JP2018044733A - Circulation type cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a temperature change of cooling liquid caused by a thermal load of liquid supplied from outside.SOLUTION: A supply system 6 supplies liquid into a liquid tank 2. A sending-out system 7 sends out the liquid stored in the liquid tank 2 to outside. A liquid circulation system 4 circulates liquid stored in the liquid tank 2. A cooler 3 cools the liquid circulating in the liquid circulation system 4 through heat exchange with a refrigerant. A temperature sensor 4b detects a sending-out temperature of the liquid sent out by the sending-out system 7. A control section 9 performs control so that the sending-out temperature of the liquid sent out by the sending-out system 7 falls within a constant temperature range by controlling an opening of a supply valve 6a on the basis of the sending-out temperature detected by the temperature sensor 4b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a circulating cooler that cools while circulating a liquid, and more particularly to control of a supply valve that adjusts the amount of liquid supplied from the outside.

  Conventionally, a circulation type cooler that cools while circulating a liquid is known. For example, Patent Literature 1 discloses an ice storage type cold water supply device that supplies water into an aquarium from an external water supply source and cools the water in the aquarium with a circulation pump while circulating the water in the aquarium. Has been. In this cold water supply apparatus, water supply is performed by opening and closing a water supply valve (supply valve) according to the water level in the water tank. That is, when the water level becomes lower than a predetermined level, the water supply valve is opened to execute water supply, and when the water level becomes equal to or higher than the predetermined level, the water supply valve is closed to stop water supply.

JP-A-8-121931

  In a conventional circulation type cooler, the temperature of the cooling liquid delivered from the delivery system is controlled to be within a certain temperature range by operating / stopping a compressor provided in the refrigerant circulation system. . The supply valve provided in the liquid supply system is opened and closed according to the liquid level in the liquid tank that stores the liquid. When supplying the liquid, the liquid is always supplied at a constant supply amount. Here, the liquid at normal temperature supplied from the outside becomes a heat load for the cooler. Therefore, if a large amount of heat load exceeding the cooling capacity of the cooler is applied, a sudden temperature change of the cooling liquid will be caused. .

  This invention is made | formed in view of this situation, The objective is to relieve the temperature change of the cooling liquid resulting from the thermal load of the liquid supplied from the outside.

  In order to solve this problem, the present invention has a liquid tank, a supply system, a supply valve, a delivery system, a circulation system, a cooler, and a control unit, and a circulation system that cools while circulating a liquid. A cooling machine is provided. Liquid is stored in the liquid tank. The supply system supplies a liquid into the liquid tank. The supply valve is provided in the supply system. The delivery system delivers the liquid stored in the liquid tank to the outside. The circulation system circulates the liquid stored in the liquid tank. The cooler cools the liquid circulating in the circulation system by exchanging heat with the refrigerant. The controller controls the opening temperature of the supply valve so as to keep the delivery temperature of the liquid delivered from the delivery system within a certain temperature range.

  Here, in the present invention, when the delivery temperature is the first temperature, the control unit sets the opening degree of the supply valve to the first opening degree, and the delivery temperature is higher than the first temperature. In the case of temperature, it is preferable to set the opening of the supply valve to a second opening that is smaller than the first opening. In this case, the control unit continuously decreases the opening of the supply valve from the first opening to the second opening as the delivery temperature rises from the first temperature to the second temperature. Also good. Alternatively, the control unit maintains the supply valve in a fully closed state until the delivery temperature decreases to the first temperature, and until the delivery temperature rises to the second temperature. The supply valve may be kept fully open.

  In the present invention, the control unit may perform feedback control based on a deviation between a delivery temperature and a set temperature as control of the opening degree of the supply valve. This feedback control includes a proportional operation for changing the opening of the supply valve in proportion to the deviation between the temperature of the delivery body and the set temperature, an integration operation for changing the opening of the supply valve based on the integral value of the deviation, PID control including differential operation for changing the opening of the supply valve based on the differential value of the deviation is preferable.

  Furthermore, in the present invention, a temperature sensor for detecting the delivery temperature of the liquid delivered from the delivery system may be further provided. In this case, the said control part controls the opening degree of a supply valve based on the sending temperature detected by the temperature sensor. Further, the control unit is based on at least one of the operating state of the compressor that liquefies the refrigerant at high pressure, the temperature of the liquid flowing through the supply system, and the pressure of the liquid flowing through the supply system, in addition to the delivery temperature. You may control the opening degree of a supply valve.

  According to the present invention, by controlling the opening degree of the supply valve, the amount of liquid supplied from the outside that becomes a heat load for the cooler is dynamically adjusted. By adjusting the amount of heat load applied from the outside itself so that the cooling liquid delivery temperature is within a certain temperature range, the temperature change of the cooling liquid due to the thermal load is mitigated, and the delivery temperature Can be accurately controlled.

Overall configuration diagram of the circulating cooler Block diagram of control system The figure which shows the characteristic of the delivery temperature and valve opening degree which concern on 1st Embodiment The figure which shows the characteristic of the delivery temperature and valve opening degree concerning 2nd Embodiment The figure which shows the characteristic of the delivery temperature and valve opening degree concerning 3rd Embodiment Explanatory drawing of valve control concerning a 4th embodiment The figure which shows the time-dependent change of the sending temperature and valve opening degree in PID control Overall configuration diagram of a circulating cooler according to a fifth embodiment Block diagram of valve control according to the fifth embodiment

(First embodiment)
FIG. 1 is a schematic overall configuration diagram of a circulation type chiller according to the present embodiment. The circulation type cooler 1 cools while circulating a liquid to be cooled. As liquid to be cooled, various liquids with fluidity are available, including cold water, drinking water, salt water, beverages (juice, beer, etc.), brine, etc. used in various fields such as food, fisheries, and chemistry. Can be used.

  The circulation type cooler 1 is mainly composed of a liquid tank 2, a cooler 3, a liquid circulation system 4, a refrigerant circulation system 5, a supply system 6, and a delivery system 7. Liquid is stored in the liquid tank 2, and a cooler 3 for cooling the liquid by heat exchange with the refrigerant is installed on the bottom surface thereof. The liquid circulation system 4 is connected to the liquid inlet / outlet of the cooler 3, and the liquid stored in the liquid tank 2 is pumped out by the pump 4 a and supplied to the cooler 3, and the liquid cooled by the cooler 3 is used. Is discharged into the liquid tank 2. The supply system 6 supplies liquid (usually normal temperature) into the liquid tank 2 from the outside.

  The temperature sensor 4 b detects the temperature of the cooling liquid sent to the outside via the delivery system 4, that is, the temperature of the liquid cooled by the circulating cooler 1 (hereinafter referred to as “delivery temperature T”). . In the configuration of FIG. 1, the flow path downstream of the liquid tank 2 and upstream of the pump 4a in the liquid circulation system 4 is shared as a part of the delivery system 7, so that a temperature sensor 4b is provided in this part. Yes. About the installation position of the temperature sensor 4b, as long as it can be regarded as the substantially same temperature as the cooling liquid sent out from the sending system 7, or the place which can specify the temperature of a cooling liquid, you may install in any place. . In the configuration of FIG. 1, the liquid tank 2, a part of the liquid circulation system 4 (downstream of the pump 4 a and upstream of the cooler 3), and the delivery system 7 are all at substantially the same temperature. A temperature sensor 4b may be installed. In this specification, the “delivery temperature” means a temperature that can be regarded as substantially the same as the temperature of the cooling liquid delivered from the delivery system 4 or the temperature of the cooling liquid because it has a correlation with the temperature of the cooling liquid. It is used as a concept that includes a wide range of temperatures that can be specified and estimated.

  The refrigerant circulation system 5 is connected to the refrigerant inlet / outlet in the cooler 1, and includes a refrigerator 5a including a compressor and a condenser, and an expansion valve 5b. During operation of the refrigerator 5a, the refrigerant circulates in the refrigerant circulation system 5 while repeating the refrigeration cycle. That is, the refrigerant supplied to the refrigerator 5a is compressed by the compressor to become a high-temperature high-pressure gas, condensed (liquefied) by the condenser, and then discharged from the refrigerator 5a as a high-pressure liquid. The high-pressure liquefied refrigerant is depressurized by the expansion valve 5 b and is supplied to the cooler 3 as a low-pressure liquid. The low-pressure liquefied refrigerant is evaporated (vaporized) by heat exchange with the liquid in the cooler 3, and is returned to the refrigerator 5a as low-pressure gas. In such a refrigerant refrigeration cycle, the liquid flowing in the cooler 3 is cooled by the heat of vaporization when the low-pressure liquefied refrigerant changes into a gas. In the refrigerant circulation system 5, an evaporating pressure sensor 5c for detecting the evaporating pressure of the refrigerant (gas suction pressure at the inlet of the refrigerating machine 5a) is provided between the cooler 3 and the refrigerating machine 5a.

  The level sensor 8 detects the liquid level (the height of the liquid surface) of the liquid stored in the liquid tank 2. When the level sensor 8 detects a decrease in the liquid level from the full liquid state, the liquid is supplied into the liquid tank 2 from an external supply source via the electric supply valve 6 a provided in the supply system 6.・ Replenished. Further, the delivery system 7 directly sends the liquid stored in the liquid tank 2 to the outside without going through the cooler 3. In the present embodiment, the delivery system 7 has one end attached to the upstream side of the cooler 3 in the liquid circulation system 4, specifically, the downstream side of the pump 4a and the upstream side of the cooler 3, and the pump 4a The liquid pumped out by is sent out to the outside. The delivery system 7 is provided with a delivery valve 7a.

  FIG. 2 is a block diagram of a control system in the circulating chiller 1. The overall operation control in the circulating cooler 1 is performed by the control unit 9. A temperature sensor 4b, an evaporation pressure sensor 5c, and a level sensor 8 are connected to the control unit 9 as sensors for detecting the state of the circulating cooler 1. The controller 9 controls the pump 4a, the refrigerator 5a, and the supply valve 6a based on sensor signals from these sensors 4b, 5c, and 8.

  Next, the operation of the circulating cooler 1 will be described. The operation mode of the circulating cooler 1 includes an initial operation and a steady operation. In the initial operation prior to the steady operation, the circulating cooler 1 is started by turning on the power supply with the delivery valve 7a fully closed, and the liquid cooled to some extent is stored in the liquid tank 2. Specifically, first, in order to quickly supply the liquid into the liquid tank 2, the opening degree θ of the supply valve 6 a is forcibly set to fully open (100%), and the maximum supply capacity of the supply system 6. Then, the liquid is supplied. Next, when the level sensor 8 detects that the liquid level in the storage tank 2 has reached a predetermined value, the operation of the pump 4a starts, whereby the liquid starts flowing through the liquid circulation system 4. Thereafter, the operation of the pump 4a is continued regardless of the operation state (operation / stop) of the cooler 5a, including during steady operation.

  Thereafter, the refrigerator 5a starts operating slightly after the start of operation of the pump 4a. As a result, heat exchange with the refrigerant in the cooler 3 occurs, and cooling of the liquid flowing through the liquid circulation system 4 is started. Here, the operating frequency of the compressor included in the refrigerator 5a is variably controlled based on the evaporation pressure of the refrigerant detected by the evaporation pressure sensor 5c so that the evaporation pressure becomes constant (for example, 80-30 Hz). Thereby, the stop time of the refrigerator 5a can be set longer, and the operation / stop switching frequency (so-called hunting) of the refrigerator 5a is suppressed, so that the operation efficiency is improved (at the time of low frequency). The refrigerator 5a may always be operated at a constant frequency.

  When the level sensor 8 detects that the liquid level in the storage tank 2 has reached a predetermined value, the supply valve 6a is fully closed (0%), and the supply of liquid from the supply system 6 is stopped. To do. Thereby, the liquid is cooled by the cooler 3, and the temperature of the cooling liquid gradually decreases.

  When the cooling of the liquid proceeds and the delivery temperature T detected by the temperature sensor 4b reaches a predetermined value, the operation mode of the circulating cooler 1 shifts from the initial operation to the steady operation. As a result, the delivery valve 7a in the fully closed state is fully opened, and delivery of the cooling liquid from the delivery system 7 is started. During steady operation, the temperature of the cooling liquid is controlled to be within a certain temperature range by adjusting the opening degree θ of the supply valve 6a in real time.

  FIG. 3 is a diagram illustrating characteristics of the delivery temperature T and the valve opening degree θ according to the first embodiment. During steady operation, the delivery temperature T is set in advance as a transition between two points A (T1, θ1) and B (T2, θ2). Here, T1 is a delivery lower limit temperature, T2 is a delivery upper limit temperature, θ1 is a maximum supply opening, and θ2 is a minimum supply opening. When the delivery temperature T is the delivery lower limit temperature T1, the opening θ of the supply valve 6a is set to the maximum supply opening θ1. When the delivery temperature T is the delivery upper limit temperature T2 (> T1), the opening degree θ of the supply valve 6a is set to the minimum supply opening degree θ2 (<θ1). An intermediate value between the two points A and B is calculated by linear interpolation (proportional control) based on the points A and B. Thereby, in this embodiment, the characteristics of the delivery temperature T and the valve opening degree θ are linear and continuous characteristics. The two points A and B are appropriately determined through experiments and simulations so that the heat load of the liquid supplied from the outside and the cooling capacity of the cooler 3 are balanced. In addition, you may change two points A and B according to the field environment of the circulation type cooler 1, and the intended purpose. The controller 9 calculates the valve opening θ (output) from the delivery temperature T (input) according to the illustrated characteristics, and variably controls the opening θ of the supply valve 6a.

  In addition, as a method for specifying the valve opening degree θ (output) based on the delivery temperature T (input), in addition to the linear interpolation based on the two points A and B described above, the delivery temperature T is set to a linear function prepared in advance. An arithmetic method for calculating the valve opening θ by substitution, a table reference method for referring to a table in which the relationship between the delivery temperature T and the valve opening θ is described, or the like may be used.

  In the normal operation, when the supply of the normal temperature liquid from the supply system 6 and the supply of the cooling liquid from the delivery system 7 are performed in parallel, the normal temperature liquid becomes a heat load for the cooler 3. When a heat load exceeding the cooling capacity of 3 is applied, the cooling liquid rises. However, in this embodiment, when the temperature sensor 4b detects an increase in the delivery temperature T, the opening degree θ of the supply valve 6a is controlled to be small. As a result, the thermal load due to the liquid supply is reduced to match the cooling capacity of the cooler 3, and the rate of increase of the delivery temperature T is reduced. On the other hand, when the temperature sensor 4b detects a decrease in the delivery temperature T, the opening degree θ of the supply valve 6a is controlled to increase. As a result, the thermal load due to the liquid supply increases so as to match the cooling capacity of the cooler 3, and the rate of decrease of the delivery temperature T decreases. By going through such a process, the heat load is dynamically adjusted to an amount commensurate with the cooling capacity of the cooler 3, and the delivery temperature T falls within a certain temperature range.

  As described above, according to the present embodiment, the supply amount of the liquid serving as a heat load for the cooler 3 is dynamically adjusted by controlling the opening degree θ of the supply valve 6 a provided in the supply system 6. . That is, as the delivery temperature T increases from T1 to T2, the opening θ of the supply valve 6a decreases continuously and linearly from θ1 to θ2. Conversely, as the delivery temperature T decreases from T2 to T1, the opening θ of the supply valve 6a increases continuously and linearly from θ2 to θ1. In this way, by controlling the amount of heat load applied from the outside and controlling the delivery temperature T within a certain temperature range, the temperature change of the cooling liquid due to the heat load can be mitigated. The temperature of the cooling liquid can be accurately controlled.

(Second Embodiment)
FIG. 4 is a diagram showing characteristics of the delivery temperature T and the valve opening degree θ according to the second embodiment. As in the first embodiment, the delivery temperature T during steady operation is set in advance so as to transition between two points A (T1, θ1) and B (T2, θ2). The characteristic between the two points A and B is a continuous characteristic in a curved shape (for example, a quadratic curve). The intermediate value between the points A and B may be calculated based on a quadratic function passing through the two points A and B, or the table reference method described above may be used. The controller 9 calculates the valve opening θ (output) from the delivery temperature T (input) according to the illustrated characteristics, and variably controls the opening θ of the supply valve 6a. Since the other points are the same as in the first embodiment, description thereof is omitted here.

  According to the present embodiment, as in the first embodiment, the temperature change of the cooling liquid due to the thermal load can be alleviated, and the temperature of the cooling liquid can be controlled with high accuracy. In particular, according to the present embodiment, the intermediate value between the two points A and B can be set with a higher degree of freedom than in the first embodiment.

(Third embodiment)
FIG. 5 is a diagram showing characteristics of the delivery temperature T and the valve opening degree θ according to the third embodiment. In the present embodiment, the valve opening degree θ is switched between fully open (100%) and fully closed (0%). Assuming that the temperature range in the steady operation is T1 to T2, the opening θ of the supply valve 6a is set to 0% until the delivery temperature T reaches the lower limit value T1 (during temperature decrease). As a result, the delivery temperature T decreases while the supply of the liquid from the supply system 6 is stopped. On the other hand, the opening degree θ of the supply valve 6a is set to 1000% until the delivery temperature T reaches the upper limit value T2 (during temperature rise). As a result, the delivery temperature T rises while the supply of liquid from the supply system 6 is being executed.

  According to the present embodiment, as in the above-described embodiments, the temperature change of the cooling liquid due to the thermal load can be alleviated, and the temperature of the cooling liquid can be accurately controlled. In particular, according to the present embodiment, the supply valve 6a is maintained in a different state during the temperature decrease from the upper limit value T2 to the lower limit value T1 and during the temperature increase from the lower limit value T1 to the upper limit value T2. It is possible to suppress the frequent switching (so-called hunting) of the supply valve 6a.

(Fourth embodiment)
In each of the embodiments described above, the method of setting the valve opening degree θ using the delivery temperature T as an input has been described. However, in this embodiment, the deviation between a predetermined set temperature (target value) and the delivery temperature T (actual value). A method for setting the valve opening θ by feedback control based on the above will be described. As an example of such feedback control, PID control (Proportional-Integral-Differential Controller) can be used.

  FIG. 6 is an explanatory diagram of valve control according to the present embodiment. The valve opening degree θ at a certain timing t1 is calculated by the following formula obtained by adding and synthesizing the proportional action P, the integral action I, and the differential action D. In the proportional operation P, the valve opening θ is changed by a correction amount proportional to the current deviation e between the set temperature (target value) and the delivery temperature T (actual value). In the integral operation I, the valve opening degree θ is changed by a correction amount proportional to the integral value of the past deviation e. In the differential operation D, the valve opening degree θ is changed based on the differential value (temperature gradient) of the deviation e.

  FIG. 7 is a diagram showing changes over time in the delivery temperature T and the valve opening degree θ in the PID control. When the delivery temperature T is decreasing, the valve opening θ is controlled so as to increase. As a result, the thermal load due to the liquid supply increases so as to match the cooling capacity of the cooler 3, and the rate of decrease in the delivery temperature T decreases. On the other hand, when the delivery temperature T is rising, the valve opening degree θ is controlled so as to be small following this. As a result, the thermal load due to the liquid supply is reduced to match the cooling capacity of the cooler 3, and the rate of increase of the delivery temperature T is reduced.

  According to the present embodiment, as in the above-described embodiment, the temperature change of the cooling liquid due to the thermal load can be reduced, and the temperature of the cooling liquid can be controlled with high accuracy. In particular, according to the present embodiment, it is possible to control the temperature of the cooling liquid with higher accuracy by performing PID control which is a kind of feedback control.

(Fifth embodiment)
FIG. 8 is an overall configuration diagram of the circulating chiller 1 according to the fifth embodiment. The difference from the configuration of FIG. 1 is that a temperature sensor 6b and a pressure sensor 6c are added to the supply system 6. Otherwise, the configuration is the same as that of FIG. The temperature sensor 6 b detects the supply temperature of the liquid supplied from the supply system 6. The pressure sensor 6 c detects the supply pressure of the liquid supplied from the supply system 6.

  FIG. 9 is a block diagram of valve control according to the present embodiment. In the present embodiment, in addition to the sensor value of the temperature sensor 4b described above, based on at least one of the sensor value of the temperature sensor 6b, the sensor value of the pressure sensor 6c, and the operating state of the compressor 5a that liquefies the refrigerant at high pressure. Thus, the opening θ of the supply valve 6a is controlled. The higher the temperature detected by the temperature sensor 6b, that is, the temperature of the liquid supplied from the supply system 6, the greater the heat load on the cooler 3. Therefore, if the valve opening θ is controlled in consideration of this temperature, the temperature of the cooling liquid can be controlled more accurately. Further, as the temperature detected by the pressure sensor 6c, that is, the pressure of the liquid supplied from the supply system 6 increases, the amount of liquid supplied per unit time increases, so the heat load on the cooler 3 increases. . Therefore, if the valve opening degree θ is controlled in consideration of this pressure, the temperature of the cooling liquid can be controlled more accurately. Furthermore, as the operating state of the compressor 5a, for example, when the compressor 5a is stopped or operating at a low frequency, the cooling capacity of the cooler 3 is reduced. Therefore, if the valve opening degree θ is controlled in consideration of this operation state, the temperature of the cooling liquid can be controlled more accurately.

DESCRIPTION OF SYMBOLS 1 Circulation type cooler 2 Liquid tank 3 Cooler 4 Liquid circulation system 4a Pump 4b Temperature sensor 5 Refrigerant circulation system 5a Refrigeration machine 5b Expansion valve 5c Evaporation pressure sensor 6 Supply system 6a Supply valve 6b Temperature sensor 6c Pressure sensor 7 Delivery system 7a Delivery valve 8 Level sensor 9 Control unit

In order to solve this problem, the present invention includes a liquid tank, a supply system, a supply valve, a delivery system, a delivery valve, a circulation system, a cooler, a temperature sensor, and a control unit. A circulation type cooler that cools while circulating a liquid is provided. Liquid is stored in the liquid tank. The supply system supplies liquid into the liquid tank from the outside . The supply valve is provided in the supply system. The delivery system delivers the liquid stored in the liquid tank to the outside. The delivery valve is provided in the delivery system. The circulation system circulates the liquid by pumping out the liquid stored in the liquid tank and discharging the pumped liquid into the liquid tank . The cooler cools the liquid circulating in the circulation system by exchanging heat with the refrigerant. The temperature sensor detects the delivery temperature of the liquid delivered from the delivery system. The control unit controls the opening temperature of the supply valve based on the delivery temperature detected by the temperature sensor so that the delivery temperature of the liquid delivered from the delivery system falls within a certain temperature range.

  Furthermore, in the present invention, the control unit includes at least one of the operating state of the compressor that liquefies the refrigerant at high pressure, the temperature of the liquid flowing through the supply system, and the pressure of the liquid flowing through the supply system, in addition to the delivery temperature. The opening degree of the supply valve may be controlled based on the above.

Claims (8)

In a circulating cooler that cools while circulating liquid,
A liquid tank in which the liquid is stored;
A supply system for supplying liquid into the liquid tank;
A supply valve provided in the supply system;
A delivery system for delivering the liquid stored in the liquid tank to the outside;
A circulation system for circulating the liquid stored in the liquid tank;
A cooler for cooling the liquid circulating in the circulation system by heat exchange with the refrigerant;
And a controller that controls a delivery temperature of the liquid delivered from the delivery system to be within a certain temperature range by controlling an opening degree of the supply valve.   When the delivery temperature is the first temperature, the control unit sets the opening degree of the supply valve to the first opening degree, and the delivery temperature is a second temperature higher than the first temperature. The circulating cooler according to claim 1, wherein the opening degree of the supply valve is set to a second opening degree smaller than the first opening degree.   The controller continuously increases the opening of the supply valve from the first opening to the second opening as the delivery temperature rises from the first temperature to the second temperature. The circulating cooler according to claim 2, wherein the circulating cooler is reduced.   The control unit maintains the supply valve in a fully-closed state until the delivery temperature drops to the first temperature, and supplies the supply valve until the delivery temperature rises to the second temperature. The circulating cooler according to claim 2, wherein the valve is maintained in a fully open state.   The circulating cooler according to claim 1, wherein the control unit performs feedback control based on a deviation between the delivery temperature and a set temperature as control of the opening degree of the supply valve.   The feedback control includes a proportional operation for changing the opening of the supply valve in proportion to the deviation, an integration operation for changing the opening of the supply valve based on an integral value of the deviation, and a differential value of the deviation. The circulating cooler according to claim 5, wherein the PID control includes a differential operation for changing an opening degree of the supply valve based on the pressure. A temperature sensor for detecting a delivery temperature of the liquid delivered from the delivery system;
The circulating cooler according to any one of claims 1 to 6, wherein the control unit controls an opening degree of the supply valve based on the delivery temperature detected by the temperature sensor. The controller controls the opening of the supply valve based on at least one of an operating state of a compressor for liquefying the refrigerant, a temperature of a liquid flowing through the supply system, and a pressure of a liquid flowing through the supply system The circulation type chiller according to claim 7, wherein:

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