JP3062565B2 - Cooling water inlet temperature control method for refrigerator in water heat storage system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for efficiently operating heat source equipment in a water heat storage system, which is one of the cooling and heat source systems for buildings and district cooling and heating.

[0002]

2. Description of the Related Art A water heat storage system is provided with a refrigerator for circulating cold water to a heat storage tank. In this refrigerator, a cooling tower is connected to a condenser by a cooling water pipe in the case of a water cooling type. That is, the heat absorbed from the heat storage tank is discharged to the outside air from the cooling tower via the condenser of the refrigerator (hereinafter, the water pipe on the heat absorption side passing through the heat storage tank is referred to as a heat storage system). , And the water pipe on the exhaust heat side passing through the cooling tower is referred to as "cooling water system").

[0003] In the water heat storage system, the cold water inlet of the heat storage system is connected to the low-temperature water side and the high-temperature water side of the heat storage tank via a mixing three-way valve.
By appropriately controlling the mixed water amount ratio on the high temperature side, the cold water inlet temperature is controlled to be constant, and stable high-efficiency operation of the refrigerator is realized.

On the other hand, also in a cooling water system of a refrigerator, a cooling water inlet is connected to a pipe from a cooling tower via a mixing three-way valve and to a direct pipe from a cooling water outlet not passing through the cooling tower. The valve controls the ratio of the amount of mixed water from the cooling water outlet side and the cooling tower passing side appropriately, and controls the cooling water inlet temperature so as not to be lower than the limit temperature of the refrigerator (for example, 25 ° C or lower).

[0005]

Conventionally, each equipment of a heat storage system and a cooling water system related to a refrigerator of a water heat storage system includes:
The rated capacity is determined up to the summer conditions under which the load increases. The temperature condition values in summer, which are the basis for calculating the rated capacity, are, for example, cooling water inlet temperature; 32 ° C., cold water inlet temperature; 10 ° C., cold water outlet temperature; However, the cooling water circulating through the condenser of the refrigerator exits the cooling water outlet, is cooled by a cooling tower installed outside, and is returned to the cooling water inlet again. (Ball temperature), the cooling capacity of the cooling tower increases and decreases, and the cooling water inlet temperature fluctuates greatly. Therefore, in the middle period, particularly in winter, the cooling water inlet temperature is significantly lower than the rated condition value (32 ° C. in the above example). However, on the other hand, the cold water inlet temperature is generally kept constant throughout the year. For this reason, at present, the cooling capacity of the cooling water system, which increases due to a decrease in the outside air wet-bulb temperature in the middle and winter seasons, is not fully utilized.
The present invention has been made in view of the above circumstances, and increases the output of a refrigerator by utilizing the cooling capacity of a cooling water system that increases due to a decrease in the outside air wet bulb temperature, thereby improving the coefficient of performance of the refrigerator. In addition, the present invention provides a method for controlling a chilled water inlet temperature of a chiller in a water heat storage system capable of shortening the operation time of a chiller and related accessories (for example, a chilled water pump, a chilled water pump, etc.), and achieves energy saving of the system. Aim.

[0006]

According to the present invention, there is provided a method for controlling a chilled water inlet temperature of a refrigerator in a water heat storage system according to the present invention, wherein an outgoing pipe of the chilled water system is connected to a low temperature side of a heat storage tank. After the return pipes connected to the low temperature side and the high temperature side of the heat storage tank are integrated by a mixing three-way valve, the return pipes are connected to the chilled water inlet of the chiller cooling water system, while the outgoing pipe of the chiller cooling water system is connected to the cooling tower. is connected, at the cold water inlet temperature control method of a refrigerator in water thermal storage system connected to a cooling water inlet of the refrigerator cooling water system by the cooling tower is changed pipes, the refrigeration
The cooling water inlet temperature of the cooling water system of the
Controlled by the mixing three-way valve in response to changes in mouth temperature
Automatic setting of the chilled water inlet temperature of the chiller chilled water system
It is characterized by being changed.

[0007]

When the inlet temperature of the cooling water cooled by the cooling tower decreases in accordance with the decrease in the outside air wet bulb temperature, the cooling capacity of the refrigerator increases due to the decrease in the condensation temperature.
Also, according to the change of the cooling water inlet temperature, the mixing three-way valve
The set value of the chilled water inlet temperature controlled by
You. For this reason, in the refrigerator, the cooling water inlet temperature is low.
Constant cooling water outlet due to increased cooling capacity below
Temperature, and the coefficient of performance of the refrigerator
And the capacity per unit time increases. did
Accordingly, the operation time of the refrigerator is shortened, and at the same time, the operation time of the auxiliary equipment, for example, the chilled water primary pump, the cooling water pump, etc. is also shortened, and the power for these is saved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method for controlling a chilled water inlet temperature of a refrigerator in a water heat storage system according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a water heat storage system for implementing a chilled water inlet temperature control method according to the present invention. A low-temperature side 1a and a high-temperature side 1b are formed in the heat storage tank 1, and water is stored by forming a temperature distribution in the heat storage tank.
For example, a cooling water pipe (not shown) for cooling on the secondary side is connected to the heat storage tank 1, and cold water is taken out by supplying cold water to an air conditioner or the like.

The heat storage tank 1 is connected to a chilled water system 5 of the refrigerator 3. Cold water line 5 connects the cold side 1a of the heat storage tank 1 and coolant outlet 7a provided on the cooler 7 of the refrigerator 3 forward
Tube (cold water往管) 9 and a low temperature side 1a, Kaekan (cold Kaekan connected once to the cold water inlet 7b of the condenser 7 are connected to a mixing three-way valve 11 of the pipe from the hot side 1b cold water mains ) 13. The return pipe 13 is provided with a cold water primary pump 15, and the cold water primary pump 15 transfers water from the heat storage tank 1 to the refrigerator 3.
Circulator 7.

[0010] A controller 17 is connected to the mixing three-way valve 11 on the chilled water system side.
The mixing three-way valve 11 is controlled based on the temperature detected by the temperature detector 19 provided in the vicinity so that the cold water inlet temperature matches the set temperature. That is, when the chilled water inlet temperature is lower than the set value, the amount of water from the high temperature side 1b is increased to increase the chilled water inlet temperature, and when the chilled water inlet temperature is higher than the set value, the amount of water from the low temperature side 1a is reduced. Control is performed to increase the chilled water inlet temperature and decrease it.

On the other hand, a cooling water system 23 is connected to the condenser 21 of the refrigerator 3. The cooling water system 23 is connected to a cooling water outlet 21 a of the condenser 21 and the cooling tower 25 and is connected to an outgoing pipe (a cooling pipe
Water往管) 27, the cooling water outlet 21a, Kaekan connected to the cooling water inlet 21b of the pipe from the cooling tower 25 once connected to the mixing three-way valve 29 of the cooling water system side condenser 21 (cooling water
Return pipe) 31. The outgoing pipe 27 has a cooling water pump 33
The cooling water pump 33 circulates cooling water between the condenser 21 and the cooling tower 25.

A controller 35 is connected to the three-way mixing valve 29 on the cooling water system side, and the controller 35 limits the cooling water inlet temperature based on the temperature detected by a temperature detector 37 provided near the cooling water inlet 21b. Below temperature (eg 2
(5 ° C. or less).

In this embodiment, a controller 35 for controlling the mixing three-way valve 29 on the cooling water system side and a controller 17 for controlling the mixing three-way valve 11 on the cooling water system side are electrically connected by signal wiring 39, The detected value of the cooling water inlet temperature detected by the temperature detector 37 is sent from the cooling water inlet temperature controller 35 to the cold water inlet temperature controller 17. Then, the controller 17 based on the detection value of the cooling water inlet temperature, cold
Change control of the set value of the water inlet temperature (for example, changing the cold water inlet temperature of 10 ° C to 10.5 ° C) can be performed. As a method of transmitting the detected value of the cooling water inlet temperature , in addition to the present embodiment, a controller for controlling the cooling water inlet temperature is used.
Cold water inlet temperature from controller 35 via central monitoring device, etc.
To controller 17 for temperature control, cooling water inlet temperature
From the detector 37 to the controller 17 for controlling the cold water inlet temperature
A method such as transmission to a computer is possible.

At this time, the chilled water inlet temperature control is performed so that the chilled water outlet temperature (5 ° C. in the above example) becomes constant.
Operation. By using the PI operation, unlike the case of only the proportional operation, the feedback control for simultaneously performing the P operation (proportional operation for outputting a signal proportional to the deviation) and the I operation (integrating operation for outputting a signal for removing the residual deviation) is performed. This makes it possible to keep the cold water outlet temperature constant.

The operation of controlling the temperature of the chilled water inlet in the water heat storage system thus configured will be described. When the outside-air wet-bulb temperature is high in summer or the like, the inlet temperature of the cooling water cooled by the cooling tower 25 is, for example, 32 ° C at the rated capacity condition value (outside-air wet-bulb temperature 27 ° C). Therefore, in this state, the cooling capacity of the refrigerator 3 becomes the rated value.

On the other hand, the inlet temperature of the cooling water cooled by the cooling tower 25 decreases as the temperature of the outside air wet bulb decreases during the intermediate period, particularly during winter. In this state, the cooling capacity of the refrigerator 3 increases due to a decrease in the condensation temperature.
Therefore, the detected value of the cooling water inlet temperature is sent from the controller 35 for controlling the cooling water inlet temperature to the controller 17 for controlling the cooling water inlet temperature, and the controller 17 automatically changes the set value of the cooling water inlet temperature. In accordance with the characteristics of the refrigerator 3, as the detected value of the cooling water inlet temperature decreases, the set temperature of the chilled water inlet increases, and as the detected value of the cooling water inlet temperature increases, the set temperature of the chilled water inlet decreases.

At this time, the refrigerator 3 cools the chilled water to a constant outlet temperature (5 ° C. in the above example) by the increased cooling capacity due to a decrease in the cooling water inlet temperature. The operating time will be reduced. Further, the coefficient of performance of the refrigerator at this time is higher than that under the rated condition. In addition, since the operation time of the refrigerator 3 is shortened, the operation time of the auxiliary equipment, for example, the cold water primary pump 15, the cooling water pump 33, and the like is also shortened, and the power is correspondingly saved.

As described above, according to the cooling water inlet temperature control method for the refrigerator in the water heat storage system described above, the cooling water
Set the chilled water inlet temperature to correspond to the detected inlet temperature.
By automatically changing, the excess capacity of the refrigerator can be sufficiently drawn out, thereby improving the coefficient of performance of the refrigerator and shortening the operation time of the refrigerator and the auxiliary machines, This makes it possible to reduce power consumption.

In the above-described embodiment, the case where the chilled water outlet temperature is kept constant at 5 ° C. has been described as an example. However, the control for increasing the chilled water outlet temperature when the cooling load is small as in the middle and winter seasons is described. It can also be performed in combination. Cold water like this
By increasing the outlet temperature , the coefficient of performance of the refrigerator 3 is further improved, and as a result, the operation time of the refrigerator 3 can be further reduced, and the electric power can be reduced accordingly.

[0020]

As described above in detail, according to the method for controlling the chilled water inlet temperature of the refrigerator in the water heat storage system according to the present invention, the chilled water inlet temperature is controlled based on the chilled water inlet temperature.
By adopting a configuration that changes the set value, it is possible to change the setting of the chilled water inlet temperature to a high temperature, especially in the middle and winter seasons when the cooling water capacity increases, and to sufficiently draw out the surplus capacity of the refrigerator.
Works. For this reason, while improving the coefficient of performance of the refrigerator, the operation time of the refrigerator and the auxiliary equipment can be shortened. As a result, the power can be reduced by that amount, and the energy saving of the system can be achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a water heat storage system for implementing a cold water inlet temperature control method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat storage tank 1a Low temperature side 1b High temperature side 3 Refrigerator 5 Cold water system 7a Cold water outlet 7b Cold water inlet 9 Outgoing pipe 11 Mixing three-way valve 13 Return pipe 21b Cooling water inlet 23 Cooling water system 25 Cooling tower 27 Outgoing pipe 31 Return pipe

Claims (2)

(57) [Claims] 1. The refrigerator according to claim 1, wherein an outgoing pipe of a refrigerator cold water system is connected to a low temperature side of the heat storage tank, and return pipes connected to the low temperature side and the high temperature side of the heat storage tank are integrated by a mixing three-way valve. In the water heat storage system, the outgoing pipe of the refrigerator cooling water system is connected to the cooling tower while the cooling tower is connected to the cooling water inlet of the refrigerator cooling water system by the return pipe. In the method for controlling a chilled water inlet temperature of a refrigerator , a cooling water inlet temperature of the refrigerator cooling water system is detected, and
According to the change of the cooling water inlet temperature, the mixing three-way valve
Of chilled water inlet temperature of the chiller chilled water system controlled by
The water heat storage system is characterized by automatically changing the value .
Control method of chilled water inlet temperature of refrigerator. 2. The water heat storage system according to claim 1,
In the method for controlling the temperature of a chilled water inlet of a refrigerator , the cooling water system of the refrigerator may be used when the cooling load is reduced in an intermediate period or a winter season.
The chilled water outlet temperature is higher than the previous set value.
Water heat storage system characterized by automatically changing to a set value
Method for controlling the temperature of the chilled water inlet of a refrigerator in Japan.