JP2021021348A - Heat transport system and control method of heat transport system - Google Patents

Abstract

To provide a technology for suppressing drive-out, in a heat transport system using a heat transport fluid composed of a water solution containing an antifreeze liquid.SOLUTION: A heat transport system comprises: a first heat exchanger for radiating the heat of a heat source by using a heat transport fluid; a second heat exchanger arranged at a downstream side of the first heat exchanger, and radiating the heat of the heat transport fluid which has passed the first heat exchanger; a pump for liquid-sending the heat transport fluid; piping for connecting the first heat exchanger and the second heat exchanger, and making the heat transport fluid circulate; a fluid temperature measurement part for measuring a temperature of the heat transport fluid; a density adjustment part arranged on the piping, and adjusting the density of an antifreeze liquid in the heat transport fluid; and a control part for controlling the density adjustment part according to the temperature of the heat transport fluid which is measured by the fluid temperature measurement part.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat transport system.

Conventionally, in a heat transport system using a liquid heat transport fluid, which has been adopted in a cooling system of an automobile or the like, a technique for suppressing freezing of the heat transport fluid due to a decrease in temperature in winter has been studied. For example, Patent Document 1 discloses a technique for suppressing freezing of a heat transport fluid by adjusting the states (continuous phase and dispersed phase) of the heat transport fluid.

Japanese Unexamined Patent Publication No. 2016-1066

Further, a technique of suppressing freezing of the heat transport fluid by adding an antifreeze solution is also adopted. Since the operating temperature range of the heat transport system differs greatly between summer and winter, dryout may occur in summer if a heat transport fluid containing antifreeze is used to suppress freezing of the heat transport fluid in winter. ..

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a technique for suppressing dryout in a heat transport system using a heat transport fluid composed of an aqueous solution containing an antifreeze solution.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following forms.

(1) According to one embodiment of the present invention, there is provided a heat transport system using a heat transport fluid composed of an aqueous solution containing an antifreeze solution. In this heat transport system, a first heat exchanger that dissipates heat from a heat source using the heat transport fluid and the heat transport fluid that is arranged downstream of the first heat exchanger and has passed through the first heat exchanger are transferred. A second heat exchanger that dissipates heat, a pump that sends the heat transport fluid, and a pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid. , A fluid temperature measuring unit that measures the temperature of the heat transport fluid, a concentration adjusting unit that is arranged on the pipe and adjusts the concentration of the antifreeze liquid in the heat transport fluid, and a fluid temperature measuring unit. A control unit that controls the concentration adjusting unit according to the temperature of the heat transport fluid is provided.

According to this configuration, a concentration adjusting unit for adjusting the concentration of the antifreeze liquid in the heat transport fluid and a control unit for controlling the concentration adjusting unit according to the temperature of the heat transport fluid measured by the fluid temperature measuring unit are provided. Therefore, the antifreeze concentration of the heat transport fluid can be appropriately adjusted according to the temperature of the heat transport fluid. Therefore, when an antifreeze solution having a vapor pressure higher than the vapor pressure of water at the same temperature is used, the concentration of the antifreeze solution in the heat transport fluid can be reduced when the temperature of the heat transport fluid is high. Therefore, by lowering the vapor pressure of the heat transport fluid and raising the boiling point, it is possible to suppress dryout due to local boiling of the heat transport fluid or the like. On the other hand, even when an antifreeze liquid having a vapor pressure equal to or lower than the vapor pressure of water at the same temperature is used, the concentration of the antifreeze liquid in the heat transport fluid can be increased when the temperature of the heat transport fluid is high. As a result, by lowering the vapor pressure of the heat transport fluid and raising the boiling point, it is possible to suppress dryout due to local boiling of the heat transport fluid or the like.

(2) According to one embodiment of the present invention, there is provided a heat transport system using a heat transport fluid composed of an aqueous solution containing an antifreeze solution. In this heat transport system, a first heat exchanger that dissipates heat from a heat source using the heat transport fluid and the heat transport fluid that is arranged downstream of the first heat exchanger and has passed through the first heat exchanger are transferred. A second heat exchanger that dissipates heat, a pump that sends the heat transport fluid, and a pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid. The antifreeze liquid concentration measuring unit for measuring the concentration of the antifreeze liquid in the heat transport fluid, the concentration adjusting unit for adjusting the concentration of the antifreeze liquid in the heat transport fluid, and the antifreeze liquid concentration measuring unit arranged on the pipe. A control unit that controls the concentration adjusting unit according to the measured concentration of the antifreeze fluid is provided.

According to this configuration, the concentration adjusting unit that adjusts the concentration of the antifreeze liquid in the heat transport fluid and the concentration adjusting unit according to the antifreeze liquid concentration measured by the antifreeze liquid concentration measuring unit that measures the concentration of the antifreeze liquid in the heat transport fluid. Therefore, for example, the antifreeze concentration of the heat transport fluid can be adjusted to a target concentration according to the antifreeze concentration of the heat transport fluid. In this configuration, the antifreeze concentration of the heat transport fluid is measured regardless of the temperature of the heat transport fluid or the outside air temperature, and the concentration adjusting unit is adjusted based on the measured value, so that the antifreeze concentration can be adjusted more appropriately. .. For example, when using an antifreeze solution whose vapor pressure is greater than the vapor pressure of water at the same temperature, use a map of the outside air temperature and the target concentration to reduce the antifreeze concentration of the heat transport fluid to an appropriate concentration when the outside air temperature is high. be able to. As a result, the vapor pressure of the heat transport fluid is lowered and the boiling point is raised, so that dryout due to local boiling of the heat transport fluid can be suppressed.

(3) In the heat transport system of the above-described embodiment, the concentration adjusting unit includes a separation membrane module capable of selectively separating the antifreeze liquid and a vapor suction unit that sucks vapor from the separation membrane module. May be good. In this way, the concentration of the antifreeze liquid in the heat transport fluid can be easily adjusted.

(4) The heat transport system of the above-described form, further including an outside air temperature measuring unit for measuring the outside air temperature of the heat transport system, and the control unit responds to an outside air temperature measured value by the outside air temperature measuring unit. , The concentration adjusting unit may be controlled. In this way, the concentration of the antifreeze liquid in the heat transport fluid can be changed according to the outside air temperature. For example, when an antifreeze liquid having a vapor pressure higher than the vapor pressure of water at the same temperature is used, the concentration of the antifreeze liquid contained in the heat transport fluid circulating in the heat transport system is reduced when the temperature is high such as in summer, and heat is generated. The antifreeze performance of the heat transport fluid can be ensured by improving the evaporation suppression performance of the transport fluid and increasing the antifreeze liquid concentration of the heat transport fluid during a low temperature such as winter. On the other hand, when an antifreeze solution having a vapor pressure equal to or lower than the vapor pressure of water at the same temperature is used, the concentration of the antifreeze solution contained in the heat transport fluid circulating in the heat transport system is increased when the temperature is high such as in summer. It is possible to improve the evaporation suppressing performance of the heat transport fluid. In this way, the antifreeze performance and the evaporation suppression performance of the heat transport fluid can be selectively improved according to the outside air temperature.

(5) In the heat transport system of the above-described embodiment, the concentration adjusting unit may further include a storage unit capable of storing the antifreeze liquid separated by the separation membrane module. In this way, the antifreeze liquid stored in the storage unit can be reused.

(6) In the heat transport system of the above-described embodiment, in the concentration adjusting unit, the storage unit may be configured to be coolable. In this way, the antifreeze liquid separated by the separation membrane module can be stored in a liquid state.

(7) In the heat transport system of the above-described embodiment, when the outside air temperature measurement value by the outside air temperature measurement unit is equal to or less than the first temperature threshold value, the control unit uses the antifreeze fluid stored in the storage unit. It may be added to the heat transport fluid. In this way, for example, if a threshold is set to the freezing temperature of the fluid obtained by removing the antifreeze component from the heat transport fluid plus a predetermined value (for example, 5 ° C.), the heat transport fluid is likely to freeze. When the temperature is reached, the heat transport fluid can add the antifreeze liquid stored in the storage unit to the circulating heat transport fluid. Therefore, the antifreeze liquid stored in the storage unit can be reused to increase the concentration of the heat transport fluid and suppress the freezing of the heat transport fluid.

(8) In the heat transport system of the above-described embodiment, the concentration adjusting unit further includes a liquid level meter for measuring the liquid level of the storage unit, and the control unit measures the outside air temperature by the outside air temperature measuring unit. When the value is equal to or less than the first temperature threshold value and the liquid level measurement value by the liquid level gauge is equal to or less than the liquid level threshold value, the antifreeze liquid stored in the storage portion is added to the heat transport fluid. May be good. By doing so, for example, by setting the liquid level threshold value to a value close to 0 (for example, 0 or more and 10 ml or less), when there is antifreeze in the storage part, the circulating heat transport fluid is sent from the storage part. Antifreeze can be added. Therefore, when the antifreeze liquid is not stored in the storage unit, it is possible to suppress the mixing of air bubbles in the heat transport fluid due to the attempt to add the antifreeze liquid from the storage unit to the heat transport fluid.

(9) In the heat transport system of the above embodiment, the vapor pressure of the antifreeze liquid contained in the heat transport fluid may be larger than the vapor pressure at the same temperature. When the vapor pressure of the antifreeze is larger than the vapor pressure at the same temperature, the boiling point becomes lower as the concentration of the antifreeze increases, so that dryout is likely to occur when the temperature of the heat transport fluid is high. Even in such a case, the evaporation suppressing performance of the heat transport fluid can be improved.

(10) In the heat transport system of the above form, the antifreeze liquid may be alcohol. Even in this way, the antifreeze performance and the evaporation suppression performance of the heat transport fluid can be selectively improved.

The present invention can be realized in various aspects, for example, in the form of a system including a heat transport system, a control method of the heat transport system, a computer program for causing a computer to execute the control method, and the like. be able to.

It is explanatory drawing which shows the schematic structure of the heat transport system in 1st Embodiment. It is explanatory drawing which conceptually shows separation of antifreeze vapor by a separation membrane module. It is explanatory drawing for demonstrating the characteristic of a PV film. It is explanatory drawing for demonstrating the concept of separation by a PV film. It is a flowchart which shows the flow of the antifreeze concentration adjustment process. It is explanatory drawing which conceptually shows the steady mode of 1st Embodiment. It is explanatory drawing which conceptually shows the concentration reduction mode of 1st Embodiment. It is explanatory drawing which conceptually shows the density | concentration increase mode of 1st Embodiment. It is a figure which shows the Example of PV membrane separation. It is a figure which shows the example calculation condition of ethanol aqueous solution dilution. It is explanatory drawing for demonstrating the ethanol composition and permeation rate of an Example. It is a figure which shows the gas-phase composition of ethanol at the time of vapor-liquid equilibrium with respect to the liquid phase composition of ethanol of the ethanol water system. It is a figure which shows the gas-liquid equilibrium curve of an ethanol water system. It is explanatory drawing which shows the schematic structure of the heat transport system in 2nd Embodiment. It is a flowchart which shows the flow of the antifreeze concentration adjustment process in 2nd Embodiment. It is explanatory drawing which conceptually shows the steady mode of 2nd Embodiment. It is explanatory drawing which conceptually shows the density | concentration reduction mode of 2nd Embodiment. It is explanatory drawing which conceptually shows the density | concentration increase mode of 2nd Embodiment. It is explanatory drawing which shows the schematic structure of the heat transport system in 3rd Embodiment. It is explanatory drawing which shows the schematic structure of the heat transport system in 4th Embodiment.

<First Embodiment>
FIG. 1 is an explanatory diagram showing a schematic configuration of a heat transport system 100 according to the first embodiment. The heat transport system 100 is a system that dissipates heat from a heat source by using a heat transport fluid (hereinafter, also simply referred to as “heat transport fluid”) composed of an aqueous solution containing an antifreeze liquid. In this embodiment, ethanol is used as the antifreeze liquid, and a heat transport fluid having a liquid phase composition (mole fraction) of ethanol of 0.4 is used.

The heat transport system 100 includes a first heat exchanger 10, a second heat exchanger 20, a first tank 30, a concentration adjusting unit 40, a pump 50 for sending a heat transport fluid, a control unit 80, and the like. A fluid temperature measuring unit 91 for measuring the temperature of the heat transport fluid, an outside temperature measuring unit 92 for measuring the outside temperature of the heat transport system 100, and a liquid level meter 93 are provided. The first heat exchanger 10, the second heat exchanger 20, the first tank 30, the concentration adjusting unit 40, and the pump 50 are connected in a ring shape via pipes 61, 62, 63, 65, 66. ing. The heat transport fluid is circulated by the pump 50 in the order of the first heat exchanger 10, the second heat exchanger 20, the first tank 30, and the concentration adjusting unit 40 via the pipes 61, 62, 63, 65, 66. ing.

The first heat exchanger 10 dissipates heat from a heat source using a heat transport fluid. In this embodiment, an automobile engine is exemplified as a heat source. The heat transport fluid circulates in a water jacket provided inside the engine. That is, the water jacket corresponds to the first heat exchanger 10.

The second heat exchanger 20 is arranged downstream of the first heat exchanger 10 and dissipates heat from the heat transport fluid that has passed through the first heat exchanger 10. In this embodiment, a radiator is used as the second heat exchanger 20. The fluid temperature measuring unit 91 is arranged on the pipe 61 connecting the first heat exchanger 10 and the second heat exchanger 20, and the measured value by the fluid temperature measuring unit 91 is output to the control unit 80.

The first tank 30 has a heat transport fluid inside. In the present embodiment, as described above, ethanol is used as the antifreeze solution, and the liquid phase composition (mole fraction) of ethanol is 0.4 in the initial state.

The concentration adjusting unit 40 adjusts the concentration of the antifreeze liquid in the heat transport fluid and flows it through the pipe 65. The concentration adjusting unit 40 includes a separation membrane module 41, a second tank 42, an ejector 43, a pipe connecting them, and a valve provided on the pipe. The separation membrane module 41 separates the antifreeze liquid from the heat transport fluid as antifreeze liquid vapor. The separation membrane module 41 is connected to the aspirator 43 via the pipe 67 on the upstream side of the flow of the heat transport fluid, and is connected to the second tank 42 via the pipe 68u and the pipe 67 branched from the pipe 67. ing. Further, the separation membrane module 41 is connected to the aspirator 43 via the pipe 64 on the downstream side of the flow of the heat transport fluid, and is also connected to the pipe 66 via the pipe 69 and the pipe 65 branched from the pipe 64. ing. The second tank 42 is connected to the aspirator 43 via the pipe 68d and the pipe 64 and is connected to the pipe 65 via the pipe 68d, the pipe 64, and the pipe 69 on the downstream side of the flow of the heat transport fluid. There is.

A first solenoid valve 44 and a fourth solenoid valve 47 are provided on the pipe 64, a second solenoid valve 46 is provided on the pipe 68d, a third solenoid valve 45 is provided on the pipe 67, and the pipe 69. A proportional valve 48 is provided on the top. By controlling these valves by the control unit 80, the concentration of antifreeze liquid in the heat transport fluid is adjusted. In the following description, the first solenoid valve 44, the second solenoid valve 46, the third solenoid valve 45, the fourth solenoid valve 47, and the proportional valve 48 are also collectively referred to as "valves 44 to 48".

The second tank 42 is an empty tank and can store the antifreeze vapor separated from the heat transport fluid by the separation membrane module 41. In this embodiment, a cooling tank is used as the second tank 42. Therefore, the antifreeze vapor separated by the separation membrane module 41 can be stored in the second tank 42 as a liquid antifreeze. Further, when the control unit 80 controls the second solenoid valve 46, the antifreeze liquid stored in the second tank 42 flows into the pipe 64 (described later). By storing the antifreeze vapor separated from the heat transport fluid by the separation membrane module 41 in the second tank 42, the antifreeze concentration of the heat transport fluid circulating in the heat transport system 100 can be reduced. Further, by allowing the antifreeze liquid stored in the second tank 42 to flow into the heat transport fluid having a reduced antifreeze liquid concentration, the antifreeze liquid concentration of the heat transport fluid circulating in the heat transport system 100 is returned (approached) to the initial state. be able to. A liquid level meter 93 is provided in the second tank 42, and a measured value of the liquid level of the liquid stored in the second tank 42 is output to the control unit 80. The second tank 42 of this embodiment is also referred to as a “storage unit”.

As the aspirator 43, for example, a metal aspirator having a water amount of 15 to 16 L / min and an exhaust speed of 10 L / min can be used. By controlling the above-mentioned third solenoid valve 45, fourth solenoid valve 47, and proportional valve 48 to adjust the flow rate of the heat transport fluid introduced into the aspirator 43, the exhaust speed of the aspirator 43 can be adjusted to the separation membrane module 41. It can be made larger than the membrane permeation rate of the antifreeze vapor in. The ejector 43 in the present embodiment is also referred to as a "steam suction unit".

The control unit 80 is a computer including a ROM, a RAM, and a CPU, and controls the entire heat transport system 100. The control unit 80 is electrically connected to valves 44 to 48, a pump 50, a fluid temperature measurement unit 91, an outside air temperature measurement unit 92, and a liquid level meter 93 provided on the pipe. The control unit 80 controls the valves 44 to 48 based on the measured values output from the fluid temperature measuring unit 91, the outside air temperature measuring unit 92, and the liquid level gauge 93 (described later). The control unit 80 has a "steady mode" in which the antifreeze concentration of the heat transport fluid is substantially the same as the initial state and circulates the heat transport fluid, and a "concentration reduction mode" in which the antifreeze concentration of the heat transport fluid is lowered from the initial state. The heat transport system 100 can be operated in three modes of "concentration increase mode" in which the antifreeze concentration of the heat transport fluid can be raised from a state in which the concentration of the antifreeze solution is lowered from the initial state to substantially the same concentration as the initial state. .. The three modes will be described in detail later.

FIG. 2 is an explanatory diagram conceptually showing the separation of antifreeze vapor by the separation membrane module 41. The separation membrane module 41 has a configuration in which a plurality of separation membranes 412 are arranged in a substantially bottomed cylindrical housing 411. The housing 411 has an inlet 413 into which the heat transport fluid is introduced, a first outlet 414 from which the antifreeze vapor separated by the separation membrane 412 flows out, and heat in which the antifreeze vapor is separated by the separation membrane 412 and the antifreeze concentration is lowered. It has a second outlet 415 through which the transport fluid flows out.

The separation membrane 412 is a separation membrane that selectively separates ethanol as an antifreeze solution. As the separation membrane 412, a pervaporation (hereinafter, also referred to as “PV”) membrane, which is a homogeneous membrane without pores, or a porous membrane can be used. In the present embodiment, the high silica zeolite membrane of the PV membrane is used as the separation membrane 412, but the separation membrane 412 is not limited to this, and a PV membrane made of silicone rubber, trimethylsilylpropine, polyvinyl alcohol or the like is used. You may. Further, a porous membrane made of polytetrafluoroethylene (PTFE) or the like may be used.

The inlet 413 (FIG. 2) of the separation membrane module 41 is connected to the pipe 63 (FIG. 1), and the heat transport fluid flows into the separation membrane module 41 (FIG. 2) through the pipe 63. The first outlet 414 of the separation membrane module 41 is connected to the pipe 67 (FIG. 1), and the antifreeze vapor (ethanol vapor) that has passed through the separation membrane 412 flows into the pipe 67. In the enlarged view shown in FIG. 5, the antifreeze vapor AF is shown by black circles, and the liquid antifreeze vapor AF is shown by white circles. The second outlet 415 of the separation membrane module 41 is connected to the pipe 64 (FIG. 1), and a part of the antifreeze liquid is separated by the separation membrane 412, and the heat transport fluid having a low antifreeze concentration (hereinafter referred to as “low concentration heat”). (Also called "transport fluid") flows into the pipe 64.

FIG. 3 is an explanatory diagram for explaining the characteristics of the PV film. The PV method is a method in which a feed solution is evaporated through a homogeneous membrane having no pores to obtain a concentrated solution as permeated vapor. In this method, the target component can be separated by the performance of the membrane itself regardless of the osmotic pressure or vapor-liquid equilibrium. FIG. 3 shows the PV performance of the high silica zeolite membrane, the silicone rubber membrane mixed with high silica zeolite, and the silicone rubber membrane. The data of Kita 1998 is described as the data of the high silica zeolite membrane 1, and the data of nomura 2002 is described as the data of the high silica zeolite membrane 2. FIG. 3 illustrates the ethanol mole fraction of the permeated vapor and the permeation flow velocity with respect to the ethanol mole fraction of the feed solution as PV characteristics. As shown in FIG. 3, these PV membranes are used to obtain a 70-90 mol% ethanol concentrate from a low concentration aqueous solution. In addition, FIG. 3 cites the figure described in the following homepage. http://chemeng.in.coocan.jp/memb/et.html

FIG. 4 is an explanatory diagram for explaining the concept of separation by the PV film. The pervaporation method (PV) is a membrane separation method in which a liquid is evaporated through a membrane, and is accompanied by a phase change of evaporation through the membrane. By flowing the mixed solution on the membrane surface and keeping the permeation side in a vacuum, the separation target component in the supplied liquid is permeated as vapor. For example, in the case of separation of an aqueous ethanol system, if a hydrophilic material (for example, polyvinyl alcohol or zeolite) in which water is easily dissolved is used in the membrane, only water vapor permeates and ethanol is concentrated in the feed solution. On the contrary, if a hydrophobic material is used, ethanol can be selectively recovered. When the "vapor phase propulsion model" is used as a model of mass transfer in pervaporation (PV) operation, the membrane permeation of components is the propulsion force between the equilibrium vapor pressure on the solution surface and the partial pressure on the permeation side through the membrane. Occurs as. At that time, since the permeability coefficient of gas / vapor can be used as the membrane permeability coefficient of each component, it can be modeled by the following equations (1) and (2). In addition, FIG. 4 and the mathematical formula are quoted from the figure described on the following homepage.
http://chemeng.in.coocan.jp/memb/m#ana1.html

ここで、Ｌ［ｍｏｌ／ｓ］：供給液中の各成分流量，Ｑ［ｍｏｌ・ｍ／（ｓ・ｍ²・ｋＰａ）］：膜透過係数，ｄ［ｍ］：膜厚み，γ：活量係数，ｐ^*［ｋＰａ］：操作温度の各純成分の平衡蒸気圧，ｘ：供給液中の低沸点成分モル分率，ｙ_p：透過側蒸気の低沸点成分濃度，Ａ［ｍ²］：膜面積，ｐ_l［ｋＰａ］：透過側圧力
成分１：低沸点成分（不凍液）、成分２：高沸点成分（水）

Here, L [mol / s]: flow rate of each component in the feed solution, Q [mol · m / (s · m ² · kPa)]: membrane permeation coefficient, d [m]: membrane thickness, γ: activity. Coefficient, p ^* [kPa]: Equilibrium vapor pressure of each pure component of operating temperature, x: Mole fraction of low boiling point component in the feed solution, y _p : Low boiling point component concentration of permeation side steam, A [m ² ]: Membrane area, _pl [kPa]: Permeation side pressure Component 1: Low boiling point component (antifreeze), Component 2: High boiling point component (water)

The antifreeze concentration adjusting process of the control unit 80 in the present embodiment will be described with reference to FIGS. 5 to 8. FIG. 5 is a flowchart showing the flow of the antifreeze concentration adjusting process. FIG. 6 is an explanatory diagram conceptually showing a steady mode described later. FIG. 7 is an explanatory diagram conceptually showing the concentration reduction mode described later. FIG. 8 is an explanatory diagram conceptually showing the concentration increase mode described later.

As shown in FIG. 5, when the control unit 80 starts the heat transport system 100 and starts the pump 50, first, the first solenoid valve 44 is opened, the second solenoid valve 46, the third solenoid valve 45, The fourth solenoid valve 47 is closed and the proportional valve 48 is fully opened (step S102). When controlled in this way, the second tank 42 and the aspirator 43 are not connected to the flow path of the heat transport fluid. Therefore, by this control, as shown by the arrow in FIG. 6, the heat transport fluid is passed through the pipes 61 to 66 and the pipe 69 to the first tank 30, the separation membrane module 41, and the first heat exchanger 10. It circulates in the order of the second heat exchanger 20 (the flow path is shown with diagonal hatching in FIG. 6). Since the aspirator 43 is not connected to the first outlet 414 (FIG. 2) of the separation membrane module 41, the antifreeze liquid in the heat transport fluid flowing into the separation membrane module 41 is not separated. Therefore, the heat transport fluid having the initial concentration of antifreeze is circulated. In the present embodiment, the mode in which the heat transport system 100 is operated with the valves 44 to 48 in the state of step S102 is also referred to as a “steady mode”. The heat transport system 100 is started, for example, at the same time as the engine is started.

When the measured value of the outside air temperature by the outside air temperature measuring unit 92 of the outside air temperature is higher than the first temperature threshold Th1 (NO in step 104), the control unit 80 proceeds to step S106. In the present embodiment, the first temperature threshold Th1 = 0 ° C. is set. In step S106, when the measured value of the fluid temperature by the fluid temperature measuring unit 91 is higher than the second temperature threshold Th2, the control unit 80 opens the third solenoid valve 45, the fourth solenoid valve 47, and the proportional valve 48. (Step S108). In the present embodiment, the mode in which the heat transport system 100 is operated with the valves 44 to 48 in the state of step S108 is also referred to as a “concentration reduction mode”. In the present embodiment, the second temperature threshold Th2 = 80 ° C. is set.

In the "concentration reduction mode", the proportional valve 48 is gradually closed according to the measured value of the fluid temperature. That is, since the fourth solenoid valve 47 is in the closed state and the proportional valve 48 is fully open at the start of the heat transport process by the control unit 80, all the heat transport fluid flowing through the pipe 64 flows into the pipe 69. (Fig. 6). On the other hand, in the "concentration reduction mode", the fourth solenoid valve 47 is in the open state, and the proportional valve 48 is gradually closed according to the temperature of the heat transport fluid. Therefore, the heat transport fluid flowing through the pipe 64 is one. The part flows into the aspirator 43, and the rest flows into the pipe 69. In step S108, for example, if the opening degree of the proportional valve 48 is controlled to be closed by 5 degrees, the proportional valve 48 is gradually closed while steps S104, S106, and S108 are repeated. As the temperature of the heat transport fluid increases, the opening degree of the proportional valve 48 decreases, so that the amount of the heat transport fluid flowing into the pipe 69 decreases and the amount of the heat transport fluid flowing into the aspirator 43 increases.

When the heat transport fluid flows into the aspirator 43, the suction port connected to the pipe 67 is depressurized, so that the antifreeze vapor is separated in the separation membrane module 41 and flows into the pipe 67. Since the second tank 42 is cooled, most of the antifreeze vapor flowing into the pipe 67 flows into the second tank 42 through the pipe 68u and is stored in the second tank 42 as a liquid antifreeze liquid. In FIG. 7, the flow of the fluid from the separation membrane module 41 to the second tank 42 or the aspirator 43 is indicated by a white arrow, and the flow path is shown with dot hatching. As the temperature of the heat transport fluid increases, the opening degree of the proportional valve 48 decreases, so that the amount of heat transport fluid flowing into the aspirator 43 increases, and as a result, the pressure at the suction port decreases, and the antifreeze liquid in the separation membrane module 41 The amount of steam separated can be increased. By this treatment, the concentration of the antifreeze liquid in the heat transport fluid is lowered, and the heat transport fluid having a low antifreeze concentration (low concentration heat transport fluid) is circulated as shown by the black arrow in FIG. In FIG. 7, diagonal hatching is attached to the flow path through which the low-concentration heat transport fluid flows.

As shown in FIG. 5, the control unit 80 repeats steps S104, S106, and S108 until the measured value (temperature of the heat transport fluid) by the fluid temperature measuring unit 91 becomes equal to or less than the second temperature threshold Th2, and in step S106. When the value measured by the fluid temperature measuring unit 91 becomes equal to or less than the second temperature threshold Th2, the low-concentration heat transport fluid is circulated without changing the state of the valves 44 to 48.

In step S104, when the value measured by the outside air temperature measuring unit 92 is equal to or less than the first temperature threshold Th1 (YES in step 104), the control unit 80 opens the second solenoid valve 46 and closes the fourth solenoid valve 47. State, the proportional valve 48 is fully opened (FIG. 8). When the fourth solenoid valve 47 is closed, the heat transport fluid does not flow into the aspirator 43, and the suction port of the aspirator 43 connected to the pipe 67 is not depressurized. Therefore, the separation membrane module 41 separates the antifreeze liquid. I won't get it. Since the second solenoid valve 46 is opened, the antifreeze liquid stored in the second tank 42 flows into the pipe 64 via the pipe 68d. In FIG. 8, the flow path through which the antifreeze liquid stored in the second tank 42 flows is provided with diagonal hatching that descends to the right, and the flow is illustrated by a white arrow. By this control, the antifreeze liquid stored in the second tank 42 is added to the circulating heat transport fluid, and the concentration of the antifreeze liquid in the heat transport fluid can be increased. In FIG. 8, the flow path of the circulating heat transport fluid is shown by a black arrow with diagonal hatching that rises to the right.

As shown in FIG. 5, when the measured value of the liquid level gauge 93 is larger than the liquid level threshold value Th3 (NO in step S112), the control unit 80 returns to step S110. In the present embodiment, the liquid level threshold Th3 = 0 is set. That is, the antifreeze liquid stored in the second tank 42 is mixed with the circulating heat transport fluid until the antifreeze liquid is exhausted in the second tank 42. By this treatment, the antifreeze concentration in the heat transport fluid is returned to substantially the same as the initial state. In the present embodiment, the mode in which the heat transport system 100 is operated with the valves 44 to 48 in the state of step S110 is also referred to as a “concentration increase mode”.

When the measured value of the liquid level gauge 93 reaches the liquid level threshold value Th3 (YES in step S112), the control unit 80 sets the valves 44 to 48 in the steady mode (the first solenoid valve 44 is open and the second solenoid valve 46 is opened). The process returns to the closed state, the third solenoid valve 45 is closed, the fourth solenoid valve 47 is closed, and the proportional valve 48 is fully opened), and the antifreeze concentration adjusting process is completed. When the antifreeze concentration adjustment process is completed, the heat transport fluid is circulated in the steady mode (FIG. 6) until the operation of the heat transport system 100 is stopped. The control unit 80, for example, stops the operation of the heat transport system 100 after a lapse of a predetermined time after the engine is stopped.

As described above, in the control unit 80, when the measured value of the outside air temperature in the outside air temperature measuring unit 92 is higher than the first temperature threshold Th1 (0 ° C.), the heat transport fluid temperature is the second temperature threshold Th2 (80 ° C.). ), The heat transport system 100 is operated in the concentration reduction mode (FIG. 7). That is, the control unit 80 controls the concentration adjusting unit according to the temperature of the heat transport fluid measured by the fluid temperature measuring unit 91 to adjust the concentration of the antifreeze liquid in the heat transport fluid.

Further, when the measured value of the outside air temperature in the outside air temperature measuring unit 92 is equal to or less than the first temperature threshold Th1 (0 ° C.) and the antifreeze liquid is stored in the second tank 42, the control unit 80 heats up. The transport system 100 is operated in the concentration increase mode (FIG. 8). Otherwise, the control unit 80 operates the heat transport system 100 in steady mode (FIG. 6).

As described above, according to the heat transport system 100 of the present embodiment, when the outside air temperature is low (0 ° C. or lower), the concentration adjusting unit 40 so that the antifreeze concentration of the heat transport fluid is substantially the same as the initial state. Adjusted by. Therefore, in the initial state, the antifreeze performance of the heat transport fluid is ensured by adjusting the antifreeze concentration of the heat transport fluid filled in the first tank 30 to a sufficient concentration so that the heat transport fluid does not freeze. can do.

By the way, ethanol as an antifreeze solution in the present embodiment has a large vapor pressure with respect to water. Therefore, in a heat transport fluid composed of an aqueous solution containing an antifreeze, if the concentration of the antifreeze is increased in order to ensure sufficient antifreeze performance, the vapor pressure of the heat transport fluid increases and the boiling point decreases, so that the outside temperature such as in summer When is high, there is a risk of dryout due to local boiling or the like. On the other hand, according to the heat transport system 100 of the present embodiment, when the outside air temperature is not low (higher than 0 ° C) and the temperature of the heat transport fluid is high (higher than 80 ° C), the antifreeze concentration of the heat transport fluid is high. Is lower than the initial state (concentration reduction mode). In the concentration lowering mode, the antifreeze concentration of the heat transport fluid can be lowered to lower the vapor pressure, so that the boiling point of the heat transport fluid can be raised. As a result, the evaporation suppressing performance of the heat transport fluid can be improved, and the dryout of the heat transport fluid can be suppressed.

Further, when the outside temperature is high such as in summer, the heat transport fluid is not sufficiently dissipated by the second heat exchanger 20, the temperature of the heat transport fluid is high, and heat transfer from the heat source to the heat transport fluid is sufficiently performed. It may not be broken. Since ethanol as an antifreeze has a low heat transfer performance with respect to water, the concentration of the antifreeze in the heat transport fluid is reduced by operating the heat transport system 100 in the concentration reduction mode in which the concentration of the antifreeze in the heat transport fluid is reduced. , Heat transfer performance can be improved.

That is, according to the heat transport system 100 of the present embodiment, the antifreeze performance of the heat transport fluid is ensured in winter by changing the antifreeze concentration of the heat transport fluid according to the outside air temperature, while the heat transport fluid in summer. Evaporation suppression performance can be ensured.

Further, in the heat transport system 100 of the present embodiment, ethanol is used as the antifreeze liquid. Since ethanol has a lower viscosity than antifreeze liquids such as ethylene glycol and glycerin, it is possible to suppress a decrease in the fluidity of the heat transport fluid. As described above, the use of an antifreeze solution having a low viscosity is preferable in that the decrease in fluidity can be suppressed, while the vapor pressure becomes higher than the case where an antifreeze solution having a high viscosity such as ethylene glycol is used as the antifreeze solution. Therefore, the possibility of dryout may increase. On the other hand, as described above, according to the heat transport system 100 of the present embodiment, it is possible to suppress the dryout of the heat transport fluid.

Further, according to 100 of the present embodiment, since the second tank 42 having a cooling function is provided, the antifreeze vapor separated by the separation membrane module 41 can be stored as a liquid. Therefore, the antifreeze liquid stored in the second tank 42 can be reused to easily and appropriately increase the concentration of the heat transport fluid.

Further, according to 100 of the present embodiment, the liquid level meter 93 for measuring the liquid level of the second tank 42 is provided, and when the measured value by the liquid level meter 93 is 0, the control unit 80 is connected to the second tank 42. The stored antifreeze is added to the heat transport fluid. That is, when the second tank 42 is empty, the second solenoid valve 46 is closed, so that air bubbles can be suppressed from being mixed into the heat transport fluid.

Further, according to the heat transport system 100 of the present embodiment, since the separation membrane module 41 using the PV film is used in the concentration adjusting unit 40 for adjusting the concentration of the antifreeze liquid in the heat transport fluid, for example, gas-liquid equilibrium. Can be used to lower the antifreeze concentration in the heat transport fluid as compared to the case where the antifreeze concentration in the heat transport fluid is lowered. Hereinafter, with reference to FIGS. 9 to 13, the effect of the example of separating the antifreeze liquid from the heat transport fluid using the PV membrane will be described in comparison with the comparative example using vapor-liquid equilibrium.

FIG. 9 is a diagram showing an example of PV membrane separation. FIG. 10 is a diagram showing example calculation conditions for diluting an aqueous ethanol solution. FIG. 11 is an explanatory diagram for explaining the ethanol composition and permeation rate of the examples. The separation membrane module of the embodiment is a double-cylindrical membrane module, in which a single-sealed membrane is inserted into a circular tube to form a double-cylindrical tube, and the other end is open. A group of double-cylindrical tubes in which the double-cylindrical tubes are alternately connected so that the membranes are lined up in series is housed in a vacuum vessel. As the high silica zeolite membrane as the PV membrane, for example, the high silica zeolite membrane described in Japanese Patent Application Laid-Open No. 2015-033688 is used. FIG. 9 shows an example using a water-ethanol system fluid at 25 ° C. FIG. 11 shows the result of calculation under the calculation conditions shown in FIG. As shown in FIGS. 10 and 11, when the volume of the heat transport fluid is 3.0 L and the initial composition (initial antifreeze concentration) is 0.40, if the target composition is 0.20, it is necessary to reach the target composition. The time is about 19 minutes. That is, when the separation membrane module 41 using the PV membrane is used, the methanol (antifreeze) composition of the ethanol-water system heat transport fluid can be reduced to 0.4 or less.

As a comparative example, an example of reducing the antifreeze concentration of the heat transport fluid by utilizing vapor-liquid equilibrium will be described.
FIG. 12 is a diagram showing the gas phase composition of ethanol at the time of vapor-liquid equilibrium with respect to the liquid phase composition of ethanol in an aqueous ethanol system. FIG. 13 is a diagram showing a vapor-liquid equilibrium curve of an ethanol water system. FIGS. 12 and 13 are calculated according to "Vapor-liquid equilibrium data collection by Excell, 2nd edition" (2012) edited by Shuzo Oe. 12 and 13 show vapor-liquid equilibrium data at a constant pressure (760 mmHg). FIG. 12 shows the gas phase composition (mole fraction) of ethanol at the time of vapor-liquid equilibrium with respect to the liquid phase composition (mole fraction) of ethanol. In the present embodiment, in the initial state, an aqueous solution having a liquid phase composition (mole fraction) of ethanol of 0.4 is used as the heat transport fluid. As shown in FIGS. 12 and 13, when the temperature of the first heat exchanger 10 is 80 ° C., the heat transport system 100 is circulated when the antifreeze concentration of the heat transport fluid is lowered by utilizing vapor-liquid equilibrium. The ethanol composition of the heat transport fluid is not diluted below 0.4.

As described above, by using the separation membrane module using the PV membrane, the antifreeze concentration can be further reduced as compared with the case where the antifreeze concentration in the heat transport fluid is lowered by utilizing vapor-liquid equilibrium.

<Second Embodiment>
FIG. 14 is an explanatory diagram showing a schematic configuration of the heat transport system 100A according to the second embodiment. The heat transport system 100A of the present embodiment differs from the heat transport system 100 of the first embodiment in that it does not have a fluid temperature measuring unit 91 and a liquid level gauge 93, and an antifreeze concentration measuring unit 94 is provided on the pipe 66. The points are controlled by the control unit 80. Regarding the heat transport system 100A of the present embodiment, the same configuration as that of the first embodiment is designated by the same reference numerals as those of the first embodiment, and the preceding description is referred to.

The antifreeze concentration measuring unit 94 detects the antifreeze concentration of the circulating heat transport fluid. The antifreeze concentration measuring unit 94 is electrically connected to the control unit 80, and the control unit 80 controls the concentration adjusting unit 40 by using the antifreeze concentration measurement value acquired from the antifreeze concentration measuring unit 94. The antifreeze concentration measuring unit 94 can use, for example, a configuration for estimating the antifreeze concentration by using ultrasonic waves and a refractive index. Further, a configuration may be used in which a MAP showing the relationship between the concentration and the physical properties (heat capacity, heat conduction, viscosity, etc.) and a sensor for measuring the physical properties are provided, and the antifreeze concentration is estimated using the measured value by the sensor.

The antifreeze concentration adjusting process of the control unit 80 in the present embodiment will be described with reference to FIGS. 15 to 18. FIG. 15 is a flowchart showing the flow of the antifreeze concentration adjusting process in the second embodiment. FIG. 16 is an explanatory diagram conceptually showing the steady mode. FIG. 17 is an explanatory diagram conceptually showing the concentration reduction mode. FIG. 18 is an explanatory diagram conceptually showing the concentration increase mode.

As shown in FIG. 15, when the pump 50 is started at the time of starting the heat transport system 100A, the control unit 80 first sets the steady mode in the same manner as in step S102 in the first embodiment (step S202). By this control, the heat transport fluid is sent through the first tank 30, the separation membrane module 41, the first heat exchanger 10, and the second through the pipes 61 to 66 and the pipe 69, as shown by the arrows in FIG. It circulates in the order of the heat exchanger 20 (the flow path is shown with diagonal hatching in FIG. 16). Since the aspirator 43 is not connected to the first outlet 414 (FIG. 16) of the separation membrane module 41, the antifreeze liquid in the heat transport fluid flowing into the separation membrane module 41 is not separated. Therefore, the heat transport fluid having the initial concentration of antifreeze is circulated.

When the current concentration value (measured by the antifreeze concentration measuring unit 94) matches the antifreeze target concentration of the heat transport fluid (YES in step S204), the control unit 80 sets the valves 44 to 48 in the steady mode (first mode). The antifreeze concentration adjustment process is completed with the solenoid valve 44 open, the second solenoid valve 46 closed, the third solenoid valve 45 closed, the fourth solenoid valve 47 closed, and the proportional valve 48 fully open). To do. Therefore, the heat transport system 100 is operated in steady mode (FIG. 16). In the present embodiment, the control unit 80 is provided with a MAP indicating the relationship between the outside air temperature and the antifreeze target concentration in advance, and the control unit 80 sets the antifreeze target concentration by using the measured value by the outside air temperature measuring unit 92.

On the other hand, when the current concentration value does not match the antifreeze target concentration of the heat transport fluid (NO in step S204), the control unit 80 proceeds to step S206. When the current concentration value is larger than the antifreeze target concentration (YES in step S206), the control unit 80 switches the valves 44 to 48 to the state of the concentration lowering mode similar to step S108 of the first embodiment (step S208). ). In the "concentration reduction mode", the fourth solenoid valve 47 is in the open state, and the proportional valve 48 is gradually closed according to the antifreeze concentration of the heat transport fluid. Therefore, the heat transport fluid flowing through the pipe 64 is partially used. Flows into the aspirator 43, and the rest flows into the pipe 69. In step S208, for example, if the opening degree of the proportional valve 48 is controlled to be closed by 5 degrees, the proportional valve 48 is gradually closed while steps S204, S206, and S208 are repeated. As the difference between the current antifreeze concentration of the heat transport fluid and the antifreeze target concentration increases, the opening degree of the proportional valve 48 decreases, so that the amount of the heat transport fluid flowing into the pipe 69 decreases and the heat flowing into the aspirator 43 decreases. The amount of transport fluid increases. In the present embodiment, the process of the concentration reduction mode is repeated until the current antifreeze concentration of the heat transport fluid reaches the antifreeze target concentration. By this treatment, the concentration of the antifreeze liquid in the heat transport fluid is lowered, and the heat transport fluid having a low antifreeze concentration (low concentration heat transport fluid) is circulated as shown by the black arrow in FIG. In FIG. 17, diagonal hatching is added to the flow path through which the low-concentration heat transport fluid flows.

In step S206 (FIG. 15), if the current concentration value is smaller than the antifreeze target concentration (NO in step S206), the control unit 80 proceeds to step S210, and the valve 44 is the same as in step S110 of the first embodiment. ~ 48 is switched to the state of the concentration increase mode. When the heat transport system 100A is operated in the concentration increase mode, the antifreeze liquid is not separated by the separation membrane module 41 as in the first embodiment, and the antifreeze liquid stored in the second tank 42 passes through the pipe 68d. It flows into the pipe 64. In FIG. 18, the flow path through which the antifreeze liquid stored in the second tank 42 flows is provided with diagonal hatching that descends to the right, and the flow is illustrated by a white arrow. By this control, the antifreeze liquid stored in the second tank 42 is added to the circulating heat transport fluid, and the concentration of the antifreeze liquid in the heat transport fluid can be increased. In FIG. 18, the flow path of the circulating heat transport fluid is shown by a black arrow with diagonal hatching that rises to the right.

According to the heat transport system 100A of the present embodiment, the antifreeze concentration of the heat transport fluid can be adjusted to a target concentration according to the antifreeze concentration of the heat transport fluid. In this configuration, the antifreeze concentration of the heat transport fluid is measured regardless of the temperature of the heat transport fluid or the outside air temperature, and the concentration adjusting unit is adjusted based on the measured value, so that the antifreeze concentration can be adjusted more appropriately. .. For example, even if the outside air temperature is low, if an antifreeze concentration sufficient to exhibit antifreeze performance against the outside air temperature is secured, the antifreeze concentration is not increased and the heat transport system 100A is operated in the steady mode. Can be driven. Therefore, it is possible to suppress a decrease in the fluidity of the heat transport fluid due to an excessive increase in the antifreeze liquid concentration.

<Third Embodiment>
FIG. 19 is an explanatory diagram showing a schematic configuration of the heat transport system 100B according to the third embodiment. The heat transport system 100B of the present embodiment differs from the heat transport system 100 of the first embodiment mainly in that it includes a pipe 70 branching from the pipe 69 and an electromagnetic valve 72 provided on the pipe 70. .. The solenoid valve 72 is electrically connected to the control unit 80 and is controlled by the control unit 80. Since the proportional valve 48 has a large pressure loss, the pipe 70 is provided as a bypass flow path that does not pass through the proportional valve 48, and the heat transport fluid flows through the pipe 70 instead of the pipe 69 in the steady mode and the concentration increase mode. By controlling by the control unit 80 so as to do so, the pressure loss can be suppressed and the energy loss can be suppressed.

<Fourth Embodiment>
FIG. 20 is an explanatory diagram showing a schematic configuration of the heat transport system 100C according to the fourth embodiment. The heat transport system 100C of the present embodiment differs from the heat transport system 100 of the first embodiment mainly in that it does not include an ejector 43, a pipe 69, and a proportional valve 48, a vacuum pump 52, and an exhaust tank 53. Is a point to be provided. As the vacuum pump 52, for example, a diaphragm type vacuum pump can be used. The vacuum pump 52 in this embodiment is also referred to as a "steam suction unit".

In the heat transport system 100C of the present embodiment, the vacuum pump 52 is used instead of the aspirator 43 of the first embodiment. In this way, for example, the suction side pressure can be made smaller (for example, 1/10), and the permeation speed can be made larger (for example, 10 times). As a result, the amount of separated vapor by the separation membrane module 41 can be increased. However, when the suction side pressure is lower than the vapor pressure of water, water in addition to ethanol may also permeate the separation membrane, and the selectivity by the separation membrane module 41 may decrease, so that the selectivity can be appropriately maintained. It is preferable to adjust the pressure to the suction side.

<Modified example of this embodiment>
The present invention is not limited to the above-described embodiment, and can be implemented in various aspects without departing from the gist thereof. For example, the following modifications are also possible.

-In the above embodiment, the concentration adjusting unit 40 may not include the separation membrane module 41 and may have a different configuration for adjusting the concentration of the antifreeze liquid in the heat transport fluid. For example, the antifreeze concentration in the heat transport fluid may be adjusted by utilizing vapor-liquid equilibrium. Even in this way, the antifreeze concentration can be adjusted according to the temperature of the heat transport fluid.

-In the above embodiment, the configuration may not include the second tank 42. That is, the structure may be such that the separated antifreeze liquid is not stored. When the second tank 42 is not provided, for example, the antifreeze concentration of the heat transport fluid can be increased by providing a tank in which the antifreeze liquid is stored in advance.

-In the above embodiment, the second tank 42 may not be configured to be coolable. Even in this way, the antifreeze fluid (including vapor and liquid) separated by the separation membrane module 41 is stored and can be reused.

-In the first embodiment, the control unit 80 may control the concentration adjustment unit 40 regardless of the outside air temperature. For example, in step S104 shown in FIG. 5, the process may proceed to step S106 from April to November and to step S110 from December to March. Further, the concentration adjusting unit 40 may be controlled only according to the temperature of the heat transport fluid regardless of the outside air temperature. Even in this way, the antifreeze concentration in the heat transport fluid can be appropriately adjusted.

-In the first embodiment, the control unit 80 may be configured not to perform the concentration increase mode processing. For example, in winter, the user may manually return the antifreeze liquid stored in the second tank 42 to the first tank 30.

-In the above embodiment, the aspirator 43 and the diaphragm type vacuum pump 52 have been exemplified as the vapor suction unit, but the present invention is not limited thereto. For example, other vacuum pumps such as wet pumps using oil or liquid can be used.

-The antifreeze solution is not limited to the above embodiment. For example, other alcohols such as methanol, ethylene glycol and glycerin may be used, or fluorine-based alcohols may be used. However, it is preferable to use an alcohol having a low viscosity such as methanol and ethanol because the fluidity of the heat transport fluid can be ensured. For example, when ethylene glycol is used as the antifreeze in the first embodiment, the vapor pressure of ethylene glycol is smaller than the vapor pressure at the same temperature. Therefore, when the concentration of the antifreeze is increased, the boiling point of the heat transport fluid rises and the heat transport fluid Dryout can be suppressed.

The heat source, the first heat exchanger, and the second heat exchanger are not limited to the above embodiments. The first heat exchanger may dissipate the heat of the heat source using the heat transport fluid, and the second heat exchanger may dissipate the heat transport fluid absorbed by the first heat exchanger.

The first temperature threshold Th1 and the second temperature threshold Th2 are not limited to the above embodiments. It can be appropriately set according to the type of antifreeze liquid, the composition of the heat transport fluid, and the like.

-In the first embodiment, an example is shown in which the antifreeze liquid adjusting process is terminated when the liquid level of the second tank 42 reaches the liquid level threshold Th3 (FIG. 5), but the liquid level threshold Th3 is not limited to the above embodiment. For example, the liquid level threshold Th3 is set to a value close to 0, for example, an arbitrary value larger than 0 and 10 or less, and in step S112, the control unit 80 determines whether the liquid level of the second tank 42 is the liquid level threshold Th3 or less. May be determined. Further, the liquid level meter 93 may not be provided, and step S110 may be performed regardless of the amount of antifreeze liquid in the second tank 42.

Although the example in which the fluid temperature measuring unit 91 is provided on the pipe 61 is shown in the first embodiment, it may be provided in the first heat exchanger 10 as a heat receiving unit. That is, the control unit 80 may control the concentration adjusting unit 40 according to the temperature of the heat receiving unit.

Although the present embodiment has been described above based on the embodiments and modifications, the embodiments of the above-described embodiments are for facilitating the understanding of the present embodiment, and do not limit the present embodiment. This aspect may be modified or improved without departing from its spirit and claims, and this aspect includes its equivalents. In addition, if the technical feature is not described as essential in the present specification, it may be deleted as appropriate.

10 ... 1st heat exchanger 20 ... 2nd heat exchanger 30 ... 1st tank 40 ... Concentration adjustment unit 41 ... Separation membrane module 42 ... 2nd tank 43 ... Aspirator 44-47, 72 ... Electromagnetic valve 48 ... Proportional valve 50 ... Pump 52 ... Vacuum pump 53 ... Exhaust tank 61-70 ... Piping 80 ... Control unit 91 ... Fluid temperature measurement unit 92 ... Outside temperature measurement unit 93 ... Liquid level meter 94 ... Concentration measurement unit 100, 100A, 100B, 100C ... Heat Transport system 411 ... Housing 412 ... Separation membrane 413 ... Entrance 414 ... 1st exit 415 ... 2nd exit

Claims (12)

A heat transport system that uses a heat transport fluid consisting of an aqueous solution containing antifreeze.
A first heat exchanger that dissipates heat from a heat source using the heat transport fluid,
A second heat exchanger, which is arranged downstream of the first heat exchanger and dissipates heat from the heat transport fluid that has passed through the first heat exchanger.
A pump that sends the heat transport fluid and
A pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid, and
A fluid temperature measuring unit that measures the temperature of the heat transport fluid,
A concentration adjusting unit arranged on the pipe and adjusting the concentration of the antifreeze in the heat transport fluid,
A control unit that controls the concentration adjusting unit according to the temperature of the heat transport fluid measured by the fluid temperature measuring unit.
To prepare
Heat transport system. A heat transport system that uses a heat transport fluid consisting of an aqueous solution containing antifreeze.
A first heat exchanger that dissipates heat from a heat source using the heat transport fluid,
A second heat exchanger, which is arranged downstream of the first heat exchanger and dissipates heat from the heat transport fluid that has passed through the first heat exchanger.
A pump that sends the heat transport fluid and
A pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid, and
An antifreeze concentration measuring unit that measures the concentration of the antifreeze in the heat transport fluid,
A concentration adjusting unit arranged on the pipe and adjusting the concentration of the antifreeze in the heat transport fluid,
A control unit that controls the concentration adjusting unit according to the concentration of the antifreeze measured by the antifreeze concentration measuring unit.
To prepare
Heat transport system. The heat transport system according to any one of claims 1 and 2.
The concentration adjusting unit
A separation membrane module capable of selectively separating the antifreeze solution and
A vapor suction unit that sucks vapor from the separation membrane module,
To prepare
Heat transport system. The heat transport system according to any one of claims 1 to 3.
further,
It is equipped with an outside air temperature measuring unit that measures the outside air temperature of the heat transport system.
The control unit
further,
The concentration adjusting unit is controlled according to the outside air temperature measured value by the outside air temperature measuring unit.
Heat transport system. The heat transport system according to any one of claims 3 and 4.
The concentration adjusting unit
further,
A storage unit capable of storing the antifreeze liquid separated by the separation membrane module is provided.
Heat transport system. The heat transport system according to claim 5.
In the concentration adjusting unit, the storage unit is configured to be coolable.
Heat transport system. The heat transport system according to claim 6.
The control unit
When the outside air temperature measurement value by the outside air temperature measuring unit is equal to or less than the first temperature threshold value, the antifreeze liquid stored in the storage unit is added to the heat transport fluid.
Heat transport system. The heat transport system according to claim 7.
The concentration adjusting unit
further,
A liquid level meter for measuring the liquid level of the storage unit is provided.
The control unit
When the outside air temperature measurement value by the outside air temperature measurement unit is equal to or less than the first temperature threshold value and the liquid level measurement value by the liquid level gauge is equal to or less than the liquid level threshold value, the antifreeze liquid stored in the storage unit is used. , Add to the heat transport fluid,
Heat transport system. In the heat transport system according to any one of claims 1 to 8.
The vapor pressure of the antifreeze liquid contained in the heat transport fluid is larger than the vapor pressure at the same temperature.
Heat transport system. In the heat transport system according to any one of claims 1 to 9.
The antifreeze is alcohol.
Heat transport system. A control method for a heat transport system that uses a heat transport fluid consisting of an aqueous solution containing antifreeze.
The heat transport system includes a first heat exchanger that dissipates heat from a heat source using the heat transport fluid.
A second heat exchanger, which is arranged downstream of the first heat exchanger and dissipates heat from the heat transport fluid that has passed through the first heat exchanger.
A pump that sends the heat transport fluid and
A pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid, and
A fluid temperature measuring unit that measures the temperature of the heat transport fluid,
A concentration adjusting unit arranged on the pipe and adjusting the concentration of the antifreeze in the heat transport fluid,
Control unit and
With
The control unit
The concentration adjusting unit is controlled according to the temperature of the heat transport fluid measured by the fluid temperature measuring unit.
How to control the heat transport system. A control method for a heat transport system that uses a heat transport fluid consisting of an aqueous solution containing antifreeze.
The heat transport system includes a first heat exchanger that dissipates heat from a heat source using the heat transport fluid.
A second heat exchanger, which is arranged downstream of the first heat exchanger and dissipates heat from the heat transport fluid that has passed through the first heat exchanger.
A pump that sends the heat transport fluid and
A pipe that connects the first heat exchanger, the second heat exchanger, and the pump to circulate the heat transport fluid, and
An antifreeze concentration measuring unit that measures the concentration of the antifreeze in the heat transport fluid,
A concentration adjusting unit arranged on the pipe and adjusting the concentration of the antifreeze in the heat transport fluid,
Control unit and
With
The control unit
The concentration adjusting unit is controlled according to the concentration of the antifreeze liquid measured by the antifreeze concentration measuring unit.
How to control the heat transport system.

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