JPH046381A - Determining method of defrosting starting time - Google Patents

Abstract

PURPOSE:To start defrosting operation based on the transition of the time of cooling operation of a cooling device, such as the ambient condition of a storing chamber, the cooling condition of materials received in the chamber and the like, by a method wherein an initial value is determined by effecting the integrating average of the operating time of a compressor in thermocycle operation proper several times after a temperature in the chamber has become lower than a set temperature by cooling operation while the defrosting operation is started when the operating time has becomes predetermined times or more of the initial value. CONSTITUTION:The counted times of a counter 25, connecting a time from the output of on-signal to the output of off-signal or the operating times of a compressor, are integrated and averaged proper several times to obtain an initial value (x) and store it while the counted times (or operating times) (p) after the operation of the initial value (x) are compared with the initial value (x) and a defrosting starting signal is outputted when the counted times (p) have become a given (k) times or more of the initial value (x).

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] Industrial Field of Application The present invention relates to a defrosting start timing determination method for determining the timing to start the unloading operation of a cooling device.

2. Description of the Related Art A defrosting control device disclosed in Japanese Patent Laid-Open No. 61-96382, for example, is known as a device for determining the timing to start defrosting in this type of cooling device. The configuration shown here includes a first timer that integrates the operating time of a cooling device used in a refrigerator or the like and generates a defrosting start output at a predetermined integrated time, and a first timer that is sufficiently longer than the integrated time. It consists of a second timer that generates a defrost start output every hour, and a defrost means that is operated by either of the defrost start outputs generated by the two timer means to remove frost from the cooler; Both of the time limit means are initialized by the defrosting start output of any of the above examples.

Problems to be Solved by the Invention In the above technology, the time to start defrosting is determined by the first and second timer means, and the two timer means each start the defrosting at a predetermined cumulative time interval. Generating start output. Additionally, the conditions under which frost builds up on the cooling device are markedly different when the temperature around the refrigerator is normal and when it is low temperature, such as in winter, so defrosting operation is performed at certain predetermined intervals. However, it has been virtually impossible to vary the defrosting period depending on changes in ambient conditions and the type of stored material as well as the cooling temperature. Moreover, when this control device is applied not only to household refrigerators but also to cooling devices that cool storage spaces with large storage volumes such as bush and hub refrigerators, the time required to start defrosting becomes longer and the unit time Another problem was that the operating efficiency of the cooling device per unit became high, leading to high running costs.

Therefore, in the present invention, the defrosting start time determination method determines the time to start the defrosting operation based on the surrounding situation of the storage, the cooling status of the items stored in the storage, and the transition of the cooling operation time of the cooling device. The present invention provides a method.

[Structure of the invention]

Means for Solving the Problems The defrosting start timing determination method of the present invention has been devised in view of the above-mentioned problems. An initial value is determined by accumulating and averaging the operating time for an appropriate number of times, and the compressor operating time for each one run after this initial value determination is compared with the initial value, and the operating time is determined to be at least a predetermined times the initial value. The system is designed to start defrosting operation when the

During thermocycle operation after the temperature inside the refrigerator drops below the set temperature due to cooling operation, the initial value used as the standard for determining the time to start weight removal is obtained by integrating and averaging the compressor operating time over an appropriate number of times. Moreover, this initial value includes factors such as ambient conditions that determine the degree of frost formation on the evaporator. Therefore, after the initial cooling operation and after the start of the cooling operation after the end of defrosting, an appropriate defrosting start time can be set in accordance with the ambient conditions.

Example The present invention will be described in detail below based on the drawings.

Reference numeral 1 denotes a cooling device installed in a storage such as a prefabricated refrigerator, and the air inside the storage is passed through an intake duct 2 with an open bottom.
The air is sucked in, heat exchanged with the evaporator 13 shown in FIG. 3, and turned into cold air, which is then blown into the storage from the discharge duct 3 to cool the inside of the storage. Reference numeral 4 represents a blower device of the cooling device 1, and reference numeral 5 represents a damper that adjusts the amount of air blown from the discharge duct 3.

FIG. 3 shows a simplified refrigerant circuit of this cooling device 1,
10 is a compressor, 11 is a condenser, 12 is a pressure reducing device, and 13 is an evaporator.

Next, the defrosting operation control device 24 will be explained.

20 is a temperature setting means for setting the temperature inside the storage to a desired temperature; 21 is a temperature detection means arranged on the air discharge side of the cooling device 1 to detect the temperature inside the storage; 22 is a compressor motor;
Reference numeral 23 denotes a cooling operation control means for operating the compressor motor 22 on and off based on the temperature T set by the temperature setting means 20 and the temperature T detected by the temperature detection means 21.

The cooling operation control means 23 generates a signal (i.e., a cooling stop signal (hereinafter referred to as an off signal)) that stops the operation of the compressor motor 22 when the detected temperature T1 falls below the set temperature T8 by a predetermined temperature (for example, 1°C). ], and when the detected temperature Tt exceeds the set temperature T8 by a predetermined temperature, it outputs a signal [i.e., a cooling start signal (hereinafter referred to as an ON signal)] that starts the operation of the compressor motor 23.

25 is a timer that measures the time from when the on signal is output to when the OFF signal is output, that is, the operating time of the compressor; 26 is the timer that measures the time measured by the timer 25 for an appropriate number of times (in this example, 3 times); ) An initial value calculation unit 27 which integrates and averages the value and stores it as an initial value or 27 compares the clocked time (i.e. operating time) p after the initial value X has been calculated with the initial value X, and calculates the clocked time p. This is a defrosting start determining unit that outputs a defrosting start signal (hereinafter referred to as a def signal) when the initial value X is equal to or more than a constant (k) times.

Note that when the defrosting start determining section 27 outputs the def' signal, it outputs a clear signal (hereinafter referred to as cl signal) for clearing the initial value to the initial value calculating section 26.

28 is a defrosting means that heats the evaporator 13 and defrosts it based on the def signal.

The above-mentioned clock section 25, initial value calculation section 26, and defrost start determining section 27 constitute the defrosting control device 24.

Further, the initial value determining unit 26 does not include the operating time from the cooling operation until the compressor first stops (so-called pull-down operation) in the appropriate number of operations. The same applies when the cooling operation is restarted after the defrosting operation is finished.

The operation of the defrosting operation control device 24 will be explained below. However, it is assumed that the refrigerated articles can be properly stored in the storage and the internal temperature is far above the set temperature T8.

(1) Since TI>TI, cooling operation control means 2
3 outputs an on signal, the compressor motor 22 becomes operational, and performs a cooling operation (pull-down operation) to lower the temperature inside the refrigerator to a set temperature, while the timer 25 starts a timer operation.

(2) The internal temperature T detected by the temperature detection means 21 during the cooling operation increases the set temperature T to a predetermined temperature (1° in this example).
C), the cooling operation control means 23 turns off.
The f' signal is output, the motor 22 is stopped, cooling is stopped, and the clock section 25 stops the time measurement operation (however, the initial value calculation section 26 does not include this clock time in determining the initial value). .

(3) When the temperature inside the refrigerator, that is, the detected temperature T1 exceeds the set temperature TI by 1°C due to the cooling stop, the cooling operation control means 23 outputs the ON signal again, so the compressor motor 22
enters the operating state and performs cooling operation in the refrigerator (cooling operation in thermocycle operation substantially starts from this point). On the other hand, based on this ON signal, the timer section 25 starts a timer operation.

4) When the detected temperature T3 falls below the set temperature T8 by 1°C due to the cooling operation in this thermocycle operation,
Since the cooling operation control means 23 outputs an off' signal,
The compressor motor 22 stops to stop cooling, and
The timekeeping section 25 stops the timekeeping operation. When the measured time at this time is A, the initial value calculation unit 26 inputs it as one of the three integrations.

(5) The operations of (3) and (4) described above are repeated to cool down the temperature inside the refrigerator with a differential of 1°C above and below the set temperature T. Then, the time measured by the timer 25 is input twice (the second time is B, and the third time is C).

(6) When the three times of measurement time are input to the initial value calculation unit 26, the initial value X of x − (A + B + C) / 3 is calculated, and this Output to 27. Then, when the fourth time measurement time is output from the time measurement units 2 and 5, the defrosting start determining unit 27 compares the initial value X with this time measurement time, and when D≧kx, While outputting the def signal,
It outputs the l signal and waits for input of the fifth time E when D<kx. In this example, the fourth time is ■,
In the fifth test, ■ was satisfied.

(7) Since the time E measured by the fifth time measurement operation satisfies D≧kx, the defrosting start determining unit 27 outputs the def signal and the cl signal, and the defrosting means 28 starts the defrosting operation. The initial value X of the initial value calculation section 26 is cleared.

At this time, the compressor motor 22 is in a stopped state because the timing operation has ended. In other words, the internal temperature T
3 is below the set temperature T3 by 1°C,
The defrost start determining unit 27 outputs the def signal, and the temperature inside the refrigerator shifts from a low state to the defrosting operation, so that the rise in temperature inside the refrigerator accompanying the defrosting operation is suppressed.

(8) When the defrosting operation is started and the end of defrosting is detected by the defrosting end detection means (not shown), the defrosting operation of the defrosting means 28 is stopped and the process returns to the above-mentioned <1>, Perform cooling operation again.

〔Effect of the invention〕

As detailed above, according to the defrosting start timing determination method of the present invention, the initial value is determined after thermocycle operation starts, and this initial value depends on the ambient conditions of the storage and the moisture content of the stored items. It changes based on the environment, and it is possible to grasp the outline of the environment from this initial value. In addition, the defrosting start time is determined by comparing this initial value with the operating time after the initial value is determined, so if the ambient temperature and humidity are low and frost is difficult to form, the defrosting cycle will be longer. While wasteful defrosting operations can be avoided, if the ambient conditions are high in temperature and humidity and frost is likely to form, the defrosting cycle will be shortened, preventing clogging of the evaporator due to frost and a reduction in heat exchange due to this clogging. This can be avoided, and defrosting operation can be performed in accordance with the ambient conditions. Furthermore, the weight removal cycle can be automatically changed depending on the season.

[Brief explanation of drawings]

Each figure shows an embodiment of the present invention. Figure 1 is a block circuit diagram of the control device, Figure 2 is an explanatory temperature characteristic diagram showing the relationship between internal temperature and time, and Figure 3 is a refrigerant diagram. The circuit diagrams, FIGS. 4 and 5, are a front perspective view and a rear perspective view of the cooling device. l... Cooling device, 22... Compressor motor, 24
... Defrosting operation control device, 25 ... Timing section, 26
...Initial value determining section, 27... Defrosting start determining section,
2B... Weight removal means.

Claims (1)

[Claims] 1. After the temperature inside the refrigerator falls below the set temperature due to cooling operation, determine the initial value by integrating and averaging the operating time of the compressor for an appropriate number of times during thermocycle operation, and after determining this initial value, calculate the compression for each time. Compare the machine operating time and the initial value,
A defrosting start timing determining method, wherein a defrosting operation is started when the operating time becomes a predetermined time or more of the initial value.