JP5459578B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device using free cooling that cools the water to be cooled returning from the device to be cooled and then sends the water to be cooled again to the device, and particularly relates to a cooling device that improves the temperature accuracy of the water to be cooled that is sent out. Is.

  Conventionally, there is one disclosed in Patent Document 1 as a cooling device that cools water to be cooled to medium to low temperatures with minimum energy. In this cooling tower in which a fluid to be cooled is passed through a heat transfer pipe and the heat transfer pipe is cooled by a fan, a radiator provided with fins in the heat transfer pipe through which the fluid to be cooled passes is provided outside the cooling tower. Provided with a compressor, a condenser, an expansion valve, an evaporator, and a chiller that repeatedly compresses and expands the refrigerant. The condenser is provided in a condenser with a fin provided with fins on the heat transfer pipe, and is disposed inside the radiator. The cooling device is disposed in the cooling tower, blows air to the radiator and the condenser by the fan of the cooling tower, cools the cooled fluid returning from the equipment to be cooled from the radiator through the evaporator of the chiller, and sends it to the equipment to be cooled. And when the temperature of the thermometer attached to the outlet pipe became higher than the set temperature, this cooling device first increased the air flow rate of the fan, and the temperature of the thermometer was still higher than the set temperature range. Occasionally, the number of operating chiller compressors is controlled. When the temperature of the thermometer falls below the set temperature range, the number of compressors operating is first stopped sequentially, and when the temperature of the thermometer falls below the set temperature range, Control is performed to reduce the air flow rate (see paragraph 0015).

  In Patent Document 2, a tank is partitioned into a plurality of water chambers by partition walls, and a valve for controlling the water flow between adjacent water chambers is provided for each water chamber, and the water chamber is always in communication with a discharge port. Further, there is described a radiator in which a thermo element that operates according to a water temperature is provided, a movable part thereof is coupled to a valve, and the number and flow rate of water chambers connected to a discharge port are changed by opening and closing the valve.

  In Patent Document 3, in a heat exchanger such as a refrigerator, a temperature detection point is provided at an intermediate temperature point in a flow path of a medium to be cooled in the heat exchanger, and a deviation between the temperature at the temperature detection point and its set temperature is set. A temperature adjusting device for adjusting the amount of cooling heat based on this is described, and it is said that the outlet temperature can be kept constant regardless of the change in cooling capacity, and that stabilization and improvement in adjustment accuracy are achieved.

JP 2000-266447 A JP-A-2-308919 JP 58-68122 A

  By the way, for equipment that requires cooling water, like laser processing machines, in order to ensure thermal stability that affects processing accuracy and avoid degradation of processing quality, high cooling water accuracy with little temperature fluctuation, Cooling performance that can sufficiently follow relatively large load fluctuations due to workpiece material, plate thickness, machining speed, and machined surface roughness is required.

However, in the cooling device described in Patent Document 1, since the temperature control is performed by comparing the temperature of the temperature detector provided at the outlet of the water to be cooled with the set temperature, the compressor and fan are controlled by PID control. Even if it is variably controlled, a hunting phenomenon occurs, and there is a problem that the temperature accuracy of the cooling water supplied to equipment that requires the cooling water is not sufficiently stabilized.
Although the radiator described in Patent Document 2 can change the heat radiation area of the radiator according to the temperature load, the total area of the radiator must be large, and the heat radiation area can be changed only in units of water chambers. Therefore, it cannot be said that the temperature control of the cooling water is sufficient.

On the other hand, in the thing of patent document 3, although a temperature system is stabilized comparatively, when there is a big load fluctuation, in order to satisfy the cooling water precision (for example, ± 1 degrees C or less) demanded in recent years. It was not enough.
The present invention has been made in view of the above problems, and provides a cooling device that can stably supply highly accurate cooling water even when there is a large load fluctuation on the apparatus side that supplies the cooling water. The purpose is that.

The present invention provides a cooling water flow circuit to be supplied with a heat exchanger, constitutes a refrigerant water circuit including the heat exchanger, a radiator through which outside air can pass, and a circulation pump, and introduces outside air into the radiator. In the cooling device having a radiator fan, a temperature detector is provided on the inlet side of the water to be cooled in the heat exchanger, and the deviation between the temperature of the water to be cooled detected by the temperature detector and the required set temperature based on, have line flow control of the coolant water circuit, the rotational speed of the radiator fan is controlled by the inverter control, the rotational speed of the radiator fan, provided at the inlet side of the cooling water in the heat exchanger The cooling device is controlled based on a deviation between the temperature of the water to be cooled detected by the temperature detector and the required set temperature .

According to the above configuration, since the flow rate of the coolant water circuit is variably controlled based on the deviation between the temperature on the inlet side of the water to be cooled in the heat exchanger and the set temperature, it is large on the equipment side that supplies the cooling water. Even if the load fluctuates, accurate cooling water can be stably supplied.

  In the present invention, the circulation pump can be provided with an inverter control device to control the flow rate of the refrigerant water circuit.

In the present invention, performs an inverter capable of controlling the compressor on the downstream side of the heat exchanger, a condenser, an expansion valve, consists of a evaporator, the heat exchange between the refrigerant and the cooling water by the evaporator A chiller unit is provided, and the compressor is inverter controlled based on a deviation between the temperature of the cooling water detected by the temperature detector provided on the inlet side of the cooling water in the evaporator and the required set temperature. Can do.

  According to the cooling device of the present invention, the flow rate of the coolant water circuit is variably controlled based on the deviation between the temperature on the inlet side of the water to be cooled in the heat exchanger and the set temperature, so that the equipment that supplies the cooling water Even if there is a large load fluctuation on the side, accurate cooling water can be stably supplied.

<First embodiment>
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual schematic diagram of a first embodiment of the cooling device of the present invention, FIG. 2 is a main control flowchart of the first embodiment of the cooling device of the present invention, and FIG. 3 is a radiator constituting a part of the present invention. FIG. 4 is a conceptual diagram illustrating low temperature difference control in a radiator circuit, FIG. 5 is a flowchart of cooling control of a refrigeration circuit constituting a part of the present invention, and FIG. Fig. 7 is a conceptual diagram for explaining cooling control of a compressor constituting a part of Fig. 7, and Fig. 7 is a flowchart of control of on-off valves constituting a refrigeration circuit.

  As shown in FIG. 1, the cooling device 1 includes a compressor 2, a condenser 3, an electronic expansion valve 4, and an evaporator 5, a refrigeration circuit 10 in which a refrigerant circulates, and a control (not shown) for controlling them. Have the device. The compressor 2 is capable of inverter control of the operating frequency, and the frequency can be varied by an instruction signal from the control device. The condenser 3 is formed by bending a copper pipe or the like through which a refrigerant flows and is provided with a cooling fin, and has a condenser fan 31 so that outside air can pass therethrough. The electronic expansion valve 4 can adjust the opening degree of the valve by a pulse signal emitted from the control device. The evaporator 5 is made of stainless steel, for example, and exchanges heat with water to be cooled flowing from a device to be cooled (not shown) to a circulation circuit 91 that circulates via a main pump 90.

  A bypass circuit 21 connecting the outlet of the compressor 2 and the inlet of the evaporator 5 is provided, and an on-off valve 23 is provided in the middle of the bypass circuit 21, and a part of the high-pressure refrigerant discharged from the compressor 2 is supplied to the inlet of the evaporator 5. It can be introduced to the side.

  Further, a stainless steel heat exchanger 6 is provided between the evaporator 5 and the main pump 90, and a refrigerant water circuit 65 is formed by the radiator 61 and the circulation pump 63, and an antifreeze liquid is circulated as a refrigerant inside. Yes. The radiator 61 is provided with a radiator fan 67 so that outside air can pass therethrough.

  An inlet temperature detector 51 is provided on the inlet side of the water to be cooled in the heat exchanger 6 of the circulation circuit 91, and the outlet side of the water to be cooled in the heat exchanger 6 and the inlet side of the water to be cooled in the evaporator 5. An intermediate temperature detector 52 is provided between them, and an outlet temperature detector 53 is provided on the outlet side of the water to be cooled in the evaporator 5. An outlet pressure detector 11 that detects the pressure of the refrigerant is provided on the outlet side of the compressor 2 of the refrigerant circuit 10. Further, the cooling device 1 includes an outside air dry bulb temperature detector (not shown).

  The circulation circuit 91 may be provided with a water storage tank 93 and a deionizer 95 so that the conductivity of the water to be cooled is kept below a predetermined value. In particular, when the conductivity of the water to be cooled becomes a problem, the evaporator 5 and the heat exchanger 6 are preferably made of stainless steel as described above.

Next, the main operation of the cooling device 1 will be described in detail with reference to FIG.
As shown in the figure, first, the main pump 90 is started (S1: Step 1). Then, the water to be cooled in the circulation circuit 91 is circulated for a predetermined time (for example, 30 seconds) (S2: Step 2), and measurement of the temperature of the water to be cooled is started. When the outlet temperature T _OUT detected by the outlet temperature detector 53 is lower than the set temperature T ₀ , it is not necessary to cool the water to be cooled, so that the state is maintained and the outlet temperature T _OUT is set to the set temperature T When it becomes ₀ or more, the process proceeds to the next step (S3: Step 3).

  Subsequently, the activation conditions for the cooling control of the refrigerant water circuit 65 and the refrigerant circuit 10 are checked simultaneously. In this way, preparation is made so that the refrigerant water circuit 65 and the refrigerant circuit 10 can be started up to step 3, and when the respective start conditions are checked at the same time, cooling of the water to be cooled is started under the optimum cooling conditions and in the shortest time. can do.

For convenience, the control of the refrigerant water circuit 65 will be described first.
First, compared with the outside air dry bulb temperature detector detecting outside air dry-bulb temperature DB and the inlet temperature detector 51 detects the inlet temperature (heat exchanger inlet temperature) T _IN, the outside air dry bulb temperature from the inlet temperature T _IN minus DB is less than the predetermined coolant water starting temperature T _fon maintains this state, the process proceeds to the next step if it is larger (S4: step 4). Then, the radiator fan 67 is activated to start inverter control of the radiator fan 67 (S5: step 5). At the same time, the circulation pump 63 is also started. The rated 60 Hz is output from the inverter that regulates the rotational speed of the circulation pump 63.

Specifically, as shown in FIG. 3, the outlet side temperature of the cooling water in the heat exchanger 6 (intermediate temperature detected by the intermediate temperature detector 52) Tc and the set temperature T ₀ required for the cooling water. Based on the deviation, a PID command value is generated (S51). That intermediate PID command value for increasing the rotational speed of the temperature Tc and the set temperature T ₀ when the deviation is large the radiator fan 67 is generated, the PID command value for decreasing the rotational speed the smaller the deviation in the opposite occurred To do.

Next, it is determined whether or not the difference between the set temperature T ₀ and the outside air dry bulb temperature DB is a predetermined value T ₂ or more (S52). The predetermined value T ₂ are, in the value to determine the cooling by the radiator 61 does not become too excessive, for example, 15 ° C.. That is, if the difference between the set temperature T ₀ and the outside air dry bulb temperature DB is greater than the predetermined value T ₂ , the coolant water is too cold, and the temperature of the water to be cooled that is heat-exchanged by the heat exchanger 6 is unnecessarily lowered. Because. When the difference between the set temperature T ₀ and the outside air dry bulb temperature DB is equal to or less than the predetermined value T _2, it is determined that the coolant water is not too cold, and the radiator fan 67 is used as it is at the frequency of the PID command value. The operation is continued and the process proceeds to Step 6 (S53).

Conversely, when the difference between the set temperature T ₀ and the outside air dry bulb temperature DB is larger than the predetermined value T ₂ , the inlet temperature (heat exchanger inlet temperature) T _{IN of the} water to be cooled in the heat exchanger 6 is set. It is determined whether or not the temperature T ₀ deviation is equal to or greater than a predetermined value T ₁ (S54). The predetermined value T ₁ is also a value that determines whether the cooling by the radiator 61 does not become too excessive, for example, 3 ° C.. When the deviation between the inlet temperature T _IN and the set temperature T ₀ is larger than the predetermined value T ₁ , it is determined that the coolant water is not too cold and the radiator fan 67 is operated as it is at the frequency of the PID command value. To continue to step 6 (S53).

Conversely, when the deviation between the inlet temperature T _IN and the set temperature T ₀ is equal to or less than the predetermined value T ₁ , the process proceeds to the low temperature difference control shown in FIG. 4 (S55). FIG. 4 shows an example of the control state in the case of a low temperature difference. FIG. 4 (a) shows the pump speed control of the circulation pump 63, FIG. 4 (b) shows the fan speed control of the radiator fan 67, and the horizontal axis ΔTf indicates the deviation between the inlet temperature T _{IN of the} water to be cooled and the set temperature T ₀ .

As shown in FIG. 4A, the predetermined value T ₁ (3 ° C. in the above example) is divided into a plurality (in this example, every 1 ° C.), the lowest pump rotation frequency (6 Hz), and the pump rotation for each division. The maximum frequency (here, 12.7 Hz, 28.6 Hz, 50 Hz) is set. And the gradient (D1, D2, D3) of the pump rotation minimum frequency and the pump rotation maximum frequency for each section is obtained. These minimum pump rotation frequency, maximum pump rotation frequency, and gradient (D1, D2, D3) are preset and stored in the control device of the cooling device 1. Within the section, the pump rotation frequency is obtained from ΔTf and this gradient (D1, D2, D3), and the circulating pump 63 is operated at this pump rotation frequency.

Further, as shown in FIG. 4B, the predetermined value T ₁ (3 ° C. in the above example) is divided into a plurality (in this example, every 1 ° C.), the lowest fan rotation frequency (15 Hz), and the fan for each division. The maximum rotation frequency (here, 15 Hz, 25 Hz, 40 Hz) is set. Then, gradients (D4, D5, D6) between the minimum fan rotation frequency and the maximum fan rotation frequency for each section are obtained. These minimum fan rotation frequency, maximum fan rotation frequency, and gradient (D4, D5, D6) are preset and stored in the control device of the cooling device 1. In the section, the fan rotation frequency is obtained from ΔTf and this gradient (D4, D5, D6), and the radiator fan 67 is operated at this fan rotation frequency.
Note that the relationships between the gradients D1 to D3 and the gradients D4 to D6 are preferably D1 <D2 <D3 and D4 <D5 <D6.

  As described above, the cooling device 1 has the refrigerant water circuit 65 (so-called free cooling circuit) by the radiator 61 and the circulation pump 63 and can cool the water to be cooled by the heat exchanger 6. Water to be cooled can be obtained. In particular, it works effectively during the period from autumn to spring, nighttime, etc., where the outside air dry bulb temperature DB is relatively low. In general, since the cooling capacity of free cooling depends on the outside air temperature, it is difficult to control the temperature of the water to be cooled. However, as shown in FIG. 3 and FIG. 4, if there is a possibility of overcooling by including a control step for determining whether or not supercooling occurs, the maximum value is set for the rotation frequency of the circulation pump 63 and the radiator fan 67. Since the provided inverter is controlled, the non-cooling water can be supplied in an accurate temperature state (for example, ± 1 ° C.).

Returning to FIG. 2 compares the inlet temperature T _IN detected by the outside air dry bulb temperature DB detected by the outside air dry bulb temperature detector inlet temperature detector 51, the outside air dry bulb temperature DB from the inlet temperature T _IN When the subtracted value is larger than the predetermined coolant water stop temperature T _foff , the process returns to step 5 to continue the control of the radiator fan 67 and the circulation pump 63, and when smaller, the process proceeds to the next step (S6: step). 6). Then, the radiator fan 67 is stopped and the PID control is turned off (S7: Step 7).

The refrigerant water start temperature T _fon and the refrigerant water stop temperature T _foff are set in advance and stored in the control device. Generally, the coolant water start temperature T _fon is set to 2 ° C., and the coolant water stop temperature T _foff is set to 1.5 ° C.

Subsequently, cooling control of the refrigerant circuit 10 will be described.
As shown in FIG. 2, when the set temperature T ₀ and the outside air dry bulb temperature DB are compared and the difference is not less than a predetermined chiller start temperature T _CON , the state is maintained and the chiller start temperature T If it is equal to or lower than _CON , the control operation of the compressor 2, the electronic expansion valve 4 and the on-off valve 23 is started (S8: Step 8 to S9: Step 9). At the start of operation, the inverter that controls the rotation speed of the compressor 2 is set to a predetermined frequency (for example, 25 Hz) for operation.

The control of the compressor 2 and the electronic expansion valve 4 and the control of the on-off valve 23 proceed simultaneously in parallel. First, the control of the compressor 2 will be described in detail.
As shown in FIG. 5 (a), a deviation ΔTt set temperature _{T 0} which is required an intermediate temperature Tc (S91). Specifically, as shown in FIG. 6A, the intermediate temperature Tc (or the inlet temperature T _IN when the refrigerant water circuit 65 is operating) is the load state of the device to be cooled (for example, a laser processing machine). It varies greatly depending on. Therefore, a deviation ΔTt set temperature T ₀ which is required an intermediate temperature Tc is the inlet temperature of the evaporator 5 in the refrigerant circuit 10. As shown in FIG. 6B, the deviation ΔTt (° C.) and the rotation frequency H ₁ (Hz) of the compressor 2 have a relationship of H ₁ = K ₁ · ΔTt (K ₁ is a coefficient). Determining the rotational frequency _{H 1} based on the equation (FIG. 5 (a), S92). That is, a small frequency is obtained when the deviation ΔTt is small, and a large frequency is obtained when the deviation ΔTt is large.

However, as shown in FIG. 6B, the compressor 2 has a low frequency region (for example, 25 Hz or less) where the inverter cannot be controlled. This low frequency region is obtained by the deviation ΔTt = H ₁ / K ₁ . Therefore, it is determined whether or not the obtained H1 is equal to or higher than the inverter control lower limit (FIG. 5A, S93). If H1 is equal to or higher than the inverter control lower limit, the compressor 2 is directly controlled at the frequency of H1 ( S94). If H1 is below the inverter control lower limit, the compressor 2 performs a constant operation at the lowest frequency (25 Hz) (S95).

Next, as shown in FIG. 5B, the electronic expansion valve 4 compares the outlet temperature T _OUT detected by the outlet temperature detector 53 with the requested set temperature T _0, and opens the electronic expansion valve 4. Adjust the degree of control. Specifically, when the outlet temperature T _OUT is higher than the set temperature T ₀ , a signal for opening the electronic expansion valve 4 is sent, and conversely, when the outlet temperature T _OUT is lower than the set temperature T ₀ , A signal for closing the electronic expansion valve 4 is sent (S96, S97, S98).

For example, the electronic expansion valve 4 is a proportional control valve having an opening degree of 100% and 480 pulses. The valve opening or closing signal output to the electronic expansion valve 4 in step 97 and step 98 outputs 24 pulses corresponding to an opening degree of 5%. Needless to say, in order to further increase the accuracy of the control temperature, it is preferable to output with a fine pulse number. The degree of increment of the pulse number may be determined by the required control temperature accuracy and the control tracking speed. Further, the valve opening or closing signal output to the electronic expansion valve 4 can be adjusted depending on the difference between the set temperature T ₀ and the outlet temperature T _out . When the valve opening or closing signal is output, the process proceeds to step 10 in FIG.

Thus, since the cooling device 1 variably controls the cooling capacity of the compressor 2 based on the deviation ΔTt between the intermediate temperature Tc and the set temperature T ₀ , there is a large load fluctuation on the equipment side that supplies the water to be cooled. Even if there is, temperature control follows with good responsiveness. Furthermore, since the opening degree of the electronic expansion valve 4 is adjusted and controlled based on the deviation between the outlet temperature T _OUT and the set temperature T ₀ , minute temperature control accuracy is improved, and a large load fluctuation is caused on the device side that supplies the cooling water. Even if there is, it is possible to stably supply water to be cooled with high temperature accuracy.

On the other hand, as shown in FIG. 7, the on / off valve 23 is controlled by comparing a predetermined temperature set in advance with each condition.
The outlet temperature T _OUT detected by the outlet temperature detector 53 is compared with the requested set temperature T _0, and if the temperature difference is larger than the predetermined temperature T ₃ , this state is maintained and the predetermined temperature T ₃ or less. In this case, the process proceeds to the next step (S101). The intermediate temperature Tc detected on the inlet side of the evaporator 5 is compared with the required set temperature T _0, and when the temperature difference is larger than the predetermined temperature T ₄ , this state is maintained and the predetermined temperature T ₄ or less is maintained. In this case, the on-off valve 23 is opened (S102, S103). Here, it is determined whether the compressor 2 is in a high load state where the operation of the compressor 2 is possible or a low load state where the operation of the compressor 2 is impossible. When the operation of the compressor 2 is impossible, the on-off valve The operation of opening the valve 23 is performed. The predetermined temperature T ₃ and the predetermined temperature T ₄ may be determined by the capacity of the compressor 2 and the temperature accuracy required for the fluid to be cooled. For example, when the temperature accuracy required for the capacity and the fluid to be cooled is ± 1 ° C., The predetermined temperature T ₃ = 0.2 ° C. and the predetermined temperature T ₄ = 1.2 ° C.

Then, the intermediate temperature Tc detected on the inlet side of the evaporator 5 is compared with the required set temperature T _0, and when the temperature difference is smaller than the predetermined temperature T ₅ , this state is maintained and the predetermined temperature T _In the case of ₅ or more, the process proceeds to the next step (S104). When the difference between the intermediate temperature Tc and the outlet temperature _{T OUT} is less than the predetermined temperature _{T 6} maintains this state, when the predetermined temperature or higher _{T 6} is closed off valve 23 (S105, S106). Here, it is determined again whether or not the compressor 2 has escaped from the low load state and inverter control operation has become possible. The predetermined temperature T ₅ and the predetermined temperature T ₆ may be determined by the capacity of the compressor 2 and the temperature accuracy required for the fluid to be cooled. For example, when the temperature accuracy required for the capacity and the fluid to be cooled is ± 1 ° C., The predetermined temperature T ₅ = 0.8 ° C. and the predetermined temperature T ₆ = 0.2 ° C. Then, the process proceeds to Step 10.

On the other hand, it has a step of forcibly opening and closing the on-off valve 23 in preparation for a case where an unexpected temperature change occurs in the water to be cooled. That is, when the value from the set temperature T ₀ by subtracting the predetermined temperature T ₇ is larger than the outlet temperature T _OUT is to open the on-off valve 23, on the other hand, by adding a predetermined temperature T ₈ to the set temperature T ₀ value Is smaller than the outlet temperature T _OUT , the on-off valve 23 is closed (S107, S108). For example, the predetermined temperature T ₇ = 0.6 ° C. and the predetermined temperature T ₈ = 0.7 ° C.

Returning to FIG. 2, when the outside air dry bulb temperature DB decreases, the set temperature T ₀ is compared with the outside air dry bulb temperature DB, and if the difference is equal to or less than the predetermined chiller stop temperature T _Coff , If the state is maintained and the temperature is equal to or higher than the chiller stop temperature T _Coff , the compressor 2 is stopped after confirming whether it has been operated for a predetermined time (for example, 2 minutes) (S10: Step 10 to S12: Step 12). That is, even if the compressor 2 is not operated, the water to be cooled can be supplied only by free cooling by the radiator 61.
However, since the compressor 2 is not preferably restarted immediately after being stopped, an interval time of a predetermined time (for example, 3 minutes) is set after the temporary stop (S13: Step 13).

Here, the chiller start temperature T _CON (for example, 14 ° C.) and the chiller stop temperature T _Coff (for example, 15 ° C.) are values obtained in advance by the cooling capacity of the radiator 61 and stored in the control device. The cooling capacity of the radiator 61 is determined by the diameter of the coolant water flowing through the radiator, the shape of the fins, the surface area, the wind speed passing through the radiator, and the like.

As described above, the cooling device 1 variably controls the cooling capacity of the compressor 2 based on the deviation between the intermediate temperature Tc detected on the inlet side of the evaporator 5 and the set temperature T _0. Even if there is a large load fluctuation on the equipment supplying side, the temperature control follows with good responsiveness, and the water to be cooled with high temperature accuracy can be stably supplied.

<Second Embodiment>
FIG. 8 shows a main control flowchart of the second embodiment of the cooling apparatus of the present invention.
In the first embodiment described above, the control of the refrigerant water circuit 65 including the radiator 61 and the control of the refrigeration circuit 10 including the compressor 2 are operated in parallel. This is an effective form for controlling the temperature of the water to be cooled without being sent in time. On the other hand, from the viewpoint of energy saving, it is more effective to lengthen the operation time of the refrigerant water circuit 65 having the radiator 61.

In the second embodiment, since the configuration of the cooling device is the same as that of the cooling device 1 shown in FIG. 1, the detailed description thereof is omitted, and the control flow shown in FIG. 8 is provided. That is, first, the main pump 90 is activated (S1A). Then, the cooling water in the circulation circuit 91 is circulated for a predetermined time (for example, 30 seconds) (S2A), and measurement of the temperature of the cooling water is started. When the outlet temperature T _OUT detected by the outlet temperature detector 53 is lower than the set temperature T ₀ , it is not necessary to cool the water to be cooled, so that the state is maintained and the outlet temperature T _OUT is set to the set temperature T When it becomes ₀ or more, the process proceeds to the next step (S3A).

First, compared with the outside air dry bulb temperature detector detecting outside air dry-bulb temperature DB and the inlet temperature detector 51 detects the inlet temperature (heat exchanger inlet temperature) T _IN, the outside air dry bulb temperature from the inlet temperature T _IN If the value obtained by subtracting DB is lower than the predetermined coolant water activation temperature T _fon , this state is maintained, and if it is greater, the process proceeds to the next step (S4A). Then, the radiator fan 67 is activated to start inverter control of the radiator fan 67 (S5A). The details of the control at this time are the same as the control flow shown in FIG.

Compares the inlet temperature T _IN detected at intermediate temperatures Tc and the inlet temperature detector 51 to be detected at the inlet side of the evaporator 5, the value is a predetermined refrigerant water stop minus the intermediate temperature Tc from the inlet temperature T _IN If the temperature is higher than the temperature T _foff , the process returns to step 5A to continue the control of the radiator fan 67 and the circulation pump 63. If the temperature is lower, the process proceeds to the next step (S6A). Then, the radiator fan 67 is stopped and the inverter control is turned off (S7A).

Simultaneously with step 3A, it is determined whether the radiator fan 67 is operating in PID control (that is, whether step 5A is being implemented) (S81A). If the radiator fan 67 is not running, by comparing the outlet temperature _{T out} and the set temperature _{T 0} (S82a), if the outlet temperature _{T out} is the set temperature _{T 0} or more, the process proceeds to step 9A.

On the other hand, when the radiator fan 67 is in operation, it is determined whether the rotational speed of the radiator fan 67 is the maximum value (S83A). That is, it is determined whether or not the cooling capacity of the refrigerant water circuit 65 reaches the maximum value and complementation in the refrigeration circuit 10 is required. Then, if the rotation speed of the fan 67 becomes a maximum value, it is determined whether meets or exceeds the outlet temperature T _out is obtained by adding a predetermined temperature T ₂₀ to the set temperature T ₀ (S84A). The predetermined temperature T ₂₀ is a value smaller than the required temperature accuracy tolerance (e.g. ± 1 ° C.), for example, 0.6 ° C..

  If the condition of step 84A or step 82A is satisfied, the control operation of the compressor 2, the electronic expansion valve 4, and the on-off valve 23 is started (S9A). Since the control flow in S9A is the same as the control flow shown in FIGS. 5 and 7, detailed description thereof is omitted.

When the outside air dry bulb temperature DB is lowered, cooling by the refrigerant water circuit 65 becomes possible again. Therefore, when the set temperature T ₀ is compared with the outside air dry bulb temperature DB and the difference is equal to or higher than the predetermined chiller stop temperature T _Coff (S10A), the intermediate temperature Tc adds the predetermined temperature T21 to the set temperature T0. If it is smaller than the above value (S10B), the compressor 2 is stopped (S11A to S12A) after confirming whether it has been operated for a predetermined time (for example, 2 minutes). That is, even if the compressor 2 is not operated, the water to be cooled can be supplied only by free cooling by the radiator 61.
However, since it is not preferable to restart the compressor 2 immediately after being stopped, an interval time of a predetermined time (for example, 3 minutes) is set after the stop (S13A).

  Therefore, since the refrigeration circuit 10 does not need to be operated until the cooling capacity of the refrigerant water circuit 65 is maximized, the water to be cooled whose temperature is controlled with energy saving can be supplied.

It is a conceptual schematic diagram of the 1st Example of the cooling device of this invention. It is a main control flowchart of the first embodiment of the cooling device of the present invention. It is a flowchart of the cooling control of the radiator circuit which comprises a part of this invention. It is a conceptual diagram explaining the low temperature difference control in a radiator circuit. It is a flowchart of the cooling control of the refrigeration circuit which comprises a part of this invention. It is a conceptual diagram explaining the cooling control of the compressor which comprises a part of this invention. It is a flowchart of control of the on-off valve which comprises a refrigerating circuit. It is a main control flowchart of the second embodiment of the cooling device of the present invention.

Explanation of symbols

1: cooling device,
2: compressor, 21: bypass circuit, 23: on-off valve,
3: Condenser, 31: Condenser fan,
4: Electronic expansion valve,
5: Evaporator, 51: Inlet temperature detector, 53: Outlet temperature detector,
6: heat exchanger, 61: radiator, 63: circulation pump, 65: refrigerant water circuit, 67: radiator fan,
10: refrigeration circuit, 11: outlet pressure detector,
90: main pump, 91: circulation circuit, 93: water storage tank, 95: deionizer

Claims (4)

A radiator for providing a heat exchanger in a cooling water flow circuit to be supplied, constituting a refrigerant water circuit of the heat exchanger, a radiator through which outside air can pass, and a circulation pump, and introducing outside air into the radiator In a cooling device having a fan,
A temperature detector is provided on the inlet side of the water to be cooled in the heat exchanger, and the flow rate control of the refrigerant water circuit is performed based on a deviation between the temperature of the water to be cooled detected by the temperature detector and the required set temperature. And
The number of rotations of the radiator fan is controlled by inverter control, and the number of rotations of the radiator fan is determined by the temperature of the water to be cooled detected by the temperature detector provided on the inlet side of the water to be cooled in the heat exchanger. A cooling device, which is controlled based on a required set temperature deviation.   The cooling device according to claim 1, wherein an inverter control device is provided in the circulation pump to control a flow rate of the refrigerant water circuit.   A compressor capable of inverter control, a condenser, an expansion valve, and an evaporator are provided downstream of the heat exchanger, and a chiller unit that performs heat exchange between the refrigerant and the water to be cooled in the evaporator is provided. The inverter is controlled by an inverter based on a deviation between a temperature of water to be cooled detected by a temperature detector provided on an inlet side of the water to be cooled in the evaporator and a required set temperature. Item 3. The cooling device according to Item 1 or 2. The expansion valve is an electronic expansion valve whose opening degree can be adjusted, an evaporator outlet temperature detector is provided on the outlet side of the water to be cooled in the evaporator, and the evaporator outlet temperature detected by the evaporator outlet temperature detector 4. The cooling device according to claim 3, wherein the opening degree of the electronic expansion valve is adjusted and controlled based on the deviation of the requested set temperature.

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