| 摘要 |
An open top refrigerated display case having an ambient air automatic defrost system and a method of operating such a case. A single air conduit extends in a U-shaped formation extends around the case and has openings at both ends in the location of the upper portions of the side walls. At least one reversible fan and a set of evaporator coils are arranged within the air conduit. During a refrigeration cycle the fan circulates air through the air conduit in a first direction towards the evaporator coils. When frost buildup within the display case has reached a certain level, the system is switched to a defrost cycle of operation. During the defrost cycle, the fan circulates the air in the opposite direction through the air conduit and draws in ambient air from outside of the display case for defrosting the evaporator coils. The ambient air, after passing over the evaporator coils and through the air conduit, is expelled from the air conduit and directed along a path towards the outer side of the refrigerated case and away from the interior of the case.
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