JPH0560433A - Frost removing system for cooler - Google Patents

Abstract

PURPOSE:To hold cooling capacity of a cooler at a constantly optimum value by removing frost formed to the cooler at a proper time. CONSTITUTION:Information from a cooler temperature detecting means 5 and information from a cooler peripheral humidity detecting means 10 are inputted to a comparing computing means 20 and compared with each other according to a fuzzy theory for computation. A cooler frost removing means 25 is controlled by means of information obtained from the comparing computing means 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique capable of keeping cooling efficiency constant by defrosting a cooler used in a freezer, a refrigerator or the like in a timely manner.

[0002]

2. Description of the Related Art In a freezer, a refrigerator or the like, a refrigerating cycle using a refrigerant is generally used to cool the inside of the refrigerator. FIG. 4 is a sectional view of the refrigerator-freezer. That is, the refrigerant is compressed by the compressor 7, the refrigerant is liquefied by a condenser (not shown), decompressed by a capillary tube (not shown), evaporated by the cooler 2, and the heat of vaporization causes the cooler 2 to evaporate. The cooling is performed and the fan is rotated by the fan motor 1 to cool the freezing compartment 8 and the refrigerating compartment 9. In this case, since the surface of the cooler 2 is usually 0 ° C. or less, the frost phenomenon occurs in the cooler 2. When frost is formed on the cooler 2, heat exchange between the cooler 2 and the inside of the refrigerator is significantly deteriorated, and the cooler 2 is cooled but the inside of the refrigerator is not cooled. The electric damper 3 is
The inflow of cold air into the refrigerator compartment 9 is controlled and the thermistor 4 in the refrigerator compartment
Detects the temperature of the freezer compartment 8, and the refrigerating compartment thermistor 6 detects the temperature of the refrigerating compartment 9.

It is necessary to defrost the cooler 2 before frost is formed on the cooler 2 and heat exchange is significantly deteriorated. Some defrosting uses a time switch, but it is not effective because it has nothing to do with the operating time of the compressor. There, the one associated with the operating time of the compressor is used. This is because when the operating time of the compressor is counted by the compressor operating time cumulative measuring means and the preset time is reached,
For example, the cooler defrosting means for heating the cooler by the heater defrosts the cooler.

The preset time is the cumulative compressor operating time before the frost formation of the cooler progresses and the heat exchange with the inside of the refrigerator significantly deteriorates, and the value is experimentally and empirically determined. It is the fixed value obtained.

[0005]

However, the above-mentioned defrosting method by accumulating the compressor operation time has the following problems.

The actual amount of frost adhered to the cooler depends on the humidity of the air around the cooler, the temperature of the cooler, and the like.
However, in the conventional method, since the start of defrosting is determined only by the cumulative operation time of the compressor, defrosting is not always optimal.

It is an object of the present invention to remove the frost adhering to the cooler at appropriate times and to keep the performance of the cooler optimal at all times.

[0008]

According to the present invention, a cooler temperature detecting means, a cooler ambient humidity detecting means, information obtained from the cooler temperature detecting means and information obtained from the cooler ambient humidity detecting means. Are provided with a comparison calculation means for comparing and calculating based on the fuzzy theory, and a cooler defrosting means controlled by information obtained from the comparison calculation means.

[0009]

With the comparison calculation means, the cooler temperature and the cooler ambient humidity are calculated at any time based on the fuzzy theory, whereby the defrosting of the cooler with a fine texture can be performed.

[0010]

FIG. 1 is a block diagram of an embodiment of the present invention. In the present invention, the cooler temperature detecting means 5 is provided on the surface of the cooler 2, and the cooler ambient humidity detecting means 10 for detecting the humidity around the cooler 2 is attached in the vicinity of the cooler 2, and information from them is provided. It is input to the comparison calculation means 20, and the cooler defrost means 25 is controlled by the calculation result.

The comparison calculation means 20 performs comparison calculation by fuzzy reasoning as follows. The result of the comparison operation is represented by a predetermined numerical value (hereinafter referred to as an addend). The addends are added at any time, and when the predetermined value is reached, the cooler defrosting means 2
A signal is output to 5 and defrosting is started.

First, a fuzzy rule is created. The inputs necessary for fuzzy inference are the cooler temperature T and the cooler ambient humidity H, and the inference result (output) is the addend F. In this example, the fuzzy rules were set by experimenting with nine types of inference rules as shown in Table 1 below.

[0013]

[Table 1]

FIGS. 2A, 2B and 2C are representations by the membership function.

In FIG. 2A, the cooler temperature T is "low".
・ Membership function in each case of "medium" and "high".
Are membership functions in the cases of “low”, “medium”, and “high” respectively. In the figure (c), the output addends are “small”, “slightly small”, and “medium”.・
The membership functions are "slightly large" and "largely". These membership functions were also empirically determined as in the case of the fuzzy rules above.

Fuzzy inference is performed as follows. Input information is obtained from each detection means for each parameter of the fuzzy rule.

For example, when the input information of the cooler temperature of -20 ° C and the cooler ambient humidity of 70% is obtained, the cooler temperature-
The goodness of fit to each membership function shown in FIG. 2A at 20 ° C. is “low” 0, “medium” 1.0,
"High" is 0, and the ambient humidity of the cooler is 70%.
The suitability to each membership function shown in (b) is “low” 0, “medium” 0.5, and “high” 0.5.
Becomes

Among the fuzzy rules shown in Table 1, the rule with the goodness of fit of each membership function is rule N.
o. 5, rule no. 6, which is a rule number. 5 becomes like Fig. 3 (a),
Rule No. 6 is as shown in FIG. Next, FIG.
By superposing the membership functions of the addends obtained from (a) and (b), FIG. 3 (c) is obtained.

By obtaining the center of gravity of the figure of FIG. 3 (c) obtained as described above, since the center of gravity is 6.4, the addend is determined to be 6.

When the addend 6 is added and the added value reaches a predetermined value, the cooler defrosting means is operated.

[0021]

According to the present invention, by using fuzzy inference, it is possible to more accurately and finely defrost the cooler, and to always keep the cooling capacity of the refrigerator / freezer constant. Therefore, it is possible to reduce wasteful power consumption and save energy.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

2 (a), (b), and (c) are diagrams showing membership functions relating to a cooler temperature T, a cooler ambient humidity H, and an addend F, respectively.

FIG. 3 (a) is a rule number. The addend for 5 is represented by a membership function, and FIG. It is the figure which represented the addend with respect to 6 by the membership function,
(C) is a figure in which (a) and (b) are represented by a superposition membership function.

FIG. 4 is a schematic cross-sectional view of a conventional refrigerator-freezer.

[Explanation of symbols]

 5 Cooler Temperature Detecting Means 10 Cooler Ambient Humidity Detecting Means 20 Comparative Calculation Means 25 Cooler Defrosting Means

Claims (1)

[Claims] 1. A cooler temperature detecting means, a cooler ambient humidity detecting means, information obtained from the cooler temperature detecting means and information obtained from the cooler ambient humidity detecting means are compared and calculated based on a fuzzy theory. A defrosting method for a cooler, comprising: a comparison calculation means for performing the cooling operation; and a cooler defrosting means controlled by information obtained from the comparison calculation means.