BSEE-AUG21-P10 Fujitsu Chiller_Layout 1 22/07/2021 15:32 Page 10


Modern chillers have many benefits in terms of both environmental impact and efficiency, says Martyn Ives, distribution sales and technical director at Fujitsu General Air Conditioning UK.

commercial market. Coupled with the option of using low global warming potential refrigerants, chillers are now often a viable alternative to VRF. Fujitsu’s partnership with GI Holding Group (GIH) means we have an extensive range of Clint liquid chillers, heat pumps and 4-pipe units with scroll compressors available, with cooling capacities ranging between 50 kW-1.2 MW, operating on R452B or R454B refrigerants in addition to R410A. Scroll and Turbocor compressor options are available from 200 kW to 3.8MW, using R513A or the ultra-low GWP R1234ze as alternatives to R134A.

A Viable options

R32 has always been a viable option for both direct expansion and hydronic applications when looking for lower GWP alternatives to R410A for comfort applications. GIH decided to offer refrigerant options that had a closer operating envelope to R410A and lower GWP. Because of the nature of the fluids, the same refrigerant oil can be used and therefore a multi refrigerant compressor can be applied, rather than stocking a dedicated compressor to each type of refrigerant.

The inclusion of aluminium microchannel heat exchangers have also decreased relative refrigerant charge quantity by up to 25 per cent compared to traditional copper and aluminium coils. With increased thermal performance and a reduction in air pressure drop, this design choice leads to both environmental and efficiency benefits whilst furthering design benefits for free cooling processes especially in data centres.

The efficiency when using R452B is 1 per cent better than R410A, with a 2 per cent decrease in cooling capacity. R454B‘s cooling capacity is 4 per cent less than R410A, but maintains the same efficiency. Its GWP is 467, compared to the 1924 of R410A and 677 of R32.

The screw and Turbocor-based products offer similar alternative options, using R513A instead of R134A and the HFO R1234ze, with an ultra-low GWP of less than 1. Being non-toxic and classified A2L, this refrigerant is also seen as an alternative to ammonia and propane.

With a range of 49 kW-1.1 MW; 4 pipe, heat pump, air cooled chillers allow dynamic design potential for providing both cooling and heating operations simultaneously to satisfy the various demands of modern buildings. A chiller operating in a single mode moves energy from one area and expels in another, chilled water being a product of the evaporator in cooling and hot water via the condenser in heating. Generally, this energy would not be reusable and in lost to the ambient air.

10 BUILDING SERVICES & ENVIRONMENTAL ENGINEER AUGUST 2021 4 pipe chiller operating in simultaneous mode, recovering energy to produce hot water for heating and potable hot water applications. Hot water

When operating simultaneously, hot water can be generated by utilising the heat rejected from the condenser via a plate heat exchanger instead of a fan, and chilled water provided from the energy absorbed by the evaporator at the same time. Energy is transferred between the two heat exchangers, maintaining the refrigeration cycle’s operating pressures. This method not only provides the ability to serve mixed applications, but it also improves system efficiency.

Simultaneous mode operation can create a system Total Energy Ratio (TER) of 8.8, that being 8.8 kW of useful energy given out in terms of both heating and cooling in ratio to every 1 kW of electrical energy

consumed. These high efficiencies are not solely realised from the concept of 4-pipe simultaneous systems, but also from the development of load control through scroll and screw compressor innovation, inverter application, along with free cooling processes, EC inverter plugin fans and more complex control algorithms. By using a third heat exchanger with simultaneous operation, either within the chiller or placed within a thermal store, energy to produce domestic hot water up to 60oC ,can also be utilised from recovered energy. This adds an efficient bivalent source to a traditional boiler or can remove the need for a boiler altogether.

The commercial use of air to water heat pumps has been extended by recent developments to achieve 80oC directly from water cooled chillers. This improvement extends design possibilities to provide potable hot water without the need for pasteurisation cycles or further energy boosts, and offers energy efficient means to pre heat water used for industrial sanitisation purposes.

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growing focus on energy recovery and multiple use products has given the chiller a new lease of life,

especially within the

CHILLER & REFRIGERANT There is more to selection than GWP

4 pipe chiller operating in cooling mode, rejecting heat energy to ambient air Read the latest at:

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