JP6971776B2 - Bleed air control device and control method - Google Patents

Description

The present invention relates to a refrigerator, and more particularly to a control device and a control method for an bleed air device.

In a refrigerator that uses a low-pressure refrigerant, the pressure inside the refrigerator may become negative depending on the operating conditions. Therefore, especially when the sealing performance deteriorates, non-condensable gas (mainly air) enters the refrigerator and condenses. There is a possibility that it will collect in the vessel. In this state, there is a concern that the non-condensable gas raises the condensing pressure and the condenser does not operate normally. For this reason, conventionally, the non-condensable gas that has entered the machine is discharged into the atmosphere by an bleed air device.

Further, due to the revision of the Freon Recovery and Destruction Law and the European F-gas regulation, it is desired to use a low GWP refrigerant which is a low pressure refrigerant for the refrigerator. However, the low GWP refrigerant is easily decomposed by oxygen, and there is a risk of producing by-products that affect the stable operation of the refrigerator. In a refrigerator using a low GWP refrigerant, if non-condensable gas invades, the low GWP refrigerant may be decomposed and the operation of the refrigerator may become unstable. Therefore, in a refrigerator using a low GWP refrigerant, it is necessary to estimate the amount of non-condensable gas (total amount of air intrusion) in the machine with high accuracy and appropriately extract air in order to maintain stable operation.

Patent Document 1 discloses that the total amount of air intrusion into the refrigerator is estimated from the structure and pressure state of the refrigerator, and the activation of the bleed air device is controlled based on the estimated total amount of air intrusion.

Japanese Unexamined Patent Publication No. 2016-65673

However, since the total amount of air intrusion changes according to various conditions such as humidity and outside air temperature, it is difficult to estimate the total amount of air intrusion with high accuracy. Therefore, even in a situation where the possibility of non-condensable gas invading is low, the amount of air intrusion may be estimated to be large, and the bleed air may be operated unnecessarily.

The present invention has been made in view of such circumstances, and provides a control device and a control method for an bleed air device capable of estimating the total amount of air intrusion with higher accuracy and further optimizing the operation of the bleed air device. The purpose is to do.

The first aspect of the present invention is a control device for controlling an air extraction device provided in a refrigerator, in which an estimation means for estimating the total amount of air intrusion into the refrigerator and the total amount of air intrusion are preset. A determination means for determining whether or not the air intrusion is equal to or greater than the permissible value, and when the total air intrusion amount is equal to or greater than the permissible value, the activation duration of the air extraction device is determined based on the total air intrusion amount, and only the activation duration is determined. The difference between the total air intrusion amount and the exhaust air amount is the start control means for activating the air extraction device, the exhaust air amount calculation means for calculating the exhaust air amount which is the amount of air actually exhausted by the air extraction device, and the exhaust air amount. It is a control device provided with a correction means for correcting at least one of the total amount of air intrusion and the start-up duration when the amount is equal to or more than a predetermined amount.

According to the above configuration, the exhaust air amount, which is the amount of air actually extracted, is calculated, and the exhaust air amount is used to determine at least one of the total amount of air intrusion and the activation duration of the bleeding device. Since the correction is made, the total amount of air intrusion can be corrected more accurately according to the actual operating condition of the refrigerator. Since the activation duration of the bleed air device is determined based on the total amount of air intrusion, even when the activation duration is corrected, the total amount of air intrusion is indirectly corrected. That is, it is possible to more accurately estimate the total amount of air intrusion according to the operating conditions. For example, even when a low GWP refrigerant is used as the refrigerant of the refrigerator, the total amount of air intrusion can be estimated more accurately, so that more stable operation can be maintained.

In the control device, the correction means at least the total amount of air intrusion and the start-up duration by multiplying by a correction constant corresponding to the difference between the total amount of air intrusion estimated by the estimation means and the amount of discharged air. Any one may be corrected.

According to the above configuration, if the difference between the estimated total air intrusion amount and the actual exhaust air amount is large, a simple calculation of multiplying the air intrusion amount and / or the start-up duration by the correction constant is possible. Corrections can be made. Therefore, the correction can be performed without imposing a processing load.

In the control device, the correction constant may be a value obtained by dividing the total amount of air intrusion from the amount of discharged air.

According to the above configuration, the correction can be performed by a simple calculation, so that the correction can be performed without imposing a processing load.

In the control device, the refrigerator is divided into a plurality of sections, the degree of influence of air intrusion is set for each section, and the estimation means estimates and estimates the amount of air intrusion for each section. The total amount of air intrusion in the entire refrigerator is estimated from the amount of air intrusion in each of the sections, and when the correction means corrects the total amount of air intrusion, the total amount of air intrusion is corrected for each section according to the degree of influence of air intrusion. The amount of air intrusion may be corrected.

According to the above configuration, the amount of air intrusion can be corrected for each section according to the degree of influence of air intrusion, so that more accurate correction can be made according to the operating state of the refrigerator and the structure in each section. It will be possible to do. Since each section has a different configuration such as the number of joints, the ease of air intrusion (degree of influence of air intrusion) is different. Therefore, it is possible to effectively correct the amount of air intrusion in the section where air easily enters by performing the correction according to the degree of influence of air intrusion. Therefore, the total amount of air intrusion can be estimated more accurately.

The second aspect of the present invention is a refrigerator that employs a low-pressure low GWP refrigerant, and is provided with an bleed air device and the above-mentioned control device.

A third aspect of the present invention is a control method for an air extraction device provided in a refrigerator, in which an estimation step for estimating the total amount of air intrusion into the refrigerator and an allowable value in which the total amount of air intrusion is preset. The determination step for determining whether the above is the case, and when the total amount of air intrusion is equal to or greater than the permissible value, the activation duration of the bleeding device is determined based on the total amount of air intrusion, and the bleeding is performed by the activation duration. The difference between the start control process for activating the device, the exhaust air amount calculation step for calculating the exhaust air amount which is the amount of air actually exhausted by the bleeding device, and the total air intrusion amount and the exhaust air amount is a predetermined amount. In the above cases, it is a control method of an air extraction device including a correction step of correcting at least one of the total amount of air intrusion and the start-up duration.

According to the present invention, there is an effect that the total amount of air intrusion can be estimated more accurately and the operation of the bleed air device can be optimized.

It is a figure which showed the schematic structure of the refrigerator which concerns on 1st Embodiment of this invention. It is a figure which showed the functional block of the control device which concerns on 1st Embodiment of this invention. It is a figure which showed the flow of the control method of the bleed air apparatus which concerns on 1st Embodiment of this invention. It is a figure which showed the flow of the exhaust air amount calculation method executed by the control apparatus which concerns on 1st Embodiment of this invention. It is a figure which showed the flow of the correction method executed by the control apparatus which concerns on 1st Embodiment of this invention. It is a figure which showed the amount of the non-condensable gas in the condenser of the refrigerator which concerns on 1st Embodiment of this invention. It is a figure which showed the amount of the non-condensable gas in the bleed air apparatus of the refrigerator which concerns on 1st Embodiment of this invention.

[First Embodiment]
Hereinafter, the first embodiment of the control device and the control method of the bleed air device according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a refrigerator 1 according to a first embodiment of the present invention. As shown in FIG. 1, the refrigerator 1 according to the present embodiment is a compression type refrigerator, and is a compressor 2 that compresses the refrigerant and a condenser 3 that condenses a high-temperature and high-pressure gas refrigerant compressed by the compressor 2. , The expansion valve 4 that expands the liquid refrigerant from the condenser 3, the evaporator 5 that evaporates the liquid refrigerant expanded by the expansion valve 4, and the non-condensable gas (mainly air) that has entered the refrigerator 1. The main configuration includes an air extraction device 6 for discharging to the atmosphere and a control device 7 for controlling each part of the refrigerator 1.
As the refrigerant, a low GWP refrigerant which is a low pressure refrigerant is adopted. Since the bleed air device 6 according to the present embodiment can estimate the amount of non-condensable gas that has entered the machine with high accuracy by performing the correction described later, it is not limited to the low GWP refrigerant and various refrigerants. It is possible to use.

The compressor 2 is, for example, a multi-stage centrifugal compressor driven by a constant speed motor or a variable speed motor. The bleed air device 6 is connected to the condenser 3 by a pipe 8, and the refrigerant gas (including the non-condensable gas) from the condenser 3 is guided to the bleed air tank 16 in the bleed air device 6 through the pipe 8. .. Further, the pipe 8 is provided with a valve 9 and a backflow prevention valve 10 for controlling the flow and shutoff of the refrigerant gas. By controlling the opening and closing of the valve 9 by the control device 7, the start and stop of the bleed air device 6 are controlled. Further, the check valve 10 prevents the backflow of the refrigerant gas (including the non-condensable gas) from the bleed air tank 16 in the bleed air device 6 to the condenser 3.

The bleed air device 6 condenses the refrigerant gas (including non-condensable gas) supplied through the pipe 8 by cooling it with a Pelche element, and separates it from the non-condensable gas. It is equipped with a pump 11 that bleeds the non-condensed gas into the atmosphere. In the bleed air tank 16, the non-condensable gas is discharged into the atmosphere, and the refrigerant gas separated from the non-condensable gas is returned to the evaporator 5 through the pipe 13 by controlling the valve 12. The configuration of the bleed air device 6 is an example, and is not limited to this configuration. The cooling method for condensing the refrigerant gas in the bleed air tank 16 is also an example of cooling using a Pelche element, and is not limited to this configuration.

Further, the bleed air tank 16 in the bleed air apparatus 6 is provided with a pressure sensor 14 and a temperature sensor 15 in order to monitor the state of the non-condensable gas accumulated inside (presence or absence of non-condensable gas, accumulated amount, etc.). .. The measured values of these sensors are transmitted to the control device 7 and used for controlling the bleed air device 6.

The configuration of the refrigerator 1 shown in FIG. 1 is an example, and is not limited to this configuration. For example, an air heat exchanger may be arranged in place of the condenser 3 to exchange heat between the cooled outside air and the refrigerant. Further, the refrigerator 1 is not limited to the case where it has only a cooling function, and may be, for example, a refrigerator having only a heating function or a refrigerator having both a cooling function and a heating function.

The control device 7 has a function of controlling the compressor 2 based on a measured value received from each sensor, a load factor sent from a higher-level system, and the like, and a function of controlling the bleed air device 6.

The control device 7 includes, for example, a CPU (central processing unit) (not shown), a memory such as a RAM (Random Access Memory), a computer-readable recording medium, and the like. A series of processing processes for realizing various functions described later is recorded in a recording medium or the like in the form of a program, and the CPU reads this program into RAM or the like to execute information processing / arithmetic processing. As a result, various functions described later are realized.

FIG. 2 is a functional block diagram showing the control functions of the bleed air device 6 extracted from the functions included in the control device 7. As shown in FIG. 2, the control device 7 includes an estimation unit 21, a determination unit 22, an activation control unit 23, a storage unit 24, an exhaust air amount calculation unit 25, and a correction unit 26. ..

The estimation unit 21 estimates the total amount of air intrusion using the degree of influence of air intrusion determined from the structural aspect of the refrigerator 1 and the function including pressure as a parameter.
The degree of influence of air intrusion is, for example, an index indicating how much air (oxygen) may invade the refrigerator 1 and is stored in advance in the storage unit 24. The degree of influence of air intrusion is determined by, for example, the structure, size, number, and the like of joints connecting pipes and the like. Further, in consideration of the case where air penetrates through the resin material and invades, the degree of influence of air intrusion may be set in consideration of the information of the resin material.

In the present embodiment, the refrigerator 1 is divided into a plurality of sections, and the degree of influence of air intrusion is set for each section.
Here, the sections can be appropriately divided. For example, depending on the operating conditions (for example, whether it is operating or stopped) and whether it is likely to have negative pressure in winter / summer, the sections showing the same tendency are divided into sections. It may be that. For example, in the summer, the pressure around the evaporator 5 tends to be negative, and in the winter, the pressure tends to be negative in places other than the refueling system both during operation and stop. From such a tendency, for example, the area around the evaporator 5 may be defined as one section, and the other parts may be defined as, for example, the area around the compressor 2 and the area around the condenser 3 as one section.

The estimation unit 21 estimates the amount of air intrusion for each section using, for example, the degree of influence of air intrusion set for each section, the pressure in each section, and the atmospheric pressure. Specifically, when the pressure in the section is higher than the atmospheric pressure, that is, when the pressure is positive, the amount of air intrusion is zero. On the other hand, when the pressure in the section is lower than the atmospheric pressure, that is, when the pressure is negative, the value obtained by multiplying the 1/2 power of the differential pressure between the pressure and the atmospheric pressure by the degree of air intrusion influence is estimated as the air intrusion amount. do. Expressed as an arithmetic expression, it becomes the following equations (1) and (2).

In the above equations (1) and (2), P (s) is the pressure [Pa (abs)] in the section s, Pat is the atmospheric pressure [Pa (abs)], and M (s) is the amount of air intrusion in the section s. [M ³ ] and E (s) are the degree of influence of air intrusion in the section s [m ³ / Pa]. The unit of the amount of air intrusion is ^{not limited to the above [m 3} ], and for example, kg, mol, or the like may be used.

The air intrusion amount M (s) in the section s indicates the amount of air that is estimated to have invaded the section s in the state of pressure and atmospheric pressure in the section s per unit time (per control cycle). ing.

When the air intrusion amount M (s) for each section is estimated in this way, the air intrusion amount M (s) is corrected by the correction unit 26, and the air intrusion amount Ma (s) is corrected. Is calculated. Then, the estimation unit 21 adds the total value of the air intrusion amount Ma (s) of each section (air intrusion amount Ms (s)) to the previous integrated value of the air intrusion amount, so that the integrated value of the air intrusion amount is obtained. That is, the total amount of air intrusion of the entire refrigerating machine 1 at the present time (hereinafter referred to as "total amount of air intrusion") is calculated. The calculation formula is as shown in the following formula (3).

In the equation (3), M (t) is the total amount of air intrusion, M (t-1) is the previously integrated value of the air intrusion amount, and ΣMa (s) is the total value of the air intrusion amount for each section calculated this time.

The determination unit 22 determines whether the total air intrusion amount M (t) estimated by the estimation unit 21 is equal to or higher than the preset allowable value Mc.

The permissible value Mc is set based on, for example, the chemical stability test of the refrigerant and the operational results. For example, the total amount of air intrusion that causes the decomposition of the refrigerant or the total amount of air intrusion that does not hinder the stable operation of the refrigerator 1 is acquired by tests and operation results, and is set to a value smaller than this total amount of air intrusion.
Here, it is necessary that the permissible value Mc and the total amount of air intrusion have the same unit. For example, when the unit of the allowable value is [mol] and the total amount of air intrusion is a unit other than [mol], the unit of the total amount of air intrusion is converted into the unit of allowable value [mol], and the converted air intrusion is performed. The total amount and the permissible value may be compared.

The activation control unit 23 activates the bleed air device 6 when the total amount of air intrusion M (t) is equal to or greater than the allowable value Mc. For example, the start control unit 23 opens the valve 9 provided in the pipe 8 to start the bleed air device 6. The activation duration of the bleed air device 6 is determined at any time according to the ratio of the total amount of air intrusion M (t) of the entire refrigerator 1 to the capacity of the refrigerator.

Further, when the start-up duration is determined at any time according to the ratio of the total air intrusion amount M (t) of the entire refrigerator 1 to the capacity of the refrigerator, the following equation (4) may be used, for example.

In the formula (4), tk is the activation duration [s] of the bleeding device 6, and Vnc is the gas capacity [m ³ ] to be bleeded, which is calculated by the above formula (5). Further, Vc is the internal volume of the freezer [m ³ ]. In equation (5), by adding a predetermined margin α to the total air intrusion amount M (t), the gas capacity to be extracted is set to be slightly larger than the actual total air intrusion amount M (t) and calculated. There is a margin in the startup duration to be performed.

The activation duration ct of the bleed air device 6 may be calculated by the following equation (6) with the volume of the gas to be bleeded and the drawing capacity of the bleed air device 6 as parameters.

In the equation (6), va is the drawing capacity [m ³ / s] of the bleed air device 6.
The start control unit 23 does not start the bleed air device 6 when the total amount of air intrusion is less than the allowable value.

The storage unit 24 stores in advance the information referred to in the processing of the estimation unit 21 and the determination unit 22 described above. For example, in addition to the air intrusion influence degree E (s) and the allowable value Mc in each section, the constants included in each calculation formula (1)-(6) are registered in advance. Further, the storage unit 24 stores a table in which the difference between the estimated total air intrusion amount M (t) and the exhaust air amount Md (t) and the correction constant c are set corresponding to each other. .. When the total air intrusion amount M (t) is smaller than the exhaust air amount Md (t), the correction constant is set to a value larger than 1, and the total air intrusion amount M (t) is the exhaust air amount Md (t). ), The correction constant c is set to a value smaller than 1. The correction constant c is set according to the difference between the estimated total air intrusion amount M (t) and the exhaust air amount Md (t). As an example, the exhaust air amount Md (t) is set as the total air intrusion amount M. It is a value divided by (t). The correction constant c may be stored in the calculation formula and calculated at the time of correction, even if it is not stored as a table in the storage unit 24.

The exhaust air amount calculation unit 25 calculates the exhaust air amount Md (t), which is the amount of air actually extracted by the bleed air device 6. When the bleed air device 6 is actually operated, the non-condensable gas is accumulated in the bleed air tank 16 in the bleed air device 6. Then, when the non-condensable gas accumulated in the bleed air tank 16 reaches a preset predetermined amount (one discharge amount D1), the valve 9 is closed and the supply of the refrigerant gas from the condenser 3 is stopped. The pump 11 provided in the bleed air tank 16 is operated to discharge the non-condensable gas into the atmosphere. When the discharge of the non-condensable gas is completed, the valve 9 is opened again, the non-condensable gas is accumulated in the bleed air tank 16, and the above discharge operation is repeated until the discharge of the non-condensable gas is completed. This discharge operation is performed once or a plurality of times depending on the amount of the non-condensable gas actually accumulated in the refrigerator 1 during the set start-up duration. Since the discharge operation is performed once or a plurality of times during the activation duration of the bleed air device 6, the actual discharge is performed by measuring the discharge amount D1 at one time and the number of times n of the discharge operations are performed. The exhaust air amount Md (t), which is the amount of air discharged, can be calculated.

The one-time discharge amount D1 is determined based on the capacity of the bleed air device 6 (mainly the bleed air tank 16). That is, when the non-condensable gas corresponding to the capacity of the bleed air tank 16 is accumulated in the bleed air device 6 (when the bleed air tank 16 is filled with the non-condensable gas), the accumulated non-condensable gas is discharged. When it is desired to discharge the non-condensable gas accumulated in the refrigerator 1 in a short time, it is preferable to use the bleed air tank 16 having a large capacity in order to increase the amount of one discharge. Further, in the case of calculating the exhaust air amount, which is the amount of air actually extracted, more accurately, it is preferable to reduce the discharge amount at one time and improve the estimation resolution of the exhaust air amount Md (t). In this case, a small capacity bleed tank 16 may be used.

The single discharge amount D1 may be arbitrarily determined with the capacity of the bleed air device 6 (mainly the bleed air tank 16) as the upper limit. In this case, the amount of non-condensable gas in the bleed air tank 16 is estimated by the pressure sensor 14 and the temperature sensor 15 installed in the bleed air device 6, and the estimated amount of non-condensable gas is arbitrarily determined. It may be compared with a fixed amount (a single emission amount D1).

The correction unit 26 has at least the estimated total air intrusion amount M (t) and the activation duration when the difference between the total air intrusion amount M (t) and the exhaust air amount Md (t) is a predetermined amount β or more. Correct any one. Therefore, the correction unit 26 includes a correction necessity determination unit 31, a correction constant update unit 32, and a correction execution unit 33. In this embodiment, a case where the total amount of air intrusion M (t) is corrected will be described. The correction of the activation duration will be described in a modified example in the latter stage.

The correction necessity determination unit 31 corrects the total air intrusion amount M (t) by determining whether or not the difference between the total air intrusion amount M (t) and the exhaust air amount Md (t) is a predetermined amount β or more. Determine if it needs to be done. As will be described later, when it is necessary to correct the total air intrusion amount M (t), the correction constant c for correcting the estimated air intrusion amount M (s) in each section is updated. As a result, the total amount of air intrusion M (t) is corrected. The predetermined amount β used in the correction necessity determination unit 31 is set within a range of an error allowed for the exhausted air amount Md (t) of the estimated total air intrusion amount M (t).

In the correction constant update unit 32, when the correction necessity determination unit 31 determines that the difference between the total air intrusion amount M (t) and the exhaust air amount Md (t) is a predetermined amount β or more, the correction constant is set. Update. The correction constant is assumed to be set to 1 as the initial setting value, and is updated each time when the correction necessity determination unit 31 determines that the total air intrusion amount M (t) needs to be corrected. Specifically, when the correction constant updating unit 32 determines that the total air intrusion amount M (t) needs to be corrected, the estimated total air intrusion amount M (t) and the exhaust air amount Md (t). ) Is read from the storage unit 24, and the read correction constant is updated by multiplying the correction constant set up to that point. For example, when the correction constant is set to 1.2 and the correction constant of 1.1 is read from the storage unit 24 by the correction constant update unit 32, a new correction constant is set to 1.2 ×. Update as 1.1 = 1.32. The update of the correction constant is updated by multiplying by a new correction constant every time it is determined that the correction of the total air intrusion amount M (t) is necessary.

The correction execution unit 33 calculates the air intrusion amount Ma (s) by multiplying the air intrusion amount M (s) of each section estimated by the estimation unit 21 by the correction constant. Then, the estimation unit 21 calculates the total air intrusion amount M (t) using the air intrusion amount Ma (s) calculated by the correction execution unit 33.

Next, a method of controlling the bleed air device 6 by the above-mentioned control device 7 will be described with reference to FIG. The correction constant c is set to 1 by default, and when the correction constant is updated by the correction unit 26, the updated correction constant c is used.
First, measured values of pressure P (s) and atmospheric pressure Pat in each section from various sensors (for example, pressure sensor and temperature sensor (not shown in FIG. 1)) provided in the refrigerator 1 and around the refrigerator 1. (S301).

Next, the air intrusion amount M (s) for each section is calculated using the pressure P (s) and the atmospheric pressure Pat in each section (S302).

Next, the air intrusion amount M (s) estimated for each section is corrected (S303). Specifically, the air intrusion amount Ma (s) is calculated by multiplying the air intrusion amount M (s) by a correction constant. Since the correction constant c is set to 1 by default, if the correction constant is not updated, M (s) = Ma (s). Further, when the correction constant is updated, the updated correction constant (≠ 1) is used, so that M (s) ≠ Ma (s).

Next, the total air intrusion amount M (t) is calculated by adding the value ΣMa (s) obtained by adding the air intrusion amount Ma (s) of each section to the previously integrated value M (t-1) of the air intrusion amount. (S304).

Next, it is determined whether or not the total amount of air intrusion M (t) is equal to or greater than the allowable value Mc (S305). Here, if both units do not match, the two are compared after performing a process of converting one unit to match the other.

In S305, when the total air intrusion amount M (t) is equal to or greater than the allowable value Mc (YES determination in S305), the activation duration is calculated based on the total air intrusion amount M (t) (S306). Then, the bleed air device 6 is activated (S307). Subsequently, it is determined whether or not the activation continuation time has elapsed (S308), and when the activation continuation time has elapsed, the bleed air device 6 is stopped (S309).
Subsequently, zero is set in the previously integrated value M (t-1) of the air intrusion amount (S310).
On the other hand, in S305, when the total air intrusion amount M (t) is less than the allowable value Mc, the total air intrusion amount M (t) calculated this time is set in the previous integrated value M (t-1) of the air intrusion amount. (S311).

The above processing is continuously performed at regular time intervals regardless of, for example, whether the refrigerator 1 is in operation or stopped.

Next, a method of calculating the exhaust air amount of the bleed air device 6 by the control device 7 described above will be described with reference to FIG.
In the flowchart shown in FIG. 4, the operation is started when the bleed air device 6 is activated by the activation control unit 23.

First, when the bleed air device 6 is activated by the activation control unit 23, the number of discharge operations n = 0 is set (S401).
Next, it is determined whether or not the activation duration has elapsed (S402), and if the activation duration has not elapsed (NO determination of S402), it is determined whether or not the bleeding operation by the bleed air device 6 has been performed. Judgment (S403). When it is determined that the ejection operation has not been performed (NO determination in S403), it is determined again whether or not the activation continuation time has elapsed (S402). It should be noted that the operation of S402 and S403 determines whether or not the discharge operation is performed within the activation duration.

When it is determined that the discharge operation of the bleed air device 6 has been performed (YES determination in S403), the number of discharge operations n is counted up (plus 1 time) (S404). When the count-up of the number of discharge operations n is completed, the process returns to S402 and the above process is repeated.

When it is determined that the activation duration has elapsed (YES determination in S402), the exhaust air amount Md (t), which is the amount of air actually extracted, is calculated (S405). Specifically, in S405, the discharged air amount Md (t) is calculated by multiplying the non-condensed gas discharge amount D1 in one discharge operation of the bleed air device 6 by the number of discharge operations n.

Next, the correction method by the above-mentioned control device 7 will be described with reference to FIG.
The flowchart shown in FIG. 5 is executed after all the exhaust operations of the bleed air device 6 are completed and the exhaust air amount Md (t) is calculated. The flowchart shown in FIG. 5 is executed every time the discharge operation of the bleed air device 6 is completed.

First, it is determined whether or not the difference (absolute value) between the total air intrusion amount M (t) and the exhaust air amount Md (t) is a predetermined amount β or more (S501). When the difference (absolute value) between the total air intrusion amount M (t) and the exhaust air amount Md (t) is smaller than the predetermined amount β (NO determination in S501), the correction constant is not updated (S502).

When the difference (absolute value) between the total air intrusion amount M (t) and the exhaust air amount Md (t) is a predetermined amount β or more (YES determination in S501), the estimated total air intrusion amount M (t) is used. A correction constant corresponding to the difference from the exhaust air amount Md (t) is read from the storage unit 24 (S503). Then, the read correction constant is updated by multiplying the correction constant that has been set up to that point (S504).

Next, the operation of discharging the non-condensable gas by the above-mentioned control device 7 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing the amount of non-condensable gas in the condenser 3 of the refrigerator 1 according to the present embodiment. FIG. 7 is a diagram showing the amount of non-condensable gas in the bleed air device 6 of the refrigerator 1 according to the present embodiment.

As shown in FIG. 6, non-condensable gas is accumulated in the refrigerator 1 depending on the operating state of the refrigerator 1 and the external environment. The amount of non-condensable gas accumulated is estimated by the estimation unit 21, and is estimated with high accuracy by being corrected by the correction unit 26. Then, when the amount of non-condensable gas accumulated in the condenser 3 (total amount of air intrusion M (t)) exceeds the permissible value Mc, the bleed air device 6 is activated and the non-condensable gas accumulated in the condenser 3 is not generated. The condensed gas is drawn into the bleeding device 6.

On the bleeding device 6 side, as shown in FIG. 7, when the amount of non-condensable gas accumulated in the condenser 3 (total amount of air intrusion M (t)) exceeds the permissible value Mc, the non-condensable gas is activated. Is drawn from the condenser 3. Therefore, the non-condensable gas is accumulated in the bleed air device 6. Then, when the non-condensable gas accumulated in the bleed air device 6 reaches a predetermined discharge amount D1, the valve 9 is closed and the non-condensable gas is discharged to the atmosphere by the pump 11. By this discharge operation, most of the non-condensable gas accumulated in the bleed air device 6 is discharged. Then, by opening the valve 9 again, the non-condensable gas is drawn from the condenser 3 into the bleed air device 6, and the non-condensable gas is accumulated in the bleed air device 6. Then, the discharging operation is repeatedly performed as described above. In the example shown in FIG. 7, in order to discharge all the non-condensable gas accumulated in the condenser 3, the case where the discharge operation is performed twice by the bleed air device 6 has been described, but the present invention is not limited to this example.

The correction unit 26 calculates the air intrusion amount Ma (s) by correcting the air intrusion amount M (s) for each section estimated by the estimation unit 21, and the estimation unit 21 calculates the air intrusion amount Ma (s). The value obtained by totaling the intrusion amount Ma (s) (air intrusion amount Ms (s)) was calculated, but the value corrected by the correction unit 26 is the air for each section estimated by the estimation unit 21. The intrusion amount is not limited to M (s). For example, when the estimation unit 21 estimates the air intrusion amount M (s) for each section, the estimation unit 21 calculates the total value (air intrusion amount Ms (s)) of the air intrusion amount M (s) in each section. Then, the correction unit 26 may perform correction on the total value (air intrusion amount Ms (s)) of the air intrusion amount M (s) of each section. Specifically, the correction unit 26 multiplies the value (air intrusion amount Ms (s)) of the sum of the air intrusion amounts M (s) of each section estimated by the estimation unit 21 by a correction constant. , The air intrusion amount Ms (s) is corrected, and the previous integrated value M (t-1) of the air intrusion amount is added to this value to calculate the total air intrusion amount M (t). The determination unit 22 determines whether the total amount of air intrusion M (t) calculated in this way is equal to or greater than the preset allowable value Mc.

Next, a modification of the correction target in this embodiment will be described. In the first embodiment, the total amount of air intrusion is corrected, but instead of or in addition to this, in this modification, the start-up duration set by the start-up control unit 23 is corrected. Since the start-up duration is determined by the total air intrusion amount M (t), the total air intrusion amount M (t) is indirectly corrected by correcting the start-up duration.

In this modification, in the storage unit 24, the difference between the total air intrusion amount M (t) and the exhaust air amount Md (t) and the correction constant c'for correcting the start-up duration are set corresponding to each other. I remember the table I'm using. Further, when the correction constant update unit 32 determines that the total air intrusion amount M (t) needs to be corrected by the correction necessity determination unit 31, the total air intrusion amount M (t) and the exhaust air amount Md (t). ), The correction constant c'for correcting the activation duration is read from the storage unit 24, and the read correction constant is set as a new correction constant to update. Then, the correction execution unit 33 multiplies the activation duration by a new correction constant to perform correction.

Next, a modification relating to the correction constant in this embodiment will be described. In this modification, the degree of influence of air intrusion is set for each section, and when the correction unit 26 corrects the total amount of air intrusion, the correction unit 26 corrects the amount of air intrusion for each section according to the degree of influence of air intrusion.

Therefore, in this modification, the storage unit 24 stores the addition constant corresponding to the degree of influence of air intrusion in each section, and the correction execution unit 33 stores the air intrusion amount M in each section estimated by the estimation unit 21. The air intrusion amount Ma (s) is calculated by multiplying (s) by the correction constant and adding the addition constant corresponding to each section. If the correction constant is not updated by the correction constant update unit 32 (when c = 1), the addition constant is not added.

The addition constant takes into account the degree of influence of air intrusion in each section and makes corrections more effectively. For this reason, the addition constant is preset by experiments or the like according to the degree of influence of air intrusion.

Therefore, in this modification, the air intrusion amount M (s) in each section is corrected in consideration of the degree of air intrusion influence in each section, so that the air intrusion amount M (s) in each section is more accurate. It can be corrected well. That is, the total air intrusion amount M (t) calculated from the air intrusion amount M (s) in each section can be corrected more accurately.

In this modification, the correction unit 26 (correction execution unit 33) multiplies the air intrusion amount M (s) of each section estimated by the estimation unit 21 by the correction constant, and the addition constant corresponding to each section. The air intrusion amount M (s) of each section is corrected (the air intrusion amount Ma (s) is calculated) by adding the above, but the correction performed by the correction unit 26 is not limited to the above. For example, the correction unit 26 first adds an addition constant corresponding to each section to the air intrusion amount M (s) of each section estimated by the estimation unit 21, so that the air intrusion amount of each section is added. Correct M (s) (weighting). Then, the correction unit 26 corrects (calculates the air intrusion amount Ma (s)) by multiplying the total value of the air intrusion amount M (s) for each corrected section by the correction constant. May be good. That is, the correction unit 26 weights the air intrusion amount M (s) estimated for each section according to the degree of air intrusion influence (addition of the addition constant), and then corrects (correction constant). May be performed.

As described above, according to the control device and control method of the bleed air device according to the present embodiment, the non-condensable gas that has entered the refrigerator 1 is estimated as the total amount of air intrusion, and the estimated total amount of air intrusion and / or It was decided to correct the activation duration of the bleed air device 6 based on the amount of discharged air, which is the amount of air actually discharged by the bleed air device 6. Therefore, the amount of air intrusion and the activation duration of the bleed air device 6 can be appropriately corrected according to the actual operating condition of the refrigerator 1. Since the activation duration of the bleed air device 6 depends on the amount of air intrusion, even when the activation duration is corrected, the total amount of air intrusion is indirectly corrected. That is, it is possible to more accurately estimate the total amount of air intrusion according to the operating conditions. For example, even when a low GWP refrigerant is used as the refrigerant of the refrigerator 1, the amount of air intrusion can be estimated more accurately, so that more stable operation can be maintained. Further, since the amount of air intrusion can be estimated more accurately, the activation of the bleed air device 6 can be optimized and unnecessary power consumption can be suppressed.

Further, since the correction is performed by a simple calculation of multiplying the air intrusion amount and / or the activation duration by the correction constant, the correction can be performed without imposing a processing load.

[Second Embodiment]
Next, the control device and the control method of the bleed air device according to the second embodiment of the present invention will be described.
In the first embodiment described above, the amount of air intrusion was estimated for each section, but in this embodiment, the total amount of air intrusion M (t) for the entire refrigerator 1 is directly calculated without dividing into sections. The point to estimate is different. That is, in the refrigerator 1 in the present embodiment, the calculation method of the total air intrusion amount M (t) by the estimation unit 21 is different from that in the first embodiment. Hereinafter, the refrigerator 1 according to the present embodiment will be mainly described with respect to the differences from the first embodiment.

The estimation unit 21 according to the present embodiment calculates the current total amount of air intrusion M (t) using the following equation (7).

In the above equation (7), Mb is the amount of air intrusion of the reference refrigerator, f (Ec'/ Vc) is a function having the degree of influence of air intrusion and the internal volume of the refrigerator as parameters, and Ec'is the structure of the reference refrigerator. The degree of air influence of the entire refrigerator 1 determined relatively based on the difference, Vc is the internal volume of the refrigerator, and f (Pet, Pct) is a function having evaporation pressure Pet and condensation pressure Pct as parameters. That is, Mb × f (Ec ′ / Vc) × f (Pet, Pct) in the equation (7) is an amount of air estimated to have invaded the entire refrigerator 1 per unit time (per control cycle). Is shown. f (Mb × f (Ec ′ / Vc) × f (Pet, Pct)) is a function having Mb × f (Ec ′ / Vc) × f (Pet, Pct) as a parameter. Specifically, f (Mb × f (Ec ′ / Vc) × f (Pet, Pct)) is the amount of air estimated to have invaded the entire refrigerator 1 (Mb × f (Ec ′ / Vc) ×. f (Pet, Pct)) is shown to be corrected.

As shown in the equation (7), the value obtained by correcting the amount of air (Mb × f (Ec ′ / Vc) × f (Pet, Pct)) estimated to have entered the entire refrigerator 1 is adjusted to the value. By adding the previous integrated value M (t-1) of the air intrusion amount, the current total air intrusion amount M (t) is calculated.

Here, the function f (Ec'/ Vc) having the degree of influence of air intrusion and the volume inside the freezer as parameters functions as a coefficient that relatively indicates the ease of air intrusion on the structural surface. That is, it is shown that the larger the value of this function is, the easier it is for air to enter from the structural aspect than the reference refrigerator. Further, the function f (Pet, Pct) of the evaporation temperature and the condensation temperature functions as a coefficient indicating the ease of air intrusion from the viewpoint of pressure (differential pressure from atmospheric pressure). That is, the more negative the pressure of the evaporator 5 and the pressure of the condenser 3, the easier it is for air to enter. Therefore, the larger this function value is, the easier it is for air to enter from the viewpoint of pressure.

In the storage unit 24 in the present embodiment, the total amount of air intrusion M for correcting the amount of air (Mb × f (Ec ′ / Vc) × f (Pet, Pct)) estimated to have invaded the entire refrigerator 1. A correction constant c ″ based on the difference between (t) and the exhaust air amount Md (t) is stored. The correction unit 26 corrects Mb × f (Ec ′ / Vc) × f (Pet, Pct) in the equation (7) by multiplying the correction constant c ″. That is, f (Mb × f (Ec ′ / Vc) × f (Pet, Pct)) is specifically a correction constant for Mb × f (Ec ′ / Vc) × f (Pet, Pct). It indicates that it is multiplied by c'. The determination unit 22 compares the total air intrusion amount M (t) calculated by the equation (7) with the permissible value Mc.

According to the control device 7 and the control method of the bleed air device 6 of the refrigerator 1 according to the present embodiment, it is not necessary to divide into each section as in the first embodiment, so that the process for calculating the air intrusion amount is performed. It is possible to reduce the burden. Further, since the value relatively determined from the difference in the structure from the reference refrigerator is used for the degree of influence of air intrusion, it is possible to reduce the labor for determining the degree of influence of air intrusion. Then, since the air intrusion amount M (t) estimated by the estimation unit 21 is corrected based on the exhaust air amount, it is possible to estimate the amount of the non-condensable gas that has entered the refrigerator 1 with higher accuracy. Is.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention.

For example, in each embodiment, the case where the control device 7 of the refrigerator 1 has a function of controlling the bleed air device 6 has been described, but the present invention is not limited to this example, and for example, the control function of the bleed air device 6 is referred to as the control device 7. May be separated and a control device dedicated to the bleed air device 6 may be separately provided.

Further, in each embodiment, the bleed air device 6 is connected to the condenser 3 by a pipe 8, but if there is a place where air tends to stay other than the condenser 3, the place is also connected by another pipe. It may have been done. In this way, by connecting the place where the air tends to stay and the bleed air device 6, it is possible to efficiently discharge the air in the machine.

Further, in each embodiment, the bleed air device 6 is activated based on the amount of air intrusion, but the refrigerant may be adversely affected by other substances such as moisture. Therefore, in addition to the amount of air intrusion, the amount of intrusion of other substances such as moisture may be estimated, and the activation and stop of the means for removing or reducing the substance may be controlled according to the estimated amount of intrusion. Further, a structure capable of constantly removing other substances (such as removing water with a filter dryer) may be provided, and other substances may be constantly removed.

1: Refrigerator 2: Compressor 3: Condensator 4: Expansion valve 5: Evaporator 6: Bleed air 7: Control device 8, 13: Piping 9, 12: Valve 10: Backflow prevention valve 11: Pump 14: Pressure sensor 15: Temperature sensor 16: Bleed air tank 21: Estimating unit 22: Judgment unit 23: Start control unit 24: Storage unit 25: Exhaust air amount calculation unit 26: Correction unit 31: Correction necessity determination unit 32: Correction constant update unit 33 : Correction execution unit

Claims (5)

It is a control device that controls the bleed air device provided in the refrigerator.
An estimation means for estimating the total amount of air intrusion into the freezer,
A determination means for determining whether the total amount of air intrusion is equal to or higher than a preset allowable value, and
When the total amount of air intrusion is equal to or greater than the permissible value, the activation duration of the bleed air device is determined based on the total amount of air intrusion, and the activation control means for activating the bleed air device for the activation duration.
Exhaust air amount calculation means for calculating the exhaust air amount, which is the amount of air actually exhausted by the bleed air device, and
A correction means for correcting at least one of the total air intrusion amount and the start-up duration when the difference between the total air intrusion amount and the exhaust air amount is a predetermined amount or more.
A control device equipped with. The correction means obtains at least one of the total air intrusion amount and the activation duration by multiplying the correction constant corresponding to the difference between the total air intrusion amount estimated by the estimation means and the exhaust air amount. The control device according to claim 1. The refrigerator is divided into multiple sections.
The degree of influence of air intrusion is set for each of the above sections.
The estimation means estimates the amount of air intrusion for each of the sections, and estimates the total amount of air intrusion in the entire refrigerator from the estimated amount of air intrusion in each of the sections.
The control device according to claim 1, wherein the correction means corrects the air intrusion amount for each section according to the air intrusion influence degree when the air intrusion total amount is corrected. A freezer that uses a low-pressure, low-GWP refrigerant.
With the bleed air device,
A refrigerator provided with the control device according to any one of claims 1 to 3. It is a control method of the bleed air device installed in the refrigerator.
An estimation process for estimating the total amount of air intrusion into the freezer, and
A determination step for determining whether the total amount of air intrusion is equal to or higher than a preset allowable value, and
A start control step of determining the activation duration of the bleed air device based on the total air intrusion amount and activating the bleed air device for the activation duration when the total air intrusion amount is equal to or more than the allowable value.
The exhaust air amount calculation step for calculating the exhaust air amount, which is the amount of air actually exhausted by the bleed air device, and the exhaust air amount calculation step.
A correction step for correcting at least one of the total air intrusion amount and the start-up duration when the difference between the total air intrusion amount and the exhaust air amount is a predetermined amount or more.
Control method having.

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