| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of cooling operation of a low temperature open showcase capable of significantly delaying the time for the frost formation without requiring the defrosting operation at least during the business hours (about a half day), and always exhibiting the stable cooling performance. SOLUTION: In the low temperature open showcase, cold air cooled by coolers 8 and 9 are circulated and supplied by a fan 10, and an opening part 4 of a storage compartment 2 is covered by an air curtain. The coolers 8 and 9 are vertically disposed plurally in series inside a cooling duct 6 divided from the storage compartment 2. In the cooling operation of the showcase, the refrigerant evaporation temperature of the cooler 8 is set so that the temperature of cold air at least of one cooler 8 on the most upstream side of the cold air flow is in the temperature range where water drops hardly freeze, and the refrigerant evaporation temperature of the other cooler 9 is set so that the temperature of cold air is lower than that temperature range.
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