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Winds of
change
The performance of air-con systems continues
to improve, thanks to technical innovation and
rising efficiency, writes Ian Vallely
T
he efficiency of air conditioning systems
has improved dramatically over the past two
decades and this has significantly reduced
their running costs, energy consumption and
impact on the environment. Figures from Daikin
UK show that, in 1990, a 28kW system running on
R22 refrigerant would have had an energy efficiency
ratio (EER) of 2.46, whereas a similarly-sized system
today can operate at an EER of 3.74 – which equates to
around 30 per cent less fuel use. (Supply of virgin R22,
of course, ceases on December 31 under refrigerant
phase-out this year).
This example is for a variable refrigerant volume
(VRV) system. VRV is Daikin’s proprietary version
of the generic variable refrigerant flow (VRF) system
produced by other air conditioning manufacturers. The
principle of VRV and VRF is broadly similar in that
they both involve the volume or flow rate of refrigerant
being matched to the required heating or cooling loads,
saving energy and enabling more accurate control.
Graham Wright, product sales manager at Sanyo Air
Conditioners, also points to VRF as a major area of
technological innovation. ‘It has been subject to year-
on-year incremental improvements that, over time,
have transformed performance out of all recognition,’
he says. monitor other building systems such as alarms,
‘The result today is incredibly sophisticated systems lighting, etc, to increase the potential for energy saving
and associated controls that are light years ahead of further.’
the first systems – dramatically cutting emissions and Mitsubishi Electric says it has gathered extensive
improving comfort for building occupants.’ test data which shows that a VRF ground source heat
Philip Ord, product marketing manager at pump system can outperform a traditional boiler/
Mitsubishi Electric Air Conditioning, agrees, adding chiller system by more than 300 per cent for heating
that modern VRF systems can offer simultaneous and cooling.
heating and cooling with full heat recovery and the ‘What the tests also prove beyond doubt is that
ability to link to other equipment such as air curtains the air source heat pump VRF system is much more
and water heaters. efficient than traditional methods,’ says Ord. ‘Add to
‘VRF air conditioning is now a serious and viable this further improvements in design and controls and
alternative to traditional carbon-based heating and new products such as VRF water heating systems or
water-cooled chiller systems,’ he says. ‘The controls air curtains, and it is clear that, if people really want to
have advanced so far that they can also control and make savings, they should look at a VRF system.’
40 CIBSE Journal December 2009 www.cibsejournal.com
CIBSEdec09 pp40-42,44 aircon.indd 40 19/11/09 16:26:12
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