TOKYO — Mitsubishi Heavy Industries Ltd. (MHI) has developed a new series of centrifugal chillers, called the ETI-Z Series, that use a new low-global warming potential (low-GWP) refrigerant, HFO-1233zd(E). The various models in the new series will be progressively launched starting this September. The ETI-Z Series are said to be the first small-size centrifugal chillers to adopt the new refrigerant.

MHI said the ETI-Z Series carries on the fundamental product concept of the ETI Series: high performance combined with compact size.

Models in the new ETI-Z Series have a cooling capacity with a range of 80 to 700 refrigeration tons (RT). High performance is achieved by reducing motor drive-energy loss through the adoption of a compressor with high-speed direct motor drive, the elimination of step-up gear, and use of fewer bearings. Together, the company said these features enable achievement of a rated coefficient of performance (COP) of 6.7 in the 200 RT class. Reliability has also been enhanced through structural simplification.

HFO-1233zd(E) has the same low GWP as carbon dioxide (CO2), i.e., 1, and an ozone depletion potential (ODP) of 0. Owing to this minimal impact in terms of greenhouse gas emissions and no impact with respect to ozone depletion, the new refrigerant is not subject to Japan’s Freon Emissions Control Law. This means that HFO-1233zd(E) is not regulated in terms of curbing emissions or leakage, recovery and destruction for disposal, etc. Compared to MHI’s current refrigerant, however, the volume of refrigerant gas is about five times greater; therefore, to achieve the same capacity, generally the size of the compressor and heat exchanger will be increased. In the ETI-Z Series, a more compact size has been realized by applying the latest blade shape, increasing the motor speed, and by adopting and optimizing the arrangement of the high-performance tubes.

The microcomputerized control panel features a new board that enables more precise control, thanks to increased speed of the central processing unit (CPU), to support energy-saving operation of the chiller. The adoption of a touch panel type liquid-crystal display both enhances operability while also improving functions that support maintenance of the main unit. Going forward, MHI plans to expand its lineup of centrifugal chillers featuring the new refrigerant by progressively developing and launching models up to 1,500 RT, including fixed-speed models.

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Publication date: 6/29/2015

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