Sanyo Develops Industrial Fridge Using CO2 Refrigerant

Dec 5, 2009 00:14 Mayuko Uno, Nikkei Electronics

Sanyo Electric Co Ltd developed an industrial refrigerator using carbon dioxide (CO₂) refrigerant, which is more environmentally friendly than alternatives for chlorofluorocarbon such as HFCs (hydrofluorocarbons).

The company applied the technologies used for its "EcoCute" heat pump-based hot water system to the refrigerator. For example, it employed a two-stage compression rotary CO₂ compressor equipped with two rotors and the "split cycle" method, which improves refrigeration capacity and efficiency by adding a medium-pressure stage to the refrigerating cycle. Also, the company downsized the compressor for use in industrial refrigerators.

HFCs, which are used for refrigerated showcases and so forth, came into wide use due to their low ozone depletion potentials (ODP), but they have high global warming potentials (GWP). Some claim that they do not do any harm if recovered and decomposed, but others warn that a considerable amount of HFC leaks when it is being used.

Recently, HFCs began to be regulated in European countries. For example, in Denmark, a tax of about ¥5,000 (approx 280 Dkr) per kg is imposed on HFCs. As a result, in the case of large-size industrial refrigerators whose indoor equipment such as a showcase and outdoor equipment (cooling machine) for heat radiation are separated, major manufactures outside Japan are now enthusiastically developing and launching products using CO₂ refrigerant.

The new refrigerator has a relatively small capacity, and its compressor and heat radiator are integrated with the main body. Because there are not many such refrigerators being developed by using CO₂ refrigerant, Sanyo Electric aims to grab a share of the market by developing small-size industrial refrigerators using CO₂ refrigerant ahead of other companies.

Sanyo Electric plans to commercialize the refrigerator in or after fiscal 2010. The challenge to the commercialization is its costs because the production volume of CO₂ compressors (including CO₂ compressors for the EcoCute) is tens of thousands while that of HFC compressors is several millions. As a result, CO₂ compressors are at least twice as expensive as HFC compressors.

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