JP2816789B2 - Cold water supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to chilled water temperature control of a computer chiller requiring a constant temperature of chilled water or a chilled water supply device for general industrial use, and more particularly to controlling the chilled water with a wide set temperature range. The present invention relates to a cold water supply device that can be used.

[0002]

2. Description of the Related Art In a conventional chilled water supply apparatus, as shown in FIG. 5, each of a compressor 1, a condenser 8, a decompressor 3, and an evaporator 4 whose capacity is variably controlled by an operation frequency is connected to a refrigerant pipe. And a control means 9 for determining the operation frequency and controlling the refrigeration capacity of the refrigeration cycle, and provided with a pump 6 for circulating the cold water cooled by the evaporator 4 to the load 5. It is connected to a chilled water circuit and configured to control the temperature of the chilled water and the set temperature of the chilled water.
The temperature of the chilled water outlet of the evaporator 4 is detected by the temperature sensor 7 and taken into the microcomputer provided in the control means 9, whereby the operating frequency of the compressor is determined by comparing with the chilled water set temperature, and the refrigeration capacity is increased or decreased. The configuration is such that the cold water temperature is controlled to the cold water set temperature. This type of chilled water supply device is described in, for example,
It is described in JP-A-2-31271 and JP-A-1-109798.

[0003]

In the conventional chilled water supply device, the refrigeration cycle is designed so that a predetermined refrigeration capacity can be obtained at the lower limit of the chilled water set temperature. When the chilled water set temperature is increased to obtain chilled water having a relatively high temperature, the refrigeration capacity becomes excessive, and the compressor enters an overload operation state.

An object of the present invention is to provide a chilled water supply device that can avoid overload operation of a compressor even if the set chilled water temperature is set to a high or low temperature.

[0005]

In order to achieve the above object, a chilled water supply device according to the present invention comprises a compressor, a condenser, a decompressor and an evaporator whose capacity is variably controlled by an operation frequency. A chilled water circuit comprising a refrigeration cycle sequentially connected by refrigerant pipes and control means for determining an operation frequency and controlling the refrigeration capacity of the refrigeration cycle, and including a pump for circulating chilled water cooled by the evaporator to a load. Connected to
In the chilled water supply device that controls the temperature of the chilled water to the chilled water set temperature, the control unit previously stores an upper limit value of an operation frequency for preventing an overload operation of the compressor in a high temperature range of the chilled water set temperature ,
When the set chilled water temperature is set to a high temperature, a means is provided for determining an upper limit value of the operating frequency in accordance with the set chilled water temperature.

[0006] A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator whose capacity is variably controlled according to the operation frequency is sequentially connected by a refrigerant pipe, and the refrigeration cycle is determined by determining the operation frequency. In a chilled water supply device that is connected to a chilled water circuit equipped with a pump that circulates chilled water cooled by an evaporator to a load, and controls the temperature of the chilled water to a chilled water set temperature, A temperature sensor is provided, and the control means stores in advance an upper limit value of an operation frequency for preventing an overload operation of the compressor in a high temperature range of the chilled water set temperature, and when the chilled water set temperature is set to a high temperature, the control unit switches to the chilled water set temperature. A configuration may be provided that includes means for determining the upper limit value of the operating frequency in accordance therewith, and means for correcting the upper limit value of the operating frequency based on the temperature detected by the temperature sensor.

[0007] The upper limit of the operating frequency may be limited to an operating frequency for obtaining a refrigerating capacity capable of cooling to a predetermined chilled water set temperature in a low temperature range.

[0008] The means for further correcting may be configured to perform correction based on the temperature of the external cooling medium for cooling the condenser.

The correction means may be configured to make correction based on the temperature of the refrigerant cooled by the condenser.

[0010] The temperature sensor may be formed of a combination of thermostats.

[0011]

A compressor, a condenser, a decompressor and an evaporator, whose capacity is variably controlled by the operating frequency, are sequentially connected by refrigerant piping, and the operating frequency is determined to determine the refrigeration cycle. In a chilled water supply device comprising a control means for controlling the capacity, connected to a chilled water circuit having a pump for circulating the chilled water cooled by the evaporator to a load, and controlling the temperature of the chilled water to a chilled water set temperature, Alternatively, a configuration may be provided in which at least frequency information and operation signals for operation and stop are input from the load side, and a means for determining the operation frequency in accordance with the operation signal is provided.

[0013] Further, the electronic equipment cooling device is provided with any one of the cold water supply devices described above.

Further, a general industrial chilled water supply device is provided with any one of the chilled water supply devices described above.

[0015]

According to the present invention, in the first embodiment of the present invention, an upper limit value of an operation frequency for preventing an overload operation of a compressor in a high temperature range of a chilled water temperature is stored in a control means in advance, and a chilled water set temperature is set. Is set to a high temperature, the control means determines the upper limit value of the operating frequency corresponding to the cold water set temperature. As the chilled water temperature approaches the set point and becomes hotter, the compressor tends to overload. However, since the operation is not performed beyond the upper limit of the operation frequency determined by the control means, an overload operation of the compressor is avoided.

In the second embodiment of the present invention, the upper limit of the operating frequency of the compressor is set to a frequency corresponding to the refrigeration capacity of the refrigeration cycle obtained in a low temperature range of the chilled water set temperature, for example, the lower limit. Thus, overload operation of the compressor is avoided, and stable refrigeration capacity can be obtained regardless of the level of the chilled water set temperature.

In the third embodiment of the present invention, the condenser is provided with a temperature sensor for detecting the temperature of the external cooling medium.
By performing the correction corresponding to the external cooling medium temperature, it is possible to avoid the overload operation of the compressor even when the cooling medium temperature changes.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a refrigeration system in which a compressor 1, a condenser (FIG. 1 shows an air-cooled condenser) 2, a decompressor 3, and an evaporator 4, which are sequentially connected by refrigerant pipes, has a capacity variable according to an operation frequency. A refrigeration cycle, and a controller (control means) 9 for determining the operation frequency and controlling the refrigeration capacity of the refrigeration cycle, and connected to a chilled water circuit having a pump 6 for sending chilled water cooled by the evaporator 4 to a load 5; A temperature sensor 7 for detecting a cold water outlet temperature at a cold water outlet of the evaporator 4;
And a temperature sensor 8 for detecting an external cooling medium temperature,
The controller 9 stores in advance an upper limit value of an operation frequency for preventing the overload operation of the compressor 1 in a high temperature range of the chilled water temperature, and when the chilled water set temperature is set to a high temperature, the controller 9 determines the operating frequency according to the chilled water set temperature. It is assumed that means for determining the upper limit is provided in the program. That is, the controller 9 can set the temperature, performs a comparison operation between the chilled water outlet temperature detected by the temperature sensor 7 and the set chilled water temperature, obtains the operating frequency of the compressor 1, and outputs the operating frequency to the compressor 1 to thereby control the refrigeration cycle. The refrigeration capacity is controlled. The temperature sensor is formed by a combination of thermostats, and the upper limit of the operating frequency is set to ON-
OFF control may be performed.

The operation of this embodiment will be described with reference to FIG. In the normal operation, the operating frequency of the compressor 1 is PI-controlled by the chilled water set temperature set by the controller 9 and the chilled water outlet temperature detected by the temperature sensor 7 and monitored by the controller 9 at regular intervals. The refrigeration capacity is controlled so that the chilled water outlet temperature approaches the chilled water set temperature. This cold water set temperature is set to a high temperature range of, for example, 15 to 25.
When the compressor is operated at the maximum frequency as shown in the graph of FIG. 2 in the conventional apparatus when the temperature is set to ° C., the refrigeration capacity becomes excessive. As a result, the compressor 1 is overloaded, and the compressor 1 may be damaged. Therefore, in the present embodiment, the controller 9 sets the chilled water set temperature to a high temperature of 15 ° C. or more by the controller 9 storing a predetermined upper limit value of the operating frequency of the compressor 1 corresponding to the chilled water set temperature. However, the refrigeration capacity is suppressed by the upper limit of the operating frequency of the compressor 1, and the overload operation of the compressor 1 can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3, when a cooling capacity of 13 kW is obtained at a predetermined chilled water set temperature in a low temperature range, for example, a chilled water temperature of 7 ° C., which is a rated point, the upper limit of the operating frequency of the compressor is set to a frequency that gives a refrigeration capacity of 13 kW. Set forth in
In other words, the maximum refrigerating capacity of the refrigerating cycle is always the same even if the cold water set temperature changes. Therefore, not only the overload operation of the compressor can be avoided, but also the refrigeration capacity equal to the rated point can be obtained irrespective of the chilled water set temperature, and chilled water with a stable chilled water temperature can be supplied.

Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. A temperature of an external cooling medium of the condenser 2, for example, a suction air temperature (hereinafter referred to as an outside air temperature) is detected by a temperature sensor 8 and taken into a controller 9. The controller 9 corrects the upper limit value of the operating frequency based on the deviation between the outside air temperature detected by the temperature sensor 8 and the reference air temperature (35 ° C.) with respect to the upper limit value (reference value) of the operating frequency in the first embodiment. Is calculated by means for correcting on a program.
FIG. 4 shows the upper limit of the operating frequency of the compressor at an outside air temperature of 15 to 40 ° C. and the corresponding refrigeration capacity. According to the present embodiment, regardless of the level of the outside air temperature, the overload operation of the compressor can be prevented, and the maximum refrigeration capacity that can be operated without any problem at the outside air temperature can be obtained.

Although the third embodiment of the present invention has been described for the case of an air-cooled condenser, even in the case of a water-cooled condenser, the temperature of the intake air of the condenser is replaced by the temperature of the cooling water inlet (the temperature of the external cooling medium). The same effect as described above can be obtained.

Further, as another embodiment, instead of the suction air temperature of the condenser, a high refrigerant pressure of the refrigeration cycle,
Alternatively, the temperature can be substituted by detecting the temperature of the refrigerant cooled by the condenser, and frequency information and operation signals such as operation and stop from the load side may be input to the controller. An electronic equipment cooling device, a general industrial cold water supply device, and the like are configured by any one of the above-described embodiments.

In the first embodiment of the present invention, the chilled water set temperature 1
Even in a high temperature setting range of 5 ° C. or more and 25 ° C. or less, the overload operation of the compressor can be prevented, and thus the operation range of the chilled water temperature can be expanded.

In the second embodiment of the present invention, the maximum refrigerating capacity is the same as the rated point regardless of the setting of the chilled water temperature, in addition to the effect of expanding the operation range of the first embodiment. There is an effect that it is possible to supply cold water at a stable cold water temperature.

In the third embodiment of the present invention, the overload operation of the compressor in the high temperature setting region can be prevented regardless of the outside air temperature, so that the operation range of the outside air temperature and the chilled water temperature can be expanded. The effect is as follows.

[0027]

According to the present invention, since the upper limit of the operating frequency is set in the high temperature range of the chilled water set temperature, the overload operation of the compressor is prevented even if the chilled water temperature is set to a high temperature, and the operating frequency is reduced. By making the upper limit equal to the operating frequency of the refrigeration capacity for obtaining the predetermined chilled water temperature in the low temperature range and correcting with the external cooling medium temperature, the operating range can be expanded regardless of the chilled water temperature and the cooling medium temperature, In addition, there is an effect that the cold water temperature is stabilized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a graph illustrating the operation of the first embodiment.

FIG. 3 is a graph illustrating the operation of the second embodiment.

FIG. 4 is a graph illustrating the operation of the third embodiment.

FIG. 5 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Decompressor 4 Evaporator 5 Load 6 Pump 7 Temperature sensor 8 Temperature sensor 9 Controller (control means)

Claims (9)

(57) [Claims] 1. A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator whose capacity is variably controlled by an operation frequency are sequentially connected by refrigerant piping, and the refrigeration is performed by determining the operation frequency. A chilled water supply device that is connected to a chilled water circuit including a pump that circulates chilled water cooled by the evaporator to a load, and that controls the refrigeration capacity of the cycle; in the control means, the cold water in the cold water in a high temperature range of the set temperature to prevent the overload operation of the compressor stores in advance an upper limit value of the operation frequency, the chilled water set temperature is set to a high temperature A chilled water supply device comprising means for determining an upper limit value of the operation frequency according to a set temperature. 2. A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator whose capacity is variably controlled by an operation frequency are sequentially connected by refrigerant piping, and the refrigeration is performed by determining the operation frequency. A chilled water supply device that is connected to a chilled water circuit including a pump that circulates chilled water cooled by the evaporator to a load, and that controls the refrigeration capacity of the cycle; In the above, a temperature sensor is provided in the condenser, and the control means includes:
An upper limit value of the operating frequency for preventing overload operation of the compressor in a high temperature range of the chilled water set temperature is stored in advance, and when the chilled water set temperature is set to a high temperature, the operation is performed according to the chilled water set temperature. A chilled water supply device comprising: means for determining an upper limit value of a frequency; and means for correcting the upper limit value of the operating frequency based on a temperature detected by the temperature sensor. 3. The chilled water supply device according to claim 1, wherein an upper limit value of the operating frequency is limited to an operating frequency that obtains a refrigerating capacity capable of cooling to a predetermined chilled water set temperature in a low temperature range. . 4. The chilled water supply device according to claim 2, wherein the correcting means performs the correction based on a temperature of an external cooling medium for cooling the condenser. 5. The chilled water supply device according to claim 2, wherein the correcting means performs the correction based on a temperature of the refrigerant cooled by the condenser. 6. The chilled water supply device according to claim 2, wherein the temperature sensor is formed by a combination of thermostats. 7. A refrigeration cycle in which a compressor, a condenser, a decompressor, and an evaporator whose capacity is variably controlled by an operation frequency are sequentially connected by refrigerant piping, and the refrigeration is performed by determining the operation frequency. A chilled water supply device that is connected to a chilled water circuit including a pump that circulates chilled water cooled by the evaporator to a load, and that controls the refrigeration capacity of the cycle; , Wherein the control means includes means for inputting at least frequency information, an operation signal of operation and stop from the load side, and determining the operation frequency in accordance with the operation signal. apparatus. 8. An electronic equipment cooling device comprising the chilled water supply device according to any one of claims 1 to 7 . 9. claims 1-7 of general industrial chilled water supply apparatus characterized in that it comprises a cold water supply device according to any one of.