JPH0648126B2 - Freezing / refrigerator cooling operation method - Google Patents

Description

The present invention relates to a refrigerating / refrigerating showcase for cooling the inside of a refrigerator by an air circulation system, or a cooling operation method for a refrigerator / refrigerator.

(B) Conventional technology For example, an air-circulation type refrigerating system that cools the inside of the refrigerator with an air curtain of cold air formed by forcibly circulating cooling air, or a refrigerated showcase and a refrigerator / freezer, The structure is roughly as shown in FIG. That is,
Circulation fans 4 and 5 are arranged in two internal and external cold air circulation passages 2 and 3 in the showcase body 1, and a compressor (not shown) and a cooler 6 that constitutes a refrigerant circuit together with a condenser are provided inside the circulation passage 2 The cool air, which has been heat-exchanged by the cooler 6, is circulated in the refrigerator to form double inner and outer cool air curtains 8 and 9 in the front opening 7 of the showcase main body 1 and the outside air and the refrigerator. The inside is shut off and the inside is cooled.

By the way, in order to keep the inside of the refrigerator at a predetermined temperature almost constant,
Thermocycle operation control is widely performed in which the operation of the cooler 6 is operated at an upper limit value of a preset reference temperature and stopped at a lower limit value. In this case, there is a differential of several degrees between the upper limit value and the lower limit value of the set temperature, and this differential does not change even if the set temperature is changed. For this control, the temperature of the circulating air in the refrigerator is generally targeted, and for example, the discharge air temperature of the circulating air is measured and compared with a predetermined upper limit value and lower limit value of the cooler O.
Operation control methods such as discharge air temperature control for performing N, OFF, suction air temperature control similarly, or calculation inside temperature control calculated by the discharge and suction air temperatures are performed. Then, a temperature controller such as a thermostat is used for these temperature controls, and for example, the temperature detecting unit 10 of this temperature controller is installed in the vicinity of the discharge port 11 of the circulating air, and the temperature of this discharge air is detected. When the temperature exceeds the upper limit of the set temperature, the compressor is driven to cool it, and when the temperature reaches the lower limit of the set temperature, the operation of the compressor is stopped to control the temperature inside the refrigerator. Also, control refrigeration
When there are a plurality of refrigerators and the like, the start and interruption of the liquid refrigerant supply to the evaporator (cooler) in the refrigerant circuit is controlled by a liquid solenoid valve or the like.

Although the inside of the refrigerator is cooled by the circulating air by such a control method, defrosting is necessary because the cooler 6 is frosted with cooling and the cooling capacity is lowered. Defrosting is performed by an appropriate method such as a heater or hot gas. After defrosting, the cooling operation is turned on and off again based on the temperature of the circulating air in the refrigerator, that is, the thermocycle operation is performed to control the temperature in the refrigerator.

(C) Problems to be solved by the invention However, since the operation of the cooler is stopped and the forced circulation air is formed by the circulation fan during defrosting,
The temperature of the inside and the stored goods also rises. And after defrosting,
The operation of the cooler is restarted, and the raised interior and stored items are cooled again by the air curtain by the circulating air. At that time, the temperature of the air curtain by the circulating air is lowered and circulates in a relatively short time, but the temperature of the inside and the stored goods is not yet lowered sufficiently. However, since the cooling control is performed based on the temperature of this circulating air, the ON / OFF cycle operation of the cooling device is performed at the time when the inside of the refrigerator and stored products do not reach the target temperature, and a stable predetermined temperature condition is maintained. It takes a long time to reach the end, and the cooling of the temperature of the stored product is delayed, resulting in deterioration of quality.

Now, I think that the above-mentioned pattern of temperature change can be better understood from the graph of FIG. That is, FIG. 3 shows the inner layer discharge air temperature A1 and the inner layer suction air temperature B of the showcase which keeps the inside temperature constant by controlling the inner layer discharge air shown in the structure of FIG.
1, changes in the internal temperature C1 and the stored product temperature D1 are shown in a graph. In the figure, each temperature rises with defrosting. The temperature drop between the internal temperature C1 and the product temperature D1 after defrosting is the inner layer discharge air temperature A1.
Since it is slower than the descent of No. 1, if the thermocycle operation is controlled with the same lower limit value as that before defrosting, the thermocycle operation is performed before the internal temperature C1 and the product temperature D1 reach the target temperatures. Therefore, it takes a long time of 60 minutes for the cooling to stabilize.

Further, as shown in Japanese Utility Model Publication No. 58-3029, in a cooling method that employs a duty cycle operation, in which the on / off time of the cooling device is alternately repeated by a timer, after the defrosting, the temperature inside the refrigerator is at the lower limit. It has been proposed to stop driving the duty cycle and turn the cooling operation on and off with the temperature controller during pull-down operation until the temperature reaches the specified value.In this case, the purpose of the temperature controller is to control the duty cycle. The cycle operation is started from when the temperature reaches a predetermined low temperature detected by the temperature controller. Since the predetermined low temperature is the inside temperature, the actual product temperature has not yet reached that temperature. However, since the duty cycle operation is started from such a time, the cooling delay of the stored product similarly occurs.

The present invention completely eliminates the above-mentioned drawbacks of the prior art,
An object of the present invention is to provide a refrigerating / refrigerating cooling operation method capable of promptly cooling the temperature of a stored item that has risen during defrosting to a target temperature and solving a delay in cooling the stored item.

(D) Means for solving the problem The cooling operation method of the freezer / refrigerator according to the present invention is ON / OFF cycle operation control of the cooling device based on the temperature of the circulating air in the refrigerator, that is, a reference set temperature. Set in advance, turn on the compressor or liquid solenoid valve at the upper limit of this set temperature to start supplying liquid refrigerant to the evaporator (cooler), and turn off the compressor or liquid solenoid valve at the lower limit to evaporate In the system that controls the temperature inside the refrigerator by interrupting the supply of liquid refrigerant to the vessel, after defrosting, set this lower limit temperature to a lower level according to the rise in temperature inside the refrigerator during defrosting. Then, the cooling operation control based on the new corrected set temperature is performed, and the stored goods by the thermocycle operation that starts before the internal temperature and the product temperature that have occurred when the lower limit value before changing the setting is reached do not reach the target temperature. Prevents delay in cooling of the The lower limit value is changed so as to return to the gradual dimension, and the lower limit value is compared with the temperature of the circulating air to determine whether to continue the cooling operation, and after the lower limit value has been exceeded, the lower limit value is set within a certain period of time. If it does not exceed the limit, the control is performed at the normal lower limit value after that point.

(E) Action The lower limit setting value of the set temperature that determines the thermocycle operation of the cooling device after defrosting can be lowered, so that the inside of the refrigerator can be cooled rapidly, and at the time when the target inside temperature is reached. You can return to normal control with.

(F) Examples Examples of the present invention will be described below.

In the open front refrigerated showcase 1 as shown in FIG. 1, the opening portion 7 has an inner and outer double air curtain.
At 8 and 9, the outside air is shut off from the inside. Here, the start and interruption of the supply of the liquid refrigerant to the cooler 6 is controlled by driving or stopping the compressor or opening and closing the liquid solenoid valve, thereby controlling the temperature of the inner layer discharge air 8. The internal temperature is kept constant. That is, the inner layer discharge air temperature is controlled so as to fall between the upper limit value and the lower limit value of the set temperature which is a preset control reference value, and the operation control of the cooling device is performed so as to maintain this temperature range. . Here, the lower limit temperature value after defrosting is calculated by the following formula, and after defrosting, the internal operation control is performed with the calculated value as a new lower limit value.

Sd ＝ So-k (K ₁ -K ₀ ) + D ・ T ・ ・ ・ (1) Sd: Lower limit value after defrosting (℃) So: Normal lower limit value (℃) k: Inside of defrosting room A coefficient that is determined by the degree to which the temperature rise affects the product temperature K ₁ : Temperature inside the chamber after defrosting (° C) or calculated temperature after defrosting K ₀ : Temperature inside the chamber before defrosting (° C) or removal Calculated chamber temperature before frost K ₁ -K ₀ : Temperature rise in chamber during defrost (° C) D: Discharge setting determined by the degree of being affected by product temperature when cooled at the lower limit after defrost Rate of increase (° C / min) T: Elapsed time after defrosting (min) The lower limit value Sd after defrosting expressed by the above formula (1) gradually changes with the elapsed time after defrosting. Go. Then, the lower limit value Sd, which changes from moment to moment, is compared with the discharge air temperature A2 at each time point.If the discharge air temperature A2 is higher than the lower limit value Sd, the cooling operation is continued, and A2 = Sd. At that point, the cooling operation is stopped. Then, the thermocycle operation is started with the temperature value obtained by adding a certain temperature range to the lower limit value Sd as the upper limit value. Then, the return to the thermocycle operation based on the normal lower limit value So is performed by the judgment result of the following two conditions, and the lower limit value setting change section of the thermocycle is formed until then.

By the way, the conditions for the determination are: (1) After Sd ≧ So, the normal lower limit value So is controlled.

(2) When (1) is performed and the recovery is not made within a certain period of time (1), the normal lower limit value So is controlled thereafter. That is.

As described above, the series of calculation of the lower limit value Sd, the comparison with the discharge air temperature A1, and the comparison judgment with the normal lower limit value So can be performed by the control of the microprocessor. Here, for example, So = −5 ° C., k = 0.5, K ₀ = −3 ° C., K ₁ = 5 ° C., D = 0.125
When the temperature is ° C / min, Sd = -3 ° C-0.5 (5-(-3)) ° C + 0.125 ° C / min × T = -7 ° C + 0.125 ° C / min × T (2)

FIG. 2 shows the temperature when the lower limit temperature after defrosting is changed based on this equation (2). As can be seen in the figure, the temperature drop of the inner layer discharge air temperature A2, the inner layer intake air temperature B2, the chamber temperature C3, and the product temperature D2 becomes faster, and the time for the chamber to reach the target temperature -3 ° C. Is 40 minutes, which is significantly improved from the time required for 60 minutes in the conventional control method in which the set value shown in FIG. 3 does not change, to be greatly shortened.

When the temperature is controlled by the upper limit value, the upper limit temperature value after defrosting is calculated by the following formula, and after defrosting, the internal operation control is performed with the calculated value as a new upper limit value.

Sd ＝ So-k (K ₁ -K ₀ ) + D ・ T ・ ・ ・ (1) Sd: Upper limit after defrosting (℃) So: Normal upper limit (℃) k: Inside of defrosting room A coefficient that is determined by the degree to which the temperature rise affects the product temperature K ₁ : Temperature inside the chamber after defrosting (° C) or calculated temperature after defrosting K ₀ : Temperature inside the chamber before defrosting (° C) or removal Calculated chamber temperature before frost K ₁ -K ₀ : Temperature rise in chamber during defrosting (℃) D: When cooled at the upper limit after defrosting, discharge setting determined by the degree to which the product temperature is affected Rate of rise (° C / min) T: Elapsed time after defrosting (min) Then, if the upper and lower limit bands are not changed, D and K in the above equation will be the same value and the band will be changed Is D,
K has different values.

(G) Effect of the invention The operating method of the present invention, in the ON, OFF cycle operation control of the cooling device, the lower limit value of the preset temperature that is the condition of the OFF operation, after defrosting, during the defrosting Since the operation is performed at the lower limit value of the correction set temperature, which has been set to a lower value according to the rise in temperature inside the refrigerator, cooling is sufficiently performed after defrosting, and the temperature of stored goods that rises during defrosting can be promptly increased. It is possible to cool to the target temperature.

Therefore, for example, when fresh food is stored, a decrease in freshness due to a temperature rise during defrosting can be minimized. Further, when the target internal temperature is reached, the thermocycle control based on the first lower limit value is entered, and the normal operation is automatically returned.

[Brief description of drawings]

Fig. 1 is a cross-sectional view of a front open type open showcase, which is a type of freezer / refrigerator, Fig. 2 is a graph showing each temperature in the showcase by this operating method, and Fig. 3 is the showcase by the conventional operating method. It is a graph which shows each temperature. 1 ... Showcase body, 2, 3 ... Cold air circulation path, 6 ...
Cooler, 10 …… Temperature detector of temperature controller, A1, A2 …… Inner layer discharge air temperature, B1, B2 …… Inner layer intake air temperature, C1, C2 …… Inside temperature, D1, D2 …… Product temperature.

Claims (1)

[Claims] 1. The temperature of the circulating air in the refrigerator is detected, and when the temperature reaches a lower limit value of a preset reference temperature, the operation of the cooling device is stopped and the upper limit value of the preset temperature is reached. In that case, in the cooling operation method of the freezer / refrigerator that performs the cycle operation of re-driving the cooling device and keeps the inside of the refrigerator at a predetermined temperature, after defrosting, the lower limit value is adjusted according to the temperature rise width during the defrosting. The cooling device is driven at the correction setting temperature that is set lower, and after driving, the operation control is performed based on the set value that changes gradually to the lower limit value of the dimension, after returning to the lower limit value, or after no return within a certain time In the case of, the cooling operation method of the freezer / refrigerator is characterized by performing a normal cycle operation after that point.