초록 ▼

A defrosting control unit for providing centralized control of the defrosting a showcase having showcase units with defrosting devices includes an environmental informer ion signal generation portion and a defrosting control portion. The signal generation portion generates a signal reflecting at lea

A defrosting control unit for providing centralized control of the defrosting a showcase having showcase units with defrosting devices includes an environmental informer ion signal generation portion and a defrosting control portion. The signal generation portion generates a signal reflecting at least one environmental parameter such as whether it is daytime or nighttime, the difference in air temperature measured at different places in a showcase unit, the deviation of the temperature difference with respect to a steady-state value, and the temporal variation of the deviation. The defrosting control portion receives the environmental information signal from the signal generation portion and sends a defrosting start signal and a defrosting end signal to the defrosting devices at a time interval . The signal generation portion may include a fuzzy reasoning portion, membership functions, and rules so that an inference on the optimal time for starting a defrosting operation can be made. The optimal time for starting a defrosting may also be obtained by a defrosting timer and a day/night judgment portion. A centralized showcase defrosting system includes such a defrosting centre unit in addition to a showcase unit having an inner duct, an evaporator and a defrosting device attached to the evaporator, the defrosting device having a heater for melting frost which has been deposited on the surface of the evaporator.

대표청구항 ▼

A defrosting control unit for a showcase having a showcase unit with an inner duct for circulating air, an evaporator provided in the inner duct to cool the air circulating in the inner duct, and a defrosting device attached to the evaporator, the defrosting device having heating means for melting f

A defrosting control unit for a showcase having a showcase unit with an inner duct for circulating air, an evaporator provided in the inner duct to cool the air circulating in the inner duct, and a defrosting device attached to the evaporator, the defrosting device having heating means for melting frost which has settled on the evaporator, the defrosting device additionally having a defrosting termination function, said defrosting control unit comprising: a situation-reflecting signal generation portion which generates a situation-reflecting signal for starting a defrosting control operation, said situation-reflecting signal generation portion including a fuzzy reasoning portion, membership functions, and rules, said situation-reflecting signal reflecting a present situation expressed in terms of a result of fuzzy reasoning conducted by said fuzzy reasoning portion, said fuzzy reasoning portion inferring an optimal time for starting a defrosting operation based on at least one environmental parameter or value derived therefrom as an element of a fuzzy set, said environmental parameter or value derived therefrom being selected from the group consisting of (a) an optimal defrosting time interval obtained from the temperature and humidity of open air, (b) a marginal defrosting time interval obtained from the temperature and humidity of open air, (c) a stable-state value, the stable-state value being an average value of a difference between the temperature of air blown out of said inner duct and the temperature of air immediately after it passes said evaporator over a period after said difference has reached a steady state, (d) a deviation, from said stable-state value, of an actual value of the difference between the temperature of air blown out of said inner duct and the temperature of air immediately after it passes said evaporator, (e) a temporal variation of said deviation, (f) a difference between a post defrosting time and said optimum defrosting interval, and (g) a difference between said post defrosting time and said marginal defrosting time; a defrosting control portion which receives said situation-reflecting signal from said situation-reflecting signal generation portion and generates, upon receipt of said situation-reflecting signal, a defrosting control start signal; and a showcase unit controller connected to said heating means, said showcase unit controller driving said heating means upon receipt of said defrosting control start signal to start a defrosting operation, wherein said defrosting control portion also generates a defrosting end signal for safety after a predetermined time from said starting of said defrosting operation if defrosting has not been stopped by said defrosting termination function of said defrosting device, and wherein said showcase unit controller terminates said defrosting operation of said heating means upon receipt of said defrosting end signal.