WO2015111222A1

WO2015111222A1 - Refrigeration device

Info

Publication number: WO2015111222A1
Application number: PCT/JP2014/051690
Authority: WO
Inventors: 佐多　裕士; 康敬落合; 章吾玉木
Original assignee: 三菱電機株式会社
Priority date: 2014-01-27
Filing date: 2014-01-27
Publication date: 2015-07-30
Also published as: JPWO2015111222A1; CN105408704B; CN105408704A

Abstract

A refrigeration device wherein a heat-source-side unit and a load-side unit are connected via liquid piping and gas piping, the heat-source-side unit having at least a compressor (1), a heat-source-side heat exchanger, a supercooling heat exchanger (5), and a liquid receiver (4), and the load-side unit having at least a load-side expansion means and a load-side heat exchanger. A refrigerant circuit is formed to circulate refrigerant in the compressor (1), the heat-source-side heat exchanger, the supercooling heat exchanger (5), the liquid receiver (4), the load-side expansion means, and the load-side heat exchanger. A sight glass (14) is provided to a side surface of the liquid receiver (4). The sight glass (14) is arranged at a position that enables confirmation of the position of the maximum liquid level (11) of the refrigerant in the liquid receiver (4) during operation throughout the year.

Description

Refrigeration equipment

The present invention relates to a refrigeration apparatus.

Conventionally, in refrigeration equipment used for cooling of supermarket showcases, cooling of refrigerated warehouses with unit coolers, etc., showcases are mainly installed in food departments, but the number, size, type, arrangement, etc., vary depending on the store. The internal volume of the evaporator arranged in the showcase differs accordingly. The unit cooler has the same evaporator volume depending on the type. Moreover, the installation place of the refrigerator which accommodates the compressor, the condenser, and the liquid receiver also differs depending on the structure of the store, and may be installed on the back of the food department or on the roof, for example. Therefore, the distance between the evaporator, the compressor, the condenser, and the liquid receiver varies depending on the installation location of the refrigerator, and the lengths of the extension pipes such as the gas extension pipe and the liquid extension pipe also differ.

In order for the refrigeration cycle to exhibit a predetermined performance, an amount of refrigerant suitable for the internal volume of the refrigeration cycle is required, but if the internal volume of the evaporator or the length of the extension pipe is different, the refrigerant required for the refrigeration cycle The amount (hereinafter referred to as the necessary refrigerant amount) is also different. Therefore, the refrigerant of the refrigerator is filled (enclosed) after configuring the refrigeration cycle on site. Further, the amount of refrigerant required for the refrigeration cycle varies depending on the state of the refrigeration cycle, and the state of the refrigeration cycle also varies depending on the outside air temperature, the operating state of the load-side equipment of the showcase, and the like. For this reason, normally, a large amount of refrigerant is charged so that the amount of refrigerant necessary for each component device such as a condenser and an evaporator is always distributed regardless of the operating state.

FIG. 7 is a diagram illustrating an example of a refrigerant circuit of a conventional refrigeration apparatus.
As a method of determining the amount of refrigerant, a sight glass 17 is provided in the liquid piping downstream of the receiver 4 as shown in FIG. 7, and the internal temperature (the temperature of the target space cooled by the evaporator) is set to the set temperature during the test operation. When the operation is stabilized, the flash gas (bubbles) in the refrigerant is visually confirmed. Then, when the flash gas disappears, the time is the amount of refrigerant with no surplus, so a method of charging a certain amount of refrigerant with respect to the amount of refrigerant has been proposed. In addition, this filling amount becomes the surplus refrigerant amount corresponding to the fluctuation of the necessary refrigerant amount due to the state change of the refrigeration cycle. This percentage is 5 to 10% of the amount of refrigerant sealed up to the point when the flash disappears according to the manufacturer's instructions, but it is the know-how of each supplier. Therefore, a large amount of refrigerant is often added.

In addition, a method of detecting the refrigerant liquid level in the receiver by using a capacitance sensor, determining that the refrigerant amount is excessive, appropriate, and insufficient, and calculating the insufficient refrigerant amount, and a sight glass on the side of the receiver A method has been proposed in which a human detects the liquid level visually and compares the relationship between the amount of refrigerant given as data and the liquid level position (height) to determine surplus, appropriateness, and shortage. And the amount of refrigerant | coolants for a surplus part and a deficiency is calculated, and if it is surplus, the refrigerant | coolant will be extracted, and if it is deficient, the method of filling will be proposed (refer patent document 1).

Japanese Patent No. 2997487 (see, for example, pages 2 to 3 and FIG. 4)

In the method of visually checking the flash gas, if the flash gas disappears once and the liquid refrigerant is stored in the receiver, it can be determined how much refrigerant is actually stored in the receiver. Absent. In particular, even if a large amount of refrigerant is accidentally charged, the inside of the liquid receiver cannot be confirmed, so that there are many cases where an overfilled state is left with unnecessary refrigerant filled. In addition, if a refrigerant leak has occurred due to equipment malfunction or service, etc., if the equipment returns to normal and flash gas is not generated when the refrigerator is restarted, It is not clear whether the amount of refrigerant in the receiver is sufficient or the amount of refrigerant in the receiver is sufficient. For this reason, the refrigerant is charged with a margin, but if the amount of refrigerant in the liquid receiver is sufficient, as a result, unnecessary refrigerant is filled, resulting in refrigerant overfilling.

In the case of refrigerant overfilling, the following disadvantages occur in addition to the high cost of the refrigerant overfilling. The amount of liquid refrigerant stored in the condenser increases, the heat exchanger performance decreases, and the pressure increases. Then, the COP decreases, the power consumption increases, and in the worst case, the operation of the refrigerator is stopped due to a high pressure abnormality. Also, if a refrigerant back is returned to the refrigerator without evaporating due to a malfunction of the evaporator, etc., if excess refrigerant accumulates in the normal accumulator, the high-pressure side becomes insufficient and the outlet of the condenser becomes liquid. Since it becomes a two-phase state, the refrigerant | coolant flow rate which passes the expansion valve 6 reduces, and it becomes difficult for a refrigerant | coolant to overflow from an accumulator. On the other hand, if there is a large amount of excess refrigerant, even if the accumulator is full of refrigerant, the high pressure side will not run out of refrigerant, the condenser outlet will remain in the liquid phase, the refrigerant flow rate will not decrease, and even if the accumulator is held The liquid refrigerant overflows. Then, the overflowing liquid refrigerant returns to the suction of the compressor, and the compressor may be damaged due to a decrease in oil concentration in the compressor, oil take-out from the compressor, or the like.

In addition, assuming that the refrigerant is overfilled, it is necessary to install an accumulator or reduce the volume of the accumulator in order to reduce the damage at the time of liquid back. It was. In addition, by closing the liquid operation valve and liquid electromagnetic valve downstream of the liquid receiver, it is possible to recover the refrigerant in the liquid receiver. The outline was large.

Further, in order to check the flash gas, it is necessary to install the sight glass 17 in the liquid pipe downstream of the receiver 4 according to the size of the liquid pipe as shown in FIG.
Also, in the unlikely event that the refrigerant leaks due to equipment malfunctions, the damage to the environment was greater.

In addition, the current situation is that the method for calculating the amount of refrigerant that is insufficient, determined by the capacitance sensor shown in Patent Document 1 as surplus, appropriate, and insufficient, is almost unpractical due to high costs. In addition, in the method of providing sight glass that can judge appropriate, surplus, and deficiency on the side of the receiver, it is appropriate for each refrigeration system in refrigerators with greatly different operating conditions such as the internal volume of the evaporator, the length of the extension pipe, and the internal temperature. The surplus and deficient refrigerant amounts differ greatly. Therefore, a large sight glass is required to cope with the change in the refrigerant amount, but this is unrealistic, and even if implemented, the cost is high.

The present invention has been made to solve at least one of the above-described problems, and can easily and properly carry out refrigerant filling at the time of trial operation or service of a refrigeration apparatus, thereby suppressing overfilling. An object of the present invention is to provide a refrigeration apparatus that can perform the above.

The refrigeration apparatus according to the present invention includes a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a heat source side unit having at least a liquid receiver, and a load side unit having at least a load side expansion means and a load side heat exchanger. Are connected via a liquid pipe and a gas pipe, the compressor, the heat source side heat exchanger, the supercooling heat exchanger, the liquid receiver, the load side expansion means, and the load side heat exchanger. In the refrigeration apparatus in which the refrigerant circuit for circulating the refrigerant is formed, a sight glass is provided on a side surface of the receiver, and the sight glass has a maximum refrigerant liquid level position throughout the year of the receiver during operation. It is provided at a position where it can be confirmed.

According to the refrigeration apparatus according to the present invention, the sight glass that can confirm the refrigerant liquid level position of the receiver is installed, and the liquid level position indicates the maximum refrigerant liquid level position during operation. Or the refrigerant filling at the time of service of the refrigeration apparatus can be carried out easily, quickly and accurately, and overfilling can be suppressed.

It is a figure which shows an example of the refrigerant circuit of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a Mollier diagram corresponding to the different condensation temperature of the refrigerating device concerning Embodiment 1 of the present invention. It is a figure which shows the liquid receiver internal liquid ratio with respect to the external temperature of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the sight glass of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the other example of the refrigerant circuit of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the sight glass of the freezing apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the refrigerant circuit of the conventional freezing apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings, the relationship of the size of each component may be different from the actual one.

Embodiment 1 FIG.
1 is a diagram illustrating an example of a refrigerant circuit of a refrigeration apparatus according to Embodiment 1 of the present invention.
The refrigeration apparatus according to Embodiment 1 includes an outdoor unit 100 and an indoor unit 200.
The outdoor unit 100 includes a compressor 1, a condenser 3, a liquid receiver 4, and a supercooling heat exchanger 5.
Further, downstream of the supercooling heat exchanger 5, the main unit 22 branches to a main flow path 22 toward the evaporator 7 of the indoor unit 200 and an injection flow path 23 toward the injection port 1 a of the compressor 1. The liquid operation valve 10 is provided, and the expansion valve 8 is provided on the injection flow path 23 side. The indoor unit 200 uses a showcase, a unit cooler, or the like.

The indoor unit 200 includes a liquid electromagnetic valve 9, an expansion valve 6, and an evaporator 7. The indoor unit 200 is connected to the outdoor unit 100 by the liquid extension pipe 18 and the gas extension pipe 19. And the refrigerant circuit which circulates a refrigerant | coolant sequentially to the compressor 1, the condenser 3, the liquid receiver 4, the supercooling heat exchanger 5, the expansion valve 6, and the evaporator 7 is formed.

The amount of refrigerant distributed to the condenser 3, the liquid receiver 4, the supercooling heat exchanger 5, the evaporator 7, the liquid extension pipe 18, and the gas extension pipe 19 is determined by the respective internal volume, performance, and operation state. Of the refrigerant filled in the refrigeration cycle, surplus refrigerant after each component device of the refrigeration cycle has an appropriate amount of refrigerant is stored in the liquid receiver 4.

The compressor 1 sucks refrigerant and compresses the refrigerant to a high temperature and high pressure state. The injection port 1 a is an intermediate pressure port that allows the refrigerant to flow into the compression chamber in the middle of compression of the compressor 1. The condenser 3 performs heat exchange between air supplied from a blower (not shown) and the refrigerant, and condenses the refrigerant into a liquid refrigerant.

The liquid receiver 4 is disposed between the condenser 3 and the evaporator 7 and stores excess refrigerant. In addition, the liquid receiver 4 should just be a container which can store an excess refrigerant | coolant. The supercooling heat exchanger 5 performs heat exchange between air and refrigerant in the same manner as the condenser 3 to supercool the liquid refrigerant. The

expansion valves

6 and 8 expand the refrigerant by decompressing it. The

expansion valves

6 and 8 may be configured by a valve whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like.

The evaporator 7 exchanges heat between air supplied from a blower (not shown) and the refrigerant to evaporate the refrigerant into a gas refrigerant. This evaporator 7 cools the target space such as a showcase. The liquid electromagnetic valve 9 controls whether the refrigerant flows into the evaporator 7 by electronic opening and closing. The liquid operation valve 10 is configured to allow the refrigerant to flow into the liquid extension pipe 18 or not by manual opening and closing.

In addition, the refrigeration apparatus according to the first embodiment includes refrigerant amount determination means 20 that determines whether or not the minimum amount of refrigerant charged in the refrigerant circuit is filled. The refrigerant amount determination means 20 can be configured by a microcomputer or the like provided on the control board of the refrigeration apparatus, for example. Temperature information detected by the first temperature sensor (TH5), the second temperature sensor (TH8), and the third temperature sensor (TH6) is input to the refrigerant amount determination means 20.

The first temperature sensor (TH5) is located at any position on the outlet side of the condenser 3 or the flow path from the portion where the refrigerant is in a two-phase state in the condenser 3 to the inlet side of the supercooling heat exchanger 5. It is provided and detects the temperature of the refrigerant.
The second temperature sensor (TH8) is provided at any position in the flow path from the outlet side of the supercooling heat exchanger 5 to the inlet side of the expansion valve 6, and detects the temperature of the refrigerant.
The third temperature sensor (TH6) detects the temperature of the air before the condenser 3 exchanges heat with the refrigerant.

In addition, the refrigerant amount determination means 20 is provided with a display unit 21 that displays the determination result and various types of information. The display unit 21 includes, for example, a 7-segment LED.
Note that a cylinder (not shown) is used when the refrigerant circuit is filled with the refrigerant.

The refrigerant circulating in the refrigerant circuit is mainly present in the condenser 3, the liquid receiver 4, the liquid extension pipe 18, the evaporator 7, and the gas extension pipe 19. When the refrigerant is in the gas phase, the higher the temperature, the higher the density. Therefore, in the condenser 3 having a larger gas phase, the refrigerant is stored in the condenser 3 as the condensation temperature is higher. As for the liquid receiver 4, the gas phase is dominant, and the higher the condensation temperature, the more the refrigerant is stored in the liquid receiver 4. In the case of the liquid phase, the density increases as the temperature decreases. Therefore, the refrigerant accumulates in the liquid extension pipe 18 as the liquid temperature decreases.

FIG. 2 is a Mollier diagram corresponding to different condensation temperatures of the refrigeration apparatus according to Embodiment 1 of the present invention. In FIG. 2, Tc represents the condensation temperature, and Te represents the evaporation temperature.
In the evaporator 7, the two-phase refrigerant throttled by the expansion valve 6 evaporates into a gas phase. However, as shown in FIG. 2, the lower the condensation temperature, the higher the wetness immediately after the expansion valve 6. Will store a lot of refrigerant.
Therefore, the seasonal variation in the amount of refrigerant required to operate the refrigeration apparatus is a relative relationship between the volume of the condenser 3 and the volume of the liquid receiver 4 and the liquid extension pipe + evaporator volume if the evaporation temperature is constant. When the proportion of the volume of the condenser 3 and the receiver 4 increases, the required refrigerant amount increases as the condensation temperature increases. When the proportion of the liquid extension pipe + evaporator volume increases, the required refrigerant amount decreases as the condensation temperature decreases. Become more.

Further, the required volume of the liquid receiver 4 is required to enable the recovery of the refrigerant in the liquid receiver 4 by closing the liquid operation valve 10 downstream of the liquid receiver 4, so that the volume of the condenser 3 And the volume of the liquid extension pipe 18 are almost determined by the volume, and the following values are obtained.

[Formula 1]
Receiver volume = (condenser volume + liquid extension pipe volume) x (125% ± 25%)

FIG. 3 is a diagram showing a ratio of the liquid in the liquid receiver 4 with respect to the outside air temperature of the refrigeration apparatus according to Embodiment 1 of the present invention. FIG. 4 is a diagram illustrating an example of the sight glass 14 of the refrigeration apparatus according to Embodiment 1 of the present invention.
FIG. 3 shows how the liquid ratio in the liquid receiver 4 (= the volume of the liquid refrigerant in the liquid receiver 4 ÷ the volume of the liquid receiver 4) changes as the outside air temperature changes. It shows by condition.

The use range of the outside air temperature around the outdoor unit 100 is -15 to 43 ° C. The graph shows how the amount of refrigerant in the liquid receiver 4 changes due to a change in the outside air temperature. Usually, the volume of the showcase is larger than the volume of the unit cooler. The graph of the condition of the pipe length of 100 m when the load in FIG. 3 is a showcase shows that the volume of the load is large, the extension pipe is long, the volume of the condenser 3 and the liquid receiver 4 is small, and the liquid in the liquid receiver 4 This is an example in which the rate of change of the ratio is maximized. The maximum value of the rate of change in the liquid ratio in the receiver 4 is 22.7% of the volume of the receiver 4 when the refrigerant amount is 43 ° C., and 0.0% when the ambient temperature is −15 ° C. The change width is 22.7%.
That is, since the required refrigerant is low at the outside air temperature of 43 ° C., a large amount of surplus refrigerant is stored in the liquid reservoir, and at the outside air temperature of −15 ° C., the necessary refrigerant is large and the surplus refrigerant is eliminated and there is no refrigerant stored in the liquid reservoir. The required amount of refrigerant tends to increase as the outside air temperature decreases. This is because the amount of change in the amount of refrigerant in the liquid extension pipe + evaporator volume is greater than the amount of change in the amount of refrigerant in the condenser 3 and the receiver 4. . The reason why there is no change in the liquid ratio in the receiver when the outside air temperature is 5 ° C. or less is that control is performed to keep the condensation temperature constant by controlling the fan air volume of the condenser 3.

Therefore, as shown in FIG. 4, the sight glass 14 is placed on the side surface of the liquid receiver 4 so that the position of the refrigerant liquid surface 11 of the liquid receiver 4 can be confirmed, and the maximum amount of refrigerant in the liquid reservoir (22 above). 7%), a margin of about 10% is provided at a maximum position of 33.0%, and this position is set as the position of the refrigerant liquid surface 11 that becomes the maximum throughout the year. The sight glass 14 is attached to a copper pipe 16 from the end plate and barrel of the liquid receiver 4. The sight glass 14 has a function of determining the presence or absence of moisture, and has a size equal to or smaller than the size of the liquid extension pipe 18. Alternatively, it may be installed directly on the shell of the liquid receiver 4, but the refrigerant flow tends to disturb the refrigerant liquid level 11 in the liquid receiver 4, making it difficult to check the refrigerant liquid level 11.

FIG. 5 is a diagram illustrating another example of the refrigerant circuit of the refrigeration apparatus according to Embodiment 1 of the present invention.
The indoor unit 100A includes a compressor 1, a condenser 3, a liquid receiver 4, and a supercooling heat exchanger 5A as in FIG. 1, but the supercooling heat exchanger 5A includes a plate heat exchanger and a copper Heat exchange between the refrigerant and the refrigerant is possible with the double pipe of the pipe. The main flow path 22 heading toward the evaporator 7 downstream of the supercooling heat exchanger 5A and the injection flow path 23 to the injection port 1a of the compressor 1 are branched. The cooling heat exchanger 5A is connected in this order.

The “outdoor unit 100” corresponds to a “heat source side unit” in the present invention.
The “indoor unit 200” corresponds to the “load unit” in the present invention.
The “condenser 3” corresponds to the “heat source side heat exchanger” in the present invention.
The “expansion valve 6” corresponds to “load-side expansion means” in the present invention.
The “evaporator 7” corresponds to the “load side heat exchanger” in the present invention.
The “liquid extension pipe 18” corresponds to the “liquid pipe” in the present invention.
The “gas extension pipe 19” corresponds to the “gas pipe” in the present invention.

Next, the flow of the refrigerant in the refrigeration apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the condenser 3. The high-temperature and high-pressure gas refrigerant that has flowed into the condenser 3 is condensed by exchanging heat with air in the condenser 3, becomes high-pressure liquid refrigerant (liquid or two-phase state), and is stored in the liquid receiver 4. The high-pressure liquid refrigerant stored in the liquid receiver 4 further exchanges heat with air in the supercooling heat exchanger 5 to become supercooled liquid refrigerant.
Here, the liquid refrigerant is stored in the liquid receiver 4 only when the refrigerant amount of each component device other than the liquid receiver 4 of the refrigeration cycle becomes an appropriate amount and surplus refrigerant is generated. When the refrigerant amount of each component device other than 4 is insufficient, only the gas refrigerant is stored in the liquid receiver 4.

Further, the high-temperature and high-pressure refrigerant branched to the injection flow path 23 downstream of the supercooling heat exchanger 5 is reduced to an intermediate pressure by the expansion valve 8 and then connected to a compression chamber in the middle of compression of the compressor 1. The discharge temperature of the compressor 1 is reduced by directly flowing into the pressure injection port 1a.
Further, in the case of FIG. 5, the high-temperature and high-pressure refrigerant branched to the injection flow path 23 side is decompressed to an intermediate pressure by the expansion valve 8 and then exchanges heat with the high-temperature and high-pressure refrigerant by the supercooling heat exchanger 5. It flows into the injection port 1a of the compressor 1.

The refrigerant quantity determination means 20 in the first embodiment uses the temperature efficiency ε of the supercooling heat exchanger 5 to check whether the refrigerant is filled with the minimum necessary quantity (the liquid refrigerant is stored in the receiver 4 and the refrigeration is performed). It is determined whether or not the refrigerant of each component device other than the liquid receiver 4 of the cycle is filled with an appropriate amount). The temperature efficiency ε of the supercooling heat exchanger 5 is determined by determining the degree of supercooling of the refrigerant at the outlet of the supercooling heat exchanger 5 (condenser 3 outlet temperature TH5—supercooling heat exchanger 5 outlet temperature TH8) by the maximum temperature difference ( It is a value divided by the condenser 3 outlet temperature TH5-the outside air temperature TH6) and is expressed by the following (Formula 1). For example, it is determined that the minimum necessary refrigerant amount is filled when ε reaches 0.6.

[Formula 2]
ε = (TH5-TH8) ÷ (TH5-TH6)

(Refrigerant charging method during trial operation)
Next, a specific method for charging the refrigerant during the trial operation using the temperature efficiency ε and the sight glass 14 of the liquid receiver 4 shown in FIG. 4 will be described.
First, after evacuating the circuit of the refrigeration apparatus, the refrigerant is charged in a state where the refrigeration apparatus is stopped. Thereafter, the refrigerant is filled little by little while operating the refrigeration apparatus. At this time, by setting the refrigerant amount determination mode with a switch or the like on the control board of the refrigeration apparatus, whether or not the minimum amount of refrigerant is filled on the LED of the board is displayed based on the above ε. For example, when the value of ε is 0.6 or more and the refrigerant reaches the minimum required amount, O (O) is displayed on the LED.

Also, if the value of ε is less than 0.6 and the minimum required amount is not reached, N is displayed on the LED. The operator performs refrigerant filling while confirming this display, and records the amount of refrigerant filled when the LED display changes from N to O (Oh) with a memo or the like. The calculation of the amount of refrigerant filled is normally performed by measuring the mass of the cylinder before and after filling. Then, from the time when the display of the LED changes from N to O (O), the amount of refrigerant filled after that becomes the surplus refrigerant amount stored as liquid refrigerant in the liquid receiver 4.

Then, after the inside of the refrigeration apparatus approaches the target temperature to some extent and the operation becomes stable, the operator can check the coolant level 11 with the sight glass 14 while checking the sight glass 14 on the side of the liquid receiver 4. Add refrigerant in small increments until When the coolant level 11 can be confirmed with the sight glass 14, the amount of the coolant is 32.0% of the volume of the receiver 4 and therefore the amount of the coolant is insufficient even if conditions such as the outside air temperature change thereafter. There is no state.

That is, the amount of refrigerant added from the time when the LED display changes from N to O (O) until the refrigerant liquid level 11 can be confirmed with the sight glass 14 on the side surface of the liquid receiver 4 becomes the surplus refrigerant. Since the outside air temperature, the evaporation temperature, and the operation frequency differ depending on the season, the necessary amount of refrigerant changes, but the amount of refrigerant that has changed can be filled.
In addition, since the refrigerant | coolant amount with which the refrigerant | coolant liquid level 11 was confirmed with the sight glass 14 is enough, it is made not to fill with a refrigerant | coolant any more.

In addition, the reading values of each sensor such as the outside air temperature TH6 when the LED display changes from N to O described above, the temperature inside the refrigerator or showcase, the length of the extension pipe, and the load are shown. If the controller in the refrigerator can recognize the local information such as the case or unit cooler from the graph in FIG. 3 or Japanese Patent Application Laid-Open No. 2012-132039, etc. Can be calculated. If the amount is displayed on the LED and can be sealed, it is not necessary to fill the coolant up to the position of the sight glass 14. For example, when the refrigerant is sealed at a value of the outside air temperature TH6 of −15 ° C., the amount of additional refrigerant may be 10% of the capacity of the receiver 4 for the margin, and the amount is displayed. In addition, when the outside air temperature TH6 is 30 ° C, the length of the extension pipe is 80m, the load is a showcase, and the refrigerant is sealed, the additional refrigerant amount is 12.1% of the volume of the receiver 4 + margin The minute 10% = 22.1% is sufficient, and the amount is displayed.

(Method of charging refrigerant at the time of service)
Next, a refrigerant charging method in a state where the refrigerant remains in the refrigerant circuit to some extent, such as when servicing a product, will be described.
The operator checks the sight glass 14 on the side of the liquid receiver 4 while operating the refrigeration apparatus. If the liquid refrigerant can be confirmed, the outside air temperature, evaporation temperature, and operating frequency differ depending on the season, and it is necessary to add a refrigerant in particular because it is filled with a sufficient amount of refrigerant including the necessary amount of refrigerant. There is no. On the contrary, when there is a possibility that a large amount of refrigerant is filled, the refrigerant is collected until the refrigerant liquid level 11 can be confirmed.

When the refrigerant liquid level 11 cannot be confirmed, the refrigerant amount determination mode is set with a switch or the like on the control board of the refrigeration apparatus, and the LED is confirmed. When the display is N, it is understood that the amount of refrigerant is less than the minimum necessary amount of refrigerant, and a large amount of additional refrigerant is required. When the display is O (O), the minimum required refrigerant amount has been reached, so adding a small amount of refrigerant changes the outside air temperature, evaporation temperature, and operating frequency depending on the season, and the required refrigerant amount changes. It can be seen that there is a high possibility that a sufficient amount of refrigerant can be filled. In particular, when the display is O (o) when the outside air temperature is low, such as in winter, it can be seen that there is a high possibility that a sufficient amount of refrigerant can be filled throughout the year.
In addition, since the refrigerant | coolant amount with which the refrigerant | coolant liquid level 11 was able to be confirmed with the sight glass 14 is enough also at the time of service, it is made not to fill with a refrigerant | coolant any more.

Next, a method for confirming the presence or absence of moisture in the refrigerant circuit using the sight glass 14 will be described.
By closing the liquid electromagnetic valve 9 or the liquid operation valve 10 during the operation of the refrigeration apparatus, the pump down for collecting the refrigerant in the liquid receiver 4 is performed. Thereby, the sight glass 14 on the side surface of the liquid receiver 4 becomes full, and the presence or absence of moisture in the refrigerant circuit can be confirmed by a not-shown moisture indicator (moisture detector) attached to the sight glass 14.

As described above, the sight glass 14 that can confirm the position of the refrigerant liquid 11 of the liquid receiver 4 is installed, and the liquid level indicates the maximum refrigerant liquid level 11 during operation. Refrigerant charging at the time of service of the refrigeration apparatus can be carried out easily, quickly and accurately, and overfilling can be prevented. Therefore, by suppressing the increase in high pressure, it is possible to save energy and reduce the amount of refrigerant charged, so that the cost, environmental impact and damage can be reduced. Furthermore, the liquid receiver 4, the accumulator (not shown), and the sight glass 14 can be made small, so that the product cost can be reduced and the product can be made compact.

Further, the sight glass 14 on the side of the liquid receiver 4 is the same as or smaller than the size of the main liquid extension pipe 18 and has a moisture indicator (moisture detector), so that the product cost can be reduced and the refrigerant can be reduced. The presence or absence of moisture can be confirmed. Therefore, it is possible to prevent problems such as corrosion of the refrigerant circuit components, rust, and the oil return hole of the accumulator caused by the ice stack caused by the moisture mixed in the refrigerant circuit, and the reliability can be improved.
Further, the sight glass 14 is taken out from the end plate and barrel of the liquid receiver 4 with a copper pipe 16, and when not installed directly on the liquid receiver 4, the refrigerant liquid surface 11 is stabilized and the presence / absence of the refrigerant liquid surface 11 can be easily confirmed. can do.

Embodiment 2. FIG.
FIG. 6 is a diagram illustrating an example of the

sight glasses

14 and 15 of the refrigeration apparatus according to Embodiment 2 of the present invention.
In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
In the second embodiment, a description will be given of a case where the refrigerant filling amount is confirmed by changing the position of the refrigerant liquid surface 11 that is maximum throughout the year depending on the season, the outside air temperature, high pressure, and the like.

If the outside air temperature is low during the refrigerant charging operation in winter or the like, if the refrigerant is charged until the coolant level 11 can be confirmed with the sight glass 14 after the LED on the control board changes from N to O (O), the refrigerant is more than necessary. May be filled. Therefore, the amount of refrigerant to be additionally charged may be changed according to the outside air temperature or the high pressure during operation of the refrigerator.

That is, as shown in FIG. 3, when the length of the extension pipe with the largest fluctuation of the refrigerant amount in the receiver 4 is 100 m and the showcase load is received, The decrease in the refrigerant amount in the liquid container 4 is 12.1%. Therefore, when the refrigerant is adjusted by a trial run at an outside air temperature of 32 ° C., the amount of additional charged refrigerant after the LED is changed from N to O (Oh) is 12.1% + the margin is 10% = 22.1. % Is acceptable.

Therefore, as a countermeasure when the refrigerant is charged when the outside air temperature is lower than 30 ° C., the sight glass (summer check) is located at 22.1% (= 12.1% + margin 10%) as shown in FIG. 15) is set, and this position is set as the refrigerant liquid level 12 position when the outside air temperature is lower than 30 ° C. That is, in the second embodiment, a sight glass (for the case where the outside air temperature is lower than 30 ° C.) 15 is added to the position of the sight glass 14 of the first embodiment. Confirm.

By doing in this way, it is possible to accurately carry out refrigerant filling at the time of trial operation or service of the refrigeration apparatus, and to prevent overfilling, as compared with the first embodiment. Therefore, by suppressing the increase in high pressure, it is possible to save energy and reduce the amount of refrigerant charged, so that the cost, environmental impact and damage can be reduced. Furthermore, the liquid receiver 4, the accumulator, and the

sight glasses

14 and 15 can be reduced, and the product cost can be reduced and the apparatus can be made compact.

1 compressor, 1a injection port, 3 condenser, 4 receiver, 5 supercooling heat exchanger, 6 expansion valve, 7 evaporator, 8 expansion valve, 9 liquid solenoid valve, 10 liquid operation valve, 11 refrigerant liquid level , 12 Refrigerant liquid level (summer), 14 sight glass, 15 sight glass (for summer check), 16 copper piping, 17 sight glass, 18 liquid extension piping, 19 gas extension piping, 20 refrigerant quantity judging means, 21 display section, 22 main flow path, 23 injection flow path, 100 outdoor unit, 100A outdoor unit, 100B outdoor unit, 200 indoor unit, 200A indoor unit, 200B indoor unit.

Claims

A heat source side unit having at least a compressor, a heat source side heat exchanger, a supercooling heat exchanger, and a liquid receiver, and a load side unit having at least a load side expansion means and a load side heat exchanger include a liquid pipe and a gas pipe. Connected through
In the compressor, the heat source side heat exchanger, the supercooling heat exchanger, the liquid receiver, the load side expansion means, and a refrigeration apparatus in which a refrigerant circuit for circulating a refrigerant in the load side heat exchanger is formed. ,
A sight glass is provided on the side of the receiver,
The said sight glass was provided in the position which can confirm the refrigerant | coolant liquid level position which becomes the maximum through the year of the said receiver during a driving | operation. The refrigeration apparatus characterized by the above-mentioned.
The volume of the receiver is
2. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is determined within a range of 125% ± 25% of a sum of a volume of the heat source side heat exchanger and a volume of the liquid pipe.
3. The refrigeration apparatus according to claim 1, wherein the sight glass is provided at a position where a refrigerant liquid level position can be confirmed when the refrigerant is 33% or less of the volume of the liquid receiver.
The refrigeration apparatus according to any one of claims 1 to 3, wherein at least one sight glass is provided at a position where the highest liquid level position when the outside air temperature is limited can be confirmed.
The refrigeration apparatus according to any one of claims 1 to 4, further comprising a refrigerant amount determination unit that determines whether or not the refrigerant charged in the refrigerant circuit is charged in an amount that is not insufficient for the refrigerant.
A first temperature sensor that is provided at any position in the flow path from the outlet side of the heat source side heat exchanger to the inlet side of the subcooling heat exchanger, and detects the temperature of the refrigerant;
A second temperature sensor that is provided at any position in the flow path from the outlet side of the supercooling heat exchanger to the inlet side of the load side expansion means, and detects the temperature of the refrigerant;
An outside air temperature sensor that detects the temperature of the air with which the heat source side heat exchanger exchanges heat with the refrigerant, and
The refrigerant amount determination means includes
The degree of supercooling is obtained from the temperature difference between the detected temperature of the first temperature sensor and the detected temperature of the second temperature sensor,
The refrigeration apparatus according to claim 5, wherein a maximum temperature difference of the supercooling heat exchanger is obtained from a temperature difference between a temperature detected by the first temperature sensor and a temperature detected by the outside air temperature sensor.
The refrigerant amount determination means includes a display unit,
The refrigeration apparatus according to claim 5 or 6, wherein the display unit displays a determination result as to whether or not the refrigerant charged in the refrigerant circuit is filled in an amount that is not insufficient for the refrigerant.
The refrigeration apparatus according to claim 7, wherein the display unit includes a 7-segment LED.
The refrigeration apparatus according to any one of claims 1 to 8, wherein the sight glass has a moisture detection function.