KR101673105B1 - Binary refrigeration cycle device - Google Patents

Abstract

The two-way refrigeration cycle apparatus includes a high-temperature side refrigerating circuit for communicating a high-temperature side compressor, a high-temperature side condenser, a high-temperature side expansion device, a cascade heat exchanger, and a high-temperature side accumulator through a high-temperature side refrigerant pipe, Temperature side refrigerant circuit communicating with the low-temperature side refrigerant pipe, a low-temperature side refrigerant circuit communicating with the low-temperature side refrigerant pipe, a low-temperature side refrigerant pipe, and a high-temperature side bypass circuit Side bypass valve provided in the high-temperature-side bypass circuit; and control means for opening the high-temperature-side bypass valve when the outside air temperature is equal to or lower than a predetermined temperature at the start-up time.

Description

[0001] BINARY REFRIGERATION CYCLE DEVICE [0002]

An embodiment of the present invention relates to a two-way refrigeration cycle apparatus having a high temperature side refrigeration cycle and a low temperature side refrigeration cycle.

A conventionally known two-way refrigeration cycle apparatus includes a high temperature side refrigeration cycle and a low temperature side refrigeration cycle, in which a high temperature side refrigeration cycle and a low temperature side refrigeration cycle share one cascade heat exchanger (intermediate heat exchanger) The refrigerant circulating in the refrigeration cycle and the refrigerant circulating in the low temperature side refrigeration cycle are heat exchanged in the cascade heat exchanger and the hot water is generated by heating the water or hot water by the high temperature side refrigerant circulating in the high temperature side refrigeration cycle.

Generally, when the refrigeration cycle is started when the outside air temperature is low, the temperature of the refrigerator oil in the compressor constituting the refrigeration cycle is lowered. As a result, the pressure rises due to the start of the compressor, and the refrigerant is dissolved in the refrigerating machine oil to dilute the refrigerating machine oil. When the dilution of the freezer oil is progressed, the amount of oil of the refrigerating machine discharged to the outside of the compressor together with the refrigerant is increased, and the oil level in the compressor is lowered, so that the lubricating operation of the compression mechanism is liable to occur.

In particular, in the high temperature side refrigeration cycle of the two-way refrigeration cycle apparatus that generates high temperature water, the condensation pressure rises quickly and the condensation pressure is high, so dilution of the refrigerator oil tends to be promoted, and there is a problem that the amount of oil in the refrigerator oil is increased.

International Publication WO2012 / 128229 A1

SUMMARY OF THE INVENTION In view of the above-described prior art, an object of the present invention is to provide a two-way refrigeration cycle device capable of suppressing the amount of oil discharged from the compressor to the outside of the compressor at the time of starting at low ambient temperature.

In order to solve the above-described problems, a two-way refrigeration cycle apparatus according to an embodiment of the present invention includes a high temperature side compressor, a high temperature side condenser, a high temperature side expansion device, a cascade heat exchanger and a high temperature side accumulator, Side refrigerant circuit communicating with the low-temperature-side refrigerant pipe through a low-temperature-side refrigerant pipe, a low-temperature-side refrigerant circuit communicating with the low-temperature side refrigerant pipe, the cascade heat exchanger, the low-temperature side expansion device, Side bypass circuit provided in the high-temperature-side bypass circuit, and a high-temperature-side bypass valve provided in the high-temperature-side bypass circuit, when the outside air temperature is lower than a predetermined temperature, And a control means for opening the valve.

The two-way refrigeration cycle apparatus having the above-described characteristics preferably further has the following suitable embodiments.

Side bypass circuit that connects the discharge side of the low-temperature side compressor and the inlet side of the low-temperature side accumulator, and a low-temperature side bypass valve provided in the low-temperature side bypass circuit. When the outdoor air temperature is lower than a predetermined value And a control means for opening the low temperature side bypass valve.

It is preferable that the control means drives the high temperature side compressor at a predetermined operating frequency while the high temperature side bypass valve is opened.

The control unit includes a low outside temperature startup mode selection unit that determines whether to execute the low outside temperature startup mode based on the intake temperature and the outside air temperature, a time when the bypass circuit is opened Temperature side bypass control means for opening the high temperature side bypass circuit in accordance with the outside air temperature when the low outside air temperature starting mode is executed; And a low-temperature side bypass control means for opening the low-temperature side bypass circuit in addition to the high-temperature side bypass circuit.

Further, the two-way refrigeration cycle apparatus according to the present invention is not limited to the above-described embodiments unless the spirit of the present invention is changed according to the application.

According to the above-described embodiment of the present invention, it is possible to provide a two-way refrigeration cycle apparatus capable of suppressing the amount of oil discharged from the compressor to the outside of the compressor at the time of starting at low ambient temperature.

In the two-way refrigeration cycle apparatus in this embodiment, when the outside air temperature is low and dilution of the freezer oil is likely to occur, the operation of the high-temperature side compressor is started with the high-temperature side bypass circuit opened, The temperature of the refrigerator oil in the compressor can be increased. As a result, dissolution of the refrigerant in the refrigerating machine oil is suppressed, and the discharge amount of the refrigerating machine oil to the outside of the compressor by dilution can be suppressed.

Other effects and advantages according to the embodiments of the present invention will become more apparent from the following description made with reference to the accompanying drawings.

1 is a configuration diagram of a refrigeration cycle showing the configuration of a two-way refrigeration cycle apparatus according to an embodiment of the present invention.
2 is a block diagram showing a configuration of a control unit (controller) of a two-way refrigeration cycle apparatus according to an embodiment of the present invention.
3 is a flowchart showing the flow of operation at the time of starting the two-way refrigeration cycle apparatus according to the embodiment of the present invention.
4 is an explanatory diagram (table) showing the relationship between the outdoor air temperature and the operation in the low ambient temperature start mode of the two-way refrigeration cycle apparatus according to the embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a configuration diagram of a refrigeration cycle showing a configuration of a two-way refrigeration cycle apparatus according to an embodiment of the present invention. The two-way refrigerating cycle apparatus R used as the high temperature water producing apparatus includes a high temperature side refrigerating cycle Ra mounted on the housing K, a low temperature side refrigerating cycle Rb and a control unit 20. [

The high temperature side refrigeration cycle Ra includes a high temperature side compressor 1 for compressing the refrigerant, a hot water heat exchanger 2 (high temperature side condenser) for condensing the refrigerant, a high temperature side expansion device 3 for decompressing the refrigerant, A cascade heat exchanger 4 for heat-exchanging the refrigerant with the refrigerant in the side refrigerating cycle Rb, and a high-temperature side accumulator 5 for gas-liquid separating the refrigerant, and these are sequentially communicated through the refrigerant pipe.

The cascade heat exchanger 4 functions as an evaporator for evaporating the refrigerant flowing through the high-temperature-side refrigerant passage 4a in the high-temperature-side refrigeration cycle Ra. Side refrigerant passage 2a through which the refrigerant in the high-temperature-side refrigeration cycle Ra flows and a water-side flow passage 2b through which water as the heating fluid flows are provided in the hot water heat exchanger 2. The water- And communicates with the pipe H. The hot water pipe H is provided with a water feed pump 18.

The discharge side of the high temperature side compressor (1) and the inlet side of the high temperature side accumulator (5) are communicated by the high temperature side bypass circuit (6). The high-temperature-side bypass circuit (6) is provided with a high-temperature-side bypass valve (7) as an opening / closing valve.

The low temperature side refrigeration cycle Rb includes a low temperature side compressor 11 for compressing the refrigerant, a four-way valve 12 for switching the direction in which the refrigerant flows in the heating operation and the defrosting operation, the cascade heat exchanger 4, Side expansion device 13 for evaporating the refrigerant, an air heat exchanger (low-temperature side evaporator) 14 for evaporating the refrigerant, and a low-temperature side accumulator 15, and these are successively communicated through the refrigerant pipe.

The cascade heat exchanger 4 functions as a condenser for condensing the refrigerant flowing through the low-temperature-side refrigerant passage 4b in the low-temperature-side refrigerating cycle Rb.

A blower (19) for blowing air to the air heat exchanger (14) is provided at a position opposed to the air heat exchanger (14).

The discharge side of the low temperature side compressor (11) and the inlet side of the low temperature side accumulator (15) are communicated by the low temperature side bypass circuit (16). The low-temperature side bypass circuit 16 is provided with a low-temperature side bypass valve 17 which is an on-off valve.

In this embodiment, R134a refrigerant is used in the high temperature side refrigeration cycle Ra and R410A refrigerant is used in the low temperature side refrigeration cycle Rb.

Since R134a used in the high temperature side refrigeration cycle Ra is low in saturated gas density and saturated pressure at the same temperature as that of R410A used in the low temperature side refrigeration cycle Rb, the R134a used in the high temperature side It is suitable as a refrigerant used in the refrigeration cycle Ra.

In the refrigeration oil, PVE (polyvinyl ether) is used in the high temperature side compressor 1 of the high temperature side refrigeration cycle Ra and POE (polyol ester) is used in the low temperature side compressor 11 of the low temperature side refrigeration cycle Rb. The PVE used as the refrigerator oil of the high-temperature side compressor 1 is suitable as a refrigerator oil of the high-temperature side compressor because the wear of the compression mechanism is less than that of POE at high temperature. On the other hand, PVE has a property that it is easy to dissolve in R134a refrigerant as compared with POE, so that it has a property that the amount of air flow is increased when starting at low ambient temperature.

In the thus constituted two-way refrigeration cycle apparatus R, the operation of the high-temperature side refrigerating cycle Ra by driving the high-temperature side compressor 1 and the operation of the low-temperature side compressor 11 by the control unit (control device) Operation of the low-temperature-side refrigeration cycle Rb is performed. Further, when the water feed pump 18 of the hot water pipe H is driven, water flows in the water side channel 2b of the hot water heat exchanger 2. [ This water is heated by the heat radiated from the high-temperature side refrigerant in the refrigerant-side flow path 2a, and becomes high temperature water of about 90 캜 or so. This hot water is supplied from the hot water pipe H to a place requiring hot water.

The relationship between the control unit 20 and each component is shown in Fig.

The high temperature side refrigerating cycle Ra and the low temperature side refrigerating cycle Rb are operated to perform heat exchange in the heat exchanger 4 including the high temperature side refrigerant passage 4a and the low temperature side refrigerant passage 4b, Side refrigerant is heated by the heat radiated from the low-temperature side refrigerant of the low-temperature-side refrigerating cycle Rb. As a result, in the high temperature side refrigeration cycle Ra, the temperature of the refrigerant sucked into the high temperature side compressor 1 becomes high and the temperature and the pressure in the high temperature side compressor 1 become higher than the temperature and the pressure in the low temperature side compressor 11, The amount of heat radiated from the refrigerant-side flow path 2a of the hot water heat exchanger 2 increases, and high-temperature water can be generated.

Next, a control unit (control device) of the two-way refrigeration cycle apparatus R according to the embodiment of the present invention will be described based on the block diagram of Fig.

The two-way refrigeration cycle apparatus R includes a control unit 20 including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) in the housing K.

The control section 20 is provided with an inverter circuit 21 for driving control of the high temperature side compressor 1, an inverter circuit 22 for driving control of the low temperature side compressor 11, an inverter circuit 23 for driving control of the blower 19, The apparatus 3, the low temperature side expansion device 13, the four-way valve 12, the high temperature side bypass valve 7, the low temperature side bypass valve 17 and the pump 18 are connected and their operation is controlled .

The control unit 20 is provided with temperature sensors 31a and 31b and pressure sensors 32a and 32b provided on the discharge side of the high temperature side compressor 1 and the low temperature side compressor 11 and a temperature sensor 33a An inlet water temperature sensor 35 provided on the inlet side of the water side flow path 2b of the hot water heat exchanger 2 and an outlet water temperature sensor 36 provided on the outlet side, A temperature sensor (not shown) provided in the cascade heat exchanger 4, a temperature sensor (not shown) provided in the air heat exchanger 14 and an outside air temperature sensor (not shown) provided in the vicinity of the air heat exchanger 14 37 are connected. 2 shows a state in which the temperature sensor 31a, the inlet water temperature sensor 35 and the outside air temperature sensor 37 are connected to the control unit 20. [

The high-temperature side compressor 1 drive control inverter circuit 21 rectifies a voltage of a power source such as a commercial AC power source and converts it into a voltage of a frequency according to a command from the control unit 20, And outputs it to the compressor motor 1M. This output becomes the driving power of the compressor motor 1M. Likewise, the inverter circuit 22 for drive control of the low-temperature side compressor 11 drives the compressor motor 11M of the low-temperature side compressor 11 and the inverter circuit 23 for drive control of the blower 19 drives the fan motor (19M). The water supply pump 18 is also driven by a water pump drive control inverter (not shown).

The control unit 20 determines operating conditions of the respective units based on information such as operation conditions input through an operation unit (not shown all) such as a touch panel or a remote controller and detection signals from various sensors, The fan motor 19M, the four-way valve 12, the expansion devices 3 and 13 and the bypass valves 7 and 17 and the pump 18 are driven.

The control unit 20 has the following functions (1) to (4) as its main functions.

(1) In the startup, based on the intake temperature Twi obtained from the detection signal of the inlet water temperature sensor 35 and the outdoor air temperature To acquired from the detection signal of the outdoor air temperature sensor 37, The outdoor temperature start mode selection means (20a).

(2) Bypass circuit open time setting means 20b for setting the time for opening the bypass circuits 6 and 16 in accordance with the outside air temperature To when the low outside temperature start mode is executed.

(3) High-temperature side bypass control means 20c for opening the high-temperature side bypass circuit 6 in accordance with the outside air temperature To when the low outside temperature startup mode is executed.

(4) Low-temperature side bypass control means 20d for opening the low-temperature side bypass circuit 16 in addition to the high-temperature side bypass circuit 6 in accordance with the outside air temperature To when the low outside temperature startup mode is executed.

Hereinafter, the operation of the two-way refrigeration cycle apparatus R will be described with reference to Figs. 3 and 4. Fig.

Fig. 3 is a flowchart of a process executed by the control unit 20 of the two-way refrigeration cycle apparatus R, and Fig. 4 is an explanatory diagram showing the relationship between the outdoor air temperature and the operation in the low ambient temperature start mode.

When the operator operates the operation unit provided on the hot water supply side or the operation unit provided on the two-way refrigeration cycle unit R or when the start of operation is instructed in accordance with the operation schedule set to any one of the operation units, the control unit 20 firstly controls the hot water heat exchanger 2, The intake air temperature Twi detected by the inlet water temperature sensor 35 provided on the inlet side of the water side flow path 2b of the outdoor unit 2b and the outdoor air temperature To detected by the outdoor air temperature sensor 37 are acquired.

The control unit 20 determines whether or not the intake temperature Twi is higher than a predetermined temperature Twis (for example, 40 deg. C) stored in advance in the control unit 20 and the ambient temperature To is a predetermined temperature T1 (For example, 20 占 폚) or less (step S1).

Here, the refrigerator oil tends to be diluted when the temperature of the refrigerator oil in the compressor is lowered and the pressure rise of the refrigerant is abrupt. When the intake temperature Twi is 40 DEG C or lower, the condensation pressure in the hot water heat exchanger 2 of the high temperature side refrigeration cycle Ra is not high, so that the pressure in the compressor does not rise sharply even when the high temperature side compressor 1 is started. Therefore, even if the temperature of the refrigerator oil is low (the outside air temperature To is low), dilution of the refrigerator oil is unlikely to occur. When the outside air temperature To is higher than 20 ° C, the temperature of the refrigerator oil in the compressor is not lowered. Therefore, when the condensation pressure in the hot water heat exchanger 2 of the high temperature side refrigeration cycle Ra is high The dilution of the freezer oil is unlikely to occur. Accordingly, the control unit 20 does not execute the low outside temperature startup mode when the intake temperature Twi is 40 DEG C or lower or the outside air temperature To is higher than 20 DEG C ("NO" in step S1).

On the other hand, when the intake temperature Twi is higher than 40 deg. C and the outside air temperature To is lower than or equal to 20 deg. C (YES in step S1), the control unit 20 executes the low outside temperature startup mode described below.

As shown in Fig. 4, the control unit 20 controls the opening time of the bypass circuit and the opening and closing of the bypass valve in accordance with the outside air temperature To.

First, the control unit 20 sets the opening time (bypass circuit opening setting time) Ts of the bypass circuit in accordance with the outside air temperature To.

The control unit 20 determines whether or not the outside air temperature To is in a range of predetermined values T1 to T2 (T2 <To? T1) (step S3). Here, T1 is 20 占 폚, for example, and T2 is -10 占 폚. If the outside air temperature To is higher than -10 ° C and is not higher than 20 ° C (in the case of "YES" in step S3), the control unit 20 proceeds to step S5 and the high temperature side bypass valve 7) is set to a predetermined time t1 (for example, 6 minutes).

If the outside air temperature To is less than -10 占 폚 (in the case of "No" in step S3), the control unit 20 proceeds to step S4 to determine whether the outside air temperature To is within the range T3 &Lt; To &lt; / RTI &gt; T2). Here, T3 is, for example, -15 占 폚.

If the outside air temperature To is higher than -15 캜 and equal to or lower than -10 캜 (YES in step S4), the control unit 20 proceeds to step S6 to set the high temperature side bypass valve 6 of the high temperature side bypass circuit 6 The opening time ts of the opening 7 is set to a predetermined time t2 (for example, 8 minutes).

The control unit 20 proceeds to step S7 and judges whether or not the temperature of the high temperature side bypass circuit 6 and the low temperature side bypass circuit 16 is equal to or more than -15 ° C (in the case of " The opening time ts of each bypass valve 7, 17 is set to a predetermined time t3 (for example, 30 minutes).

The control unit 20 opens the high temperature side bypass valve 7 of the high temperature side bypass circuit 6 and then starts the operation of the high temperature side compressor 1 (step 8). In step S9, the operation of the low-temperature side compressor 11 is started.

The high temperature side bypass valve 7 of the high temperature side refrigeration cycle Ra is opened and part of the gas refrigerant discharged from the high temperature side compressor 1 is discharged to the high temperature side bypass circuit 6 Side accumulator 5 via the first and second heat exchangers. The gas refrigerant introduced into the high-temperature side accumulator 5 is sucked into the high-temperature side compressor 1 to warm the freezer oil in the compressor. With the lapse of time, the temperature of the gas refrigerant discharged from the high-temperature side compressor 1 rises and the temperature of the refrigerating machine oil rises.

At this time, the control unit 20 acquires the temperature Td of the discharge gas refrigerant detected by the temperature sensor 31a, and determines whether or not the discharge gas temperature Td exceeds a predetermined temperature (step S12).

In the present embodiment, this predetermined temperature is 80 deg. C obtained by subtracting a predetermined value alpha (for example, 10 deg. C) from the hot water set point temperature Twos (e.g., 90 deg. C) set by the operation unit.

When the discharged gas refrigerant temperature Td exceeds 80 占 폚 (Twos-10 占 폚) ("No" in step S11) in step 12S, the control unit 20 determines that the refrigerating machine oil in the compressor 1 is sufficiently warmed And the high temperature side bypass valve 7 is closed (step S14).

Even if the discharge gas refrigerant temperature Td does not exceed 80 DEG C (in the case of "YES " in step S11), the control unit 20 determines that the elapsed time t from the opening of the high- If it is determined that the refrigerator oil in the compressor 1 has been warmed up (step S13: YES), the opening-time setting time ts (6 minutes in step S5 and 8 minutes in step S6) 7 are closed (step S14).

Then, the control unit 20 closes the high-temperature-side bypass valve 7, then releases the low outside temperature start mode (step S15), and shifts to normal operation.

When the high temperature side bypass valve 7 is opened, the control unit 20 sets the high temperature side compressor 1 to a constant operating frequency (for example, 30 Hz) . If the operating frequency of the high-temperature side compressor 1 is suddenly increased or the compressor is driven at a high operating frequency under conditions in which the refrigerating machine oil is liable to be diluted, the amount of oil discharged from the compressor to the outside of the compressor is increased. Therefore, when the low ambient temperature start mode is executed, the operation frequency of the high-temperature side compressor 1 is maintained at 30 Hz, so that the amount of oil discharged from the compressor to the outside of the compressor can be suppressed.

On the other hand, as compared with the high-temperature side compressor 1, the low-temperature side compressor 11 is driven at the same operating frequency as normal operation because dilution of the freezer oil is less likely to occur. If the low temperature side compressor (11) is driven at a low operating frequency, the low temperature side refrigeration cycle (Rb) is insufficient to heat the high temperature side refrigeration cycle (Ra), and it takes time to rise the high temperature side refrigeration cycle (Ra). Therefore, in order to raise the discharge gas temperature Td of the high-temperature side compressor 1 quickly, the low-temperature side compressor 11 is driven similarly to the normal operation.

Next, the operation in the low outside temperature starting mode in the case where the outside air temperature To is extremely low will be described.

In the case where the outside air temperature To is extremely low such as -15 ° C (predetermined temperature T3) or less, the refrigerant circulation amount decreases due to stagnation of the high temperature side refrigerant in the high temperature side refrigeration cycle Ra, Side refrigerant in the low-temperature-side refrigerant cycle Rb is not completely dissipated in the cascade heat exchanger 4 because the high-temperature-side refrigerant in the low-temperature-side refrigerant cycle Rb is opened and the high-temperature-side compressor 1 is driven at a low operating frequency. As a result, the pressure on the high-pressure side in the low-temperature-side refrigeration cycle Rb sharply rises, and the operation of the two-way refrigeration cycle apparatus R is forcibly stopped due to the action of a protective device such as a high-pressure switch. In this way, when the outside air temperature To is extremely low, the two-way refrigeration cycle apparatus R may not be able to operate.

Therefore, when the outside air temperature To is lower than -15 占 폚 (in the case of "NO " in step S4), the control unit 20, in order to enable the two-way refrigeration cycle apparatus R to be operated even under the extremely low ambient temperature condition, After the bypass circuit opening set time ts is set to t3 for 30 minutes (step S7), the high temperature side bypass valve 7 is opened (step S10) and the low temperature side bypass valve 17 is opened (Step S11).

(T1: step S5) or eight minutes (t2: step S6) because the refrigerating machine oil in the high-temperature side compressor 1 is unlikely to be warmed up under the situation where the outside air temperature is extremely low. (T3) for a longer period of 30 minutes.

After the bypass circuit opening set time ts is set, the high-temperature side bypass valve 7 of the high-temperature side bypass circuit 6 is opened by the instruction from the control unit 20, and the operation of the high-temperature side compressor 1 (Step S10). In response to a command from the control unit 20, the low temperature side bypass valve 17 of the low temperature side bypass circuit 16 is opened to start the operation of the low temperature side compressor 11 (step S11).

At this time, the high-temperature side compressor (1) is driven at a low operating frequency (30 Hz constant) and the low temperature side compressor (11) is driven at the normal operating frequency.

The low temperature side bypass valve 17 is opened so that a part of the gas refrigerant discharged from the low temperature side compressor 11 flows into the low temperature side accumulator 15 through the low temperature side bypass circuit 16. [ The gas refrigerant flowing into the low temperature side accumulator 15 is sucked into the low temperature side compressor 11. A part of the gas refrigerant discharged from the low temperature side compressor 11 flows to the low temperature side bypass circuit 16 so that the rapid rise of the high pressure side pressure of the low temperature side refrigerating cycle Rb can be suppressed, It is possible to avoid a forced stop due to a high pressure abnormality.

When the discharge gas refrigerant temperature Td of the high-temperature side compressor 1 exceeds 80 占 폚 (Twos-10 占 폚) ("NO" in step S12), the controller 20 sufficiently warms the refrigerating machine oil in the high- , And commands the high-temperature side bypass valve 6 and the low-temperature side bypass valve 16 to be closed (step S14).

Even if the discharge gas refrigerant temperature Td does not exceed 80 占 폚 (Twos-10 占 폚) (YES in step S12), the control unit 20 controls the high-pressure side bypass valve 7 and the low-temperature side bypass valve 17 (YES in step S13), it is determined that the refrigerating machine oil in the high-temperature compressor 1 has been warmed, and accordingly, the high-temperature side bypass The valve 7 and the low-temperature-side bypass valve 17 are closed (step S14).

Subsequently, the control unit 20 closes the high temperature side bypass valve 7 and the low temperature side bypass valve 17, then releases the low outside temperature start mode (step S15) and shifts to normal operation.

With the above-described configuration, the two-way refrigeration cycle apparatus R can be operated even under the situation where the outside air temperature To is extremely low.

As described above, in the two-way refrigerating cycle apparatus R of the present embodiment, when the outside air temperature is low and the dilution of the freezer oil is likely to occur, the high temperature side bypass circuit 6 is opened while the high temperature side compressor The temperature of the refrigerating machine oil in the compressor can be increased by introducing the high-temperature gas refrigerant into the inside of the compressor. As a result, dissolution of the refrigerant in the freezer oil can be suppressed, and the discharge amount of the freezer oil to the outside of the compressor can be suppressed by dilution.

Further, in the two-way refrigeration cycle apparatus R in this embodiment, the bypass circuit 16 of the low-temperature-side refrigeration cycle Rb is also opened to prevent the high-pressure abnormality of the low-temperature-side cycle Rb have.

Furthermore, the two-way refrigeration cycle apparatus R according to the present invention is not limited to the hot water generation apparatus, but is configured according to the application and is not limited to the above-described embodiments.

For example, if a heat exchanger that absorbs heat from the hot water of a factory or the like is used in place of the air heat exchanger 14 of the low temperature side refrigeration cycle Rb, there is no possibility that the air heat exchanger 14 is conceived on the surface of the heat exchanger Therefore, it is possible to remove the four-way valve 12 for making the low-temperature-side refrigeration cycle Rb reverse cycle.

The refrigerant used in the high temperature side refrigeration cycle Ra and the low temperature side refrigeration cycle Rb is not limited to R134a and R410A but may be a refrigerant such as R32, R245fa, HFO-1234yf and HFO-1234ze.

Although the present embodiment has been described above, the above-described embodiment is presented as an example, and it is not intended to limit the scope of the embodiment. This new embodiment can be implemented in various other forms, and various omissions, substitutions, and alterations can be made without departing from the gist of the invention. These embodiments and their modifications fall within the scope and spirit of the invention, and are included in the scope of the invention as defined in the claims and their equivalents.

1: High-temperature side compressor
2: Hot water heat exchanger
3: High-temperature side expansion device
4: Cascade heat exchanger
5: High-temperature side accumulator
6: High-temperature side bypass circuit
7: High temperature side bypass valve
Ra: High temperature side refrigeration circuit
11: Low-temperature side compressor
12: Four way valve
13: Low temperature side expansion device
14: Air heat exchanger
15: Low-temperature accumulator
16: Low-temperature side bypass circuit
17: Low temperature side bypass valve
18: water pump
Rb: Low temperature side freezing circuit
K: housing
20: control unit (control means)
21, 22, 23: inverter device

Claims (4)

A two-way refrigeration cycle apparatus for producing high temperature water,
Temperature side refrigerant circuit for communicating the high-temperature side compressor, the high-temperature side condenser, the high-temperature side expansion device, the cascade heat exchanger, the high-temperature side accumulator,
A low-temperature-side refrigerant circuit communicating with the low-temperature-side refrigerant pipe through the low-temperature-side compressor, the cascade heat exchanger, the low-temperature-side expansion device,
A high temperature side bypass circuit for connecting the discharge side of the high temperature side compressor and the inlet side of the high temperature side accumulator,
A high temperature side bypass valve provided in the high temperature side bypass circuit,
A low-temperature side bypass circuit for connecting the discharge side of the low-temperature side compressor and the inlet side of the low-temperature side accumulator;
A low temperature side bypass valve provided in the low temperature side bypass circuit,
Wherein when the outside air temperature is equal to or lower than the first temperature, the control unit opens the high temperature side bypass valve and opens the low temperature side bypass valve when the outside air temperature is lower than the second temperature lower than the first temperature, And a second refrigerating cycle unit that is connected to the second refrigerating cycle unit. delete 2. The refrigerating cycle control device according to claim 1, wherein the control means drives the high-temperature side compressor at a predetermined operating frequency lower than an operating frequency during normal operation while the high-temperature side bypass valve is opened. Device. The air conditioner according to any one of claims 1 to 3, wherein the control means is configured to select a low outside temperature starting mode based on the temperature of the inlet side of the fluid to be heated in the high temperature side condenser and the outside air temperature, A bypass circuit open time setting means for setting a time for opening the bypass circuit in accordance with the outside air temperature when the low outside temperature startup mode is executed; Side bypass control means for opening the low-temperature side bypass circuit in addition to the high-temperature side bypass circuit in accordance with the outside-air temperature when the low-temperature-side startup mode is executed; and a low- Refrigeration cycle equipment.

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