Pioneering VRF system includes world-first aluminium heat exchanger

Mitsubishi Electric has announced the ultimate in commercial heating and cooling for UK businesses with the launch of the City Multi YLM VRF (Variable Refrigerant Flow) range of air conditioners.

The R410A system includes a unique flat tube aluminium micro-channel heat exchanger which the company believes is a pivotal step change in providing more effective and efficient heat transfer. Protected with a special zinc coating, the aluminium heat exchanger is ideal for the UK’s temperate climate.

YLM has been designed for seasonal efficiency from day one and in addition to the use of aluminium, includes selectable increased and automated evaporating temperature control, optimised design of refrigerant circuit and components, and the ability to provide heat during defrost.

“Available in January, YLM delivers real, tangible and measureable improvements and is optimised to suit the UK’s conditions”, explains Mark Grayston, Air Conditioning Product Manager.

The use of aluminium has called for a complete redesign of refrigerant distribution and heat exchange which, along with several other innovative design changes ensures optimum performance in real UK applications. 

Together the improvements offer up to 27 per cent annual energy saving compared to the previous equivalent City Multi systems.

Units are available to deliver from 22 - 101kW capacity to a building in both heat pump and heat recovery variants, with up to 50 indoor units connectable to the largest model. 

The smallest unit in the range, the PUHY-EP200YLM-A model is just 740 x 920 x 1710mm in size, making it transportable in a standard building lift.

The world-first use of flat tube aluminium micro-channel heat exchanger in a VRF system not only delivers greater efficiency, it also means that the YLM delivers 26 per cent more contact with the refrigerant and 30 per cent more piping per area.  At the same time, it reduces both weight and footprint and offers 10 per cent less system refrigerant volume than previous models.

This offers designers a much more flexible system, especially where EN378 restrictions are in place, such as hotels, and offers improved efficiency and performance and higher heat transfer.

The design changes include a new compressor optimised specifically to maximise efficiency during part load, therefore offering high seasonal efficiencies and helping to reduce standby power consumption by 50 per cent by using an induction-heated compressor.

The YLM range also includes a redesigned bellmouth grille to aid airflow, reduce static pressure and lower the energy consumption of the new DC fan motor.

“Two of the most important aspects that YLM addresses are the defrost cycle and occupant comfort levels”, adds Grayston. 

Defrost is integral to any heat pump and whilst it is always important to manage this with good design and control, the YLM provides the choice to offer continuous heating to cover all situations.

Available across the entire YLM range, in heat pump, heat recovery, single and multiple modules, this can provide 30 – 50 per cent capacity to indoor units during the defrost cycle using hot gas defrost technology.

YLM also brings a level of comfort above and beyond a standard VRF system, with an improved air off temperature that delivers better control in three high sensible modes and an automated dynamic control mode.

“We see YLM as a game changer in the UK air conditioning industry and believe it raises the bar in terms of comfort, design and efficiency”, ends Grayston.

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