WO2016084174A1

WO2016084174A1 - Refrigeration cycle device

Info

Publication number: WO2016084174A1
Application number: PCT/JP2014/081282
Authority: WO
Inventors: 篤史岐部; 池田　隆; 悠介有井
Original assignee: 三菱電機株式会社
Priority date: 2014-11-26
Filing date: 2014-11-26
Publication date: 2016-06-02
Also published as: CN106796056A; JPWO2016084174A1; JP6316452B2; CN106796056B

Abstract

Provided is a refrigeration cycle device that increases refrigeration capacity in a supercooling device, and is able to prevent condensation on pipes without performing an insulating process on the pipes. This refrigeration cycle device is equipped with: a condenser fan 7 that sends air to a condenser 2; a supercooling device 4 that is connected downstream from the condenser 2 and upstream from a first expansion device 5, and that supercools a refrigerant flowing from the condenser 2; a pipe temperature detection means 9 that detects the temperature of a refrigerant pipe 300 connecting a load device 200 and a heat source device 100 in which the refrigerant flowing from the supercooling device 4 flows; an outside temperature detection means 8 that detects the temperature of air drawn into the condenser 2; and a control device 10 that controls the rotational speed of the condenser fan 7 such that the difference when the temperature of the refrigerant pipe connecting the heat source device 100 and the load device 200 is subtracted from the temperature of the air drawn into the condenser 2 does not exceed a set value.

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus.

Generally, a refrigeration cycle apparatus used for an air conditioner or the like includes a compressor, a condenser (heat radiator), an expansion valve, and an evaporator, and is connected by a pipe for circulating a refrigerant. The high-temperature and high-pressure refrigerant compressed by the compressor is liquefied by heat exchange with the outside air in the condenser, and the liquefied refrigerant becomes a low-temperature fluid mixed with gas and liquid through an expansion valve, and is heat-exchanged and vaporized in the evaporator. The vaporized refrigerant enters the compressor again. The refrigeration cycle apparatus circulates the refrigerant in this way.
The conventional refrigeration cycle apparatus further includes a supercooling device that supercools the refrigerant flowing out of the condenser, and a part of the liquid refrigerant flowing out of the condenser is vaporized due to a pressure drop of the liquid refrigerant or heat intrusion. Various proposals have been made to suppress the formation of flash gas (see, for example, Patent Document 1 and Patent Document 2). When the flash gas is generated, the flow rate of the refrigerant flowing into the expansion device on the downstream side of the condenser is reduced correspondingly, and the refrigeration capacity of the refrigeration cycle apparatus is reduced.

In patent document 1, in order to suppress that a refrigerating capacity falls by generation | occurrence | production of flash gas, the supercooling device comprised with the double tube heat exchanger etc. is installed in the downstream of a condenser, and it condenses with a condenser. A refrigeration cycle apparatus having a configuration in which the temperature of a liquefied refrigerant is lowered to perform supercooling has been proposed.
Moreover, in patent document 2, the mode (condensation suppression priority mode) which has the control means which suppresses that the piping which connected the supercooling apparatus and the indoor unit (load apparatus) condenses with the refrigerant | coolant which flowed out from the condenser. And a mode (refrigeration capacity priority mode) that lowers the liquid refrigerant temperature in the supercooling device and prioritizes the refrigerating capacity, and can be switched, and the supercooling amount of the supercooling apparatus is adjusted according to the mode to be selected A refrigeration cycle apparatus has been proposed.

Japanese Patent No. 3376844 (FIG. 1) Japanese Patent Laying-Open No. 2014-153036 (pages 8-15, FIG. 8)

As in the refrigeration cycle apparatus proposed in Patent Document 1, when the refrigerant is cooled by the supercooling device and supercooled, the refrigeration capacity increases, but the temperature of the liquid refrigerant flowing out of the supercooling device May be below temperature. When the temperature of the pipe connecting the supercooling device and the indoor unit (load device) is lower than the ambient temperature, condensation tends to occur on the surface. In convenience stores and supermarkets where refrigeration cycle equipment is widely used, the refrigerant circuit piping of refrigeration cycle equipment is often placed on the back of the ceiling, etc. Since water leaks from the ceiling, it is necessary to insulate the piping. Moreover, the length may be about 100 m depending on the scale of the store, and the heat insulation process is not simple and there is a problem such as an increase in construction costs. In addition, in a store where construction has already been completed, adding heat insulation treatment to piping such as the back of the ceiling has problems such as poor workability and a lot of time and cost for the construction.

The refrigeration cycle apparatus proposed in Patent Document 2 is provided with switching means between a mode in which refrigeration capacity is given priority and a priority mode in which condensation is suppressed. In the condensation suppression priority mode, the flow rate of the supercooling refrigerant in the supercooling device is increased, and the amount of injection flowing from the supercooling device to the intermediate pressure of the compressor is increased, so that the intermediate pressure of the compressor and the condenser The condensation temperature is increased, and the temperature on the liquid refrigerant side of the supercooling device is increased to a temperature at which no condensation occurs. On the other hand, in the refrigeration capacity priority mode, similarly to Patent Document 1, there is a problem that the temperature of the pipe connecting the supercooling device and the indoor unit (load device) is lowered, resulting in pipe condensation. Further, in the dew condensation suppression mode, since the injection flow rate to the intermediate pressure of the compressor is increased, there is a problem that the discharge temperature from the supercooling device is lowered and the compressor fails due to the liquid back on the intermediate pressure side of the compressor. is there. Moreover, when the heat exchange capacity of the condenser is small and the high pressure pressure is likely to increase with respect to the input of the compressor, it is possible to suppress dew condensation by increasing the injection flow rate. However, if the heat exchange capacity of the condenser is large and it is difficult to increase the high pressure with respect to the input of the compressor, the intermediate pressure cannot be increased even if the injection flow rate to the intermediate pressure of the compressor is increased. There is a problem in that the temperature of the liquid refrigerant that has passed through the supercooling device does not rise to a temperature at which no condensation occurs, and the piping is condensed.

The present invention has been made in order to solve the above-described problems, and it is possible to more easily prevent the dew condensation of the pipe without performing a large-scale construction such as a heat insulation treatment on the pipe. An object is to provide an apparatus.

A refrigeration cycle apparatus according to the present invention has a refrigeration cycle in which a compressor, a condenser, a first expansion device, and an evaporator are connected by a refrigerant pipe, and a heat source device on which the compressor and the condenser are mounted; A refrigeration cycle apparatus including a load device on which the evaporator is mounted; a condenser fan that sends air to the condenser; and a downstream side of the condenser and an upstream side of the first expansion device And a pipe temperature for detecting a temperature of a refrigerant pipe connecting the load device with the supercooling device for supercooling the refrigerant flowing out of the condenser, the heat source device through which the refrigerant flowing out of the supercooling device flows Detecting means, outside air temperature detecting means for detecting the temperature of the air sucked into the condenser, and refrigerant piping connecting the heat source device and the load device from the temperature of the air sucked into the condenser Pull temperature As the difference does not exceed the set value, in which a control device for controlling the rotational speed of the condenser fan.

In the refrigeration cycle apparatus according to the present invention, when the difference between the outside air temperature value for detecting the condenser suction temperature and the pipe temperature after the supercooling device exceeds the set value, the control device controls the rotation speed of the condenser fan. By controlling to reduce and increasing the condensation temperature of the refrigerant in the condenser, the temperature of the refrigerant flowing out of the condenser is raised to be higher than the outside air temperature, so that the heat source device and the load device circuit Condensation can be prevented. Further, even when the condenser has a large heat exchanger capacity, it is possible to prevent the condensation of the pipe. Accordingly, it is possible to more easily prevent the dew condensation on the pipe without performing a large-scale construction such as heat insulation treatment on the pipe.

3 is an example of a circuit configuration of a refrigeration cycle apparatus according to Embodiments 1 to 3 of the present invention. It is a Mollier diagram of the refrigerating cycle device concerning Embodiment 3 of the present invention. It is an example of the control flow of the refrigerating-cycle apparatus which concerns on Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is an example of a refrigerant circuit configuration of a refrigeration cycle apparatus 500 according to Embodiment 1 of the present invention.

(Description of configuration of refrigeration cycle apparatus 500)
The refrigeration cycle apparatus 500 shown in FIG. 1 corresponds to, for example, a refrigerator. The heat source device 100 to be installed, the piping 300 and the piping 400 that connect the load device 200 and the heat source device 100 are provided. The pipe 300 is a pipe through which the liquid refrigerant passes, and the pipe 400 is a pipe through which the suction gas passes.
The refrigeration cycle apparatus 500 includes a compressor 1 that compresses and discharges refrigerant, a condenser 2 (heat radiator) that condenses the refrigerant, and a liquid reservoir that is connected downstream of the condenser 2 and separates into liquid refrigerant and gas refrigerant. 3, a supercooling device 4 that cools and supercools the refrigerant flowing out of the liquid reservoir 3, a first expansion device 5 that decompresses the refrigerant, and an evaporator 6 that evaporates the refrigerant. The refrigeration cycle apparatus 500 includes a refrigeration circuit in which the compressor 1, the condenser 2, the liquid reservoir 3, the supercooling device 4, the first expansion device 5, and the evaporator 6 are connected by refrigerant piping. ing.

(Heat source device 100)
The heat source device 100 includes a compressor 1, a condenser 2, a liquid reservoir 3, and a supercooling device 4.
In addition, the heat source device 100 supplies air to the condenser 2, and promotes heat exchange between the air and the refrigerant flowing through the condenser 2, and supplies the expanded refrigerant to the supercooling device 4. An injection pipe 43 for sending the refrigerant that has passed through the two expansion device 42 and the supercooling device 4 to the intermediate pressure of the compressor 1 is provided. As the second expansion device 42, for example, an electronic expansion valve or a circuit in which capillary tubes having different lengths and electromagnetic valves are combined in parallel can be adopted. In the present embodiment, the second expansion device 42 will be described by taking an electronic expansion valve as an example.

The heat source device 100 is a pipe that detects the temperature of the outside air temperature sensor 8 that detects the temperature of the air sucked into the condenser 2 and the pipe 300 that connects the load device 200 downstream of the supercooling device 4 and the heat source device 100. A temperature sensor 9 and a control device 10 that takes in the detected values of the outside air temperature sensor 8 and the pipe temperature sensor 9 and controls the rotational speed of the condenser fan 7 are provided.

(Load device 200)
The load device 200 includes a first expansion device 5 and an evaporator 6. The refrigerant piping after exiting the condenser 2 and passing through the liquid reservoir 3 branches off downstream of the supercooling device 4 of the heat source device 100, and one is connected to the load device 200 through the piping 300. The refrigerant piping that has passed through the first expansion device 5 and the evaporator 6 in the load device 200 is connected to the suction side of the compressor 1 in the heat source device 100 through the piping 400.

(Compressor 1 and condenser 2)
The compressor 1 sucks a refrigerant, compresses the refrigerant, and discharges the refrigerant in a high temperature and high pressure state. The compressor 1 has a refrigerant discharge side connected to a condenser 2 (heat radiator) and a refrigerant suction side connected to a pipe 400. In addition, the compressor 1 is comprised by an inverter compressor etc., for example. In the first embodiment, the case where one compressor 1 is installed has been described as an example. However, the present invention is not limited to this, and a plurality of compressors may be provided in series or in parallel.
The condenser 2 has an upstream side connected to the discharge side of the compressor 1 and a downstream side connected to the liquid reservoir 3. The condenser 2 performs heat exchange between the refrigerant discharged from the compressor 1 and air. In addition, the condenser 2 is comprised by the plate fin and tube type heat exchanger which can exchange heat between the refrigerant | coolant which flows through the condenser 2, and the air which passes a fin, for example.

(Liquid reservoir 3)
The liquid reservoir 3 separates the refrigerant into a liquid refrigerant and a gas refrigerant, and the upstream side is connected to the condenser 2 and the downstream side is connected to the supercooling device 4. More specifically, the liquid reservoir 3 separates the gas-liquid two-phase refrigerant flowing out of the condenser 2 into a liquid refrigerant and a gas refrigerant. The liquid reservoir 3 is configured to supply the liquid refrigerant to the supercooling device 4 and to stay in the liquid reservoir 3 for the gas refrigerant.

(Supercooling device 4)
The supercooling device 4 is connected to the liquid reservoir 3 on the upstream side and connected to the first expansion device 5 mounted on the load device 200 via the pipe 300 on the downstream side. The supercooling device 4 cools the refrigerant supplied from the liquid reservoir 3 and takes the degree of supercooling of the refrigerant before flowing it through the pipe 300. The supercooling device 4 is used to ensure the refrigeration capacity of the refrigeration cycle device 500.
The subcooling device 4 is not particularly limited with respect to the cooling method of the refrigerant circulating in the heat source device 100 and the load device 200, but employs, for example, a double pipe heat exchanger, a plate type heat exchanger, or the like. In the first embodiment, as an example, the case where the supercooling device 4 has a plate heat exchanger will be described as an example.

The plate type heat exchanger of the supercooling device 4 is formed with a flow path through which two refrigerants flow. That is, the first flow path 41 through which the refrigerant circulating through the heat source device 100 and the load apparatus 200 flows, and the second flow path 45 through which the refrigerant that cools the refrigerant flowing through the flow path flows.
Since the supercooling device 4 includes a plate heat exchanger that can supply the cold heat of the refrigerant flowing through the second flow path 45 to the refrigerant flowing through the first flow path 41, the supercooling degree is reduced to the refrigerant flowing through the pipe 300. Can be turned on.

(Injection piping 43)
The injection pipe 43 is a pipe whose upstream end is connected to the pipe 300 and whose downstream end is connected to the compressor 1. That is, the injection pipe 43 is a pipe that injects refrigerant into the compressor 1 via the first flow path 41 of the supercooling device 4, the second expansion device 42, and the second flow path 45 of the supercooling device 4. The second expansion device 42 and the second flow path 45 of the supercooling device 4 are connected to the injection piping 43 in order from the upstream side.
The compressor 1 has an intermediate port (not shown) that is a process in the middle of compression from a low pressure that is a pressure when taken from the suction side of the compressor 1 to a high pressure that is a pressure higher than the low pressure. The downstream end of the injection pipe 43 is connected to this intermediate port.

(Second expansion device 42)
The second expansion device 42 is for expanding the refrigerant, and has an upstream side connected to the pipe 300 and a downstream side connected to the second flow path 45 of the supercooling device 4. The second expansion device 42 is constituted by an electronic expansion valve whose opening degree is variable, for example. The opening degree of the second expansion device 42 is controlled by the control device 10.

In the present embodiment, the second expansion device 42 is described as an electronic expansion valve. However, the present invention is not limited to this, and in a plurality of capillary tubes connected in parallel, electromagnetic waves can be placed upstream or downstream of the capillary. A configuration may be employed in which the amount of restriction in the expansion device is controlled by installing a valve or the like for controlling a flow path such as a valve and controlling the number of passes through the capillary tube.

(Control device 10 and setting device 11)
The control device 10 detects a detection result of a temperature sensor (not shown) that detects the detected values of the outside air temperature sensor 8 and the piping temperature sensor 9, the discharge refrigerant temperature of the compressor 1, the compressor shell temperature, and the intake refrigerant temperature. Based on the detection result of a pressure sensor (not shown) that detects each of the high-pressure side pressure and the low-pressure side pressure of the compressor 1, the output of the setting device 11, etc. ), The rotational speed (including operation and stop) of the condenser fan 7 attached to the condenser 2 and the fan (not shown) attached to the evaporator 6, the opening degree of the first expansion device 5, and the supercooling device 4. And so on. In addition, this control apparatus 10 is comprised, for example with a microcomputer.
In FIG. 1, the setting device 11 is connected to the control device 10, which is used in the second embodiment. The setting device 11 includes a setting value display unit and a setting value input unit, and includes, for example, a switch, a button, or a combination thereof.
In addition, although the control apparatus 10 shall be mounted in the control board (not shown) of the heat-source apparatus 100 with the setting apparatus 11, it is not limited to it, For example, it is mounted in the load apparatus 200 side. Also good.

(First expansion device 5 and evaporator 6)
The first expansion device 5 is for expanding the refrigerant, and the upstream side is connected to the supercooling device 4 via the pipe 300 and the downstream side is connected to the evaporator 6. In addition, the 1st expansion | swelling apparatus 5 is comprised with the electronic expansion valve, capillary tube, etc. whose opening degree is variable, for example. The evaporator 6 performs heat exchange between the refrigerant decompressed by the first expansion device 5 and the air. In addition, the evaporator 6 is comprised with the plate fin and tube type heat exchanger which can heat-exchange between the refrigerant | coolant which flows through the evaporator 6, and the air which passes a fin similarly to the condenser 2, for example. .

(Operation of refrigeration cycle apparatus 500)
Next, the operation of the refrigeration cycle apparatus 500 of FIG. 1 will be described.
The refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant by performing heat exchange between a medium such as air and the refrigerant in the condenser 2 after being compressed into a high-temperature and high-pressure superheated gas by the compressor 1. . The liquid refrigerant exiting the condenser 2 is separated into gas and liquid in the liquid reservoir 3 and is converted into a liquid refrigerant to which supercooling is added at a high pressure by the supercooling device 4.
The supercooling device 4 branches the first flow path 41 from which the refrigerant is sent from the liquid reservoir 3 and a part of the refrigerant that has flowed through the first flow path 41 on the downstream side of the supercooling device 4. And a second flow path 45 through which the refrigerant expanded by the expansion device 42 and converted into a low-pressure two-phase gas is provided. That is, the refrigerant that has become low-pressure two-phase gas expanded by the second expansion device 42 enters the supercooling device 4 and exchanges heat with the high-pressure liquid refrigerant flowing through the first flow path 41. The low-pressure two-phase gas that has entered the supercooling device 4 exchanges heat with the liquid refrigerant on the high-pressure side of the first flow path 41, passes through the injection pipe 43, and enters the intermediate pressure (intermediate port) of the compressor 1. The low-pressure two-phase gas refrigerant that has entered the intermediate pressure of the compressor 1 is suppressed to a discharge temperature rise of the compressor 1 and is compressed into a high-temperature and high-pressure superheated gas.
Of the liquid refrigerant supercooled at high pressure by the supercooling device 4, the liquid refrigerant flowing toward the load device 200 exits the heat source device 100, passes through the pipe 300, and enters the load device 200. The supercooled liquid refrigerant that has entered the load device 200 is expanded by the first expansion device 5 into a low-pressure two-phase gas, and is heat-exchanged with the surrounding air and water in the evaporator 6 to be in a state of low-temperature and low-pressure superheated gas It becomes. The low-temperature and low-pressure superheated gas leaves the load device 200, passes through the pipe 400, and returns to the heat source device 100. Then, it is again sucked into the compressor 1 and compressed into a high-temperature and high-pressure superheated gas. Thereafter, the above refrigerant circuit cycle is repeated.

Thus, in the refrigeration cycle apparatus 500 described above, the liquid refrigerant that has exited the condenser 2 can increase the capacity of the refrigeration cycle apparatus 500 by lowering the liquid refrigerant temperature by the supercooling apparatus 4. However, when the pipe temperature of the pipe 300 is lower than the surrounding dew point temperature by the supercooling device 4, dew condensation occurs from the pipe surface. For example, condensed water hangs down the ceiling of a store where the pipe 300 is disposed. In order to avoid this, the following means is adopted in the refrigeration cycle apparatus 500 of the first embodiment.

(Control of condenser fan 7)
When the refrigeration cycle apparatus 500 is activated, the control device 10 determines the temperature of the outside air temperature sensor 8 that detects the air suction temperature of the condenser 2 and the temperature of the pipe 300 downstream of the supercooling device 4 in the heat source device 100 during the operation. The detected values of the pipe temperature sensor 9 to be detected are taken in and compared with each other. And when the piping temperature of the piping 300 is substantially equal to the suction air temperature of the condenser 2, the control apparatus 10 continues operation | movement as it is, without performing special control. On the other hand, when the temperature difference obtained by subtracting the pipe temperature value of the pipe 300 from the suction temperature value of the condenser 2 exceeds the set value, the condenser fan 7 is stopped or decelerated. To control. For example, when the intake air temperature of the condenser 2 is 6K higher than the pipe temperature of the pipe 300, the rotation speed of the condenser fan 7 is controlled to be reduced to an upper limit of 80% of the normal rotation speed.
When the rotational speed of the condenser fan 7 decreases, the amount of air per unit time fed into the condenser 2 decreases, so that a decrease in the refrigerant temperature in the condenser 2 is suppressed. Then, the temperature of the refrigerant flowing into the supercooling device 4 rises and the temperature of the refrigerant passing through the pipe 300 also rises, so that the temperature of the pipe 300 rises compared to before the rotational speed of the condenser fan 7 is lowered. Become.

As described above, according to the refrigeration cycle apparatus 500 of the present embodiment, when the intake air temperature of the condenser 2 is 32 ° C., when the pipe temperature of the pipe 300 becomes lower than 26 ° C., the temperature of the pipe 300 becomes 26 ° C. Until this is reached, the rotational speed of the condenser fan 7 is reduced from 100% to 80%. When the pipe temperature is 26 ° C., the relative humidity at which the surface of the pipe 300 is condensed is RH = 62%. Therefore, if the installation environment of the refrigeration cycle apparatus 500 is a relative humidity RH = 62% or less, it is possible to exhibit the ability to ensure maximum supercooling without causing condensation in the pipe 300. .
For example, by controlling the refrigeration cycle apparatus 500 as described above and preventing the condensation on the pipe 300, when the pipe 300 is installed on the ceiling of the store, breeding of mold on the ceiling due to condensed water, or from the ceiling Can prevent water leakage. In addition, since the refrigerant can be supercooled within a range in which condensation does not occur in the pipe 300, a large-scale work such as heat insulation treatment is not required for the liquid pipe disposed on the ceiling or the like, and the refrigeration cycle apparatus 500 is eliminated. It is possible to reduce the installation cost of the installation. Furthermore, the supercooling device 4 can be easily applied when a supercooling device is added to increase the refrigeration capacity with respect to the refrigeration cycle device of an existing store where piping has already been installed.

Embodiment 2. FIG.
In the first embodiment, the method of stopping or decelerating the condenser fan 7 when the temperature difference obtained by subtracting the pipe temperature value of the pipe 300 from the suction temperature value of the condenser 2 exceeds the set value has been described. In the present embodiment, a configuration in which the set value can be changed from the heat source device 100 and the air volume of the condenser fan 7 can be changed according to the set value will be described.

The refrigeration cycle apparatus 500 according to the present embodiment includes a control unit 10 in the heat source apparatus 100 including a display unit for setting values and a setting device 11 that is a setting value input unit.
The refrigerant circuit diagram and operation of the refrigeration cycle apparatus 500 according to the present embodiment are the same as those in the first embodiment.
The control device 10 periodically detects the detection value of the pressure sensor that detects the high-pressure side pressure and the low-pressure side pressure of the compressor 1, the detection value of the pipe temperature sensor 9 that detects the temperature of the pipe 300, and condensation. The detected value of the outside air temperature sensor 8 that detects the air suction temperature of the condenser 2 is read, and it is predicted not to exceed the set value of the temperature difference between the air suction temperature of the condenser 2 and the temperature of the pipe 300, and the condenser fan The air volume of 7 is adjusted.

Here, the switch or button is used to input the set value of the temperature difference between the air suction temperature of the condenser 2 and the temperature of the pipe 300, but it has a schedule function and sets the set value for each daily time zone in advance. The set value may be changed for each time zone. In addition, the heat source device 100 and the load device 200 are electrically connected to each other by communication, and a set value of a temperature difference between the air suction temperature of the condenser 2 and the temperature of the pipe 300 is set by an operation from the load device 200 side. The configuration may be changed.
In addition, as a value input to the control device 10, relative humidity may be input instead of the difference between the air suction temperature of the condenser 2 and the temperature of the pipe 300. In that case, the dew point is calculated from the input relative humidity and the detected value of the air suction temperature of the condenser 2, and the required temperature of the pipe 300 is calculated. Then, the air volume of the condenser fan 7 is adjusted in accordance with the operating state of the refrigeration cycle apparatus 500 so that the temperature of the pipe 300 does not fall below the calculated temperature.

As described above, according to the present embodiment, the air volume of the condenser fan 7 can be adjusted by inputting a set value from the outside. By inputting an appropriate set value, the pipe temperature of the pipe 300 can be controlled at a temperature that does not always cause condensation. Thereby, in addition to the effects described in the first embodiment, the set value can be flexibly changed in accordance with the local environment where the refrigeration cycle apparatus is installed.

Embodiment 3 FIG.
In the present embodiment, the refrigeration cycle apparatus 500 according to the first and second embodiments is configured not only to adjust the air volume of the condenser fan 7 but also to suppress condensation by adjusting the opening degree of the second expansion device 42. Is described.

[Flow of refrigerant cycle when dew condensation is suppressed by adjusting opening of second expansion device 42]
The refrigeration cycle apparatus 500 according to the present embodiment is the same refrigerant circuit as in the first and second embodiments.
By instructing the control device 10 from the setting device 11, the refrigeration cycle device 500 does not increase the degree of supercooling and the refrigeration capacity priority mode, which is an operation mode in which the degree of supercooling is increased for the refrigerant that has passed through the supercooling device 4. It is possible to operate by switching the dew condensation suppression priority mode that is the mode.

The flow of the refrigerant flowing through the supercooling device 4 and the like will be described with reference to FIG.
The high-pressure refrigerant that has flowed out of the liquid reservoir 3 flows into the first flow path 41 of the supercooling device 4. The refrigerant that has flowed into the first flow path 41 is cooled by exchanging heat with the refrigerant that has flowed into the second flow path 45, and is supercooled.

A part of the supercooled refrigerant that flows out from the first flow path 41 of the supercooling device 4 flows out from the heat source device 100 via the pipe 300 and flows into the load device 200. The remainder of the refrigerant that has flowed out of the first flow path 41 of the supercooling device 4 flows into the injection pipe 43 and branches off from the flow of the pipe 300, is reduced in pressure through the second expansion device 42, and decreases in temperature. Then, the refrigerant having the lowered temperature flows into the second flow path 45 of the supercooling device 4 and exchanges heat with the refrigerant in the first flow path 41.

The refrigerant that has flowed out from the second flow path 45 of the supercooling device 4 is used to lower the temperature of the gas refrigerant that flows into the intermediate port of the compressor 1 through the injection pipe 43 and is discharged from the compressor 1. That is, the refrigerant that has flowed out of the second flow path 45 of the supercooling device 4 is injected into the compressor 1 to suppress the temperature rise of the gas refrigerant discharged from the compressor 1, and to suppress deterioration of the refrigeration machine oil. Used.

When the opening degree of the second expansion device 42 is increased, the flow rate of the refrigerant branched from the pipe 300 and supplied to the injection pipe 43 is increased. On the other hand, the refrigerant pressure entering the intermediate port of the compressor 1 is small because the pressure reduction amount is small. The intermediate pressure (pressure) increases and the refrigerant temperature tends to increase. Accordingly, the pressure of the gas discharged from the compressor 1 (high pressure) also increases. Conversely, when the opening degree of the second expansion device 42 is reduced, the flow rate of the refrigerant branched from the pipe 300 and supplied to the injection pipe 43 is reduced, the refrigerant pressure (intermediate pressure pressure) is reduced, and the refrigerant temperature is also reduced. Become. Along with this, the pressure of the gas discharged from the compressor 1 (high pressure) also decreases.

[Mollier diagram of refrigeration cycle apparatus 500]
FIG. 2 is a Mollier diagram of the refrigeration cycle apparatus 500 according to the third embodiment. A refrigerant state corresponding to the opening degree of the second expansion device 42 will be described with reference to the Mollier diagram of FIG.
In the description of FIG. 2, qualitative explanation is given for the case where the opening degree of the second expansion device 42 is (1) smaller and (2) the case where it is relatively larger than (1). To do.
In both cases (1) and (2), the case where the “low pressure”, which is the pressure after depressurization by the first expansion device 5, is assumed to be the same, will be described.
The case (1) corresponds to the solid line in FIG. 2, and the case (2) corresponds to the dotted line in FIG.

First, the case of (1) will be described.
When the opening degree of the second expansion device 42 is made smaller than in the case (2), the intermediate pressure and the high pressure (refrigerant condensation temperature = refrigerant saturated liquid temperature) are lowered as shown by the solid line in FIG.
In the case of (1), the “high pressure” which is the pressure of the refrigerant flowing into the condenser 2 from the compressor 1 and the refrigerant flowing out of the condenser 2 is relatively lower than in the case of (2). (See P1 and Q1 in FIG. 2). For this reason, when the heat dissipation performance in the condenser 2 is the same, the refrigerant temperature flowing out of the condenser 2 (≈refrigerant condensation temperature = refrigerant saturated liquid temperature) is more relative than in the case of (2). It becomes low.

In the case of (1), the “intermediate pressure” that is the pressure of the refrigerant passing through the second expansion device 42 and flowing through the injection pipe 43 is also relatively lower than in the case of (2) (FIG. 2 P2 and Q2).
That is, as compared with the case of (2), in the case of (1), before “lowering the high pressure” and “passing through the first flow path 41 of the supercooling device 4 and flowing into the second expansion device 42” (Refer to P1), and the temperature of the “intermediate pressure” refrigerant reduced by the second expansion device 42 also decreases (see P2).
Therefore, in the case of (1), the liquid refrigerant after heat exchange in the supercooling device 4 flows out at a lower temperature than in the case of (2). That is, low temperature refrigerant flows through the first expansion device 5, and the enthalpy difference between the refrigerant inflow side and the refrigerant outflow side of the evaporator 6 can be increased, and the refrigeration capacity of the refrigeration cycle apparatus 500 can be increased. Will improve.

Furthermore, in the case of (1), since the required power of the compressor 1 is reduced due to the decrease in the “high pressure”, the power consumption is also reduced. Therefore, COP (ratio of refrigerating capacity and power consumption) is increased and energy is saved.

In addition, as described in (1), when the opening degree of the second expansion device 42 is reduced, it is described that “the temperature of the high-pressure liquid refrigerant is decreased” compared to the case of (2). If the opening degree of the second expansion device 42 is too small, the refrigerant flow rate in the injection pipe 43 becomes too small, and heat exchange between the first flow path 41 and the second flow path 45 is performed in the supercooling device 4. It should be noted that the temperature of the high-pressure liquid refrigerant in the first flow path 41 may increase instead.
The second expansion device 42 also serves as an injection for lowering the temperature of the refrigerant discharged from the compressor 1. For this reason, if the opening degree of the second expansion device 42 is made smaller than necessary, the discharge refrigerant temperature of the compressor 1 may rise and the compressor 1 may break down. Therefore, it should be noted that it is necessary to maintain a minimum opening degree at which the compressor 1 does not break down.

Next, the case of (2) will be described.
When the opening degree of the second expansion device 42 is increased, this is the reverse of (1). That is, as compared with (1), “increase in high pressure” and “increase in refrigerant temperature before passing through the first flow path 41 of the supercooling device 4 and flowing into the second expansion device 42”. (Refer to Q1), the temperature of the “intermediate pressure” refrigerant decompressed by the second expansion device 42 is also increased (see Q2).
Note that in the case of (2), the flow rate of the refrigerant flowing into the intermediate port of the compressor 1 is relatively larger than that in (1), the discharged refrigerant temperature is lowered, and the compressor 1 is broken. It is to cause.

Thus, the refrigerant state can be changed according to the opening degree of the second expansion device 42.
Executing the refrigeration capacity priority mode in the refrigeration cycle apparatus 500 corresponds to approaching the Mollier diagram shown by the solid line in FIG. 2, and executing the dew condensation suppression priority mode in the refrigeration cycle apparatus 500 is indicated by the dotted line in FIG. This corresponds to approaching the Mollier diagram shown in FIG.
The refrigeration capacity priority mode and the dew condensation suppression priority mode have been qualitatively described based on FIG. 2, and then a specific control method for the dew condensation suppression priority mode by adjusting the opening of the second expansion device 42 will be described. .

[Control flow in the dew condensation suppression priority mode by adjusting the opening of the second expansion device 42]
FIG. 3 is an example of a control flow of the dew condensation suppression priority mode by adjusting the opening of the second expansion device 42 of the refrigeration cycle apparatus 500 according to the present embodiment. Also, the control start (START) in FIG. 4 is the time when the dew condensation suppression priority mode is set by adjusting the opening of the second expansion device 42. With reference to FIG. 3, the dew condensation suppression priority mode by the opening degree adjustment of the second expansion device 42 will be described.

(Step U0)
The control device 10 shifts to control in the dew condensation suppression priority mode by adjusting the opening of the second expansion device 42.

(Step U1)
The control device 10 determines whether or not the discharge refrigerant temperature of the compressor 1 is equal to or higher than a preset value (lower limit specified value). The preset value is set to 70 ° C., for example. If the value is equal to or greater than the preset value, the process proceeds to step U2. If it is not equal to or greater than the preset value, the process proceeds to step U3.

(Step U2)
The control device 10 increases the opening degree of the second expansion device 42.
When the refrigerant discharge temperature of the compressor 1 is equal to or higher than a lower limit specified value (for example, 70 ° C.), the opening degree of the second expansion device 42 is increased, and the “high pressure” and “intermediate pressure” are increased, Increase the temperature of the “high-pressure liquid refrigerant”. This “high-pressure liquid refrigerant” is a refrigerant that flows through the pipe 300, but as the temperature of the “high-pressure liquid refrigerant” increases, the temperature of the pipe 300 also increases, and condensation is suppressed.
In addition, the opening degree of the 2nd expansion apparatus 42 in this step U2 is larger than the opening degree of the 2nd expansion apparatus 42 in below-mentioned step U3.

(Step U3)
The control device 10 reduces the opening degree of the second expansion device 42.
When the discharge refrigerant temperature of the compressor 1 is equal to or lower than the lower limit specified value, the discharge refrigerant temperature of the compressor 1 is too low, causing a failure. Therefore, the discharge refrigerant of the compressor 1 is reduced by reducing the opening degree of the second expansion device 42, reducing the flow rate of the refrigerant injected into the compressor 1, and reducing the injection flow rate for cooling the discharge refrigerant of the compressor 1. Increase temperature.
However, in this step U3, the opening degree of the second expansion device 42 is reduced so that the temperature of the pipe 300 is in a range where condensation does not occur.

[Control when Condensation Suppression Priority Mode is Adjusted by Adjusting Opening of Second Expansion Device 42 for Adjusting Air Volume of Condenser Fan 7]
In the present embodiment, the control in the case where the dew condensation suppression priority mode based on the opening degree adjustment of the second expansion measure is used together with the air volume adjustment of the condenser fan 7 will be described.
When control is performed to reduce the rotational speed of the condenser fan 7, the temperature of the pipe 300 is increased and the condensation is suppressed in order to suppress the temperature drop of the refrigerant flowing out of the condenser 2.
On the other hand, the control means for suppressing condensation in the condensation suppression priority mode described above uses the injection pipe 43 and the second expansion device 42, and the high-pressure and high-temperature discharge refrigerant temperature of the compressor 1 is changed to the liquid back. It should be lowered to the extent that it does not. That is, the opening degree of the second expansion device 42 is increased, and the injection flow rate to the intermediate pressure of the compressor 1 is increased. When the injection flow rate increases, the input (work amount) in the compressor 1 increases, and the high pressure of the condenser 2 and the intermediate pressure of the injection pipe 43 increase. Therefore, since the liquid temperature of the pipe 300 after heat exchange in the supercooling device 4 becomes the saturation temperature of the intermediate pressure, an increase in the injection flow rate increases the liquid temperature of the pipe 300 (Q1 in FIG. 2). And Q2). That is, when the pipe temperature of the pipe 300 is lower than the air suction temperature of the condenser 2, the difference obtained by subtracting the pipe temperature of the pipe 300 from the air suction temperature of the condenser 2 is reduced, so that dew condensation on the pipe 300 is suppressed. Can be controlled in the direction.

That is, the combined use of the dew condensation suppression priority mode by adjusting the air volume of the condenser fan 7 and adjusting the opening of the second expansion device 42 can further improve the dew condensation prevention effect of the pipe 300.
In particular, when the heat exchanger capacity of the condenser 2 is large, even if the opening of the second expansion device 42 in the dew condensation suppression priority mode described above is increased (for example, in the case of U2 in FIG. 3), The increase rate of the flow rate (that is, intermediate pressure) of the injection pipe 43 is small, the discharge side of the compressor 1 is not high pressure, and the increase range of the pipe temperature of the pipe 300 is small. Moreover, if the opening degree of the second expansion device 42 is increased too much, the refrigerant discharged from the compressor 1 is cooled too much, and the temperature of the refrigerant discharged becomes low, leading to failure of the compressor 1 in some cases. In such a case, the difference between the intake air temperature of the condenser 2 and the temperature of the pipe 300 is detected, and if the difference value exceeds the set value, the rotational speed of the condenser fan 7 is reduced, The temperature of the piping 300 can be raised. That is, by using together with the dew condensation suppression priority mode by adjusting the opening degree of the second expansion device 42 for adjusting the air volume of the condenser fan 7, the dew condensation of the pipe 300 is prevented without excessively increasing the opening degree of the second expansion device 42. The prevention effect can be ensured.

Further, when the control for decelerating the rotation speed of the condenser fan 7 and the dew condensation suppression priority mode by adjusting the opening of the second expansion device 42 are used in combination, it is necessary to excessively increase the opening of the second expansion device 42. In addition, since the injection flow rate to the intermediate pressure of the compressor 1 does not become excessively large, liquid back at the intermediate pressure of the compressor 1 does not occur.

1 compressor, 2 condenser (radiator), 3 liquid reservoir, 4 subcooling device, 5 first expansion device, 6 evaporator, 7 condenser fan, 8 outside air temperature sensor, 9 pipe temperature sensor, 10 control device, 11 setting device, 41 1st flow path, 42 2nd expansion device, 43 injection pipe, 45 2nd flow path, 100 heat source device, 200 load device, 300 (liquid refrigerant passes), 400 (suction gas passes) Piping, 500 refrigeration cycle equipment.

Claims

A heat source device having a compressor, a condenser, a first expansion device, and a refrigerant circuit in which an evaporator is connected by a refrigerant pipe, and in which the compressor and the condenser are mounted, and a load device in which the evaporator is mounted In the refrigeration cycle apparatus comprising:
A condenser fan that sends air to the condenser;
A subcooling device connected to the downstream side of the condenser and upstream of the first expansion device, and for supercooling the refrigerant flowing out of the condenser;
A pipe temperature detecting means for detecting a temperature of a refrigerant pipe connecting the heat source device and the load device through which the refrigerant flowing out of the supercooling device flows;
An outside air temperature detecting means for detecting the temperature of the air sucked into the condenser;
The rotational speed of the condenser fan is controlled so that the difference obtained by subtracting the temperature of the refrigerant pipe connecting the heat source device and the load device from the temperature of the air sucked into the condenser does not exceed a set value. A refrigeration cycle apparatus comprising:
The refrigeration cycle apparatus according to claim 1, further comprising a setting device for inputting the set value.
An injection pipe having one end connected to the compressor and the other end connected between the supercooling device and the first expansion device;
A second expansion device that depressurizes the refrigerant flowing through the injection pipe,
The supercooling device is:
A first flow path whose upstream side is connected to the condenser and whose downstream side is connected to the other end of the first expansion device and the injection pipe;
A second flow path connected to the injection pipe on the downstream side of the second expansion device,
The refrigeration cycle apparatus according to claim 1 or 2, comprising a heat exchanger that exchanges heat between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path.
The controller is
When the discharge refrigerant temperature of the compressor is equal to or higher than a preset lower limit value, the opening degree of the second expansion device is larger than when the discharge refrigerant temperature of the compressor is less than a preset lower limit value. The refrigeration cycle apparatus according to claim 3, wherein