Wasted energy has cost
Air conditioning accounts for over 30 per cent of annual electricity consumption, in a typical office, 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/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 and Z Powerranges, recognise the demand from building managers 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 among other critical functions, automatically regulates fan speed to optimize efficiency and maintain constant condensing temperatures in ambient conditions down to -10º.
Another way to reduce a chiller’s operating costs is by incorporating within it 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 12oC and the ambient is 11oC, free cooling can be activated. Free cooling is particularly effective in the
Most buildings have a requirement for a constant supply of hot water, if only for sanitary purposes, and this will usually be generated by a gas or electric water heating system. A water chiller at full load conditions will be rejecting into the atmosphere, the heat removed through the air conditioning system plus the power input to it, a significant amount of energy.
For just a small fraction of the capital cost, most chillers can be fitted with a desuperheater, a heat recovery vessel, through which, for example, boiler feed water can be passed. The desuperheater can raise water temperatures as high as 70ºC, thereby considerably reducing the load on the buildings water heating system and the associated fuel costs.
As fuel prices continue to escalate, it will become essential for facilities managers to be able to easily recognise efficient chillers in order to specify the most efficient unit for a building. 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 and Z Powerseries from Coolmation have been developed by Rhoss to provide the best EER (European Efficiency Ratio) performance available in their range, (76.5kWup to 1470 kW cooling capacities). Like the majority of chillers now available from Coolmation, they are also approved and listed under the Government’s ECA scheme. This means that if the client purchases an ECA approved chiller, he can set off 100% of his capital allowances against profits in year one and not over the usual three years which can create a valuable cash flow improvement.
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Editor’s note 1: The performance of the Powercool and Z Power series is verified by testing carried out in the new Rhoss Laboratory. This new facility is one of only two in Europe, capable of operating chillers at their full capacity up to 1500kW, and has recently been officially endorsed by Eurovent to carry out certification tests.
Editor’s note 2: Rhoss is one of
For further information please contact:
Managing Director Wildwood Public Relations
Coolmation Ltd The Orchard
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Tel: 01425 478971 Tel: 01403 892720
Fax: 01425 470745 Fax: 01403 892721
Web: www.coolmation.co.uk Email: sara@wildwoodpr.co.uk
