JP2899437B2 - Air conditioning system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system using a primary side as a heat source and a secondary side as a load via an outgoing header and a return header.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional air conditioning system, which is a closed type air conditioning system in which a primary side is used as a heat source via a header and a secondary side is used as a load. That is, loads 3, 3 composed of, for example, an air conditioner or the like are connected to the water supply side of the outgoing header 1 via a pump variable flow control device 2 composed of a plurality of pumps by a water supply pipe. The loads 3, 3 are connected to the return header 5 via corresponding valves 4, 4 by return water pipes. The return header 5 and the forward header 1 are connected by a balance pipe 6, and the balance pipe 6 is provided with a valve 7. Refrigerators 9, 9 are connected to the outlet side of the return header 5 via constant flow chilled water pumps 8, 8,
The refrigerators 9 are connected to the inlet side of the outgoing header 1. The refrigerating machines 9 and 9 have constant flow cooling water pumps 10 and 1 respectively.
The cooling towers 11 and 11 are connected to each other via a zero.

That is, the flow rate of the chilled water sent from the outgoing header 1 is adjusted by the pump
The air flows into the air conditioner No. 3 to perform a cooling operation. The return water whose temperature has increased due to heat exchange by the cooling action of the air conditioners of the loads 3 and 3 flows into the return header 5. The cold water whose temperature has risen and has flowed out of the return header 5 is cooled by the refrigerators 9 and 9 having the cooling towers 11 and 11.
And flows into the outbound header 1.

[0004] In such an air conditioning system, a secondary variable flow rate system is used in which the water supply amount is changed by a pump variable flow control device 2 using an inverter as a pump in accordance with the fluctuation of the secondary loads 3 and 3. Adopted to save energy. On the other hand, on the primary side, energy saving is neglected in the sense of ensuring stable operation of the refrigerators 9 and 9, and the constant flow cold water pumps 8 and 8 and the constant flow cooling water pumps 10 and 10 are used on both the cold water side and the cooling water side. Constant flow methods have been employed.
Further, in such an air conditioning system, it is necessary to control the start and stop of the refrigerators 9 and 9 in accordance with the fluctuation of the loads 3 and 3. It is essential to keep. Conventional control methods adopted for this purpose include water supply temperature compensation control based on the outlet temperatures of the refrigerators 9 and 9 and control based on calorific value calculation of the loads 3 and 3.

[0005]

However, in order to save energy, if stable operation of the refrigerator can be ensured, not only the flow rate on the secondary side but also the flow rate on the primary side is affected by the fluctuation of the load. It is effective to adopt a variable flow rate method using a.

Further, in the conventional control system, the control of the secondary flow rate and the control of stopping the operation of the refrigerator due to the load fluctuation are respectively independent control systems, and the forward header and the return header are changed depending on the control timing. Cold water flowed from the upstream header to the return header, or vice versa, due to the flow of the connecting balance pipe, and the secondary side water supply temperature could not be compensated. Furthermore, when the warming-up time of the refrigerator is long, the temperature of the refrigerator cold water outlet changes, and this tendency is greatly generated.

The present invention has been made in view of the above circumstances, and has as its object to provide an air-conditioning system that saves energy while ensuring stable operation of a heat source.
It is an object of the present invention to provide an air conditioning system that compensates for a secondary water supply temperature when a heat source starts and stops.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an air conditioning system having a primary side as a heat source and a secondary side as a load via a forward header and a return header. And a bypass pipe having a valve provided between the inlet and the outlet of the heat source, and means for controlling the flow rates of the primary water flow and the secondary water flow. It is characterized by the following.

In the above air conditioning system, the load state and the flow rate of water in the balance pipe are detected, and the load state and the flow rate of water after a predetermined time required for starting and stopping the heat source are predicted and inferred in advance. The heat source is controlled to start and stop.

[0010]

According to the above-mentioned means, energy can be saved by adopting the variable flow rate method for the primary water flow while ensuring stable operation of the heat source. Also, by performing load prediction and prediction of the water balance on the primary and secondary sides, the start and stop control of the heat source is performed,
Further, by controlling the bypass valve in consideration of the rise of the heat source, a control system that compensates for the secondary-side water supply temperature when the heat source starts and stops can be realized.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of the air conditioning system according to the present invention at the time of cooling, which is a closed type air conditioning system in which a primary side is used as a heat source via a header and a secondary side is used as a load. That is, loads 3, 3 composed of, for example, an air conditioner or the like are connected to the water supply side of the outgoing header 1 via a pump variable flow control device 2 composed of a plurality of pumps by a water supply pipe. The loads 3, 3 are connected to the return header 5 via corresponding valves 4, 4 by return water pipes. The return header 5 and the forward header 1 are connected by a balance pipe 6, and a flow meter 12 is provided on the balance pipe 6. Refrigerators 9 and 9 are connected to the outlet side of the return header 5 via valves 13 and 13 and variable flow chilled water pumps 14 and 14, and the refrigerators 9 and 9 are connected to the inlet side of the forward header 1. . Cooling towers 11 are connected to the refrigerators 9 via variable flow cooling water pumps 15. The valve 1
Connection points of the variable flow chilled water pumps 14, 14
The refrigerators 9 and 9 and the connection point of the forward header 1 are connected to each other by bypass pipes 16 and 16, respectively. The bypass pipes 16 and 16 are provided with valves 17 and 17, respectively.

That is, the flow rate of the chilled water sent from the outgoing header 1 is adjusted by the pump
The air flows into the air conditioner No. 3 to perform a cooling operation. The return water whose temperature has increased due to heat exchange by the cooling action of the air conditioners of the loads 3 and 3 flows into the return header 5. The cold water whose temperature has risen and has flowed out of the return header 5 is cooled by the refrigerators 9 and 9 having the cooling towers 11 and 11.
And flows into the outbound header 1. Next, an embodiment of the air conditioning system of the present invention will be compared with a conventional air conditioning system.

In the conventional air-conditioning system, since the primary chilled water has a constant flow rate and the secondary chilled water has a variable flow rate, the flow of the balance pipe connecting the outgoing header and the return header due to the load fluctuation and the operation and stop of the refrigerator. However, the cold water flows from the outgoing header to the return header or vice versa, and the secondary side water supply temperature compensation could not be performed. Not done,
The water supply temperature was disturbed.

On the other hand, in one embodiment of the air conditioning system of the present invention, the flow meter 12 is mounted on the balance pipe 6 and the variable flow rate of the chilled water is controlled so that the flow rate in the balance pipe 6 is controlled to substantially zero. The primary chilled water flow rate is made variable by the pumps 14 and 14 to eliminate the change in the secondary-side water supply temperature from the outgoing header 1 due to the fluctuation of the loads 3 and 3, and the variable flow rate chilled water pump 14 and 1
4 to reduce the transfer power. As the load on the refrigerators 9 and 9 decreases, the amount of cooling water is reduced by the variable flow rate cooling water pumps 15 and 15 so that the variable flow rate cooling water pump 1
It is also possible to reduce the transfer power of 5,15.

Further, in the conventional air conditioning system, the refrigerator is started and stopped according to the temperature of the chilled water inlet of the refrigerator or the calorific value of the load, but actually, until the chilled water of a predetermined temperature is obtained by starting the operation. Required a certain amount of time, which sometimes resulted in inability to compensate for the secondary chilled water supply temperature.

On the other hand, in one embodiment of the air conditioning system of the present invention, the start-up and stop of the refrigerators 9 and 9 are obtained by capturing the outside air state, the state of the loads 3 and 3 and the change in the flow rate in the balance pipe 6. For example, a load state and a water flow state after a predetermined time such as 30 minutes necessary for the operation are predicted and inferred in advance by applying a fuzzy theory as shown in FIG.

Specifically, start / stop is controlled by a flow as shown in FIG. First, the inverter output state of the chilled water pump, the secondary side water supply temperature, the secondary side load heat amount obtained from the return water temperature and the secondary side water supply amount, the outside air temperature, and the outside air enthalpy obtained from the outside air humidity are used as sensor information. Then, a regression equation is created, and estimated values of the pump output state value, the load calorie, and the outside air enthalpy after N minutes are calculated. Using these values as antecedents, fuzzy inference is applied to determine start / stop.

In the fuzzy inference, first, a start / stop judgment is performed based on an estimated value of the outside air enthalpy after N minutes and a predicted heat load value after N minutes as an antecedent part. A final judgment is made based on these two start / stop judgment results.

FIG. 4 shows a membership function of the fuzzy inference in the latter.
If the pump output state does not change even after N minutes, it indicates that the refrigerator does not start and stop regardless of the flow rate of the balance pipe.

In this case, by controlling the valves 17, 17 of the bypass pipes 16, 16, it is possible to prevent high-temperature water from entering the secondary side when the refrigerators 9, 9 are started and shut down. In addition, the secondary chilled water supply temperature can be compensated.

In the above embodiment, the air conditioning system for cooling is described. However, the present invention is not limited to this, and the air conditioning system for heating can be similarly implemented by using a heat source as a heater.

[0023]

As described above, according to the present invention, by adopting the variable flow rate system for the primary water flow, it is possible to save energy while ensuring stable operation of the heat source. Also, by performing load prediction and prediction of the water balance on the primary and secondary sides by applying fuzzy logic, the start and stop of the heat source is controlled, and the rise of the heat source is considered, and the bypass valve is controlled to control the heat source. A control system for compensating the secondary side water supply temperature at the time of starting and stopping can be made possible.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of the present invention.

FIG. 2 is a configuration explanatory view showing a conventional air conditioning system.

FIG. 3 is an explanatory diagram showing an example of fuzzy inference according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an example of a fuzzy membership function in the fuzzy inference of FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outgoing header, 2 ... Pump variable flow control device, 3 ... Load, 4 ... Valve, 5 ... Return header, 6 ... Balance pipe, 9
.. Refrigerator, 11 cooling tower, 13 valve, 14 variable flow chilled water pump, 15 variable flow cooling water pump, 16 bypass pipe, 17 valve.

Continued on the front page (72) Inventor Makoto Ishikawa 1-20 Akebonocho, Toyota City, Aichi Prefecture Daidan Corporation Toyota Branch (72) Inventor Junji Hasegawa 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Invention Person Takuro Kodama 1st Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A 1-148549 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F24F 5 / 00,11 / 02

Claims (2)

(57) [Claims] 1. An air conditioning system having a primary side as a heat source and a secondary side as a load via an outgoing header and a return header, a flowmeter provided in a balance pipe between the outgoing header and the return header, and a heat source. An air-conditioning system comprising: a bypass pipe having a valve provided between an inlet and an outlet of the air conditioner; and means for controlling the flow rates of the primary water flow and the secondary water flow. 2. Detecting the load condition and the flow rate of water in the balance pipe, and predicting and in advance predicting the load condition and the flow rate of water after a predetermined time required for starting and stopping the heat source, and starting and stopping the heat source. The air conditioning system according to claim 1, wherein the air conditioning system is controlled.