JP6138186B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus including a supercooling heat exchanger that supercools refrigerant condensed by an air-cooled condenser.

In a refrigeration apparatus that performs a refrigeration cycle, as a means for increasing cooling capacity, there is a method of adding supercooling to a liquid refrigerant pipe through which liquid refrigerant flows in a refrigerant circuit.
When supercooling is added to the liquid refrigerant pipe, the cooling capacity increases by increasing the amount of supercooling added, but the temperature of the liquid refrigerant pipe falls below the ambient air temperature, and the low-temperature liquid refrigerant flows into the refrigerant pipe. If it flows through the pipe, condensation tends to occur on the pipe surface.

In convenience stores and supermarkets where refrigeration equipment is often used, the refrigerant piping of the refrigeration equipment is often placed behind the ceiling, so if condensation occurs on the surface of the refrigerant piping, the growth of mold, etc. Leakage of water may occur and cause trouble.
Therefore, it is conceivable to take a heat-insulating treatment by, for example, winding a heat insulating material around the refrigerant pipe.
However, the length of the refrigerant pipe may be about 100 m depending on the object, and the heat insulation process is not simple, and there is a problem that costs such as construction costs increase.

In addition, when the refrigeration apparatus is updated, a new refrigeration apparatus may be installed using existing refrigerant piping.
In such a case, the existing refrigerant pipe may not be heat-insulated.
If additional heat insulation treatment is applied to the existing refrigerant piping, the workability is poor and the construction becomes complicated, the construction time and cost increase, and in some cases it is not possible to take measures such as heat insulation treatment. There was a problem that could not be avoided.

  In view of this, several techniques for preventing dew condensation in the liquid refrigerant piping of the refrigerant circuit in a refrigeration apparatus having a refrigerant circuit have been proposed.

  As a conventional technique, in a refrigeration apparatus that circulates a refrigerant in a secondary circuit and conveys cold heat in the primary circuit, a reheat heat exchanger is provided in the main liquid pipe, and the primary circuit is provided in the reheat heat exchanger. And a refrigerating apparatus that reheats the secondary refrigerant flowing through the main liquid pipe with the high-pressure primary refrigerant has been proposed (see, for example, Patent Document 1).

  As another conventional technique, a refrigeration cycle apparatus including a controller that controls the cooling amount of the liquid refrigerant based on the liquid refrigerant piping temperature and the ambient temperature has been proposed (see, for example, Patent Document 2).

  Furthermore, as another conventional technique, a main unit comprising a refrigeration apparatus including a compressor, a condenser, and a liquid receiver, indoor equipment including a decompression apparatus and an evaporator, and indoor piping connecting the refrigeration apparatus and the indoor equipment. In the refrigeration cycle, a refrigeration cycle apparatus including a sub refrigeration cycle including a supercooling heat exchanger that supercools refrigerant flowing out of the condenser between the condenser and the decompression device has been proposed (for example, And Patent Document 3).

JP 2001-221462 A JP 2007-225260 A JP 2009-002647 A

  However, in these refrigeration apparatuses, the liquid refrigerant temperature is higher than the dew point temperature of the ambient air by reheating the liquid refrigerant by the configuration of a plurality of refrigerant circuits or heat medium circuits or by controlling the amount of supercooling of the liquid refrigerant In order to prevent condensation from occurring in the refrigerant pipe, the refrigerant circuit configuration and the refrigerant control of the refrigeration apparatus are complicated in both cases.

  An object of the present invention is to solve the above-described problems, and in a refrigeration apparatus that adds supercooling to a liquid refrigerant pipe constituting a refrigerant circuit to increase the cooling capacity, the liquid refrigerant pipe It is an object of the present invention to provide a refrigeration apparatus that prevents condensation of liquid refrigerant piping with a simple additional circuit configuration that does not require heat insulation.

The refrigeration apparatus according to the present invention includes:
A compressor for compressing the refrigerant;
An air-cooled condenser that performs heat exchange between the refrigerant compressed by the compressor and ambient air, and dissipates heat of the refrigerant to condense;
A supercooling heat exchanger that supercools the refrigerant condensed by the air-cooled condenser;
A first decompression device for decompressing the refrigerant from the supercooling heat exchanger;
An evaporator for evaporating the refrigerant decompressed by the first decompression device;
A gas refrigerant pipe connecting the outlet side of the evaporator and the suction side of the compressor;
A liquid refrigerant pipe connecting the outlet side of the supercooling heat exchanger and the inlet side of the first decompression device;
A refrigeration apparatus comprising:
One end is connected between the compressor and the air-cooled condenser, the other end is connected between the supercooling heat exchanger and the liquid refrigerant pipe, and a part of the refrigerant from the compressor A reheat circuit through which
A bypass pressure reducing device that is provided in the reheat circuit and adjusts the flow rate of the refrigerant flowing through the reheat circuit,
The refrigerant decompressed by the bypass decompression device joins the supercooled refrigerant from the supercooling heat exchanger on the inlet side of the liquid refrigerant pipe and flows into the liquid refrigerant pipe.

The refrigeration apparatus according to the present invention includes:
A compressor for compressing the refrigerant;
An air-cooled condenser that performs heat exchange between the refrigerant compressed by the compressor and ambient air, and dissipates heat of the refrigerant to condense;
A liquid receiver for storing liquid refrigerant from the air-cooled condenser liquefied by the air-cooled condenser;
A supercooling heat exchanger that supercools the refrigerant from the receiver;
A first decompression device for decompressing the refrigerant from the supercooling heat exchanger;
An evaporator for evaporating the refrigerant decompressed by the first decompression device;
A gas refrigerant pipe connecting the outlet side of the evaporator and the suction side of the compressor;
A liquid refrigerant pipe connecting the outlet side of the supercooling heat exchanger and the inlet side of the first decompression device;
A refrigeration apparatus comprising:
One end is connected to the outlet side of the liquid receiver, the other end is connected to the inlet side of the liquid refrigerant pipe, and includes a reheat circuit through which a part of the refrigerant from the liquid receiver flows.
The refrigerant flowing into the reheat circuit joins the supercooled refrigerant from the supercooling heat exchanger on the inlet side of the liquid refrigerant pipe and flows into the liquid refrigerant pipe.

  According to the refrigeration apparatus of the present invention, the liquid refrigerant temperature flowing into the liquid refrigerant pipe can always be maintained higher than the dew point temperature regardless of the operating conditions (ambient air temperature and compressor capacity). Since the temperature of the refrigerant flowing through the refrigerant pipe is always higher than the dew point temperature, dew condensation on the liquid refrigerant pipe can be prevented without performing heat insulation on the liquid refrigerant pipe.

It is a freezing circuit diagram which shows the freezing apparatus which concerns on Embodiment 1 of this invention. FIG. 2 is a Ph diagram illustrating state transition of the refrigerant in FIG. 1. It is a flowchart which shows the flow of control treatment of the flow control valve of FIG. It is a figure which shows the various state changes with respect to ambient air temperature of the freezing apparatus of FIG. It is a freezing circuit diagram which shows the freezing apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the various state changes with respect to the bypass flow volume to the reheat circuit of the freezing apparatus of FIG. It is a flowchart which shows the flow of control treatment of the bypass pressure-reduction apparatus of the freezing apparatus of FIG. It is a freezing circuit diagram which shows the freezing apparatus which concerns on Embodiment 3 of this invention.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals, and description thereof will be omitted.

1 is a refrigeration circuit diagram showing a refrigeration apparatus according to Embodiment 1 of the present invention.
This refrigeration apparatus has a heat source side unit 100 and a load side unit 200, which are connected by a refrigerant pipe. Further, the heat source side unit 100 includes a reheat unit 300.
The heat source side unit 100 includes a compressor 1, an air-cooled condenser 2, a liquid receiver 3, a supercooling heat exchanger 4, and a second decompression device 10.
The load side unit 200 includes a first pressure reducing device 5 and an evaporator 6.
The reheat unit 300 includes a reheat heat exchanger 20 installed on the suction side of the air-cooled condenser 2, a first flow control valve 21, a second flow control valve 22, and a check valve 23. .
Between the heat source side unit 100 and the load side unit 200, the suction side of the compressor 1 and the outlet side of the evaporator 6 are connected by a gas refrigerant pipe 7, and the outlet side of the supercooling heat exchanger 4 and the first side are connected. The inlet side of the decompression device 5 is connected by a liquid refrigerant pipe 8.

  This refrigeration apparatus includes a main refrigerant circuit A in which refrigerant circulates through a compressor 1, an air-cooled condenser 2, a receiver 3, a supercooling heat exchanger 4, a first decompression device 5, and an evaporator 6, and a main refrigerant circuit A. Injection that bypasses part of the refrigerant between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8 in the refrigerant circuit A and injects into the compressor 1 via the second decompression device 10 and the supercooling heat exchanger 4. From the refrigerant circuit B, and the reheat circuit C that causes the liquid refrigerant between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8 to flow through the reheat heat exchanger 20 and return to the inlet side of the liquid refrigerant pipe 8, A refrigerant circuit is configured.

  The air-cooled condenser 2 is provided with a condenser blower 9 that blows ambient air. The condenser air blower 9 is a fan that blows air, and includes a centrifugal fan, a multiblade fan, and the like driven by a DC motor (not shown), and can adjust the air flow rate. ing.

The compressor 1 sucks refrigerant and compresses the refrigerant to a high temperature and high pressure state. The compressor 1 is composed of a positive displacement compressor capable of varying the operating capacity (frequency). As a control method for varying the operation capacity, for example, there is a method by driving a motor controlled by an inverter.
In addition, the refrigerant supplied from the injection circuit B can be injected into a compression chamber (for example, an intermediate compression chamber in the middle of compression) in the compressor 1.
In FIG. 1, only one compressor 1 is provided. However, the present invention is not limited to this, and two or more compressors may be connected in parallel or in series.

  The air-cooled condenser 2 is configured to exchange heat by exchanging heat between the high-temperature and high-pressure refrigerant discharged from the compressor 1 and the air supplied as a heat source from the surroundings. The air-cooled condenser 2 is constituted by, for example, a cross fin type fin-and-tube heat exchanger constituted by a heat transfer tube and a large number of fins.

  The liquid receiver 3 is a metal reservoir for storing excess refrigerant liquefied in the main refrigerant circuit A.

The first decompression device 5 and the second decompression device 10 decompress and expand the refrigerant. The first decompression device 5 adjusts the flow rate of the refrigerant flowing through the main refrigerant circuit A, and the second decompression device 10 adjusts the flow rate of the refrigerant flowing through the injection circuit B. It is good to comprise with the electronic expansion valve which can adjust the opening degree of a throttle | throttle by not shown.
In addition to the electronic expansion valve, other types may be used as long as they have a similar function, such as a mechanical expansion valve adopting a diaphragm for the pressure receiving portion, a temperature expansion valve, a capillary tube, or the like. Good.

The evaporator 6 exchanges heat between the low-temperature and low-pressure refrigerant decompressed by the first decompression device 5 and the fluid to be cooled.
The evaporator 6 may be constituted by, for example, a cross fin type fin-and-tube heat exchanger constituted by a heat transfer tube and a large number of fins.
When a fin-and-tube heat exchanger is used, the heat exchange medium is air, and the medium delivery device uses driving means (not shown) such as a fan.

However, the evaporator 6 is not limited to the fin-and-tube heat exchanger, and a large number of thin plates are arranged at intervals, the peripheral portion is sealed, and the space formed between the thin plates is alternately formed as a refrigerant flow path. And a plate heat exchanger as a water flow path.
When a plate heat exchanger is used and the heat exchange medium is a fluid such as water, the heat exchange medium is supplied to the evaporator 6 using a delivery device (not shown) such as a pump. do it.
The heat exchange medium is not limited to water, and may be another fluid as long as it exhibits a similar action.

  Although FIG. 1 shows an example in which only one evaporator 6 is mounted, the present invention is not limited to this, and two or more evaporators are connected in parallel or in series. May be. Further, the evaporator 6 may be constituted by a heat pipe heat exchanger, a microchannel heat exchanger, a shell and tube heat exchanger, a double tube heat exchanger, or the like.

The supercooling heat exchanger 4 includes a refrigerant that flows from the receiver 3 toward the liquid refrigerant pipe 8 in the main refrigerant circuit A, and a refrigerant that flows toward the compressor 1 via the second decompression device 10 in the injection circuit B. Heat exchange.
The subcooling heat exchanger 4 is a plate type heat exchange in which, for example, a large number of thin plates are arranged at intervals, the peripheral edge is sealed, and the space formed between the thin plates is alternately used as a refrigerant flow path and a cooled fluid flow path. It is recommended to use a vessel.
The subcooling heat exchanger 4 is not limited to a plate heat exchanger, and may be another type of heat exchanger as long as it plays a similar role.

  The reheat heat exchanger 20 exchanges heat between the low-temperature liquid refrigerant flowing through the reheat circuit C and the ambient air blown by the condenser blower 9.

  The first flow rate control valve 21, which is a reheat flow rate control valve, controls the flow rate at which the liquid refrigerant between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8 flows to the reheat circuit C. The second flow rate control valve 22 controls the flow rate at which the liquid refrigerant exiting the supercooling heat exchanger 4 flows through the main refrigerant circuit A.

  In the heat source side unit 100, valves 11a and 11b are provided on the refrigerant outlet side of the gas refrigerant pipe 7 and on the refrigerant inlet side of the liquid refrigerant pipe 8, and for example, opening and closing of these ball valves, on-off valves, operation valves, etc. It consists of a valve that can be operated.

In addition, the refrigeration apparatus includes a measurement control unit 30.
This measurement control unit 30 is based on detection values (measurement information such as pressure and temperature) detected by various detection means and operation details instructed by a user of the refrigeration apparatus, It controls to the opening degree of the pressure-reducing devices 5, 10, the opening degree of each flow control valve 21, 22, the fan blowing amount of the condenser blowing device 9, and the like.
The measurement control unit 30 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU and software executed thereon. .

On the suction side of the air-cooled condenser 2, dew point temperature detecting means 40 for detecting the dew point temperature of the air sucked into the air-cooled condenser 2 (that is, the ambient air around the heat source side unit 100) is installed.
Further, a supercooling liquid temperature detecting means 50 is installed in the liquid refrigerant section at the outlet of the supercooling heat exchanger 4.

There is no particular limitation on the type of refrigerant used in the refrigeration apparatus, and any refrigerant can be used.
For example, natural refrigerants such as carbon dioxide (CO ₂ ), hydrocarbons, helium, and the like, and refrigerants that do not contain chlorine such as R410A and alternative refrigerants such as R407C and R404A may be employed.

Next, the operation of the refrigeration apparatus having the above configuration will be described with reference to FIG.
FIG. 2 is a Ph diagram illustrating the state transition of the refrigerant in the refrigeration apparatus of FIG.
The high-temperature and high-pressure gas refrigerant (point 1 shown in FIG. 2) discharged from the compressor 1 reaches the air-cooled condenser 2, and the refrigerant is condensed and liquefied by the heat exchange action by the ventilation of the condenser blower 9. Becomes a refrigerant. The high-pressure and low-temperature refrigerant that has been condensed and liquefied becomes a saturated liquid state, and a part of the saturated liquid is stored in the receiver 3 (point 2 shown in FIG. 2).
Thereafter, the liquid refrigerant exchanges heat with the low-temperature refrigerant flowing through the injection circuit B in the supercooling heat exchanger 4 and is supercooled (point 3 shown in FIG. 2).

After the refrigerant leaves the supercooling heat exchanger 4, a part of the refrigerant is bypassed from the main refrigerant circuit A to the injection circuit B, and the remaining refrigerant flows through the liquid refrigerant pipe 8 to the first decompression device 5. The pressure is reduced to form a two-phase refrigerant, which is sent to the evaporator 6 (point 4 shown in FIG. 2).
The two-phase refrigerant sent to the evaporator 6 is evaporated by a heat exchange action with the heat exchange medium from the outside, and becomes a low-pressure gas refrigerant (point 5 shown in FIG. 2).
The low-pressure gas refrigerant flows through the gas refrigerant pipe 7 and is sucked into the compressor 1.

On the other hand, the refrigerant bypassed from the main refrigerant circuit A to the injection circuit B is decompressed to an intermediate pressure by the second decompression device 10 to become a low-temperature two-phase refrigerant (point 6 shown in FIG. 2), and then the supercooling heat exchange is performed. Heat is exchanged with the high-pressure refrigerant in the vessel 4, heated (point 7 shown in FIG. 2), and injected into the compressor 1.
Inside the compressor 1, after the sucked refrigerant (point 5 shown in FIG. 2) is compressed and heated to an intermediate pressure (point 8 shown in FIG. 2), it merges with the injected refrigerant and the temperature drops. (Point 9 shown in FIG. 2) is again compressed to a high pressure and discharged (point 1 shown in FIG. 2).

The opening degree of the first flow control valve 21 is always fully open, and the opening degree of the second flow control valve 22 is always fully closed.
As a result, the liquid refrigerant flowing out of the supercooling heat exchanger 4 and flowing through the main refrigerant circuit A is introduced into the reheating circuit C. The liquid refrigerant introduced into the reheat circuit C is heated by the heat exchange action with the ambient air blown by the condenser blower 9 in the reheat heat exchanger 20. Thereafter, the heated liquid refrigerant returns to the inlet side of the liquid refrigerant pipe 8.

Here, the opening degree of the first flow control valve 21, which is the reheat flow control valve, has been described as fully open, and the opening degree of the second flow control valve 22 has been fully closed. However, the opening degree can be adjusted according to the operating state of the refrigeration apparatus. Done.
Hereinafter, an operation method of the flow control valves 21 and 22 will be described.

The operation method of the flow control valves 21 and 22 will be described based on the flowchart of FIG. FIG. 3 is a flowchart showing a flow of control treatment of the first flow rate control valve 21 and the second flow rate control valve 22 of the refrigeration apparatus.
The first flow control valve 21 and the second flow control valve 22 change the opening according to the state of the liquid refrigerant temperature supercooled by the supercooling heat exchanger 4 and the dew point temperature of the ambient air.
Note that the opening control of the first flow control valve 21 and the second flow control valve 22 is performed by the measurement control unit 30.

  The measurement control part 30 sets the opening degree of the 1st flow control valve 21 and the 2nd flow control valve 22 to an initial value after a driving | operation start first (step S1). In this embodiment, the initial opening value of the first flow control valve 21 is fully opened, and the initial opening value of the second flow control valve 22 is fully closed.

Next, the measurement control unit 30 detects the supercooling liquid temperature Tl by the supercooling liquid temperature detecting means 50 (step S2).
Subsequently, the measurement control unit 30 detects the ambient air dew point temperature DP by the dew point temperature detecting means 40 (step S3).

  When the ambient air dew point temperature DP is higher than the supercooled liquid temperature Tl (step S4; YES), the first flow control valve 21 is fully opened and the second flow control valve 22 is fully closed ( Step S5), otherwise (step S4; NO), the opening of the first flow control valve 21 is fully closed, the opening of the second flow control valve 22 is fully opened (step S6), and the flow is terminated. To do.

  When the supercooled liquid temperature Tl becomes lower than the ambient air dew point temperature DP by controlling the opening degree of the flow control valves 21 and 22 in this way, the supercooled liquid refrigerant is reheated by the reheat heat exchanger 20. The liquid refrigerant is heated by the heat exchange action with the surrounding air and flows to the liquid refrigerant pipe 8, but in other cases, the liquid refrigerant is directly liquid without passing through the reheat heat exchanger 20. It flows into the refrigerant pipe 8.

  As described above, according to the refrigeration apparatus according to Embodiment 1, the liquid refrigerant temperature flowing into the liquid refrigerant pipe 8 is independent of the operating conditions (ambient air temperature and compressor capacity) as shown in FIG. Can always be maintained at a temperature higher than the dew point temperature of the ambient air, so that condensation on the surface of the liquid refrigerant pipe 8 can be prevented without subjecting the liquid refrigerant pipe 8 to heat insulation.

  In addition, based on the supercooled liquid refrigerant temperature and the dew point temperature of the surrounding air, the liquid refrigerant is controlled not to be reheated under low humidity (low dew point temperature) conditions in which condensation does not occur in the liquid refrigerant pipe 8. Thus, it is possible to avoid a cooling capacity lowering state due to an increase in liquid refrigerant temperature under unnecessary conditions.

  In the refrigeration apparatus of the first embodiment, the air-cooled condenser 2 and the reheat heat exchanger 20 are separated, but a part of the air-cooled condenser on the air suction side is used as a reheat heat exchanger. The air-cooled condenser 2 and the reheat heat exchanger 20 may be integrated by a method such as use.

Further, instead of the dew point temperature detecting means 40, an ambient air temperature detecting means may be used.
In this case, when the air temperature detected by the ambient air temperature detecting means for detecting the air temperature of the ambient air is lower than the value of the supercooled liquid refrigerant temperature detected by the supercooled liquid temperature detecting means 50 The first flow rate control valve 21 that is a reheat flow rate control valve is closed, and when the value is higher than that value, the first flow rate control valve 21 is opened.
Moreover, the opening degree of a 1st flow control valve and a 2nd flow control valve may change continuously other than full open or full close.

Embodiment 2. FIG.
FIG. 5 is a refrigeration circuit diagram showing a refrigeration apparatus according to Embodiment 2 of the present invention.
In this embodiment, in the heat source side unit 100, a part of the high-temperature discharge gas refrigerant between the compressor 1 and the air-cooled condenser 2 is bypassed from the main refrigerant circuit A, and the supercooling heat exchanger 4 and liquid A reheat circuit C connected by a bypass pipe so as to return to the liquid refrigerant section between the refrigerant pipe 8 and a bypass flow rate control valve 25, a bypass pressure reducing device 24 and a check valve 23 installed in the reheat circuit C. The reheating unit 300 is provided.

The bypass decompression device 24 decompresses and expands the refrigerant. The bypass pressure reducing device 24 adjusts the flow rate of the refrigerant flowing in the reheat circuit C, and is preferably composed of an electronic expansion valve capable of adjusting the opening of the throttle by a stepping motor (not shown).
In addition to the electronic expansion valve, other types may be used as long as they have a similar function, such as a mechanical expansion valve adopting a diaphragm for the pressure receiving portion, a temperature expansion valve, a capillary tube, or the like. Good.

  The bypass flow rate control valve 25 controls the flow rate of bypassing the discharged gas refrigerant between the compressor 1 and the air-cooled condenser 2 from the main refrigerant circuit A to the reheat circuit C.

In the refrigeration apparatus of this embodiment, when the bypass flow rate control valve 25 is fully opened, a part of the high-temperature discharge gas refrigerant discharged from the compressor 1 is bypassed to the reheating circuit C.
The discharged gas refrigerant bypassed to the reheat circuit C flows through the reheat circuit C and is reduced in pressure by the bypass pressure reducing device 24, and directly into the liquid refrigerant portion between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8. The temperature of the liquid refrigerant flowing into the liquid refrigerant pipe 8 rises by being injected and joining with the supercooled refrigerant from the supercooling heat exchanger 4.

FIG. 6 is a diagram showing the relationship between the flow rate of the bypass refrigerant flowing through the reheating circuit C and each refrigerant temperature in this refrigeration apparatus.
As shown in the figure, the temperature of the liquid refrigerant flowing into the liquid refrigerant pipe 8 increases linearly as the flow rate of the bypass refrigerant flowing through the reheat circuit C increases.
Therefore, the amount of increase in the liquid refrigerant temperature can be adjusted by controlling the bypass refrigerant flow rate by the bypass pressure reducing device 24.

Hereinafter, a specific operation method of the bypass pressure reducing device 24 will be described based on the flowchart of FIG.
FIG. 7 is a flowchart showing a flow of control processing of the bypass pressure reducing device 24.
The bypass pressure reducing device 24 changes the opening according to the state of the liquid refrigerant temperature flowing into the liquid refrigerant pipe 8 and the ambient air temperature. The opening control of the bypass pressure reducing device 24 is executed by the measurement control unit 30.

  The measurement control unit 30 first sets the opening of the bypass pressure reducing device 24 to an initial value after the operation is started (step S11). In this embodiment, the initial opening value of the bypass pressure reducing device 24 is fully closed.

  Next, the measurement control unit 30 detects the liquid refrigerant temperature Tr flowing into the liquid refrigerant pipe 8 by the liquid refrigerant temperature detection means 51 (step S12). Subsequently, the measurement control unit 30 detects the ambient air temperature To by the ambient air temperature detection means 41 (step S13).

When the liquid refrigerant temperature Tr is higher than the ambient air temperature To (step S14; YES), the opening of the bypass pressure reducing device 24 is maintained as it is and the flow is ended.
In other cases (step S14; NO), the opening degree of the bypass pressure reducing device 24 is increased (step S15), and the flow is terminated.

  By controlling the opening degree of the bypass pressure reducing device 24 in this way, the liquid refrigerant temperature flowing into the liquid refrigerant pipe 8 can be always higher than the ambient air temperature.

Here, the opening degree of the bypass pressure reducing device 24 is changed according to the state of the liquid refrigerant temperature flowing into the liquid refrigerant pipe 8 and the ambient air temperature, but the dew point temperature of the ambient air may be used instead of the ambient air temperature. .
In that case, the ambient air dew point temperature detecting means 40 may be installed in place of the ambient air temperature detecting means 41, and the ambient air dew point temperature DP may be replaced instead of the ambient air temperature To in the flowchart of FIG.

Further, although the bypass flow control valve 25 is fully opened, the dew point temperature is lowered under low humidity conditions where the outside air temperature and relative humidity are low, and condensation in the liquid refrigerant pipe 8 is less likely to occur. The opening degree of the bypass flow control valve 25 may be changed according to the ambient air temperature To or the ambient air dew point temperature DP so as not to cause this.
In this case, for example, when the ambient air temperature To or the ambient air dew point temperature DP is lower than a predetermined value, the opening degree of the bypass flow control valve 25 is fully closed.

  According to the refrigeration apparatus according to the second embodiment, the liquid refrigerant temperature flowing into the liquid refrigerant pipe 8 is always kept higher than the dew point temperature regardless of the operating conditions (ambient air temperature and compressor capacity). Therefore, the same effect as the refrigeration apparatus of Embodiment 1 can be obtained.

  Further, based on the supercooled liquid refrigerant temperature and the dew point temperature of the surrounding air, by controlling so that the liquid refrigerant is not reheated under low humidity (low dew point temperature) conditions in which condensation does not occur in the liquid refrigerant pipe 8, The same effect as the refrigeration apparatus of Embodiment 1 can be obtained.

Embodiment 3 FIG.
FIG. 8 is a refrigeration circuit diagram showing a refrigeration apparatus according to Embodiment 3 of the present invention.
In the heat source side unit 100 of the refrigerating apparatus according to Embodiment 3 of the present invention, a part of the high-temperature saturated liquid refrigerant between the liquid receiver 3 and the supercooling heat exchanger 4 is bypassed from the main refrigerant circuit A. A reheat circuit C connected by a bypass pipe so as to return to the supercooled liquid refrigerant section between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8, and a bypass installed in the reheat circuit C. A reheat unit 300 including a flow control valve 25 and a check valve 23 is provided.

  In the refrigeration apparatus of this embodiment, when the bypass flow control valve 25 is fully opened, a part of the high-temperature saturated liquid refrigerant between the liquid receiver 3 and the supercooling heat exchanger 4 is discharged from the main refrigerant circuit A. Bypassed to the reheat circuit C, directly injected into the supercooled liquid refrigerant section between the supercooling heat exchanger 4 and the liquid refrigerant pipe 8, and joined with the supercooled refrigerant from the supercooling heat exchanger 4. Thus, the temperature of the liquid refrigerant flowing into the liquid refrigerant pipe 8 increases.

In this embodiment, when the ambient air temperature detected by the ambient air temperature detecting means 41 is lower than the liquid refrigerant temperature detected by the liquid refrigerant temperature detecting means 51, the opening degree of the bypass flow rate control valve 25 is fully closed. When the ambient air temperature is higher than the liquid refrigerant temperature, the bypass flow rate control valve 25 is fully opened.
Instead of the ambient air temperature detection means 41, the dew point temperature detection means 40 may be used.
In this case, when the dew point temperature detected by the dew point temperature detecting means 40 is lower than the value of the supercooled liquid refrigerant temperature detected by the supercooled liquid temperature detecting means 50, the opening degree of the bypass flow control valve 25 Is fully closed, and when the value is higher than that, the opening of the bypass flow control valve 2 is fully opened.
Further, the bypass flow rate control valve 25 may be a valve whose opening degree changes continuously other than fully open and fully closed.

  According to the refrigeration apparatus according to Embodiment 3, the temperature of the liquid refrigerant flowing into the liquid refrigerant pipe 8 is always maintained higher than the dew point temperature regardless of the operating conditions (ambient air temperature and compressor capacity). Since the refrigerant temperature flowing through the liquid refrigerant pipe 8 is always higher than the dew point temperature, the same effect as the refrigeration apparatus of the first embodiment can be obtained.

  Further, the first embodiment is controlled based on the supercooled liquid refrigerant temperature and the dew point temperature of the ambient air so that the liquid refrigerant is not reheated under a low humidity (low dew point temperature) condition in which pipe condensation does not occur. The same effect as the refrigeration apparatus can be obtained.

  In the refrigeration apparatus according to this embodiment, the heat source side unit 100 includes the reheat unit 300. However, the reheat unit 300 is installed outside the heat source side unit 100. It is good also as a structure of.

In the refrigeration apparatus of each of the embodiments described above, the configuration in the case where there is one load side unit B has been described as an example. However, the present invention is not limited to this, and there are two or more load side units B. It is possible to have more than one. Moreover, even if each capacity | capacitance of a some load side unit differs from large to small, all may be the same capacity | capacitance.
Further, for example, the contents of the refrigerant flow path configuration (piping connection), the configuration of the refrigerant circuit elements such as the compressor, the heat exchanger, and the expansion valve are not limited to the contents described in each embodiment. However, it can be appropriately changed within the scope of the technology of the present invention.

1 compressor, 2 air-cooled condenser, 3 receiver, 4 supercooling heat exchanger, 5 first decompression device, 6 evaporator, 7 gas refrigerant piping, 8 liquid refrigerant piping, 9 condenser blower, 10 2nd Pressure reducing device, 11a valve, 11b valve, 20 Reheat heat exchanger, 21 First flow control valve (Reheat flow control valve), 22 Second flow control valve, 23 Check valve, 24 Bypass pressure reducing device, 25 Bypass flow Control valve, 30 measurement control unit, 40 dew point temperature detection means, 41 ambient air temperature detection means, 50 supercooled liquid temperature detection means, 51 liquid refrigerant temperature detection means, 100 heat source side unit, 200 load side unit, 300 reheat unit A main refrigerant circuit, B injection refrigerant circuit, C reheat circuit.

Claims (2)

A compressor for compressing the refrigerant;
An air-cooled condenser that performs heat exchange between the refrigerant compressed by the compressor and ambient air, and dissipates heat of the refrigerant to condense;
A supercooling heat exchanger that supercools the refrigerant condensed by the air-cooled condenser;
A first decompression device for decompressing the refrigerant from the supercooling heat exchanger;
An evaporator for evaporating the refrigerant decompressed by the first decompression device;
A gas refrigerant pipe connecting the outlet side of the evaporator and the suction side of the compressor;
A refrigeration apparatus having a liquid refrigerant pipe connecting an outlet side of the supercooling heat exchanger and an inlet side of the first decompression device,
One end is connected between the compressor and the air-cooled condenser, the other end is connected between the supercooling heat exchanger and the liquid refrigerant pipe, and a part of the refrigerant from the compressor A reheat circuit through which
A bypass pressure reducing device that is provided in the reheat circuit and adjusts the flow rate of the refrigerant flowing through the reheat circuit;
Liquid refrigerant temperature detecting means for detecting the liquid refrigerant temperature at the liquid refrigerant pipe inlet;
Ambient air temperature detection means for detecting the air temperature of the ambient air, and
The refrigerant decompressed by the bypass decompressor joins the supercooled refrigerant from the supercooling heat exchanger on the inlet side of the liquid refrigerant pipe and flows into the liquid refrigerant pipe,
Based on the liquid refrigerant temperature detected by the liquid refrigerant temperature detection means and the air temperature detected by the ambient air temperature detection means, the bypass pressure reducing device is configured so that the liquid refrigerant temperature becomes higher than the air temperature. refrigerating apparatus opening of Ru is adjusted. A compressor for compressing the refrigerant;
An air-cooled condenser that performs heat exchange between the refrigerant compressed by the compressor and ambient air, and dissipates heat of the refrigerant to condense;
A supercooling heat exchanger that supercools the refrigerant condensed by the air-cooled condenser;
A first decompression device for decompressing the refrigerant from the supercooling heat exchanger;
An evaporator for evaporating the refrigerant decompressed by the first decompression device;
A gas refrigerant pipe connecting the outlet side of the evaporator and the suction side of the compressor;
A refrigeration apparatus having a liquid refrigerant pipe connecting an outlet side of the supercooling heat exchanger and an inlet side of the first decompression device,
One end is connected between the compressor and the air-cooled condenser, the other end is connected between the supercooling heat exchanger and the liquid refrigerant pipe, and a part of the refrigerant from the compressor A reheat circuit through which
A bypass pressure reducing device that is provided in the reheat circuit and adjusts the flow rate of the refrigerant flowing through the reheat circuit;
Liquid refrigerant temperature detecting means for detecting the liquid refrigerant temperature at the liquid refrigerant pipe inlet;
Dew point temperature detecting means for detecting the dew point temperature of the ambient air,
The refrigerant decompressed by the bypass decompressor joins the supercooled refrigerant from the supercooling heat exchanger on the inlet side of the liquid refrigerant pipe and flows into the liquid refrigerant pipe,
Based on the liquid refrigerant temperature detected by the liquid refrigerant temperature detection means and the dew point temperature detected by the dew point temperature detection means, the bypass pressure reducing device is configured so that the liquid refrigerant temperature becomes higher than the dew point temperature. refrigerating apparatus opening Ru is adjusted.

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