JPH01147290A - Heat moving device - Google Patents

Abstract

PURPOSE:To rapidly detect a trouble due to flash gas and to execute immediate and ordinary natural circulation, by a method wherein, through detection of a natural circulation trouble on a refrigerant, based on an output signal for the trouble, a refrigerant is forcibly circulated. CONSTITUTION:When flash gas is produced in a liquid pipe 3 and a natural circulation trouble on the fluid of a refrigerant in a system is produced, the measurement value of a liquid flow meter 17 is reduced to zero, and a measurement value signal therefrom is outputted to a controller 16. A timer is incorporated in the controller 16, and after a given time elapses, measurement by the liquid flow meter 17, i.e. second measurement, is effected. The presence of a natural circulation trouble on a refrigerant is determined depending upon whether the second measurement value is zero or not. When the second measurement value is zero, it is determined that the natural circulation trouble on the refrigerant occurs, the controller 16 closes main routes 6 and 7 and solenoid valves 10 and 11, and outputs a control signal by means of which a pump 15 and a booster fan 20 in bypass routes 8 and 9, respectively, are operated. When the pump 15 and the booster fan 20 or either of them is operated, a refrigerant in a system is forcibly circulated.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a natural refrigerant circulation type heat transfer device.

[Prior art]

In general, a gravity heat pipe is known as a device that transfers heat by naturally circulating a refrigerant within the system while changing the gas-liquid phase as it transfers heat. This gravity heat pipe is equipped with a condenser at the top and an evaporator at the bottom, and between these is a refrigerant liquid pipe (hereinafter simply referred to as a liquid pipe) through which liquid-phase refrigerant flows and a gas-phase refrigerant. It is connected by an ascending refrigerant gas pipe (hereinafter simply referred to as a gas pipe), and a refrigerant as a heat transfer medium is sealed inside the pipe. The refrigerant sealed inside absorbs the heat load in the evaporator installed at the bottom, changes from the liquid phase to the gas phase, rises in the gas pipe, and reaches the condenser installed at the top. In addition, the refrigerant that reaches the condenser releases heat here and changes from the gas phase to the liquid phase.
The liquid flows down the pipe by gravity and returns to the evaporator installed at the bottom. In this way, the refrigerant circulates within the gravity heat pipe while repeatedly undergoing phase changes as it transfers heat.

[Problems to be solved by the invention]

By the way, in the condenser when the refrigerant undergoes normal natural circulation in the gravity heat pipe, the refrigerant that is in the state of superheated steam or dry saturated steam is cooled until it becomes the state of saturated liquid. Then, the saturated refrigerant liquid flows through the liquid pipe and is supplied to the evaporator. The refrigerant liquid flowing in the liquid pipes in such a state is likely to generate flash gas. For example, when the pressure decreases due to pressure loss due to pipe resistance, the refrigerant liquid falls below the saturation pressure and a part of it vaporizes. When the en = 4- talpi rises due to heat received from the outside of the liquid pipe, the refrigerant liquid exceeds the saturation point, and in this case as well, part of the refrigerant liquid vaporizes and flash gas is generated. When using a heat transfer device based on a gravity heat pipe as a means of transferring heat between a heat source unit and a load unit in an air conditioning system, for example, a refrigerant liquid is constantly supplied to the load unit. A liquid receiver is installed immediately downstream of the condenser to supply the refrigerant to the evaporator. is configured to flow out from this liquid receiver. The refrigerant liquid that flows out from this liquid receiver is almost in a saturated liquid state, and the water head pressure itself is small at the position where it has just flowed out from the liquid receiver, so there is a slight pressure loss in the piping. Even if there is, or even a slight amount of heat enters from outside the liquid pipe, flash gas is likely to be generated. When flash gas is generated, the refrigerant turns into a wet vapor state, with refrigerant liquid and refrigerant gas mixed together, and the specific volume of the refrigerant itself increases. Moreover, this flash gas is generated in the form of bubbles and rises within the liquid pipe, thereby obstructing the flow of the refrigerant liquid within the liquid pipe. Therefore, the amount of refrigerant circulated decreases, resulting in a decrease in the cooling capacity of the evaporator. Additionally, if the amount of flash gas generated increases, the pressure loss within the liquid pipe will further increase, creating a vicious cycle in which the amount of flash gas generated will further increase, and eventually the natural circulation of the refrigerant will stop. Become. The present invention has been devised in view of these two problems and to effectively solve them. Therefore, the purpose of this system is to provide a heat transfer device that can quickly detect the occurrence of flash gas in the liquid pipes and cause natural circulation failure of the refrigerant, and immediately resume normal natural circulation. It is about providing.

[Means for Solving the Problems] The heat transfer device according to the present invention solves the problems of the prior art and achieves the above objects. It is structured as follows. Zunawaji has a condenser in the upper part and an evaporator in the lower part, and these condensers and evaporators are connected by a refrigerant liquid pipe and a refrigerant gas pipe, and the gas-liquid phase changes inside the condenser and evaporator. In a heat transfer device which is filled with a refrigerant that naturally circulates between the containers and has a liquid receiver in the middle of the refrigerant liquid pipe,
a detection means for monitoring a natural circulation state of the refrigerant, detecting a natural circulation failure of the refrigerant and outputting a detection signal thereof; and a forced circulation means for forcibly circulating the refrigerant based on an output signal of the detection means. It is equipped with Further, between the detection means and the forced circulation means, a detection signal is inputted and an operation signal is outputted in order to automatically drive the forced circulation means based on the detection signal outputted by the detection means. A controller may be provided. That is, a controller is interposed between the detection means and the forced circulation means, and the forced circulation means automatically operates according to an operation signal output from the controller based on a detection signal output from the detection means. It may be driven by In other words, the present invention also includes a case where, for example, a signal such as an alarm is issued based on the detection signal, and the driving force of the forced circulation means is input by manual switching based on this alarm signal. The detection means may be constituted by a liquid flow needle provided in the refrigerant liquid pipe near the refrigerant outlet of the liquid receiver, and a gas flow meter provided in the refrigerant gas pipe, and in that case, the A controller is required, the controller detecting as soon as the readings of both the liquid flow needle and the gas flow meter are zero, and that the first measurement of the liquid flow needle is zero. and if the measured value of the gas flow meter at that time is other than O, then a second measurement of the liquid flow tooth needle is performed after a predetermined period of time has elapsed since the measurement, and the second measured value is 0 again. It is configured to output the operation signal at a certain time. In addition, the detection means may be constituted by a pressure sensor that detects a pressure difference between the inside of the liquid receiver and the inside of the refrigerant liquid pipe near the refrigerant inlet of the evaporator. Moreover, it may be configured by an ultrasonic transmitter and an ultrasonic receiver provided in the refrigerant liquid pipe on the downstream side of the liquid receiver. Furthermore,
A liquid flow meter provided in the refrigerant liquid pipe near the refrigerant outlet of the liquid receiver, and a flow rate adjustment valve provided in the refrigerant liquid pipe near the refrigerant inlet of the evaporator and outputting a valve opening signal. may be configured. On the other hand, the forced circulation means may be provided in the middle of at least one of the refrigerant liquid pipe or the refrigerant gas pipe, and may be constituted by a pressurized fluid machine such as a pump or a blower that forcibly circulates the refrigerant. Alternatively, the condenser may be a first condenser, and a second condenser may be provided in parallel with the first condenser and cool the refrigerant at a lower temperature than the first condenser. [Function] According to the heat transfer device of the present invention, the refrigerant gas heated and vaporized by heat exchange in the evaporator rises in the refrigerant gas pipe and flows into the condenser; The refrigerant gas is cooled and condensed through heat exchange, and is temporarily stored in a liquid receiver through a refrigerant liquid pipe.Furthermore, this refrigerant liquid is supplied to the evaporator at a flow rate corresponding to the heat load on the evaporator. The refrigerant liquid flows down the pipe from the receiver to the evaporator for natural circulation. If flash gas is generated in the refrigerant liquid pipe for some reason while this natural circulation is occurring, and the flow of the refrigerant causes a natural circulation failure, the detection means will detect that the failure has occurred. and a detection signal is output. When this detection signal is output, the operation of the forced circulation means is started automatically or by manual switching. When the forced circulation means is operated, the forced circulation means provides new circulation force to the refrigerant flow that is losing or has lost its natural circulation force. Then, the natural circulation disturbance caused by the flash gas in the refrigerant liquid pipe is removed, the natural circulation force is restored, and the process is stopped. First, when using a liquid flow meter installed in the refrigerant liquid pipe near the refrigerant outlet of the liquid receiver and a gas flow meter installed in the refrigerant gas pipe as means for detecting natural circulation failure, it is necessary to Inside, the refrigerant liquid flow rate and refrigerant gas flow rate are always measured, and the measured value of the liquid flow meter is used, and the measured value of the gas flow meter is set to G, and when L≠0 and G≠0, and when L≠0 and G
When =O, each measured value is output as a signal from each flowmeter to the controller, and the controller determines that the natural circulation of the refrigerant is normal. That is, the refrigerant is circulated by natural circulation force without the need to operate the forced circulation means. Furthermore, when L=O and G=0, each measured value is output from each flow meter to the controller as a detection signal indicating that an abnormality has been detected, and the controller indicates that the natural circulation of the refrigerant has stopped, i.e. It is determined that natural circulation failure has occurred in an abnormal state, and the controller immediately outputs an operation signal to operate the forced circulation means based on this detection signal. However, the measured value signals from these flowmeters are output only when the heat transfer device is in operation, and when the transfer device is not in operation, L=O and G−〇 Of course, in that case, no measurement value signal is output. Furthermore, when L=O and G≠0, each measured value is output as a signal from each flowmeter to the controller, but this measured value signal indicates that the flow of the refrigerant liquid is obstructed by the generation of flash gas. (abnormal state), or the flow control valve installed near the refrigerant inlet of the evaporator is temporarily closed for flow control (normal state).
It is not clear whether this is the case. Therefore, in this case, the secondary measurement value obtained from the liquid flowmeter again after a certain predetermined time delay is set to T,2, and an abnormal state is determined depending on whether or not this secondary measurement value signal is L2-〇. A determination is made as to whether the condition is normal or not. This predetermined time is the time from when the refrigerant has progressed to evaporation in the evaporator until the flow control valve is opened to supply the refrigerant, and is set, for example, in a timer built into the controller. The second time after this predetermined time has elapsed.
When the next measured value signal is L2-0, the controller determines that it is a detection signal indicating an abnormal state, and the controller outputs an operation signal for operating the forced circulation means based on this detection signal. In addition, when using a pressure sensor that detects the difference between the pressure in the receiver and the pressure in the refrigerant liquid pipe near the refrigerant inlet of the evaporator as a means of detecting natural circulation failure, flash gas may be detected in the refrigerant liquid pipe. When the natural circulation stops, the differential pressure becomes 0, so the measured value signal is the differential pressure P.
A detection signal that =0 is output from the pressure sensor. Alternatively, each measurement value signal from each pressure sensor installed at the two locations mentioned above is output to the controller, and if the differential pressure P = 0 according to the two measurement value signals, this is a detection signal indicating a natural circulation disorder. It is determined by the controller that there is. In addition, when using an ultrasonic transmitter and an ultrasonic receiver installed in the refrigerant liquid pipe on the downstream side of the liquid receiver as a means for detecting natural circulation disturbances, the ultrasonic transmitter installed in the refrigerant liquid pipe Ultrasonic waves are constantly being transmitted and received by an ultrasonic receiver. The propagation time of ultrasonic waves when refrigerant liquid is filled between the transmitter and receiver in the refrigerant liquid pipe is different from the propagation time when refrigerant gas exists between them. It will be longer if . If flash gas is generated for some reason during the natural circulation of refrigerant and that gas is present between the transmitter and receiver, it will be more likely to occur than if the space between the transmitter and receiver is filled with refrigerant liquid. A long propagation time is also detected, and a flash gas detection signal is output as a natural circulation failure detection signal. When flash gas is generated within the refrigerant liquid pipe, the flash gas flows back through the liquid pipe and remains in the refrigerant liquid pipe immediately downstream of the liquid receiver. Therefore, if a transmitter and a receiver are provided in the refrigerant liquid pipe section immediately downstream of the liquid receiver, the generation of flash gas can be quickly detected and this detection signal can be extracted. In addition, each time an ultrasonic wave collides with the inner wall of a refrigerant liquid pipe, it is reflected and propagates in a zigzag pattern within the pipe, so the distance between the transmitter and receiver can be set arbitrarily, and the longer the distance between them, the longer the ultrasonic wave will be. The longer the time, the higher the probability of detecting the presence of flash gas, and the higher the detection accuracy. Furthermore, other means for detecting natural circulation disturbances include a liquid flow meter installed in the refrigerant liquid pipe near the refrigerant outlet of the liquid receiver, and a flow control valve installed in the refrigerant liquid pipe near the refrigerant inlet of the evaporator. When using a heat transfer device, the flow rate of the refrigerant liquid is always measured during operation of the heat transfer device, but when the measured value of this liquid flow meter is 0, the flow of the refrigerant liquid is obstructed by the generation of flash gas. It is not clear whether this is the case (abnormal state) or whether the flow control valve is temporarily closed for flow control (normal state). Therefore, in this case, we directly monitor the open/close status of the flow control valve, and if the measured value of the liquid flow meter is 0 even though it is not fully closed (even slightly open), natural circulation failure due to the generation of flash gas is detected. It can be determined that this is occurring. In other words, it is assumed that a natural state failure detection signal is output when a signal indicating that the flow rate control valve is even slightly open and a signal indicating that the measured value of the liquid flow meter is 0 are output at the same time. Further, based on the detection signals obtained from each of the detection means as described above, forced circulation means for forcibly circulating the refrigerant is operated in order to eliminate natural circulation disturbances. That is,
If a bypass path is provided in the refrigerant liquid pipe and a pump as a pressurized fluid machine is installed in this bypass path, the refrigerant liquid can be forced to flow by temporarily operating the pump. In addition, for other pressurized fluid machines, if a bypass path is provided in the refrigerant gas pipe and a fan is installed in this bypass path, the negative pressure on the suction side of the fan can be reduced by temporarily operating the fan. grow bigger,
A force is applied to suck the refrigerant liquid in the refrigerant liquid pipe through the evaporator, and the refrigerant liquid can be forced to flow. Furthermore, as a forced circulation means in place of the pressurized fluid machine, a second condenser is arranged in parallel with the condenser (referred to as the first condenser).
A condenser is additionally provided, and the second condenser cools the refrigerant gas at a lower temperature than the first condenser, thereby temporarily increasing the condensing capacity. As a result, the pressure within the gas pipe drops rapidly, and a force acts to suck the refrigerant liquid within the refrigerant liquid pipe through the evaporator, forcing the refrigerant liquid to flow. be able to.

【Effect of the invention】

As is clear from the above description, the present invention provides the following excellent effects. That is, in a heat transfer device that transfers heat by naturally circulating a refrigerant, even if flash gas is generated in the liquid pipe and this causes a natural circulation failure of the refrigerant, this natural circulation failure can be quickly detected,
By immediately forcing the refrigerant to circulate, the natural circulation force can be restored.

【Example】

Preferred embodiments of the present invention will be described below with reference to FIGS. 1 to 5.
This will be explained with reference to the figures. FIG. 1 is a schematic diagram showing a schematic configuration of a first embodiment of a heat transfer device according to the present invention adopted in an air conditioning system. The heat transfer device according to the present invention has a gravity heat pipe as its basic structure, and a condenser 1 is installed in the upper part, that is, a high place, and a group of air conditioning units 2, which correspond to evaporators, are installed in the lower part, that is, a low place. It is set up as follows. That is,
A heat exchanger 23 within the air conditioning unit 2 functions as an evaporator. Between the condenser 1 and the air conditioning unit 2, there is a liquid pipe 3 through which liquid phase refrigerant flows down by gravity, and a gas pipe 4 through which gas phase refrigerant rises under gas pressure, forming a natural refrigerant circulation cycle. is connected to. Further, a liquid receiver 5 is interposed in the liquid pipe 3 immediately downstream of the condenser 1. A liquid pipe 3 is taken out in parallel from the liquid receiver 5 into two paths, a main path 6 and a bypass path 8, and a solenoid valve 10 is connected to the main path 6, and a pump 15 as forced circulation means is connected to the bypass path 8. are provided respectively. On the downstream side of the position where the bypass path 8 of the liquid pipe 3 joins the main path 6, a liquid flow meter 17 is provided as a detection means for measuring the flow rate of the refrigerant liquid and outputting a signal of the measured value. On the other hand, in the gas pipe 4, two routes, a main route 7 and a bypass route 9, are installed in parallel on the upstream side of the condenser 1, and the main route 7 is equipped with a solenoid valve +1, and the bypass route 9 is equipped with a forced circulation valve. A booster fan 20 as a means is interposed, and a gas flow meter 24 as a detection means is provided downstream of these for measuring the flow rate of refrigerant gas and outputting a signal of the measured value. In the figure, 16 indicates that detection signals from the liquid flow meter 17 and the gas flow meter 24 are input to each pump I5 and the booster fan 2.
0 and the solenoid valve 10.11. Therefore, the operation of the pump 15, booster fan 20, and solenoid valve 10.11 is controlled by the liquid flow meter 1.
7 and the measured value signals of the gas flow meter 24. That is, the liquid flow meter 17 measures the flow rate of the refrigerant liquid in the liquid pipe 3,
The gas flow meter 24 measures the flow rate of the refrigerant gas in the gas pipe 4, and if the natural circulation of the refrigerant in the system is occurring smoothly, the liquid flow meter 17 and the gas flow meter 2 measure the flow rate of the refrigerant gas in the gas pipe 4.
Both of the measured values of 4 are other than 0, and the measured value signals are output to the controller I6. Based on this measured value signal, the controller 16 opens the solenoid valves IO and 11 in the main paths 6 and 7, and generates an operation signal to stop (not operate) the pump 15 and booster fan 20 in the bypass paths 8 and 9. Output. In this case, natural circulation is maintained even without the forced circulation force of the pump 15 or the booster fan 20. Furthermore, if flash gas is generated in the liquid pipe 3 and a natural circulation disorder occurs in the flow of refrigerant in the system, the measured value of the liquid flow meter 17 will first become 0, and the measured value signal will be sent to the controller. 16
Output to. However, if the measured value of the liquid flow meter 17 becomes 0, the heat load on each air conditioning unit 2 is small, and the flow rate control valves 25 that control the refrigerant supply to the heat exchanger 23 are completely closed. It may be closed. In that case, evaporation of the refrigerant liquid in the heat exchanger 23 progresses over a certain period of time, and after that period of time, the flow rate control valve 25 is opened to supply refrigerant to the heat exchanger 23. Therefore, the measured value of the liquid flow meter 17 will show a value other than 0 if no natural circulation disorder of the refrigerant occurs. Therefore, in this embodiment, a timer (not shown) is built into the controller 16, and after a predetermined period of time, the liquid flowmeter 17 again performs measurement, that is, secondary measurement, and the secondary measurement value is Whether or not there is a natural circulation disorder of the refrigerant is determined based on whether or not the value is 0. If the secondary measurement value is other than 0, it is determined that all the flow rate control valves 25 are in a normal state where they are simply closed, and the controller 16, based on this measurement value signal, Open the solenoid valves 10 and 11 in the main paths 6 and 7, and pump 15 in the bypass paths 8 and 9.
and booster 20 = outputs an operation signal to stop (do not operate) fan 20; On the other hand, if the secondary measurement value is O, it is determined that a natural circulation disorder of the refrigerant has occurred, and the controller 16 closes the solenoid valves 10 and 11 of the main paths 6 and 7, and closes the solenoid valves 10 and 11 of the main paths 6 and 7. The operation signal for operating the pump 15 and booster fan 20 of No. 9 is output. The measured value of the liquid flow meter 17 is O, and the gas flow meter 24
If the measured value is other than 0, both cases are considered, which are normal and abnormal as described above.
7 and the gas flow meter 24 are 0, it can be immediately determined that there is an abnormal state. That is,
The reason why the measured value of the liquid flow meter 17 is 0 is because all the flow control valves 25 are fully closed (normal state), or the natural circulation of the refrigerant is disturbed due to the generation of flash gas (abnormal state). Two cases are possible. In a normal state, once the refrigerant in the heat exchanger 23 has evaporated to a certain extent, the flow control valve 25 is opened to supply refrigerant liquid into the heat exchanger 23, and the refrigerant is always kept in the heat exchanger 23. The state remains filled with liquid. Therefore, the heat exchange, that is, the evaporation of the refrigerant proceeds smoothly, and it is impossible for the flow rate of the refrigerant gas to become zero in the gas pipe 4. However, in the case of an abnormal state, even if the refrigerant evaporates within the heat exchanger 23, the refrigerant liquid is not supplied to the heat exchanger 23, so if all the remaining refrigerant evaporates, the gas pipe 4 The refrigerant flow rate becomes 0. In such a case, when the measured values of both flowmeters 17 and 24 become 0 while the air conditioning system is operating, it is immediately determined that there is an abnormality, and the solenoid valves IO and 7 of the main paths 6 and 7 are Close 11,
An operation signal for operating the pump 15 and booster fan 20 in the bypass paths 8 and 9 is output from the controller 16. In this embodiment, the pump 15 and the booster fan 20 are provided as forced circulation means, but only one of them may be provided. When the pump 15 and/or the booster fan 20 are operated, the refrigerant in the system is forced to circulate. Also, if the refrigerant in the system is forced to circulate, the liquid flow meter 17
detects the flow of refrigerant liquid in liquid pipe 3 (the measured value is other than 0), so solenoid valves lO and 11 are opened, and pump 1
5 and booster fan 20 are stopped to maintain or resume natural circulation of the refrigerant. FIG. 2 is a schematic diagram showing a schematic configuration of a second embodiment of the heat transfer device according to the present invention employed in an air conditioning system. The structure is roughly the same as that of the embodiment shown in FIG. 1, but the difference from the first embodiment is that the detection means is a pair of pressure sensors 18,
This point is made up of 9. Note that other components similar to those in the first embodiment shown in FIG. 1 are given the same numbers as in FIG. 1, and redundant explanations are omitted. One of these pair of pressure sensors 18, 19 is connected to the liquid receiver 5.
One is mounted on the top of the liquid pipe 3 to detect the pressure of the gas phase inside the liquid receiver 5, and the other is mounted on the part of the liquid pipe 3 near the refrigerant liquid inlet of the air conditioning unit 2, and its height The head pressure of the refrigerant liquid at the location is detected. When flash gas is generated in the liquid pipe 3 and the flow of the refrigerant liquid stops, the refrigerant liquid existing downstream of the part where the flash gas blocks the liquid pipe 3 is unable to exchange heat within the air conditioning unit 2. As it progresses, it evaporates more and more, so the head pressure of the refrigerant drops rapidly, and if the refrigerant circulation is not restarted, the pressure in the liquid pipe 3 near the refrigerant inlet of the air conditioning unit 2 will eventually decrease. The pressure becomes equal to the pressure of the gas phase portion within the liquid receiver 5. The pressure sensors 1g and 19 output a detection signal to the controller 16 when the pressure difference between these two locations becomes O or becomes smaller than a certain value, and the controller 16 outputs a detection signal to the solenoid valve 10 and An operation signal for closing the fan 11 and operating the pump 15 and the booster fan 20 is output. Although this embodiment also includes a pump 15 and a booster fan 20 as forced circulation means, it is of course possible to include only one of them. pump 1
When the booster fan 5 and/or the booster fan 20 are operated, the refrigerant in the system is forced to circulate. Furthermore, when the refrigerant in the system is forcibly circulated, the liquid pipe 3 is filled with refrigerant liquid, so the water head pressure increases, and the pressure sensors 18 and 19 detect a predetermined pressure difference, so the solenoid valve 1
0 and 11 are opened, pump 15 and booster fan 20 are deactivated, and natural circulation of the refrigerant is resumed. FIG. 3 is a schematic diagram showing a schematic configuration of a third embodiment of the heat transfer device according to the present invention adopted in an air conditioning system. This embodiment has approximately the same structure as the embodiment shown in FIG. 1, but the difference from the first embodiment is that the detection means is constituted by an ultrasonic transmitter 26 and an ultrasonic receiver 27. Note that other components similar to those in the first embodiment shown in FIG. 1 are given the same numbers as in FIG. 1, and redundant explanations are omitted. These ultrasonic transmitter 26 and ultrasonic receiver 27 are installed in the liquid pipe 3 on the downstream side of the point where the bypass path 8 and the main path 6 join, and are connected between them at all times or for a certain period of time. Ultrasonic waves are transmitted and received at intervals. The ultrasonic waves emitted from the transmitter 26 are transmitted to the liquid pipe 3.
It propagates in the liquid tube 3 in a zigzag pattern while being reflected on the inner circumferential wall surface of the liquid pipe 3, and reaches the receiver 27. When the refrigerant liquid is filled between the transmitter 26 and the receiver 27 in the liquid pipe 3, the ultrasonic propagation speed between them is constant, and the ultrasonic propagation speed between the transmitter 26 and the receiver 27 is constant. The reference time required for ultrasound propagation in this state can be obtained from the distance. If refrigerant gas generated as flash gas in the liquid pipe 3 exists between the transmitter 26 and the receiver 27,
During this time, the propagation speed of the ultrasonic wave becomes slower than when the refrigerant liquid is filled, and therefore the time required for propagation becomes longer than the reference time. The time required for this propagation is input to the controller 16 as a measurement value signal, and when the measurement value becomes longer than the reference time, the measurement value signal is used as a detection signal that the generation of flash gas is detected and sent to the ultrasonic transmitter. 26 and an ultrasonic receiver 27 to the controller 16. From the controller 16, each pump 15, booster fan 20
And an operation signal is output to the solenoid valve 10.11. That is, the operation of pump I5, booster fan 20, and electromagnetic valve 10.11 is controlled based on the measured value signal of ultrasonic transmitter 26 and ultrasonic receiver 27, and the measured value signal is transmitted to transmitter 26 and receiver. 27, the solenoid valves 10 and II of the main paths 6 and 7 are opened and the bypass paths 8 and 9 are opened.
When an operation signal to stop (do not operate) the pump 15 and booster fan 20 is output from the controller 16, and on the other hand, it indicates that flash gas is present between the transmitter 26 and the receiver 27. , the detection signal is output from the transmitter 26 and the receiver 27 to the controller 16, and the controller 16 outputs the detection signal to the solenoid valves 10 and 1.
An operation signal for closing pump 15 and operating pump 15 and booster fan 20 is output to each. Although this embodiment also includes a pump 15 and a booster fan 20 as forced circulation means, it is also possible to include only one of them, as in the first and second embodiments. The pump 15 and the booster fan 20 are
Alternatively, when either one of them is operated, the refrigerant in the system is forced to circulate, and as a result, the refrigerant liquid in the system flows down inside the liquid pipe 3, and the refrigerant gas generated as flash gas is transferred to the liquid receiver. 5, or flows into the heat exchanger 23 in the air conditioning unit 2 together with the refrigerant liquid, and further flows into the gas pipe 4, in which case there is no refrigerant gas in the liquid pipe 3, In other words, natural circulation of the refrigerant becomes possible. In this state, there is no refrigerant gas between the transmitter 26 and the receiver 27, so the measured value signal indicates the reference time, and the solenoid valve IO of the main paths 6 and 7
and 11 are opened, the operation of the pump 15 and booster fan 20 of the bypass paths 8 and 9 is stopped,
Natural circulation of refrigerant is resumed. FIG. 4 is a schematic diagram showing a schematic configuration of a fourth embodiment of the heat transfer device according to the present invention employed in an air conditioning system. This embodiment has almost the same structure as the embodiment shown in FIG. 1, but the difference from the first embodiment is that the detection means is the liquid flowmeter 17
and a flow control valve 25 provided at the refrigerant inlet of the heat exchanger 23 of each air conditioning unit 2. Note that other components similar to those in the first embodiment shown in FIG. 1 are given the same numbers as in FIG. 1, and redundant explanations are omitted. As explained in the first embodiment, the measured value of the liquid flow meter 17 becomes 0 when flash gas is generated in the liquid pipe 3 and a natural circulation disorder occurs in the flow of the refrigerant in the system. There may also be a case where the heat load on the air conditioning unit 2 is small and all the flow control valves 25 of the respective heat exchangers 23 are fully closed. Therefore, a valve opening signal indicating whether or not the flow control valve 25 is fully closed is output from each flow control valve 25 to the controller 16. On the other hand, the liquid flow meter 17 also outputs its measured value signal to the controller 16. In other words, of course, if the flow rate measurement value is other than 0,
Even if the measured value is O, if the valve openings of each flow rate control valve 25 are all fully closed, it is determined that the natural circulation state of the refrigerant is normal, and the controller 16 controls the opening of these valves. Based on the temperature signal and the measured value signal, the solenoid valves 10 and II of the main paths 6 and 7 are opened, and the pump 15 of the bypass paths 8 and 9 is opened.
And outputs an operation signal to stop the operation of the booster fan 20 (do not operate). In this case, pump I
5 or the forced circulation force of the booster fan 20, natural circulation is maintained. In addition, the flow rate measurement value is 0,
If even one of the flow rate control valves 25 is open rather than fully closed, it is determined that the natural circulation of the refrigerant is abnormal, and the controller 16 controls these measurement value signals and valve opening. Based on the degree signal, an operation signal is output that closes the solenoid valves IO and 11 in the main paths 6 and 7 and operates the pump 15 and booster fan 20 in the bypass paths 8 and 9. Although this embodiment also includes a pump 15 and a booster fan 20 as forced circulation means, it is also possible to include only one of them, as in the 1.2.3 embodiment. When the pump 15 and/or the booster fan 20 are operated, the refrigerant in the system is forced to circulate, and the refrigerant flows through the open flow rate control valve 25, causing the liquid to flow. Since the measured value of the flowmeter 17 is other than 0, it is determined that the natural circulation state of the refrigerant is normal, so the solenoid valves 10 and 11 are opened, the operation of the pump 15 and the booster fan 20 is stopped, and the natural circulation of the refrigerant is stopped. Circulation resumes. FIG. 5 is a schematic diagram showing a schematic configuration of a fifth embodiment of the heat transfer device according to the present invention adopted in an air conditioning system. This embodiment is almost the same as the first embodiment in that a liquid flow meter 17 and a gas flow meter are used as detection means, but the difference from the first embodiment is that a pump 15 and a booster are used as forced circulation means. The second condenser 21 without using the fan 20
The point is that it has the following. That is, on the upstream side of the liquid receiver 5, the condenser 1 in the first embodiment is referred to as a first condenser 1°, and a second condenser 21 is provided in parallel with the first condenser 1°. In this case, the means for cooling the refrigerant in order to condense it in the first condenser 1' is cold water taken out from a low temperature heat storage tank 22 as a heat source device provided to perform normal natural circulation. °C~7
Chilled water at a temperature of about °C is used, but as a means of cooling the refrigerant in order to condense it in the second condenser 21, brine at a temperature of about O'C to 3 °C is used at a lower temperature than the cold water. ing. The gas pipe 4 branches into a first
A solenoid valve 12.13 for selecting and switching which condenser is to be operated is provided at a location connected to the condenser 1'' and the second condenser 21. A solenoid valve 14 is also provided in the liquid pipe 3 between the liquid receiver 5 and the liquid receiver 5.These solenoid valves 12, 13, and 14 receive detection signals from the liquid flow meter 17 and the gas flow meter 24 via the controller 16. In other words, the liquid flow meter 17 controls the flow rate of the refrigerant liquid in the liquid pipe 3 based on the gas flow meter 24.
measures the flow rate of the refrigerant gas in the gas pipe 4, and if the natural circulation of the refrigerant within the system is occurring smoothly, the solenoid valve I3 is opened and the solenoid valves 12 and 14 are closed. An operation signal for operating the first condenser 1' is output from the controller 16. Also, if the measured value of the liquid flow meter 17 is 0 and the gas flow meter 2
If the measured value of the liquid flow meter 17 is other than 0, the timer in the controller 16 operates as in the case of the first embodiment, and the secondary measured value of the liquid flow meter 17 after a predetermined period of time is 0. The presence or absence of a natural circulation disorder of the refrigerant is determined based on whether or not the condition occurs. If the secondary measured value is other than 0, the controller 16 outputs an operating signal to open the solenoid valve I3 and close the solenoid valve 12.14 to operate the first condenser 1'. If the second measurement value is 0, the controller 16 outputs an operation signal that closes the solenoid valve 13 and opens the solenoid valve 12.14 to operate the second condenser 21. Further, if the measured value of the liquid flow meter 17 is 0 and the measured value of the gas flow meter 24 is also 0, it is immediately determined that an abnormal state exists, and the solenoid valve 13 is closed and the solenoid valve 12.1 is closed.
The controller 16 outputs an operation signal to open the condenser 4 and operate the second condenser 21. When the second condenser 21 is operated, the refrigerant condensation capacity is significantly greater than when the first condenser 1' is operated, so the pressure inside the gas pipe 4 is rapidly reduced and the heat The refrigerant liquid in the liquid pipe 3 is sucked through the exchanger 23, and the refrigerant in the system is forced to circulate. Further, when the refrigerant in the system is forced to circulate, the measured value of the liquid flow meter 17 becomes other than 0, so the solenoid valve 13 is opened and the solenoid valve 1
2.14 is closed, the first condenser 1' is operated, and the natural circulation of the refrigerant is resumed. As explained in the fifth embodiment, the first
The fact that the second condenser 21 can be provided in place of the pump 15 and the booster fan 20 in the embodiment is the same for the 2.3.4 embodiment, and although not shown, the 2.3.
．． The fourth embodiment may also include the second condenser 21 of the fifth embodiment as a forced circulation means in place of the pump 15 and booster fan 20 of the first embodiment.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a schematic configuration of a first embodiment of the heat transfer device according to the present invention adopted in an air conditioning system, and FIG. FIG. 3 is a schematic diagram showing the schematic configuration of the third embodiment of the heat transfer device according to the present invention adopted in the air conditioning system; FIG. 4 is the schematic diagram of the present invention. FIG. 5 is a schematic diagram showing a schematic configuration of a fourth embodiment of the heat transfer device according to the present invention adopted in an air conditioning system, and FIG. FIG. 2 is a schematic diagram showing the configuration. ■... Condenser, 2... Air conditioning unit as evaporator,
3 Refrigerant liquid pipe, 4... Refrigerant gas pipe, 5 ・Liquid receiver, 15
... Pump as forced circulation means, 16... Controller,
17.Liquid flowmeter as a detection means, I 8.19.
Pressure sensor as detection means, 20 Booster fan as forced circulation means, 21 Second condenser as forced circulation means, 24 Gas flow meter as detection means, 25 Flow rate control valve, 26 Detection Ultrasonic transmitter as a means, 27...Ultrasonic receiver as a detection means Patent Applicant: Takenaka Corporation (and one other person)

Claims (8)

[Claims] (1) has a condenser (1) at the top and an evaporator (2) at the bottom, and these condensers (1) and evaporators (2) are connected to refrigerant liquid pipes (3) and refrigerant gas pipes (4). ), and the condenser (1) and evaporator (2) undergo a gas-liquid phase change inside.
), and has a liquid receiver (5) in the middle of the refrigerant liquid pipe (3), the natural circulation state of the refrigerant is monitored, and the refrigerant is detection means (17,
18, 19, 24, 25, 26, 27) and forced circulation means (15 , 20, 21). (2), the detection means (17, 18, 19, 24, 25
, 26, 27) and the forced circulation means (15, 20, 21)
), and the forced circulation means (15, 20, 21) is connected to the detection means (17, 18, 1).
9, 24, 25, 26, 27) is automatically driven by an operation signal output from the controller (16) based on a detection signal output from the heat transfer device (16). (3), the detection means (17, 24) includes the liquid receiver (
5), a liquid flow meter (17) provided on the refrigerant liquid pipe (3) near the refrigerant outlet of the refrigerant gas pipe (4), and a gas flow meter (24) provided on the refrigerant gas pipe (4); 16) immediately when the measured values of both the liquid flow meter (17) and the gas flow meter (24) are 0, and the primary measured value of the liquid flow meter (17) is 0.
In addition, if the measured value of the gas flow meter (24) at that time is other than 0, a second measurement of the liquid flow meter (17) is performed after a predetermined period of time has passed since the measurement, and the second measurement is performed. The heat transfer device according to claim 2, wherein the operation signal is output when the value is 0 again. (4) The detection means (18, 19) may include the liquid receiver (
5) a pressure sensor (18,
19) The heat transfer device according to claim 1 or 2, comprising: (5) The detection means (26, 27) may include the liquid receiver (
5) The heat refrigerant according to claim 1 or 2, comprising an ultrasonic transmitter (26) and an ultrasonic receiver (27) provided in the refrigerant liquid pipe (3) on the downstream side of Mobile device. (6), the detection means (17, 25) includes the liquid receiver (
A liquid flow meter (17) provided in the refrigerant liquid pipe (3) near the refrigerant outlet of the evaporator (2), and a valve opening of the liquid flow meter (17) provided in the refrigerant liquid pipe (3) near the refrigerant inlet of the evaporator (2). The heat transfer device according to claim 1 or 2, comprising a flow rate regulating valve (25) that outputs a temperature signal. (7) The forced circulation means (15, 20) is provided in the middle of at least one of the refrigerant liquid pipe (3) or the refrigerant gas pipe (4), and has a pressure for forcibly circulating the refrigerant. A heat transfer device according to any one of claims 1 to 6, comprising a fluid machine (15, 20). (8), the forced circulation means (21) includes the condenser (1);
) is a first condenser (1'), and a second condenser (1') that is provided in parallel with the first condenser (1') and cools the refrigerant at a lower temperature than the first condenser (1'). 21) A heat transfer device according to any one of claims 1 to 6.