Patent ID: 8689573

Claim:
A refrigerated merchandiser comprising: a case defining a product storage area, the case including a door providing access to the product storage area, and at least one product support configured to support product in the product storage area; a refrigeration system in communication with the product storage area, the refrigeration system including a refrigeration circuit having a compressor, a condenser, and an evaporator in series, the refrigeration system operable in a refrigeration mode configured to discharge a refrigerated airflow into the product storage area along a discharge passageway to refrigerate the product and to maintain the product within a predetermined temperature range without freezing the product, the refrigeration system configured to receive the refrigerated airflow from the product storage area along a return passageway, the refrigeration system further operable in a defrost mode configured to defrost the evaporator; a sensor coupled to the case and configured to sense one or more defrost conditions of the case and to generate one or more signals indicative of the defrost conditions; and a controller in electrical communication with the sensor to receive the signals indicative of the defrost conditions, the controller in communication with the refrigeration system to control the refrigeration system in the refrigeration mode and in the defrost mode, the controller including an algorithm for calculating when to initiate the defrost mode, and for calculating a duration of the defrost mode, the controller programmed to vary the refrigeration system between the refrigeration mode and the defrost mode based on the signals indicative of the defrost conditions and the calculations by the algorithm.