JP2001241735A - Air conditioning system and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning system in which energy is saved more than a conventional system under low load. SOLUTION: Heat source apparatus 1a, 1b,... and primary pumps 11a, 11b,... are provided, respectively, on a plurality of channels between a primary supply header 2 and a primary return header 3 and secondary pumps 21a, 21b,... are provided, respectively, on a plurality of channels between the primary supply header 2 and a secondary return header 4. A pressure regulation valve 16 is provided on a bypass pipe 15 between the primary supply header 2 and the primary return header 3 and the pressure difference across the pressure regulation valve 16 is detected by means of a differential pressure detector 17. When the thermal load on the indoor side reaches the lower limit of the flow rate control range of any one of the secondary pumps 21a, 21b,..., a controller 30 stops the secondary pumps 21a, 21b,... entirely and operates the primary pumps 11a, 11lb,... while keeping the pressure difference detected by the differential pressure detector 17 at such a level as permitting circulation of heating medium to heat utilizing apparatus on the indoor side by regulating the opening of the pressure regulation valve 16 thus supplying heating medium to the indoor side.

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 for circulating a heat medium (hot or cold) between a heat source device and a room.

[0002]

2. Description of the Related Art As an air conditioning system provided conventionally, as shown in FIG. 3, a plurality of heat source devices (cooling source devices or heating source devices) 1a, 1b,. The heat medium (cold water or hot water) supplied from 1b,... Passes through the primary outgoing header 2 and is then sent to the indoor heat utilization equipment (generally an air conditioner), and the heat medium from the heat utilization equipment is converted to primary heat. Heat source devices 1a, 1b,.
An air conditioning system has been proposed in which the heat medium is circulated between the heat source devices 1a, 1b,... And the heat utilization device (see Japanese Patent No. 2899437). In general, the heat source devices 1a, 1b,... Including the primary forward header 2 and the primary return header 3 are called primary sides, and
The indoor side is 2 for the next header 2 and the primary return header 3.
Called the next side. On the primary side, each heat source device 1a, 1b,
Are provided with primary pumps 11a, 11b,... Respectively. The primary pumps 11a, 11b,... Are controlled by variable flow devices 12a, 12b,. It is variable. In the example shown in FIG. 3, each of the primary pumps 11a, 11b,... Is driven by an electric motor, so that the heat source devices 1a, 1b,.
a, 11b,... or the amount of water supply becomes variable.

On the secondary side, a plurality of secondary pumps 21a, 21 are provided between the primary forward header 2 and the heat utilization equipment.
are arranged, and the secondary pumps 21a, 21b,.
The heat medium that has passed through is sent to the heat utilization equipment through the secondary outgoing header 4. The secondary pumps 21a, 21b,... Have variable water supply amounts similarly to the primary pumps 11a, 11b,.
Also, the number of operating units or the amount of water supply is variable so as to supply heat according to the heat load on the indoor side. That is, the amount of water supplied to the secondary pumps 21a, 21b,... Is controlled collectively by the variable water supply capacity device 22 including one inverter.

In this configuration, the amount of water required by the heat load on the indoor side is one of the secondary pumps 21a, 21b,.
The secondary pumps 21a, 21b,... Correspond to a case in which the water supply capacity becomes significantly smaller than the water supply capacity of the vehicle and falls below the lower limit value of the control range allowed for the water supply capacity variable device.
, A bypass pipe 7 is provided between the first forward header 2 and the second forward header 4, and a pressure control valve 6 is provided at an intermediate portion of the bypass pipe 7. A configuration is adopted in which excess water with respect to the water supply capacity of the pumps 21a, 21b, ... is circulated through the bypass pipe 7. This type of configuration is described in JP-A-9-178248.

[0005]

However, as described above, the amount of water required by the heat load on the indoor side is significantly smaller than the water supply capacity of one of the secondary pumps 21a, 21b,... In the case (that is, when it becomes smaller than the lower limit of the control range of the variable water supply capacity control device 22),
There is a problem that the amount of heat obtained by the heat source devices 1a, 1b,.

In order to save energy, a large number of secondary pumps 21a, 21b,... Having a small water supply capacity are provided, or the secondary pumps 21a, 21b,.
It is conceivable to provide another one having a small water-supplying capacity, but in any case, the secondary pumps 21a, 21
.. leads to an increase in the number of devices b,...

The present invention has been made in view of the above circumstances, and an object thereof is to cope with a low load without increasing the number of secondary pumps. An object of the present invention is to provide an air conditioning system that saves energy and a control method thereof.

[0008]

According to a first aspect of the present invention, there is provided a plurality of units which are provided on a plurality of flow paths formed between a primary forward header and a primary return header, respectively, for heating or cooling a heating medium. Heat source equipment and a plurality of heat source devices with variable heat medium flow rates
A second pump, a plurality of secondary pumps respectively provided in a plurality of flow paths formed between the first forward header and the second forward header, and having a variable flow rate of the heat medium; A bypass pipe formed between the secondary return header, a pressure control valve provided on the bypass pipe, a differential pressure detector for detecting a pressure difference between before and after the pressure control valve, a secondary forward header and a primary forward header The indoor heat utilization device disposed on the flow path formed between the header and the number of operating heat source devices and the number of operating primary pumps so as to supply heat corresponding to the amount of heat used indoors, and A control device for controlling the flow rate, the number of operating secondary pumps and the flow rate, wherein the control device has a heat load on the indoor side of 1
When the secondary pump reaches the lower limit of the control range of the flow rate by the two secondary pumps, all the secondary pumps are stopped, and the differential pressure detected by the differential pressure detector is adjusted by adjusting the opening of the pressure control valve. The primary pump is operated to send the heat medium to the heat utilization device while maintaining the heat medium to the extent possible to circulate the heat medium to the indoor heat utilization device.

According to a second aspect of the present invention, in the first aspect of the present invention, the control device stops all the secondary pumps when the flow rate of the secondary pump reaches a lower limit of a control range. .

According to a third aspect of the present invention, in the first aspect of the present invention, a secondary return header for collecting a heat medium returning from the heat utilization device is provided between the indoor heat utilization device and the primary return header. A flow meter is provided between the secondary return header and the primary return header. In the control device, the flow rate detected by the flow meter is larger than the lower limit value of the control range of the flow rate by the secondary pump, and only the primary pump is used. The invention according to claim 4, wherein all the secondary pumps are stopped when the secondary pump stop flow rate falls below a preset secondary pump stop flow rate within a range where the supply of the heat medium to the heat utilization device is possible. The invention according to any one of claims 1 to 3, wherein the heat source device is a heat source device.

In a fifth aspect of the present invention, in the first to third aspects, the heat source heat medium is a cold heat source device.

[0012] According to a sixth aspect of the present invention, there are provided a plurality of heat source devices for heating or cooling the heat medium on a plurality of flow paths formed between the primary forward header and the primary return header, respectively, and a flow rate of the heat medium. Are provided, and a plurality of secondary pumps, each having a variable flow rate of the heating medium, are provided in a plurality of flow paths formed between the primary forward header and the secondary forward header. A pressure control valve is provided on a bypass pipe formed between the primary outgoing header and the primary return header, and an indoor side is provided on a flow path formed between the secondary outgoing header and the primary outgoing header. A heat utilization device is arranged, and when the indoor heat load reaches near the lower limit of the flow rate control range of one secondary pump, all the secondary pumps are stopped and the opening of the pressure control valve is adjusted. Operating the primary pump while sending the heat medium to the heat utilization equipment. .

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, all the secondary pumps are stopped when the lower limit value of the flow rate control range of the secondary pump is reached.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the flow rate returned from the indoor heat utilization equipment is larger than the lower limit of the flow rate control range of the secondary pump, and the heat utilization equipment uses only the primary pump. All secondary pumps are stopped when the secondary pump stop flow rate falls below a preset secondary pump stop flow rate within a range in which the supply of the heat medium to the secondary pump is possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In this embodiment, as shown in FIG. 1, a plurality of primary pumps 11a and 11b (the number is not limited to five in the figure). ,…
, And each of the primary pumps 11a, 11b,.
Are connected to the primary side header 2 through heat source devices (cooling source device or hot source device) 1a, 1b,... Respectively, and are connected to the inlet side of the primary pumps 11a, 11b,.
The next return header 3 is connected. Primary pump 11a, 1
1b,... Are flow rate variable devices 12a composed of inverters.
12b,... Are controlled so that the water supply amount is variable. Therefore, the heating medium (hot water or cold water) supplied from each of the heat source devices 1a, 1b,.
The heat medium introduced into the primary outgoing header 2 by the pressure of the primary pumps 11b, and returned from the indoor heat utilization device (for example, an air conditioner) is heated by the pressure of the primary pumps 11a, 11b,. 1a, 1b,...

The primary forward header 2 includes a plurality of (in the figure, six, but not intended to be limited) secondary pumps 21a, 2a.
1b,... Are connected, and the secondary pumps 21a, 2
The secondary forward header 4 is connected to the output side of 1b,.
The heating medium is sent from the second forward header 4 to the indoor heat utilization equipment. Each of the secondary pumps 21a, 21b,...
.. Are controlled so that the rotation speed of the electric motor is variable. Here, the number of indoor heat utilization devices is not particularly specified.

On the other hand, the heat medium from the indoor heat utilization equipment is 2
Once collected in the secondary return header 5, it is returned from the secondary return header 5 to the primary return header 3 through the flow meter 13 and the temperature detector 14. The primary return header 3 includes a primary pump 11a,
Since the input sides of 11b,... Are connected, the heat medium returned to the primary return header 3 is supplied to the primary pumps 11a, 11b,.
Are sent to the heat source devices 1a, 1b,. A temperature detector 18 that detects the temperature of the heat medium returned from the heat utilization device is disposed in the primary return header 3.

The primary water supply header 2 and the primary return header 3 are 1
The primary bypass pipe 1 is connected through the secondary bypass pipe 15
A pressure control valve 16 is provided at an intermediate portion of 5. The primary bypass pipe 15 is provided to bypass a difference between the supply amount of the heat medium (the amount sent from the primary forward header 2) and the return amount (the amount returned to the primary return header 3). Primary bypass pipe 1
5 is provided with a pressure control valve 16 and a differential pressure detector 17 for detecting a pressure difference before and after the pressure control valve 16, that is, a pressure difference between the primary forward header 2 side and the primary return header 3 side.

The secondary outgoing header 4 distributes the heat medium to the indoor heat utilization equipment, and the secondary return header 5 is provided for collecting the heat medium returned from the heat utilization equipment. The second forward header 4 is provided with a temperature detector 23 for detecting the temperature of the heat medium sent to the indoor heat utilization equipment. Although not shown in FIG. 1, a differential pressure detector for detecting a pressure difference between the secondary forward header 4 and the secondary return header 5 is provided, and the output of the differential pressure detector is controlled by the pressure regulating valve 16. It may be used as information.

Incidentally, a flow meter 13, a temperature detector 14,
The measurement values detected by the differential pressure detector 17, the temperature detector 18, and the temperature detector 23 are input to the control device 30, and the heat source devices 1a, 1b,..., The primary pumps 11a, 11b,.
A signal indicating the operation state of the secondary pumps 21a, 21b, ... is also input to the control device 30. The measurement values and signals input to the control device 30 are input to an input processing unit 31 provided in the control device 30.
Processing unit 33 composed of a microcomputer through
Is input to The arithmetic processing unit 33 creates control information based on the measurement values and signals input through the input processing unit 31, and outputs heat information from the heat source devices 1 a, 1 b,.
..., the flow rate variable devices 12a, 12b, ..., the water supply capacity variable devices 22a, 22b, ..., and the pressure control valve 16 are controlled.

Next, the operation will be described. Generally, in this type of air conditioning system, the opening of a valve attached to the indoor heat utilization equipment is adjusted according to the heat load on the indoor side, so the heat load on the indoor side is reflected in the flow rate. I have. Therefore, the control device 30 can know the amount of heat required on the indoor side by the flow rate of the flow meter 13, and operates the number of secondary pumps 21a, 21b,... .. Are given to adjust the amount of water supplied by each of the secondary pumps 21a, 21b,... To cope with fluctuations in the indoor thermal load.

In the control device 30, the second forward header 4
The temperature difference between the temperature of the heat medium detected by the temperature detector 23 provided in the primary return header 3 and the temperature of the heat medium detected by the temperature detector 18 provided in the primary return header 3 is used to calculate the flow rate detected by the flow meter 13. By multiplying, the amount of heat required on the indoor side is calculated,
The number of heat source devices 1a, 1b, ... corresponding to the calculated amount of heat
, And the primary pumps 11a, 11b,... Are operated, and the flow rates of the primary pumps 11a, 11b,. Respond to fluctuations in the internal heat load.
In this state, the pressure control valve 16 provided in the bypass pipe 15
Is fully opened, and a surplus of the heat medium is allowed to freely pass through the bypass pipe 15 between the primary forward header 2 and the primary return header 3.

Here, when the number of operating secondary pumps 21a, 21b,... Becomes one when the indoor thermal load decreases, the heat source devices 1a, 1b,.
a, 11b,... are also one. From this state, the heat load on the indoor side further decreases, and the secondary pump 21
When the water flow rate becomes smaller than the minimum water flow rate permitted for a, 21b,... (that is, the water flow capacity variable devices 22a, 22b,.
.. (Below the lower limit of the control range).
The control of a, 21b,... cannot respond to the heat load on the indoor side. Therefore, in the present embodiment, when such a state is reached, all the secondary pumps 21a, 21b,.
.. Are given from the control device 30 to the water supply capacity variable devices 22a, 22b,. at the same time,
One primary pump 11a, 11b,
.., So that the water supply amount is maximized.
Gives instructions to the flow rate variable devices 12a, 12b,.
The heat medium is circulated between the indoor heat utilization devices only by the water supply pressures of the primary pumps 11a, 11b,.... Further, the water supply pressure of the primary pumps 11a, 11b,... Corresponding to the lower limit value of the control range of the flow rate variable devices 12a, 12b,. The pressure regulating valve 16 is adjusted so that the differential pressure becomes the target value.
Control. Here, a value preset in the control device 30 is used as the target value. Thus, the primary pump 1
1a, 11b,... And the pressure control valve 16
It is possible to supply the heat medium to the indoor side through the secondary outgoing header 4 by adjusting.

When the heat load on the indoor side is reduced and the heat load on the indoor side is increased from the above-described state in which only one primary pump 11a, 11b,. Flow rate increases and the secondary pump 2
1a, 21b,... To control the water supply capacity 22
When the flow rate becomes within the control range of a, 22b, ..., the secondary pumps 21a, 21b, ... are started, and the pressure control valve 16 is fully opened to return to the normal control state. At this time,
Control the flow rate of the primary pumps 11a, 11b,... To return to the normal control state.

Hereinafter, the reason why a required amount of heat medium can be supplied when the heat load on the indoor side is reduced by the above-described control will be described. Now, the heat source devices 1a, 1b, 1c, the primary pumps 11a, 11b, 11c, and the secondary pump 21
a, 21b, and 21c are used three by three. The secondary pumps 21a, 21b, and 21c have the same specifications. With the flow rate as the horizontal axis and the pressure as the vertical axis, the primary pumps 11a, 11b, 11c and the secondary pump 2
FIG. 2 shows the water supply capacity with respect to 1a, 21b and 21c and the resistance of the pipe. In FIG. 2, curves a, b, c
Indicates the water supply capacity when one secondary pump 21a, 21b, 21c is operated, when two pumps are operated, and when three pumps are operated, and a curve d indicates the primary pumps 11a, 11b, 21c.
The water supply capacity when one unit 11c is operated is shown, and the curve e indicates the minimum water supply capacity of one secondary pump 21a, 21b, 21c. Further, a curve f is a pipe resistance on the primary side, a curve g is a pipe resistance on the indoor side (this pipe resistance is known to have a pressure proportional to the square of the flow rate), and a curve h.
Indicates the combined pipe resistance between the primary side and the indoor side.

In FIG. 2, the water supply pressure Ps when the indoor side has the maximum load is a pressure corresponding to the intersection of the curves c and g, and is proportional to the square of the flow rate when the indoor side has the maximum load. To a relatively high pressure. Also, the flow rate Vs corresponding to this pressure on the curve a is the water supply amount of one of the secondary pumps 21a, 21b, 21c at the time of the maximum load. The pressure corresponding to this flow rate Vs on the curve d is
This is the water supply pressure Pp per one of the primary pumps 11a, 11b, 11c at the time of the maximum load. On the other hand, when the load on the indoor side is small, the required flow rate is small, and the water supply pressure is considerably small. For example, if the amount of water required on the indoor side becomes one third of the maximum load, the secondary pumps 21a, 21b,
The water supply pressure required for 21c is reduced to one-ninth. In FIG. 2, the minimum controllable flow rate Vn of the secondary pumps 21a, 21b, 21c is the intersection of the curve e indicating the minimum water supply capacity of the secondary pumps 21a, 21b, 21c and the curve g indicating the pipe resistance on the indoor side. Flow rate corresponding to.

By the way, the pipe resistance on the primary side is relatively small because the pipes are divided into paths corresponding to the heat source devices 1a, 1b, 1c, regardless of the number of operating heat source devices 1a, 1b, 1c. Primary pumps 11a, 11b, 11c
The required water supply pressure is relatively small. Here, since the piping on the indoor side is designed according to the amount of water required at the time of maximum load, the primary pump 1 is provided in a range corresponding to the amount of water supplied per one of the primary pumps 11a, 11b, and 11c.
The water supply pressure required for 1a, 11b, 11c is usually lower than the water supply pressure required for circulation on the primary side.

The pipe resistance when the heat medium is circulated in the entirety of the pipe on the primary side and the pipe on the indoor side is as shown by a curve h.
However, in the main piping path on the indoor side, the pipe resistance on the indoor side is applied, and the curve g can be applied. However, among the heat utilization equipment on the indoor side, the one that has the longest circulation path of the heat medium has the flow path (that is, from the final branch point to the first junction) connected only to that heat utilization equipment. Since the pipe resistance is designed in accordance with the heat utilization equipment, the water supply pressure required to circulate the part must be secured as the required terminal pressure Pb separately from the water supply pressure to other parts. . Accordingly, in the curve i, the curve h indicating the pipe resistance when the heat medium is circulated through the pipes on the primary side and the pipes on the indoor side as a whole is the required terminal pressure Pb.
Are added. Conversely, the pressure when the flow rate is 0 in the curves h and i is the required terminal pressure Pb in the heat utilization device.

As can be understood from the above description, the primary pumps 11a, 11b and 11c are usually
The operation is performed so as to maintain the flow rate and the water supply pressure corresponding to the intersection between the curve d indicating the water supply capacity of 11b and 11c and the curve f indicating the pipe resistance on the primary side. On the other hand, if the heat load on the indoor side is reduced and all the secondary pumps 21a, 21b, 21c are stopped, the pipe resistance obtained by combining the pipe resistance on the primary side and the pipe resistance on the indoor side is further required. Pressure Pb
, And the primary pumps 11a, 11b, 11c are operated so as to maintain the flow rate and the water supply pressure corresponding to the intersection of the curve i indicating the primary-side pipe resistance.
The flow rate of the primary pumps 11a, 11b, 11c at this time is hereinafter referred to as a secondary pump stop flow rate Va. At this time, since the flow rate required from the indoor side decreases, the flow rate decreases, but the primary pumps 11a, 11b, 1
The water supply pressure of 1c rises. If the required flow rate on the indoor side is equal to or less than the flow rate corresponding to this intersection, the primary pump 11
The heat medium can be circulated only by a, 11b, and 11c. Here, in order to circulate the heat medium on the indoor side, it is necessary to secure a required pressure difference between the secondary forward header 4 and the secondary return header 5, but a pressure control valve 16 provided in the bypass pipe 15 is required. Is fully opened, a necessary pressure difference between the secondary forward header 4 and the secondary return header 5 cannot be secured, and the primary pumps 11a, 11b, 11c and the bypass pipe 1
5, the heat medium circulates. Therefore,
The pressure detected by the differential pressure detector 17 is a pressure corresponding to the difference between the value obtained by adding the terminal required pressure to the pipe resistance on the primary side and the indoor side and the pipe resistance on the primary side (that is, the pressure on the indoor side). The opening amount of the pressure control valve 15 is adjusted so that the pressure (Pd obtained by adding the pipe resistance and the required terminal pressure) is Pd. By adjusting the opening amount of the pressure control valve 15 in this manner, a pressure for sending the heat medium to the indoor side can be secured, and the heat medium can be circulated to the indoor side.

The minimum controllable flow rate Vn of the secondary pumps 21a, 21b, 21c is usually 3 times the maximum flow rate.
0-40%, and the secondary pumps 21a, 21b, 21
Primary pump 11a, 11b, 11c when c stops
Hardly exceeds the secondary pump stop flow rate Va, and when the lower limit value of the control range of the secondary pumps 21a, 21b, 21c is reached, all the secondary pumps 21a, 2c
By stopping 1b and 21c, the primary pump 1
The heat medium can be circulated under the control of only 1a, 11b and 11c.

The heat source equipment 1a, 1b, 1c can circulate the heat medium if the flow rate of the heat medium fluctuates and the flow rate is at least about 50% of the rated flow rate. is there. In other words, the heat source devices 1a, 1b, 1
The flow rate of the heat medium passing through c must be at least about 50% of the rated flow rate. Heat source equipment 1a, 1
The flow rates of b and 1c are less than 50% of the rated flow rate when the primary side pipe resistance is extremely larger than the indoor side pipe resistance or the terminal required pressure Pb is large. Does not occur in most air conditioning systems, so the configuration of the present embodiment can be applied to most air conditioning systems.

(Second Embodiment) In the first embodiment, only one secondary pump 21a, 21b,... Is operated, and the secondary pump 21a required for the heat load on the indoor side is operated. , 21b,.
a, 22b,... secondary pumps 21a, 21b,.
When the lower limit of the control range is reached, all the secondary pumps 21a, 21b,.
In this embodiment, the water supply is performed only by the primary pumps 11a, 11b,... from the state in which the secondary pumps 21a, 21b,. The timing for shifting to is different from that of the first embodiment.

That is, in the present embodiment, the secondary pump 21
The indoor circulating water amount detected by the flow meter 13 used for controlling the water supply amounts of a, 21b,... is compared with the secondary pump stop flow amount Va shown in FIG. Are stopped at a point in time when the flow rate falls below the secondary pump stop flow rate Va.

When the configuration of this embodiment is adopted, the secondary pump stop flow rate Va must be determined in advance, and the overall pump control flow rate Va is determined by examining the overall characteristics of the air conditioning system. However, after reaching the lower limit of the control range of the secondary pumps 21a, 21b,..., All the secondary pumps 21a, 21b,.
, The flow rate required according to the heat load on the indoor side is smaller than the secondary pumps 21a, 21b,.
The primary pump 11a,
.., And the operation time of the secondary pumps 21a, 21b,... At the time of low load is shorter than that of the first embodiment. That is, at the time of a low load, the secondary pump 21 is lower than in the first embodiment.
.., and the power consumption is further reduced. Other configurations and operations are the same as those of the first embodiment.

[0035]

According to the first aspect of the present invention, there are provided a plurality of heat source devices which are provided on a plurality of flow paths formed between a primary outgoing header and a primary return header to heat or cool a heating medium, respectively. A plurality of primary pumps whose flow rates of the heat medium are variable;
A plurality of secondary pumps respectively provided in a plurality of flow paths formed between the next header and the secondary header and having a variable flow rate of the heat medium, and a primary forward header and a primary return header; A bypass pipe formed therebetween, a pressure regulating valve provided on the bypass pipe, a differential pressure detector for detecting a pressure difference before and after the pressure regulating valve, and a second forward header and a first forward header. The indoor heat utilization device disposed on the formed flow path, the number of operating heat source devices, the number of operating primary pumps, the flow rate, and the secondary pump so as to supply heat corresponding to the amount of heat used indoors And a controller for controlling the number of operating units and the flow rate. When the indoor heat load reaches the vicinity of the lower limit of the flow rate control range of one secondary pump,
While stopping the next pump, while adjusting the opening amount of the pressure regulating valve, while maintaining the differential pressure detected by the differential pressure detector to the extent that circulation of the heat medium to the indoor heat utilization equipment becomes possible. Operating the primary pump to send a heat medium to the heat utilization equipment, and stopping the secondary pump when the required water volume on the indoor side reaches near the lower limit of the control range of the flow rate by the secondary pump. Because the heat medium is circulated only by the primary pump, compared to the conventional configuration in which only one secondary pump is operated at low load and the heat medium is circulated wastefully, only the amount of stopping the secondary pump at low load It will save energy. In addition, the operation time of the secondary pump is shortened as a whole, and the life of the secondary pump is extended.

According to a second aspect of the present invention, in the first aspect of the present invention, the control device stops all the secondary pumps when the flow rate of the secondary pump reaches a lower limit of a control range. Since the lower limit value of the control range of the flow rate by the secondary pump is used as a reference, the stop point of the secondary pump can be set without analyzing the operation of the air conditioning system.

According to a third aspect of the present invention, in the first aspect of the present invention, a secondary return header for collecting a heat medium returning from the heat utilization device is provided between the indoor heat utilization device and the primary return header. A flow meter is provided between the secondary return header and the primary return header. In the control device, the flow rate detected by the flow meter is larger than the lower limit value of the control range of the flow rate by the secondary pump, and only the primary pump is used. Stops all secondary pumps when the secondary pump stop flow rate falls below a preset secondary pump stop flow rate within a range where the heat medium can be supplied to the heat utilization equipment. The secondary pump stop flow rate is set in advance. However, the period during which the secondary pump is stopped is longer than that of the second aspect of the invention, so that energy is saved and the life of the secondary pump is longer than that of the second aspect.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the heat source device is a heat source device, and the room can be heated.

According to a fifth aspect of the present invention, in the first to third aspects of the present invention, the heat source heat medium is a cold heat source device, thereby enabling indoor cooling.

According to a sixth aspect of the present invention, there are provided a plurality of heat source devices for heating or cooling the heat medium on a plurality of flow paths formed between the primary forward header and the primary return header, respectively, and the flow rate of the heat medium. Are provided, and a plurality of secondary pumps, each having a variable flow rate of the heating medium, are provided in a plurality of flow paths formed between the primary forward header and the secondary forward header. A pressure control valve is provided on a bypass pipe formed between the primary outgoing header and the primary return header, and an indoor side is provided on a flow path formed between the secondary outgoing header and the primary outgoing header. A heat utilization device is arranged, and when the indoor heat load reaches near the lower limit of the flow rate control range of one secondary pump, all the secondary pumps are stopped and the opening of the pressure control valve is adjusted. Operating the primary pump while feeding the heat medium to the heat utilization equipment. Since stopping the secondary pump to circulate the heat medium only in the primary pump when the request amount of water chamber side reaches the vicinity of the lower limit of the control range of the flow rate by the secondary pump,
Compared to the conventional configuration in which only one secondary pump is operated at a low load and the heat medium is circulated wastefully, energy is saved by stopping the secondary pump at a low load. In addition, the operation time of the secondary pump is shortened as a whole, and the life of the secondary pump is extended.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, all the secondary pumps are stopped when the lower limit of the flow rate control range of the secondary pump is reached. Can be set without analyzing the operation of the secondary pump.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the flow rate returned from the indoor heat utilization equipment is larger than the lower limit of the control range of the flow rate by the secondary pump, and the heat utilization equipment only uses the primary pump. When the secondary pump stop flow rate falls below a preset secondary pump stop flow rate within a range where the supply of the heat medium to the secondary pump is possible, the secondary pump stop flow rate is set in advance. The period during which the secondary pump is stopped is required, but it is necessary to set
In this case, energy is saved and the service life of the secondary pump is extended.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory view of the above.

FIG. 3 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 .. 1a, 1b,... Heat source equipment 2 Primary outgoing header 3 Primary return header 11a, 11b,. Pump 30 control device

Claims (8)

[Claims] 1. A plurality of heat source devices provided on a plurality of flow paths formed between a primary outgoing header and a primary return header for heating or cooling a heating medium and a flow rate of the heating medium are variable. A plurality of primary pumps, a plurality of secondary pumps respectively provided in a plurality of flow paths formed between the first forward header and the second forward header, and having a variable flow rate of the heat medium; A bypass pipe formed between the next header and the first return header, a pressure control valve provided on the bypass pipe, a differential pressure detector for detecting a pressure difference between before and after the pressure control valve, and a second forward header The indoor heat utilization equipment disposed on the flow path formed between the header and the primary forward header, and the number of operating heat source equipment and the primary heat source equipment to supply heat corresponding to the heat used on the indoor side A control device for controlling the number of pumps operated and the flow rate and the number of secondary pumps operated and the flow rate When the indoor thermal load reaches near the lower limit of the flow rate control range of one secondary pump, all the secondary pumps are stopped and the pressure control valve is opened. The primary pump is operated to adjust the amount of heat to the heat utilization device while maintaining the differential pressure detected by the differential pressure detector to such an extent that the heat medium can be circulated to the indoor heat utilization device. An air conditioning system characterized by sending a heat medium. 2. The air conditioning system according to claim 1, wherein the control device stops all the secondary pumps when a lower limit value of a control range of the flow rate of the secondary pump is reached. 3. A secondary return header for collecting a heat medium returning from the heat utilization device is provided between the indoor heat utilization device and the primary return header, and between the secondary return header and the primary return header. A flow meter is provided, and in the control device, the flow rate detected by the flow meter is larger than the lower limit value of the control range of the flow rate by the secondary pump, and the heat medium can be supplied to the heat utilization device only by the primary pump. 2 set in advance in a certain range
The air conditioning system according to claim 1, wherein all the secondary pumps are stopped when the secondary pump stop flow rate is reduced. 4. The air conditioning system according to claim 1, wherein the heat source device is a heat source device. 5. The air conditioning system according to claim 1, wherein the heat source device is a cold heat source device. 6. A plurality of heat source devices for heating or cooling the heating medium on a plurality of flow paths formed between the primary outgoing header and the primary return header, and a plurality of heating mediums having variable flow rates. Primary pumps are provided, and a plurality of secondary pumps each having a variable flow rate of the heat medium are provided in a plurality of flow paths formed between the primary forward header and the secondary forward header. A pressure control valve is provided on a bypass pipe formed between the header and the primary return header, and the indoor heat utilization device is arranged on a flow path formed between the secondary forward header and the primary forward header. When the heat load on the indoor side approaches the lower limit of the flow control range of one secondary pump, all the secondary pumps are stopped, and the primary pump is adjusted while adjusting the opening of the pressure control valve. An air conditioning system comprising: Control method. 7. The control method for an air-conditioning system according to claim 6, wherein all secondary pumps are stopped when the lower limit value of the control range of the flow rate of the secondary pump is reached. 8. A range in which the flow rate returned from the indoor heat utilization equipment is larger than the lower limit of the flow rate control range of the secondary pump and the supply of the heat medium to the heat utilization equipment by only the primary pump is possible. 7. The control method for an air conditioning system according to claim 6, wherein all secondary pumps are stopped when the secondary pump stop flow rate falls below a preset secondary pump stop flow rate.