JP2019045077A - Refrigerant system including direct contact heat exchanger - Google Patents

Abstract

To provide a refrigerant system having a direct contact heat exchanger, which is capable of stably operating without a stop due to air bubbles of a pump that conveys a transport refrigerant to a thermal load without using a self-contained pump. To provide a system. A refrigerant system 1 of the present invention reduces the pressure of an HSC refrigerant, an outdoor heat exchanger 12 which exchanges heat between a heat source and a heat source cycle refrigerant (HSC refrigerant), a compressor 11 which compresses the HSC refrigerant, and A pressure reducing unit 13, a direct contact heat exchanger 30 for heat exchange between the HSC refrigerant and a transport refrigerant (water refrigerant) in direct contact with the HSC refrigerant, an indoor heat exchanger 21 for heat exchange between the heat load and the water refrigerant, Accepts a pump 22 for pumping water refrigerant from the direct contact heat exchanger 30 toward the indoor heat exchanger 21, a water refrigerant going from the direct contact heat exchanger 30 to the pump 22, and an HSC refrigerant mixed in the water refrigerant And a gas-liquid separator 23 for gas-liquid separation. [Selected figure] Figure 1

Description

  The present invention relates to a refrigerant system provided with a direct contact heat exchanger in which two types of refrigerants are in direct contact with each other.

At present, HFC (hydrofluorocarbon) refrigerant represented by R410A is used for equipment using refrigeration cycle such as air conditioners and refrigerators, but against the background of strengthening regulations to prevent global warming. The development of refrigerants with low GWP (Global-warming potential) is in progress.
In addition to low GWP, various refrigerants are being developed in consideration of safety such as cycle efficiency (performance) and nonflammability.

The inventor of the present invention has a heat source cycle (refrigeration cycle) in which a heat source cycle refrigerant such as HFC refrigerant circulates, a heat transfer loop for transferring water refrigerant to a heat load, a heat source cycle refrigerant and water refrigerant in a tank. A refrigerant system provided with a direct contact heat exchanger to be in direct contact is proposed (Patent Document 1). In the direct contact heat exchanger, the heat source cycle refrigerant and the water refrigerant are mixed.
According to Patent Document 1, in the heating operation where the density difference between the heat source cycle refrigerant and the water refrigerant in the direct contact heat exchanger is smaller than that in the cooling operation, the heat source cycle refrigerant passing through the direct contact heat exchanger is depressurized and then separated tank The heat source cycle refrigerant and the water refrigerant are sufficiently separated by transferring them to the downstream side.

JP, 2015-87051, A

Although the heat source cycle refrigerant and the water refrigerant mixed in the direct contact heat exchanger are separated by the density difference, it is difficult to separate them sufficiently. Therefore, the liquid phase or the gas phase (bubbles) of the heat source cycle refrigerant is mixed in the water refrigerant which is transported by the pump from the direct contact heat exchanger toward the heat load.
The degree of dryness of the heat source cycle refrigerant mixed in the water refrigerant is increased by the influence of the heat generation of the drive unit of the pump that pumps the water refrigerant. As a result, the bubbles of the heat source cycle refrigerant generated in water stay in the impeller of the pump, etc., so that the back pressure for rotating the pump becomes insufficient, and the pump may be stopped.
To avoid that, you can use a self-contained pump that can operate even if air bubbles stagnate, but a self-contained pump is very expensive compared to typical pumps that require liquid back pressure .

  As mentioned above, the present invention is a refrigerant system provided with a direct contact heat exchanger, and without using a self-contained pump, the stop by the bubble of the pump which conveys a conveyance refrigerant to heat load is avoided, and it is stabilized. An object of the present invention is to provide an operable refrigerant system.

  The refrigerant system according to the present invention includes a heat source side heat exchanger that exchanges heat between a heat source and a heat source cycle refrigerant, a compressor that compresses the heat source cycle refrigerant, a pressure reduction unit that reduces the pressure of the heat source cycle refrigerant, and a heat source cycle refrigerant A direct contact heat exchanger for heat exchange with the transfer refrigerant in direct contact with the heat source cycle refrigerant, a heat load side heat exchanger for heat exchange between the heat load and the transfer refrigerant, and a heat load side heat exchanger from the direct contact heat exchanger A pump for pumping the transport refrigerant toward the exchanger; a gas-liquid separator for receiving the transport refrigerant from the direct contact heat exchanger to the pump; and a heat-source cycle refrigerant mixed in the transport refrigerant for gas-liquid separation It is characterized by having.

  The refrigerant system according to the present invention preferably includes a bubble destructor having a narrow opening through which the transport refrigerant flowing to the pump passes through the gas-liquid separator.

  The refrigerant system of the present invention comprises a gas phase outflow path for letting the gas phase of the heat source cycle refrigerant separated from the transport refrigerant in the gas liquid separator flow out to the outlet side of the heat load side heat exchanger, and It is preferable to include a pressure loss application portion which is located on the outlet side and which is a throttle or a valve.

  The refrigerant system of the present invention comprises an indoor unit equipped with a heat load side heat exchanger, an outdoor unit equipped with a heat source side heat exchanger, a compressor, and a direct contact heat exchanger, an indoor unit and an outdoor unit, and a pump. It is preferable to have a gas-liquid separator, and internal and external connection piping provided with a pressure loss imparting portion.

  The refrigerant system of the present invention preferably includes an internal heat exchanger that exchanges heat between the heat source cycle refrigerant that has passed through the heat source side heat exchanger and the heat source cycle refrigerant that is drawn into the compressor.

  In the refrigerant system according to the present invention, the pressure reducing portion receives at least a part of the pressure reducing range of the heat source cycle refrigerant, and directly reduces the pressure of the gas-liquid two-phase flow of the transfer refrigerant passing through the direct contact heat exchanger and the heat source cycle refrigerant. It is preferable to have a pressure reduction part after contact.

  In the refrigerant system of the present invention, the direct contact heat exchanger functions as an evaporator in a heat source cycle configured to include a compressor, a pressure reducing unit, a heat source side heat exchanger, and a direct contact heat exchanger, It is preferable that the transport refrigerant that has passed through the exchanger is used to cool the thermal load.

  The refrigerant system of the present invention has a direction in which the heat source cycle refrigerant discharged from the compressor flows directly into the contact heat exchanger, and a direction in which the heat source cycle refrigerant flowing out from the direct contact heat exchanger is sucked into the compressor It is preferable to have a direction switching valve capable of switching the flow direction of the heat source cycle refrigerant. In that case, depending on the flow direction of the heat source cycle refrigerant, the transport refrigerant passing through the direct contact heat exchanger is subjected to the cooling or heating of the heat load.

According to the present invention, the heat source cycle refrigerant is mixed in the transfer refrigerant flowing out of the direct contact heat exchanger, and as a measure against the increase in dryness due to the heat input by the pump, the direct contact heat exchanger The transport refrigerant is made to flow into the pump via the liquid separator. Since the dryness of the gas-liquid two-phase flow is lowered by the gas-liquid separator, the pump does not stop due to air bubbles even if the dryness is increased thereafter.
Therefore, mixing of the heat source cycle refrigerant into the transport refrigerant can not be practically avoided, and the refrigerant system operates stably without reaching the stop of the pump in a situation where dryness is increased due to heat input by the pump. be able to.
When the bubble breaking portion is provided in addition to the gas-liquid separator, the bubbles contained in the transport refrigerant are subdivided even after the gas-liquid separation, so that the bubble can be prevented from being caught in the pump more sufficiently.

It is a figure showing typically the composition of the refrigerant system concerning a 1st embodiment. It is a figure showing typically the composition of the refrigerant system concerning a 2nd embodiment. It is a figure which shows typically the structure of the refrigerant | coolant system which concerns on 3rd Embodiment (at the time of cooling operation). It is a figure which shows typically the structure of the refrigerant | coolant system which concerns on 3rd Embodiment (at the time of a heating operation).

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First Embodiment
The refrigerant system 1 shown in FIG. 1 includes a direct contact heat exchanger 30 in which the heat source cycle refrigerant and the transport refrigerant are brought into direct contact in order to obtain high heat exchange efficiency.
The refrigerant system 1 uses the cold heat obtained for the transport refrigerant by the refrigeration cycle of the heat source cycle refrigerant for cooling the heat load.

(Description of refrigerant)
As a heat source cycle refrigerant (HSC (Heat Source Cycle) refrigerant), an HFC refrigerant, an HFO refrigerant, etc. can be used, for example.
As HFC (Hydro Fluoro Carbon) refrigerant, R410A and R32 can be illustrated.
As HFO (Hydro Fluoro Olefin) refrigerant, R1234ze and R1234yf can be illustrated. From the viewpoint of reducing the global warming potential (GWP), it is preferable to use a HFO-based refrigerant.
In addition, as the heat source cycle refrigerant, for example, a hydrocarbon (HC) refrigerant such as propane and isobutane can be used. Those HC-based refrigerants have lower GWP compared to R1234ze and R1234yf.

  The refrigerant used as the heat source cycle refrigerant (hereinafter, HSC refrigerant) can be appropriately selected in consideration of cycle efficiency, GWP, and the like. Two or three or more refrigerants can also be used as the heat source cycle refrigerant.

As the transport refrigerant, for example, water is suitable. Hereinafter, the transport refrigerant is referred to as a water refrigerant. The water refrigerant has a GWP of 0. In addition, the water refrigerant does not have flammability.
The water refrigerant is in the liquid phase over the temperature change region in the refrigerant system 1.

(Schematic configuration of refrigerant system)
The refrigerant system 1 is configured as an air conditioner that uses outside air as a heat source and performs cooling operation (cooling) to cool indoor air as a heat load. The refrigerant system 1 includes an outdoor unit 1A, an indoor unit 1B, and an inside / outside connecting pipe 1C connecting the outdoor unit 1A and the indoor unit 1B.

The outdoor unit 1A includes a compressor 11, an outdoor heat exchanger 12, a pressure reducing unit 13, a direct contact heat exchanger 30, a solenoid valve 14, and a housing (not shown) for housing them.
The indoor unit 1B is provided with an indoor heat exchanger 21 and a housing (not shown) for housing the indoor heat exchanger 21.
The internal and external connection piping 1 </ b> C is provided with a pump 22, a gas-liquid separator 23, a bubble breaking part 24 and a pressure loss giving part 26.

  The above-described device configuration can be appropriately changed in accordance with the installation space of the case and the like. For example, the pump 22, the gas-liquid separator 23, the bubble breaking part 24, and the pressure loss providing part 26 can be disposed in the indoor unit 1B.

The HSC refrigerant forms a heat source cycle 10 (refrigeration cycle) consisting of compression by the compressor 11, condensation by the outdoor heat exchanger 12, expansion by the pressure reducing unit 13, and evaporation by the direct contact heat exchanger 30.
In the direct contact heat exchanger 30, the transport refrigerant cooled by heat exchange with the heat source cycle refrigerant is circulated by driving the heat transport loop 20 connecting the direct contact heat exchanger 30 and the indoor heat exchanger 21 by the pump 22. Do.

  Hereinafter, each component with which the refrigerant system 1 is provided will be described.

(Components related to heat source cycle)
The compressor 11 compresses and discharges the HSC refrigerant. From the viewpoint of environmental load and the like, it is preferable to use an oil-free compressor in which refrigeration oil (lubricating oil) is not used.

  The outdoor heat exchanger 12 performs heat exchange indirectly between the HSC refrigerant and the outside air via a tube or the like through which the HSC refrigerant flows. In order to promote heat exchange, it is preferable to blow the outside air toward the outdoor heat exchanger 12 by a fan.

The pressure reducing unit 13 reduces the pressure of the HSC refrigerant. An expansion valve, a capillary tube or the like can be used as the pressure reducing portion 13.
It is preferable that the pressure reducing unit 13 be adjusted by the control unit (not shown) included in the refrigerant system 1 so as to maintain the evaporation pressure adapted to the set temperature so that the heat load (room air) becomes the set temperature.

The direct contact heat exchanger 30 brings the HSC refrigerant and the water refrigerant into direct contact for heat exchange. The direct contact heat exchanger 30 includes a tank 31 storing water refrigerant, an HSC refrigerant inlet 32A, an HSC refrigerant outlet 32B, a water refrigerant inlet 33A, and a water refrigerant outlet 33B.
The HSC refrigerant inlet 32A is located below the tank 31, and the HSC refrigerant outlet 32B is located above the tank 31.

The water refrigerant stored in the tank 31 and the HSC refrigerant having a temperature lower than that of the water refrigerant flowing into the tank 31 from the HSC refrigerant inlet 32A are directly contacted and mixed in the tank 31. Give and receive the heat.
Here, the HSC refrigerant having passed through the pressure reducing portion 13 boils while being mixed with the water refrigerant under a predetermined set pressure in the tank 31, and floats in water as bubbles. The heat transfer between HSC refrigerant and water refrigerant is promoted by the latent heat accompanying the phase transition from liquid phase of HSC refrigerant to gas phase and the HSC refrigerant sufficiently contacting with the water refrigerant in the process of rising as bubbles. The water refrigerant in the tank 31 is cooled.

  A member to which the flow of the HSC refrigerant flowing in from the HSC refrigerant inlet 32A may be disposed may be disposed inside the tank 31 so that the HSC refrigerant and the water refrigerant contact more sufficiently. The HSC refrigerant inlet 32A is not limited to the bottom of the tank 31, but may be provided at an appropriate position such as the side wall of the tank 31.

In the tank 31, the HSC refrigerant and the water refrigerant are separated based on the difference in density.
The gas phase of the HSC refrigerant flows out of the space above the liquid level inside the tank 31 to the outside of the tank 31 through the HSC refrigerant outlet 32 B, and is sucked into the compressor 11.

  According to the direct contact heat exchanger 30, since the heat transferers and the heat transferers are in direct contact with each other, the heat transferers and the heat transferers are indirectly in contact with each other through the tube etc. High heat exchange efficiency can be obtained as compared to conventional heat exchangers.

  The solenoid valve 14 is opened by the control unit (not shown) of the refrigerant system 1 while the refrigerant system 1 is in operation, and is closed when the refrigerant system 1 is in operation. During operation, since the HSC refrigerant is pushed into the tank 31, the water refrigerant in the tank 31 does not flow out from the HSC refrigerant inlet 32A, so the solenoid valve 14 is opened. When the operation is stopped, the electromagnetic valve 14 is closed to prevent the water refrigerant in the tank 31 from flowing out from the HSC refrigerant inlet 32A to the piping forming the heat source cycle.

(Component for water transport loop)
The water refrigerant flowing out of the water refrigerant outlet 33 B to the outside of the tank 31 is utilized for cooling the heat load, and then flows into the tank 31 from the water refrigerant inlet 33 A. The water refrigerant is circulated by the heat transfer loop 20 with the transfer force given by the pump 22.
The presence of a water refrigerant in the heat transfer loop 20 comprising the direct contact heat exchanger 30, the pump 22, and the indoor heat exchanger 21 makes the refrigerant system even if the HSC refrigerant is combustible. As a whole, the flammability can be reduced.

  The indoor heat exchanger 21 through which the water refrigerant flows indirectly performs heat exchange between the water refrigerant and the indoor air which is a heat load. In order to promote heat exchange, it is preferable to blow the room air sucked by the fan toward the room heat exchanger 21. The indoor heat exchanger 21 and the fan can be configured, for example, as a fan coil unit.

The pump 22 pumps the water refrigerant from the direct contact heat exchanger 30 toward the indoor heat exchanger 21.
The pump 22 in the present embodiment is provided in a pipe (a part of the inner and outer connection pipe 1C) connecting the direct contact heat exchanger 30 and the indoor heat exchanger 21.
As the pump 22, any type of pump such as a positive displacement type or a non positive displacement type can be used.

(Problem to be solved from the present embodiment)
By the way, in the tank 31 of the direct contact heat exchanger 30, it is difficult to sufficiently separate the HSC refrigerant and the water refrigerant based on the difference in their respective densities.
Therefore, the HSC refrigerant in the gas phase or the liquid phase is mixed in the water refrigerant flowing through the heat transfer loop 20. The gas-liquid two-phase fluid consisting of the water refrigerant and the HSC refrigerant is affected by the heat generation of the drive unit such as the motor of the pump 22 and the degree of dryness is increased. The degree of dryness is large when passing the pump 22 received. Therefore, in addition to the bubbles of the HSC refrigerant flowing out of the direct contact heat exchanger 30, and after flowing out of the direct contact heat exchanger 30, the bubbles generated in water due to the vaporization of the HSC refrigerant stay in the pump impeller or the like. If the back pressure is insufficient, the pump 22 stops because it is not self-contained. If the pump 22 is stopped, the transfer of cold heat to the heat load will be stopped.

  If the HSC refrigerant and the water refrigerant are not sufficiently separated in the direct contact heat exchanger 30, the water refrigerant mixes in the HSC refrigerant circulating in the heat source cycle 10. In order to suppress the decrease in cycle efficiency due to it, for example, as described in JP-A-2015-68541, mixing of the water refrigerant and the HSC refrigerant is performed inside the tank 31 of the direct contact heat exchanger 30. It is effective to separate the water refrigerant and the HSC refrigerant sufficiently by dividing them into a mixing chamber to be separated and a separation chamber in which separation is performed due to the density difference of the mixture of water refrigerant and HSC refrigerant transferred from the mixing chamber. .

(Gist of the present embodiment, and characteristic configuration)
The present embodiment provides a measure to prevent the pump 22 from being stopped due to the mixing of the HSC refrigerant into the water refrigerant flowing through the heat transfer loop 20. In the present embodiment, in order to stably operate the refrigerant system 1 without causing the function stop of the heat transfer loop 20 due to the stop of the pump 22, a gas refrigerant is received from the direct contact heat exchanger 30 to achieve gas-liquid separation. The main feature is that the liquid separator 23 is provided in the heat transfer loop 20.

Even if the water refrigerant (HSC refrigerant mixed) flowing out of the water refrigerant outlet 33B of the direct contact heat exchanger 30 is in the state of gas-liquid two-phase flow, the gas-liquid separator 23 achieves gas-liquid separation. Thus, preferably a liquid phase or a gas-liquid two-phase fluid with as low a degree of dryness as possible is supplied to the pump 22.
The gas-liquid separator 23 receives the water refrigerant traveling from the direct contact heat exchanger 30 to the pump 22 together with the HSC refrigerant mixed in the water refrigerant, and separates the water refrigerant into a liquid phase and a gas phase (HSC refrigerant). The liquid phase (mainly water refrigerant) separated from the gas phase by the gas-liquid separator 23 flows out from the water refrigerant outlet 231 of the gas-liquid separator 23 and flows into the pump 22.

  The gas-liquid separator 23 is connected to a pipe on the outlet 211 side of the indoor heat exchanger 21 through a pipe 25 attached to the upper part where the gas phase is accumulated. By connecting from the gas phase part of the gas-liquid separator 23 to the outlet 211 side of the indoor heat exchanger 21, the pressure difference necessary for the outflow of the gas phase, that is, the pressure in the gas-liquid separator 23, and Since the difference with the pressure on the low outlet 211 side is obtained, the gas phase of the HSC refrigerant flows out from the gas-liquid separator 23 through the pipe 25 to the outlet 211 side according to the pressure difference. The pipe 25 for discharging the HSC refrigerant is hereinafter referred to as a gas phase outlet 25.

As described above, by connecting from the gas phase part of the gas-liquid separator 23 to the outlet 211 side of the indoor heat exchanger 21, a pressure difference necessary for the outflow of the gas phase of the HSC refrigerant can be obtained. Therefore, although not essential, in order to allow the gas phase to flow out more reliably, a throttling or solenoid valve (26) may be provided on the outlet 211 side of the indoor heat exchanger 21 to apply pressure loss to the required limit. preferable. The throttling or solenoid valve is referred to as a pressure loss application unit 26.
In the present embodiment, as in the second embodiment (FIG. 2), the pressure of the gas phase separated from the liquid phase by the gas-liquid separator 23 is the pressure between the gas-liquid separator 23 and the suction side of the compressor 11. It can also be configured to be drawn into the compressor 11 according to the difference.

As the gas-liquid separator 23, an appropriate mechanism can be adopted among the gravity-tank type, centrifugal separation type, surface tension type, collision separation type gas-liquid separation mechanism and the like.
In the gravity tank type, the centrifugal type, and the collision type, the water refrigerant mixed with HSC refrigerant is received from the direct contact heat exchanger 30 into the tank, and the density difference between the gas phase and the liquid phase is used in the tank. Gas and liquid separation. In the case of gravity tank type and collision separation type in which the liquid phase is accumulated at the bottom of the tank, use a vertically long vertical tank in which gravity works, from the viewpoint of suppressing the liquid phase being involved in the gas phase flow in the tank. Is preferred. In the collision separation type, a member for colliding fluid is installed in the tank.
In the centrifuge type, it is preferable to use a tank with a large diameter in order to enhance the separation effect by the centrifugal force. The centrifugal separation type is advantageous in that the liquid phase is distributed on the outer peripheral side of the inside of the tank and the gas phase is distributed on the inner peripheral side, and therefore, it is advantageous from the viewpoint of preventing entrainment.
In the surface tension equation, the liquid phase is separated from the gas phase by holding the liquid phase in the groove by surface tension.

(Operation by characteristic configuration)
Since the gas phase and the liquid phase are not completely separated even by the gas-liquid separator 23 of the above-described mechanism, the liquid phase flowing out from the liquid-phase outlet 231 of the gas-liquid separator 23 has a gas phase (bubbles). Although it is small, it is mixed. However, after passing through the gas-liquid separator 23, the dryness is lower than in the case where the gas-liquid separator 23 is not passed, and the amount of the gas phase in the water refrigerant is reduced. As a result, after passing through the gas-liquid separator 23, the degree of dryness is increased by the influence of the heat of the pump 22, and the bubbles generated in the water refrigerant also decrease. Therefore, even if air bubbles in the water refrigerant stay on the surface of a member (an impeller or the like) of the pump 22, the air bubbles stay on a part of the surface of the member and most of the surface of the member of the pump 22 The liquid (mostly water refrigerant) contacts. Therefore, since the back pressure of the pump 22 is secured, the pump 22 does not stop.

(Preferred configuration and function)
Here, if the growth of air bubbles contained in the water refrigerant that has passed through the gas-liquid separator 23 and the aggregation of air bubbles are prevented, the back pressure of the pump 22 can be more sufficiently secured. Therefore, a bubble breaking portion 24 for breaking and breaking bubbles is added between the gas-liquid separator 23 and the pump 22, and the water refrigerant flowing out of the gas-liquid separator 23 is allowed to flow into the bubble breaking portion 24. preferable.
The bubble breaking portion 24 is, for example, an orifice or a mesh, a filter or the like having a narrow opening through which the water refrigerant passes. A disk or the like in which a large number of minute openings are formed can also be used as the bubble breaking portion 24. The bubble destructor 24 may be provided integrally with the gas-liquid separator 23.

  Since bubbles larger than the size of the opening of the bubble breaking part 24 are broken when passing through the bubble breaking part 24, restricting the size of the bubble in the water refrigerant passing through the bubble breaking part 24 according to the size of the opening Can. The dimensions of the opening of the bubble breaking portion 24 are determined in consideration of the flow rate required for the heat transfer loop 20. The bubble destructor 24 may be disposed at a plurality of locations between the gas-liquid separator 23 and the pump 22.

By preventing the growth and aggregation of air bubbles in the water refrigerant by the air bubble destruction portion 24, a cavity is not formed in the water refrigerant, so that the back pressure of the pump 22 by the liquid can be obtained more reliably.
In order to suppress the growth and reaggregation of bubbles in the water refrigerant after passing through the bubble breaking portion 24, the bubble breaking portion 24 is preferably disposed in the vicinity of the pump 22. The bubbles are broken and subdivided by the bubble breaking portion 24 close to the heat source of the pump 22. Therefore, even if the bubbles grow and aggregate, the operation of the pump 22 is not disturbed.

  Even if the size of the gas-liquid separator 23 is not increased so as to promote the separation of the gas phase and the liquid phase, the bubbles are fragmented by the bubble breaking portion 24 so that the operation of the pump 22 is hindered by the bubbles. You can avoid coming. Therefore, since the size of the gas-liquid separator 23 can be reduced, the size of a set of the gas-liquid separator 23 and the bubble breaking part 24 can also be reduced in size, and these can be easily installed in the inside and outside connection piping 1C. Can. Also when installing the set of the gas-liquid separator 23 and the bubble destruction part 24 in the indoor unit 1B, the size of the indoor unit 1B can be suppressed.

(Effect by this embodiment)
As described above, since it is difficult to sufficiently separate the water refrigerant and the HSC refrigerant mixed in the direct contact heat exchanger 30, the HSC refrigerant is mixed in the water refrigerant extracted from the direct contact heat exchanger 30. And although the fact that the degree of dryness is increased and air bubbles are generated in the water refrigerant itself can not be avoided by the influence of heat generation of the motor etc. of the pump 22, according to the refrigerant system 1 of the present embodiment, the gas-liquid separator 23, and preferably the provision of the bubble disrupter 24, allows a back pressure to be obtained for a typical pump 22 that requires priming as compared to the case where they are not provided.
Therefore, the stop of the pump 22 due to the stagnation of air bubbles can be prevented in advance while using the inexpensive typical pump 22 without introducing the expensive self-supplying type of fugal pump and the like.

  Since there is no need for a special self-contained pump, in an existing air conditioning system not equipped with the direct contact heat exchanger 30, the water pump (22) and the piping for water refrigerant flow are left, and the air conditioner components The refrigerant system 1 can be easily realized by replacing only the configuration corresponding to the heat source cycle 10 including the direct contact heat exchanger 30. In other words, the refrigerant system achieves high heat exchange efficiency with low GWP because the water refrigerant as a natural refrigerant and the HSC refrigerant are brought into direct contact with each other by directly using the pump 22 having a long service life as compared with the air conditioner. Promote the use of

As long as it is between the water refrigerant outlet 33 B of the direct contact heat exchanger 30 and the inflow portion of the pump 22, the gas-liquid separator 23 and the bubble breaking portion 24 are installed at appropriate places regardless of the installation location. Can be installed, so the degree of freedom of the installation location is high.
For example, the gas-liquid separator 23 and the bubble breaking portion 24 can be provided in the inside and outside connection piping 1C connecting the outdoor unit 1A and the indoor unit 1B. If these are provided in the inner and outer connection piping 1C, the housing sizes of the indoor unit 1B and the outdoor unit 1A are not affected.

  By adding pipes such as the gas-liquid separator 23 and the bubble breaking part 24 and the gas phase outlet 25 associated with them to an appropriate place with respect to the existing refrigerant system provided with the direct contact heat exchanger 30 The refrigerant system 1 of the present embodiment can be realized. Here, the complete assembly including the gas-liquid separator 23, the bubble breaking portion 24, the gas phase outlet 25 and the pressure loss applying portion 26 is also provided as an expansion kit for suppressing the retention of the bubbles in the pump 22. good.

In order to more sufficiently suppress the influence of air bubbles in the water refrigerant on the operation of the pump 22, the head 22 is provided with a head difference so that the pump 22 is positioned below the direct contact heat exchanger 30, Air bubbles may be directed to direct contact heat exchanger 30 and float.
However, in the refrigerant system 1 of the present embodiment, the head difference accompanied by the restriction on the arrangement of the devices is not necessarily required, and it is sufficient if the gas-liquid separator 23 is provided at a minimum. Even if a head difference is given, it is difficult to reliably prevent air bubbles in the water refrigerant from flowing into the pump 22. Therefore, in order to suppress the stagnation of air bubbles in the pump 22, gas-liquid separation by the gas-liquid separator 23 is necessary. It is.

In the refrigerant system 1 of the present embodiment, the gas phase flowing out of the gas-liquid separator 23 is drawn into the compressor 11 according to the pressure difference between the gas-liquid separator 23 and the suction side of the compressor 11. You can also In this case, in order to prevent the water refrigerant mixed in the gas phase of the HSC refrigerant from being sucked into the compressor 11, the HSC refrigerant traveling from the gas-liquid separator 23 to the compressor 11 is absorbed by water. It is preferable to adsorb.
As described above, in the case where the gas phase from the gas-liquid separator 23 is sucked into the compressor 11, the gas-liquid separator 23 may be a compressor 11 in consideration of realistic piping (gas-phase outlet 25). , That is, the housing of the outdoor unit 1A in which the compressor 11 is disposed.
On the other hand, in the present embodiment, the gas phase from the gas-liquid separator 23 is made to flow out to the outlet 211 side of the indoor heat exchanger 21, so for example, the gas-liquid separator 23 is provided in the inside and outside connecting piping 1C. In this case, the gas phase outlet 25 can also be provided in the inside and outside connection piping 1C. Alternatively, if the gas-liquid separator 23 is provided in the indoor unit 1B, the gas phase outlet 25 can also be provided in the indoor unit 1B. That is, it is possible to avoid the restriction that the piping of the refrigerant circuit becomes complicated or the installation location of the gas-liquid separator 23 is limited to the outdoor unit 1A. If the gas phase from the gas-liquid separator 23 is made to flow out to the heat transfer loop 20 by water refrigerant instead of the heat source cycle 10 by HSC refrigerant, even if water is mixed in the gas phase from the gas-liquid separator 23 no problem.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
In the first embodiment described above, the dryness is reduced by the gas-liquid separator 23 on the heat load side of the direct contact heat exchanger 30 in contrast to the increase in the dryness due to the heat input by the pump 22. Furthermore, in the second embodiment, the dryness is lowered on the heat source side more than the direct contact heat exchanger 30. Thereby, the generation of air bubbles in the direct contact heat exchanger 30 is suppressed.

  Hereinafter, matters different from the first embodiment will be mainly described. The same components as those of the first embodiment are denoted by the same reference numerals.

  In addition to the components of the refrigerant system 1 according to the first embodiment, the refrigerant system 2 (FIG. 2) according to the second embodiment includes an internal heat exchanger 15 for exchanging heat between HSC refrigerants in the heat source cycle 10 There is.

  The internal heat exchanger 15 exchanges heat between the refrigerant drawn into the compressor 11 and the refrigerant that has passed through the outdoor heat exchanger 12. The refrigerant discharged from the compressor 11 and radiated to the outside air by the outdoor heat exchanger 12 is further radiated to the refrigerant sucked into the compressor 11 in the internal heat exchanger 15. The internal heat exchanger 15 ensures a large degree of subcooling.

According to the internal heat exchanger 15, the void ratio in the gas-liquid two-phase flow before the HSC refrigerant having passed through the outdoor heat exchanger 12 directly flows into the contact heat exchanger 30 is compared to the case without the internal heat exchanger 15. It can be lowered. The void ratio is a volume ratio occupied by gas in the gas-liquid two-phase flow, and if the void ratio is low, generation of bubbles in the direct contact heat exchanger 30 can be suppressed.
That is, the void ratio is lowered by the amount of the increase in the subcooling by the internal heat exchanger 15 to suppress the generation of air bubbles in the direct contact heat exchanger 30. According to this action, the size of the gas-liquid separator 23 used for the purpose of removing air bubbles from the water refrigerant can be reduced.

By the way, if the HSC refrigerant having passed through the internal heat exchanger 15 is temporarily decompressed by an expansion valve or the like and then directly flowed into the contact heat exchanger 30, the direct contact heat exchanger 30 is decompressed because it is decompressed. Boiling is promoted at the same time, so the generation of bubbles is also promoted.
Therefore, from the viewpoint of sufficiently obtaining the effect of suppressing the generation of air bubbles in the direct contact heat exchanger 30 by the internal heat exchanger 15, the outdoor heat exchanger 12 and the direct contact heat exchanger 30 in the first embodiment (FIG. 1) The pressure reducing section 13 located between the two is eliminated, and a direct pressure reducing section 27 is provided between the direct contact heat exchanger 30 and the gas-liquid separator 23.
After direct contact, the pressure reduction unit 27 is responsible for at least a part of the pressure reduction range of the heat source cycle 10 until the pressure of the HSC refrigerant boosted by the compressor 11 is completely reduced to a predetermined lower limit pressure. The pressure of the gas-liquid two-phase flow is reduced before the gas-liquid two-phase flow is separated by gas-liquid separation.

As described above, since the water refrigerant and the HSC refrigerant are not sufficiently separated in the direct contact heat exchanger 30, the HSC refrigerant is mixed in the water refrigerant flowing through the heat transfer loop 20. Therefore, the heat source cycle 10 by compression, condensation, expansion by reduced pressure, and evaporation of the HSC refrigerant is configured including the direct contact post-contact pressure reduction unit 27. In addition to the direct contact heat exchanger 30, the evaporation of the HSC refrigerant is also responsible for the indoor heat exchanger 21.
After direct contact, the gas flows from the pressure reducing section 27 into the gas-liquid separator 23, and the gas phase separated from the liquid phase by the gas-liquid separator 23 flows out into the tank 31 of the direct contact heat exchanger 30, and the HSC refrigerant outlet It is drawn into the compressor 11 from within the tank 31 through 32B.
In the second embodiment, as in the first embodiment (FIG. 1), the gas phase separated from the liquid phase by the gas-liquid separator 23 is made to flow out to the outlet 211 side of the indoor heat exchanger 21. It can also be configured.

  The direct contact post-pressure reducing unit 27 can be configured to take the entire pressure reducing range of the HSC refrigerant, or a pressure loss is given by the solenoid valve 14 located in front of the HSC refrigerant inlet 32A of the direct contact heat exchanger 30. In particular, the pressure reducing range of the HSC refrigerant may be shared by the solenoid valve 14 and the pressure reducing portion 27 after direct contact. In this case, the pressure reducing portion of the heat source cycle 10 is configured by the solenoid valve 14 and the pressure reducing portion 27 after direct contact.

  If both the solenoid valve 14 and the direct contact after pressure reduction unit 27 are provided, the heat source cycle 10 is sufficiently established by appropriately setting the pressure loss of each of the solenoid valve 14 and the direct contact after pressure decrease unit 27. , Considering the cycle efficiency, it is possible to adapt to a system of various purposes.

If the internal heat exchanger 15 is provided as in the second embodiment, the dryness of the refrigerant after being throttled by the solenoid valve 14 is reduced, so that the gas phase is less likely to be generated in the direct contact heat exchanger 30. Become. Therefore, it is possible to prevent the pump 22 from biting the gas due to the mixture of the gas phase into the water refrigerant, so it is possible to avoid stopping the pump 22 and to contribute to the stable operation of the refrigerant system 2.
By suppressing separation and removal of HSC refrigerant gas from the water refrigerant by the gas-liquid separator 23 and dividing the bubbles by the bubble destroying portion 24 while suppressing the generation of bubbles in the direct contact heat exchanger 30, the gas of the pump 22 The risk of biting can be reduced as much as possible.

Third Embodiment
Next, a third embodiment of the present invention will be described with reference to FIGS. 3 and 4.
The third embodiment shows an application example to an air conditioner used both for cooling and heating.
The refrigerant system 3 of the third embodiment includes a direction switching valve 18 in addition to the components of the refrigerant system 1 of the first embodiment (FIG. 1).

  The direction switching valve 18 directs the HSC refrigerant discharged from the compressor 11 to flow directly into the contact heat exchanger 30 (FIG. 4), and the HSC refrigerant flowed out from the direct contact heat exchanger 30 to the compressor 11 The flow direction of the HSC refrigerant can be switched between the intake direction (FIG. 3). For example, a four-way valve can be used as the direction switching valve 18.

When the direction switching valve 18 switches the flow of the HSC refrigerant to the direction in which the HSC refrigerant flowing out of the direct contact heat exchanger 30 is drawn into the compressor 11 as shown in FIG. 3, the direct contact heat exchanger The water refrigerant cooled by passing through 30 is used to cool the heat load.
During the cooling operation shown in FIG. 3, the direct contact heat exchanger 30 functions as an evaporator. At this time, in the direct contact heat exchanger 30, the HSC refrigerant flowing into the tank 31 from the HSC refrigerant inlet 32A is in direct contact with the water refrigerant in the tank 31, mixed, and heat-exchanged.

On the other hand, when the direction switching valve 18 switches the flow of the HSC refrigerant from the compressor 11 to flow directly into the contact heat exchanger 30, as shown in FIG. The water refrigerant heated by passing through is provided for the heating of the heat load.
During the heating operation shown in FIG. 4, the direct contact heat exchanger 30 functions as a condenser. When the HSC refrigerant and the water refrigerant are mixed in the tank 31 during the heating operation, the density difference between the water refrigerant and the HSC refrigerant is smaller at the predetermined condensation temperature than the pressure during the cooling operation. It is difficult to separate the water refrigerant and the HSC refrigerant.

As a measure to the above-mentioned problem at the time of heating operation, in the present embodiment, during the heating operation (FIG. 4), the water refrigerant in the tank 31 flows through the pipe 19 through the pipe 19 provided in the tank 31 The HSC refrigerant is indirectly contacted to exchange heat.
The conduit 19 is used only during the heating operation and not used during the cooling operation. Flow path of HSC refrigerant discharged from the compressor 11 and flowing through the pipe 19 to the pressure reducing section 13 and flowing from the pressure reducing section 13 through the solenoid valve 14 during cooling operation flows into the tank 31 and the upper portion of the tank 31 In order to switch the flow path of the HSC refrigerant flowing out toward the compressor 11 from the above, the refrigerant system 3 of the present embodiment is provided with the on-off valves 191, 192.

During the cooling operation (FIG. 3), the on-off valve 191 is closed and the on-off valve 192 is opened. Then, as in the case of the refrigerant system 1 (FIG. 1) of the first embodiment, the HSC refrigerant flowing into the tank 31 from the HSC refrigerant inlet 32A is in direct heat contact with the water refrigerant in the tank 31 to exchange heat.
Then, in the same manner as in the first embodiment, in consideration of the increase in dryness due to heat input by the pump drive unit, the dryness is reduced in advance by the gas-liquid separator 23, and the air bubbles are subdivided by the air bubble destruction portion 24. I am doing it. Therefore, the refrigerant system 3 can be stably operated without trapping the air bubbles and stopping the pump 22.

During heating operation (FIG. 4), the on-off valve 192 and the solenoid valve 14 are closed, and the on-off valve 191 is opened. Then, the HSC refrigerant discharged from the compressor 11 flows through the pipe 19 and is indirectly heat-exchanged with the water refrigerant in the tank 31. Then, the hot water in the tank 31 is supplied to the heat load by the heat transfer loop 20.
During the heating operation, the dryness of the liquid taken out of the tank 31 to the heat transfer loop 20 is smaller than in the cooling operation, so the necessity for measures against stopping the pump 22 by the bite of air bubbles is lower than in the cooling operation. It can be said. However, even during the heating operation, the water refrigerant mixed with the HSC refrigerant may be made to flow into the pump 22 through the gas-liquid separator 23 and the bubble breaking part 24 as in the cooling operation, and the refrigerant system 3 is stable. To work.

  According to this embodiment, in addition to the fact that high heat exchange efficiency can be obtained by directly contacting the water refrigerant and the HSC refrigerant in the tank 31 during the cooling operation, the stop of the pump 22 due to the entrapment of air bubbles is realized. In the heating operation, the heat source cycle can be reliably established by indirectly contacting the water refrigerant in the tank 31 with the HSC refrigerant, and the refrigerant system 3 operates stably including the heat source side. It can be done. Therefore, the refrigerant system 3 used for both cooling and heating can be provided.

As a measure against the difficulty in separating the water refrigerant and the HSC refrigerant in the tank 31 during the heating operation, the present invention is not limited to the indirect heat exchange between the water refrigerant and the HSC refrigerant as in this embodiment. Strategies can be adopted.
For example, as described in FIG. 1 of JP-A-2015-87051 (Patent Document 1), another process is performed after the liquid mixture of water refrigerant and HSC refrigerant in the tank of the direct contact heat exchanger is depressurized. It may be transferred to a separation tank, and the water refrigerant and the HSC refrigerant may be separated based on the density difference in the separation tank. Water refrigerant separated from the HSC refrigerant is returned from the separation tank to the heat transfer loop.

  The same cooling as the refrigerant system 3 of the third embodiment can be achieved by adding the direction switching valve 18, the pipe line 19, and the on-off valves 191 and 192 to the components of the refrigerant system 2 of the second embodiment (FIG. 2). It is possible to configure a dual-use system for heating and to obtain the same effects as those of the third embodiment.

  In addition to the above, the configurations described in the above embodiment can be selected or changed to other configurations as appropriate without departing from the spirit of the present invention.

As the transport refrigerant, not only water but, for example, brine can be used. As the brine, one having ethylene glycol or propylene glycol as a main component can be exemplified.
And the refrigerant system of the present invention can be applied not only to an air conditioner but also to a freezer, a water heater, a chiller and the like.

1 to 3 refrigerant system 1A outdoor unit 1B indoor unit 1C inside and outside connection piping 10 heat source cycle 11 compressor 12 outdoor heat exchanger (heat source side heat exchanger)
13 pressure reducing unit 14 solenoid valve 15 internal heat exchanger 18 direction switching valve 19 pipe line 20 heat transfer loop 21 indoor heat exchanger (heat load side heat exchanger)
22 pump 23 gas-liquid separator 24 bubble breaking part 25 gas phase outlet 26 pressure loss giving part 27 direct contact after pressure reducing part 30 direct contact heat exchanger 31 tank 32A HSC refrigerant inlet 32B HSC refrigerant outlet 33A water refrigerant inlet 33B water refrigerant Outlet 191, 192 On-off valve 211 Outlet of the indoor heat exchanger 231 Water refrigerant outlet

Claims (8)

A heat source side heat exchanger that exchanges heat between a heat source and a heat source cycle refrigerant;
A compressor for compressing the heat source cycle refrigerant;
A pressure reducing unit that reduces the pressure of the heat source cycle refrigerant;
A direct contact heat exchanger that exchanges heat between the heat source cycle refrigerant and a transport refrigerant that is in direct contact with the heat source cycle refrigerant;
A heat load side heat exchanger that exchanges heat between the heat load and the transport refrigerant;
A pump for pumping the carrier refrigerant from the direct contact heat exchanger to the heat load side heat exchanger;
And a gas-liquid separator that receives and separates the carrier refrigerant traveling from the direct contact heat exchanger to the pump and the heat-source cycle refrigerant mixed in the carrier refrigerant.
A refrigerant system characterized by A bubble destructing portion having a narrow opening through which the transport refrigerant flowing to the pump passes through the gas-liquid separator.
The refrigerant system according to claim 1. A gas phase outflow path for causing the gas phase of the heat source cycle refrigerant separated from the transport refrigerant in the gas liquid separator to flow out to the outlet side of the heat load side heat exchanger;
And a pressure loss application unit which is located on the outlet side of the heat load side heat exchanger and which is a throttle or a valve.
The refrigerant system according to claim 1 or 2. An indoor unit provided with the heat load side heat exchanger;
An outdoor unit provided with the heat source side heat exchanger, the compressor, and the direct contact heat exchanger;
The indoor unit and the outdoor unit are connected, and the pump, the gas-liquid separator, and the internal and external connection piping provided with the pressure loss imparting unit are provided.
The refrigerant system according to claim 3. The heat source cycle refrigerant that has passed through the heat source side heat exchanger, and an internal heat exchanger that exchanges heat with the heat source cycle refrigerant that is drawn into the compressor.
The refrigerant system according to any one of claims 1 to 4. The pressure reducing portion is at least a part of the pressure reducing range of the heat source cycle refrigerant, and after direct contact which reduces the pressure of the gas-liquid two-phase flow between the transfer refrigerant passing through the direct contact heat exchanger and the heat source cycle refrigerant With decompression unit,
The refrigerant system according to claim 5. The direct contact heat exchanger is
Functions as an evaporator in a heat source cycle configured to include the compressor, the pressure reduction unit, the heat source side heat exchanger, and the direct contact heat exchanger,
The transport refrigerant that has passed through the direct contact heat exchanger is used to cool the heat load,
The refrigerant system according to any one of claims 1 to 6. A direction in which the heat source cycle refrigerant discharged from the compressor flows into the direct contact heat exchanger, and a direction in which the heat source cycle refrigerant flowing out from the direct contact heat exchanger is drawn into the compressor It has a direction switching valve capable of switching the flow direction of the heat source cycle refrigerant,
According to the flow direction of the heat source cycle refrigerant, the transport refrigerant passing through the direct contact heat exchanger is provided for cooling or heating of the heat load,
The refrigerant system according to any one of claims 1 to 7.

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