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The best of both worlds

McQuay is making some big efficiency claims with its new ATS chiller, which incorporates variable load technology to maximise performance, says Julian Milnes

McQuay UK has unveiled what it claims is the world’s most advanced air-cooled chiller, with savings of up to 30 per cent compared with a traditional non-invertor chiller.

Furthermore, the company says its ATS Chillers remove the decision of whether to specify an inverter driven unit depending on the need to maximise efficiency at full or part load.

Key to this ability is the inclusion of a single screw compressor with built-in inverter and variable volume ratio (VVR) technology, said to maximise performance at both part and full loads. This incorporates a moving slide positioned by the controller in 2 possible positions, thus getting the variation of the compressor volume ratio and the discharge side geometry.

The effect of these operations is the optimisation of the compressor efficiency depending on the chiller working conditions.

James Henley, chiller technical manager at McQuay UK, says: “When you have to design your chiller installation or select the units that best match your needs, how many times have you thought: ‘Which compromise should I take – an inverter-driven unit that offers high efficiency at part loads or a non-inverter driven solution that offers high efficiency at full load?’

“The combination of inverter control and VVR mean incomparable efficiencies at part loads and the top efficiency values at full load, all within the same chiller. It’s like having two compressors in one.

“With the introduction of our pioneering ATS chiller, you no longer have to wrestle with that dilemma. The ATS unit gives you the best of both worlds in a single chiller with no need to compromise on efficiency or reliability.”

Running on R-134a refrigerant and available in three versions, from 170 to 730kW, the ATS Chillers have a capacity range three times as wide as the units they replace. Furthermore, full load efficiency (EER) is said to be 35 per cent better, seasonal efficiency (ESEER), 26 per cent higher, and the unit 30 per cent smaller.

It also features a twin circuit for redundancy and an in-built inverter design that McQuay claim ensures a power factor constantly higher than 0.95 at full load. All the unit’s electronic components and boards are sealed by special coating that protects them against moisture and vibrations to ensure reliability, while two electrical motors sizes have been selected to optimise chiller efficiency throughout the whole frequency range (20-90Hz). Depending on the nominal frequency of the chiller the compressors will be equipped with the most efficient motor.

In-built temperature control maintains a constant 40 deg C throughout the entire functional envelope by means of a regulating valve, controlled by a solid-state relay. Heaters are switched on during stand-by hours at low ambient temperatures to eliminate moisture and prevent freezing.

Furthermore, to achieve the optimum working point the ACS’s condensing pressure management system allows the controller to modulate the chiller’s running conditions, while condenser coils made with internally enhanced seamless copper tubes arranged in a staggered row pattern further improve efficiency.

Other features of the ATS chiller include:

nin integrated sub-cooling circuit to ensure perfect uniformity of temperature distribution;

neconomised refrigerant circuits;

nthe latest shell and tube evaporators to get the best heat transfer and highest capacity, and to grant the lowest range of pressure drops values;

naxial condenser fans with wing-profile blades with superior aerodynamic performances and acoustic efficiency for the greatest possible comfort; and

ninverter-driven and brushless fans are used to achieve the best efficiencies.

There are three efficiency versions available – Silver, Gold and Platinum, which come with an ESEER rating of 15.0, 5.4 and 5.8 average respectively.

McQuay is keen to stress that despite a premium price for the technology, ATS chillers provide a sound return on investment thanks to significant energy savings. The company claims the chillers use up to 50 per cent less energy than traditional non-inverter chillers. In comfort cooling applications, the payback period of an ATS chiller (compared to a non-inverter unit) is typically around three years, and one year in process cooling applications.

Reliability is also highlighted, with a series of tests, including risk analysis; acoustic, endurance and vibration tests, and electromagnetic compatibility all being incorporated.

McQuay claims the chillers and compressors have been tested for more than 12,000 hours in factories, on selected job-sites in Europe and Middle-East, and at extreme ambient temperatures of up to 50 deg C in Dubai.

The ATS chillers will be available to order from October.

Designs on smart cooling

LG has a brace of products breathing new life into the technology of splits, while retaining an element of style, as RAC reports

LG’s well-known Artcool range of indoor split and multi split units, available in a variety of 2.5 kW, 3.5 kW and 5 kW versions, offers an alternative to conventional white wall mounts, combining aesthetics and energy efficiencies for the domestic and light commercial markets.

The top of the range Artcool Gallery wall mounted unit is designed to resemble a framed picture and comes with a changeable photo for the front panel. LG also offers a selection of conventional standard white wall mounted units and also the Artcool Mirror unit, with a striking mirror finish (see below). 

The LG Artcool Gallery units are energy efficient, rated A/A, while the Artcool Mirror offers an A++ rating, and both use DC inverter drives, inverter driven fan motors and sophisticated controls. The DC inverter automatically adjusts the unit’s power to maintain room temperature rather than repeatedly starting and stopping the compressor.

Artcool units also offer night silent operation, LG says, along with its “neo-plasma” air purifying system, and other features such as auto cleaning and the manufacturer’s Gold Fin anti-corrosion technology for added longevity.

Artcool’s three-way blow configuration gives draught free airflow and when placed over a bed or desk it is possible to block the airflow to the bottom louvre, thereby avoiding drafts from the unit.

For quick room cooling such as in hotels, the JetCool feature is claimed to be able to cool a room to 18 deg C in just 30 minutes, while dehumidification mode accurately senses the room’s temperature and controls humidity without overcooling.

The Gallery units are designed with infra-red control and pipe access through the back so there are no untidy ancillaries to spoil the look of the installation, LG says. However, it notes that it’s not all about looks - the Artcool Gallery units promise a Seasonal Energy Efficiency Rating (SEER) of 5.3 and Seasonal COP of 3.5.

The Artcool Mirror units, meanwhile, offer a SEER of up to 6.2 and SCOP of up to 4.0.

At the same time, the high COP range of commercial splits or “H-Inverter” offers high efficiency for commercial applications via a wide range of cassette, ducted or ceiling suspended units. These split-type air conditioning units feature powerful air throw, allergy reduction filters and responsive step controls.

LG’s H-Inverter range is available in sizes from 3.5 kW to 14 kW, with 3-phase power supply options over 10 kW. System SEER’s can be up to 6.11, the manufacturer notes, with an energy rating of A++.

The system also offers significant design flexibility for a split type unit, the manufacturer adds, with piping lengths of up to 75 m, and a maximum height level difference of 30 m.

The H-Inverter claims significantly higher energy efficiencies than constant-speed non-inverter units, up to 60 per cent energy savings.

There are also a number of end-user benefits from using the range, LG says, such as the Plasmaster 4S (where the 4S stands for Skin Care, Silence, Safety and Savings), which encompasses a triple deodorising filter; a plasma filter; auto and a noise level of just 18 dB.

LG says its plasma Air Purifying System was initially developed to not only reduce microscopic contaminants and dust but to also remove house mites and other allergens that cause asthma symptoms. It uses an enzyme to destroy house mites, while dust particles are burned and eliminated by an electric field.

In addition, new Skew Fan technology ensures minimal noise from the unit, while by pressing the Quiet Mode button the fan speed automatically changes to “low” for lowest noise operation.

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