JPH0772641B2 - Refrigeration system control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigeration system having a refrigerator, a heat storage tank, and a load side heat exchanger, and particularly to a control method thereof.

(B) Conventional technology Generally, the conventional technology of the refrigeration system using the heat storage tank is “Air Conditioning and Refrigeration” VOL /
26NO / 9 There were some as described in P.44 to P.60 and also P.91 to P.99. The former one uses the ice stored in the heat storage tank using night power during the time period when the cooling operation is required to reduce the capacity of the refrigerator at the peak of the cooling load or when the cooling operation is started. It was a supplement. Further, in the latter, the operation of the refrigerator is controlled while the predicted load amount and the remaining ice amount are compared with each other by the microcomputer so that all the ice can be used during the daytime air conditioning period.

(C) Problems to be Solved by the Invention In the conventional technique thus configured, the heat storage tank is mainly used to compensate for the lack of the capacity of the refrigerator. These systems control the operation of the refrigerator by performing cooling and releasing the heat from the heat storage tank during the daytime air conditioning time and measuring and predicting the magnitude of the load at relatively short predetermined cycle intervals.
There were cases where the number of times the refrigerator was started and stopped increased, the number of equipment failures increased, and the system reliability deteriorated. In addition, in the case of air-conditioning load, even if the entire load does not fluctuate rapidly throughout the day, if the refrigerating machine start-up cycle is shortened, the load side heat exchanger will be The cycle of temperature fluctuations of the brine circulating through is shortened. That is, the temperature variation of the air conditioning load (room temperature) becomes fast, and the user may feel uncomfortable. Furthermore, in such a system, the amount of ice making at night is designed to correspond to about 50 to 60% of the total amount of heat that cools during the air conditioning period, and when the refrigerator is operating for a long time during the air conditioning period, That is, when the utilization rate of the heat storage tank is low, there is a case where all the ice in the heat storage tank cannot be used during the air conditioning period and some of the ice remains in the heat storage tank. Due to such remaining ice, there is a problem that the ice grows every day, hinders the flow of brine in the heat storage tank, and deteriorates the heat storage efficiency of the heat storage tank.

In view of such a problem, the present invention provides a control method for reducing the number of times of starting and stopping of a refrigerator to control a failure of the refrigerator and to control ice remaining in a heat storage tank.

(D) Means for Solving the Problems The present invention introduces a heat source side brine that has been heat-exchanged by a refrigerator to an ice heat storage tank in which a use-side brine is stored, and the heat exchange side is used by this ice heat storage tank. In the control system of the refrigeration system in which the water heat exchanger for guiding the brine to the load side heat exchanger and for exchanging heat between the use side brine and the heat source side brine is provided in parallel with the ice heat storage tank, the refrigerator is driven. A first mode for cooling the ice heat storage tank by cooling the ice heat storage tank, a second mode for cooling the load by circulating the utilization side brine between the ice heat storage tank and the load side heat exchanger, and the heat source side for the water heat exchanger. And a third mode for guiding the brine to cool the use-side brine, and to circulate the use-side brine between the ice heat storage tank and the load-side heat exchanger to cool the load. When the second mode operation is performed for a predetermined time Together with this second
When the temperature of the outside air is equal to or higher than a predetermined value at the end of the mode operation, the operation is switched to the third mode, and when the temperature of the outside air is equal to or lower than the predetermined value, the operation in the second mode is continued.

(E) Action When such a control method of the refrigeration system is used, the heat storage tank is allowed to cool in the cooling mode, and during this period and after the cooling by the ice storage is carried out in the second mode, the temperature of the outside air is changed. When the value is equal to or less than the predetermined value, the operation in the second mode in which the operation of the refrigerator is stopped is continuously performed, so that the number of times the refrigerator is started and stopped is reduced and the utilization efficiency of the heat storage tank is increased.

(F) Example An example of the present invention will be described below with reference to the drawings. First
The figure is a schematic diagram of a refrigeration system. In the figure, reference numeral 1 denotes a chiller unit (refrigerator), which cools brine flowing from the pipe port P and then discharges it from the pipe port S. As this unit, a unit using a compressor, a unit using an absorption refrigerator, or the like can be used. Reference numeral 2 denotes a heat storage tank, which circulates the heat source side brine cooled by the chiller unit 1 to make ice therein for cold storage. Reference numeral 3 is a load side heat exchanger, and a fan coil unit or the like can be used. A brine ice heat exchanger 4 cools the water (use side brine) returned from the load side heat exchanger 3. The temperature of the heat source side brine circulating through the chiller unit 1, the heat storage tank 2, and the brine water heat exchanger 4 is set to about -6 ° C. The temperature of water (use side brine) circulating from the heat storage tank 2 to the load side heat exchanger 3 and the brine water heat exchanger 4 is about 7
Set to ℃. Chiller unit 1, heat storage tank 2, brine water heat exchanger 4, brine pump 5, solenoid on-off valve 6,
7, the check valve 8 and the brine pipe are connected, and when the electromagnetic on-off valve 6 is in the open state and the electromagnetic on-off valve 7 is in the closed state, the brine pump 5 is driven and the heat source side brine is indicated by the solid arrow. Flow toward the heat storage tank 2, ice is made in the heat storage tank 2, and when the electromagnetic on-off valve 6 is closed and the electromagnetic on-off valve 7 is open, the brine pump 5 is driven to flow the heat source side brine in the direction of the dotted line arrow. Water heat exchanger 4
The water returned from the load side heat exchanger 3 is cooled by. The heat storage tank 2, the load side heat exchanger 3, and the brine water heat exchanger 4 are connected by a temperature control valve 9, a water pump 10 and a water pipe. The temperature control valve 9 mixes cold water having different temperatures supplied to the piping ports A and B to keep the temperature of the cold water discharged from the piping port C at a substantially constant value (about 7 ° C.). That is, by driving the water pump 10, the cold water flows as shown by the alternate long and short dash line and circulates through the load side heat exchanger 3.

FIG. 2 is an explanatory diagram showing a daily operating state of the present system. In the figure, I to VI are time zones separated by predetermined times. Time zone I is a cold storage mode (first mode: ice making operation), and after opening the electromagnetic on-off valve 6 and closing the electromagnetic on-off valve 7 shown in FIG. 1, the chiller unit 1 and the brine pump 5 are operated. Make ice in the heat storage tank 2. The amount of ice made is equivalent to about 50 to 60% of the total cooling heat during the daytime (when the load needs to be cooled). When the amount of ice made in the heat storage tank 2 reaches this amount, the ice making operation is started. Stop. The amount of ice making can be examined by using the water level rise in the heat storage tank 2 or an ice sensor.

Time zones II to V are the cooling operation of the load in the daytime,
In time zone II, the operation of the chiller unit 1 and the brine pump 5 (first mode) is stopped, and the operation of the water pump 10 (second mode) is stopped.
Mode) only. Thereby, the cooling operation using the ice in the heat storage tank 2 is performed from the load side heat exchanger 3. That is, the heat storage tank 2 performs the cooling operation.

In time zones III to V, the outside air temperature To is detected, and at the beginning of time zone III, three states of To ≦ 22, 22 <To <29, To ≧ 29 are determined.
First, when To ≧ 29, the chiller unit 1 shown in FIG.
The brine pump 5 is operated, the electromagnetic on-off valves 6 and 7 are set in a predetermined state, and the brine is caused to flow in the direction of the dotted arrow to perform the water cooling operation, that is, the follow-up cooling operation, and the cooling operation is performed as in the time zone II. Do. That is, the load cooling operation is performed from both the chiller unit 1 and the heat storage tank 2. This time zone III is maintained until 12:00. In other words, when the operation in the second mode (cooling operation) ends, the temperature of the outside air reaches a predetermined value (29
(° C) or higher, the operation is switched from the second mode operation to the third mode operation (additional cooling operation).

On the other hand, when 22 <To <29 (when the temperature of the outside air is below the predetermined value (29 ° C)), the second mode operation (cooling operation) is continued and maintained until the time reaches 15:00, during which time When the amount of ice in the heat storage tank 2 is 20% or less, the cooling operation of the load is performed by using the above-mentioned additional cooling operation together.

When To ≦ 22 or when the time has passed 15:00, only the cooling operation is performed, and this operation is maintained until the time becomes 18:00. During this period, when the temperature of the cold water on the outlet side of the heat storage tank 2 becomes 10 ° C. or higher (it is judged that all the ice in the heat storage tank 2 has melted), the above-mentioned additional cooling operation is performed.

The time zone VI is a time zone in which the extended operation is performed, and the above-mentioned additional cooling operation is performed as necessary until the time of 22:00.

The operation of such time zones II to V is as shown in the flowchart of FIG. Therefore, the control unit includes a program or electronic circuit that performs such an operation.

In the refrigeration system configured as described above, first the time 8
Only the cooling operation (second mode operation) is performed from 00:00 to 10:00, and the second temperature is adjusted to the outside air temperature at 10:00 from 10:00 to 15:00, that is, when the outside air temperature is equal to or higher than a predetermined value (29 ° C). The mode operation is switched to the third mode operation (additional cooling operation), and when the outside air temperature is lower than the predetermined value (29 ° C), the second mode operation (cooling operation) is continued.

(G) Effect of the Invention According to the present invention, the heat source side brine that has been heat-exchanged by the refrigerator is guided to the ice heat storage tank in which the use-side brine is stored, and the use-side brine that has been heat-exchanged in this ice heat storage tank is subjected to the load-side heat exchange. To the vessel,
In the control system of the refrigeration system in which the water heat exchanger for exchanging heat between the utilization side brine and the heat source side brine is provided in parallel with the ice heat storage tank, the first mode of driving the refrigerator to cool the ice heat storage tank and A second mode in which a load side brine is circulated between an ice heat storage tank and a load side heat exchanger to cool a load; and a heat source side brine is guided to the water heat exchanger to cool the use side brine. And a third mode in which the load is cooled by circulating the use-side brine between the ice heat storage tank and the load-side heat exchanger, and the second-mode operation is performed for a predetermined period of time after the first-mode operation. When the temperature of the outside air is equal to or higher than the predetermined value at the end of the operation in the two modes, the operation is switched to the third mode, and when the temperature of the outside air is equal to or lower than the predetermined value, the second
Continue to operate in the mode. Therefore, it is possible to increase the utilization rate of the heat storage tank that performs only cooling in the second mode, and it is possible to control that cold heat remains in the heat storage tank at the end of the third mode.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a refrigeration system using the control method of the present invention, FIG. 2 is an explanatory diagram showing operation modes with respect to time of the refrigeration system shown in FIG. 1, and FIG.
It is a flowchart showing the operation mode of the figure. 1 ... Chiller unit, 2 ... Heat storage tank, 3 ... Load side heat exchanger, 4 ... Brine water heat exchanger.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kohei Sato 2-18 Keiyo Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP 62-162839 (JP, A) JP Sho 61-213432 (JP, A) JP-A-62-206337 (JP, A)

Claims (1)

[Claims] 1. A heat source side brine that has been heat-exchanged by a refrigerator is guided to an ice heat storage tank in which the use side brine is stored, and the use side brine that has been heat-exchanged in this ice heat storage tank is guided to a load side heat exchanger, Further, in the control system of the refrigeration system in which the water heat exchanger for exchanging heat between the use side brine and the heat source side brine is provided in parallel with the ice heat storage tank, the first mode of driving the refrigerator to cool the ice heat storage tank. And a second mode in which the load side brine is circulated between the ice heat storage tank and the load side heat exchanger to cool the load, and the heat source side brine is guided to the water heat exchanger to cool the use side brine. And a third mode for cooling the load by circulating the utilization side brine between the ice heat storage tank and the load side heat exchanger, and the second mode operation is performed for a predetermined time after the first mode operation. , This second
When the temperature of the outside air is equal to or higher than a predetermined value at the end of the operation in the mode, the operation is switched to the third mode, and when the temperature of the outside air is equal to or lower than the predetermined value, the operation in the second mode is continued. Refrigeration system control method.