Coolmation have been developed to provide the best EER (European Efficiency Ratio) performance available in their range, (76.5kW up to 182 kW cooling capacities).

Like the majority of chillers now available from Coolmation, they 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.

All Coolmation equipment available to UK customers is designed for high reliability and manufactured to internationally recognised quality standards.

With offices in Lancashire, Leicestershire, Bedfordshire, Bristol and a Head Office in Ringwood, Hampshire, Coolmation operates nationwide in chiller sales and installation, service, hire and technical support.

For further information call freephone 0800 731 5466.

Gary Franklin, managing director of cooling specialist Coolmation.

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