JP2010127564A - Heat source system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promote energy saving by avoiding an energy loss generated by the control of the operating number of heating medium pumps in a heat source system. <P>SOLUTION: The heat source system includes a pump control means 5 setting a flow rate value Qs (Qs1-Qs3) at each intersection point X1-X3 between pump performance curves L1-L3 with respect to each operating number N and a pump control line M being a threshold flow rate, reducing one from the operating numbers N of the heating medium pumps when a load flow rate Q of a load device becomes lower than the threshold flow rate Qs, and adding one to the operating numbers N of the heating medium pumps when the load flow rate Q becomes higher than the threshold flow rate Qs. Based on detection information by a flow rate detection means FS for detecting the load flow rate Q, the pump control means 5 executes pump output control for adjusting an output of at least one heating medium pump out of the operating heating medium pumps in accordance with a change in the load flow rate Q. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat source system used in an air conditioner or the like, and more specifically, a plurality of heat medium pumps are arranged in parallel in a heat medium supply path for supplying a heat medium cooled or heated by a heat source machine to a load device. The present invention relates to a heat source system equipped with pump control means for changing the number of operating heat medium pumps in accordance with a change in load flow rate that is a heat medium flow rate required by a load device.

  Conventionally, in this type of heat source system, the following control methods (a) to (c) have been adopted to change the number of operating heat medium pumps according to the change in the load flow rate accompanying the increase or decrease of the heat load. (See Patent Document 1).

  (A) As shown in FIG. 5, the heat medium feed flow rate Q when each of the operation heat medium pumps is operated at the maximum output (generally the rated maximum output) in the heat medium pump operation with each operation number N. Pump performance curves L1 to L3 for each operating number N showing a correlation with the heat medium supply pressure P (that is, pumps related to flow rate and pressure when the entire heat medium pump in the operating state is regarded as one pump) Performance curve).

  (B) As a supply pressure control of the heat medium supplied to the load device, a so-called discharge pressure that adjusts the heat medium supply pressure P to the load device to a constant target pressure Pms in the heat medium pump operation with each operation number N. In contrast to the constant control, the flow rate value Qs ′ (Qs1 ′ to Qs3 ′) corresponding to the target pressure Pms (constant) of the constant discharge pressure control on the pump performance curves L1 to L3 for each of the operating units N is a threshold value. The flow rate.

(C) Based on the detection information of the flow rate detection means for detecting the load flow rate Q, for each of the threshold flow rates Qs ′, when the load flow rate Q decreases below the threshold flow rate Qs ′, the number N of operating heat medium pumps is decreased by one. When the load flow rate Q increases above the threshold flow rate Qs', the number N of operating heat medium pumps is increased by one.
In other words, every time the load flow rate Q decreases below each threshold flow rate Qs ′, the number N of operating heat medium pumps is decreased by one, and every time the load flow rate Q increases above each threshold flow rate Qs ′. Increase the operating number N of heat medium pumps one by one.

  That is, in this conventional system, each heat medium pump flow rate ΔQ of each heat medium pump obtained when each of the heat medium pumps is operated at the maximum output under a pressure condition in which the heat medium supply pressure P is a constant value Pms. The threshold flow rate Qs ′ (Qs1 ′ to Qs3 ′) is set by the distribution (generally at regular intervals), and the number of operating heat medium pumps according to the change of the load flow rate Q using these threshold flow rates Qs ′ as the number change index N was changed.

  Further, instead of the above-described constant discharge pressure control, as supply pressure control, as shown in FIG. 5, a load flow rate Q and a supply pressure P necessary to supply the load medium with the heating medium of the load flow rate Q are provided. The pump control line M showing the correlation with the pressure is set in consideration of the pipe resistance, etc., and the pressure value corresponding to the load flow rate Q (current flow rate) at each time point on the pump control line M is set as the target pressure Pm. An improved system for adjusting the heat medium supply pressure P to the load device to the target pressure Pm at each time point (that is, the target pressure that changes as the load flow rate Q changes) based on the detection information of the medium supply pressure P is also proposed. (See Patent Document 2).

  However, even in this improved system, the above-mentioned conventional method is followed for controlling the number of operating heat medium pumps, and the maximum output of each of the heat medium pumps is achieved under pressure conditions where the heat medium supply pressure P is a constant value Pms. The threshold flow rate Qs ′ (Qs1 ′ to Qs3 ′) set by the distribution for each heating medium feed flow rate ΔQ of the heating medium pump obtained when operating with the heat medium pump is used as the number change index, and the heating medium according to the change in the load flow rate Q The number of pumps N was changed.

JP 58-93974 A JP 2002-31376 A

  However, in the above-described conventional control of the number of operating pumps, the operating number N−1 is temporarily smaller than the number N of operating heat medium pumps determined by comparing the threshold flow rate Qs ′ (Q1 ′ to Q3 ′) with the load flow rate Q. Even when the heat medium pump is operated, the heat medium can be supplied to the load device without any problem on both the flow surface and the pressure surface (that is, the operating number N determined by comparing the threshold flow rate Qs ′ and the load flow rate Q). However, there were frequent occurrences of situations where the number of pumps actually exceeded that required.

  And when the heat medium pump is operated with the number N of operation more than necessary as described above, a plurality of heat medium pumps are operated in a state where the individual outputs are reduced, resulting in a decrease in pump efficiency. In this respect, the excess pump output is increased and the output loss of the heat medium pump is increased, or the total inevitable energy loss caused by the operation of the individual heat medium pumps is increased. There was room for improvement in achieving energy.

  In view of this situation, the main problem of the present invention is to eliminate the above problems and promote energy saving by adopting a rational control mode in changing the number of operating heat medium pumps.

The first characteristic configuration of the present invention relates to a heat source system, and the characteristic is as follows:
While interposing a plurality of heat medium pumps in parallel arrangement in the heat medium feed path for supplying the heat medium cooled or heated by the heat source machine to the load device,
A heat source system equipped with pump control means for changing the number of operating heat medium pumps according to a change in load flow rate that is a heat medium flow rate required by the load device,
Set the pump performance curve for each number of operating units that shows the correlation between the heat medium supply flow rate and the heat medium supply pressure when each of the operating heat medium pumps is operated at the maximum output in the operation of the heat medium pump with each operating number. With
Setting a pump control line indicating the correlation between the load flow rate and the supply pressure required to supply the load medium with the heat medium of the load flow rate,
Each of the flow rate value at each intersection of the pump performance curve and the pump control line for each number of operating units or its neighboring flow rate value is set as the threshold flow rate,
With respect to these settings, the pump control means, based on the detection information of the flow rate detection means for detecting the load flow rate, as the pump operation number control,
For each of the threshold flow rates, when the load flow rate decreases below the threshold flow rate, the number of operating heat medium pumps decreases by one, and when the load flow rate increases above the threshold flow rate, the number of operating heat medium pumps decreases by one. It is in the point which is made the structure to increase.

  That is, in this configuration (see FIG. 2), each of the intersections X1 to X3 between the pump performance curves L1 to L3 and the pump control line M for each of the operating units N described above corresponds to each operating unit N (N = 1, 2, In the heat medium pump operation in 3), the flow rate / pressure correlation indicated by the pump control line M under the condition that each of the operation heat medium pumps is operated at maximum output (that is, the load flow rate Q and the heat medium of the load flow rate Q are used as the load device) (Correlation with the supply pressure necessary for supplying to the pump) is a point indicating the upper limit pump operating state for each number of operating units.

  Accordingly, when each of the flow rate values Qs (Qs1 to Qs3) at the intersections X1 to X3 is set as a threshold flow rate, as described above, when the load flow rate Q decreases below the threshold flow rate Qs for each of the threshold flow rates Qs, the heat medium pump If the operating number N of the heat medium pump is decreased by one and the operating number N of the heat medium pump is increased by one when the load flow rate Q increases above the threshold flow rate Qs, the heat medium corresponding to the change in the load flow rate Q is obtained. While avoiding a situation in which the heat medium pump is operated with an operation number N more than necessary in changing the number of pumps to be operated, the heat medium with the load flow rate Q can be appropriately supplied to the load device.

  That is, the number of heat medium pumps obtained by operating each heat medium pump at the maximum output under a pressure condition where the heat medium supply pressure P is a constant value Pms is changed according to the distribution for each heat medium supply flow rate ΔQ. In the above-described conventional method in which the threshold flow rate Qs ′ (Qs1 ′ to Qs3 ′) is set as an index (see FIG. 5), the operation of the heat medium pump is determined by comparing the threshold flow rate Qs ′ with the load flow rate Q. Even if the heat medium pump is operated with an operation number one less than the number N, an excessive number of operation units can supply the heat medium to the load device without any problem on both the flow rate side and the pressure side, as shown by Qs1 to Qs1 ′ in FIG. It occurs in each of the flow rate range and the flow rate range of Qs2 to Qs2 ′. On the other hand, according to the above configuration, such a situation can be avoided and the number N of operating heat medium pumps can be avoided. To the extent possible at each time point It can be minimized, thereby, it is possible to promote energy saving.

  In the above example, three heat medium pumps are provided. However, the number of heat medium pumps arranged in parallel in the heat medium supply path is not limited to three and may be two or more. Any number of units may be used, and the plurality of heat medium pumps may have different specifications such as maximum output.

  Not all of the equipped multiple heat medium pumps are subject to change in the number of operating units, but some of the equipped heat medium pumps are always operated during system operation, and only other multiple pumps May be the target of changing the number of operating units.

  The pump performance curves L1 to L3 for each operation number N indicate the flow rate / pressure correlation when each of the operation heat medium pumps is operated at the rated maximum output, or each of the operation heat medium pumps is substantially maximum. Any of those showing a flow rate / pressure correlation in the case of operation with output may be used.

  Although it is desirable to obtain the pump control line M by actual measurement, an approximate curve, a broken line, a straight line, or the like obtained by simulation or calculation may be used as the pump control line M in order to facilitate the implementation of the system. Further, when an approximate one obtained by simulation or calculation is adopted as the pump control line M, it is desirable to use the pump control line M after correcting the obtained pump control line M based on actual measurement data or the like.

  The pump performance curves L1 to L3, the pump control lines M, and their intersections X1 to X3 for each number of operating units N do not have to be drawn on the figure, and are recognized only by the pump control means as equations and coordinates. In addition, the pump performance curves L1 to L3, the pump control line M, or their intersections X1 to X3 and the threshold flow rate Qs (Qs1 to Qs3) are set to default values. Either a method of storing in the pump control means by simple input or a method of causing the pump control means to calculate by inputting required data may be adopted.

  The threshold flow rate Qs (Qs1 to Qs3) as the number change index does not necessarily exactly match the flow rate values at the intersections X1 to X3 between the pump performance curves L1 to L3 and the pump control lines M for each number N of operating units. For example, the flow rate value slightly smaller than the flow rate value at each of the intersections X1 to X3 is set to the threshold flow rate Qs in anticipation of the safety factor, or conversely, the actual maximum output of each heat medium pump is larger than the rated maximum output. For example, a flow rate value slightly larger than the flow rate value at each of the intersection points X1 to X3 may be set as the threshold flow rate Qs, and the flow rate value near the flow rate value at each of the intersection points X1 to X3 may be set as the threshold flow rate Qs.

  The flow rate detecting means for detecting the load flow rate Q may be either one that directly detects the heat medium flow rate Q in the load device or one that is indirectly detected, and various detection methods thereof. Can be adopted.

The second feature configuration of the present invention specifies an embodiment suitable for the implementation of the first feature configuration.
The pump control means outputs the output of at least one heat medium pump of the operation heat medium pumps according to the change of the load flow rate based on the detection information of the flow rate detection means for detecting the load flow rate together with the pump operation number control. The pump output control to be adjusted is executed.

  That is, according to this configuration, in addition to the pump operation number control, the output of at least one heat medium pump of the operation heat medium pumps is adjusted according to the change in the load flow rate Q. In the heat medium pump operation, the upper threshold flow rate Qs for operating each of the operation heat medium pumps at the maximum output (that is, the number change index on the side that increases the number of operation of the heat medium pump by one from the current operation number) In the state where the load flow rate Q is reduced from the threshold flow rate Qs), the output of at least one operating heat medium pump is adjusted to the lower side than the maximum output, and the output of the entire operating heat medium pump is reduced accordingly. To do.

  That is, compared with always operating the operating heat medium pump at the maximum output in the operation of the heat medium pump with each operating number N, the energy consumption of the entire operating heat medium pump can be reduced by the amount of the above output reduction, Thereby, energy saving can be promoted more effectively, coupled with the above-mentioned pump operation number control that can reliably minimize the number N of operating heat medium pumps within a possible range at each time point.

  In order to adjust the output of the operation heat medium pump, either an adjustment mode in which the output of the operation heat medium pump is continuously changed in accordance with a change in the load flow rate Q or an adjustment mode in which the output is changed step by step is adopted. However, in any case, it is desirable to adjust the output of the operating heat medium pump according to the change of the load flow rate Q in the form in which the pump control line M is the reference line for output adjustment.

  The output adjustment of the operation heat medium pump according to the change of the load flow rate Q is not limited to the operation of all the heat medium pump operations at each operation number N by the pump operation number control, but the heat medium pump at each operation number N You may make it implement only about the one part heat medium pump driving | operation of driving | operation.

  In order to adjust the output of the operating heat medium pump, various output adjustment methods can be employed, including adjustment of the pump rotation speed by inverter control (frequency control).

  As the flow rate detection means used in this configuration, various detection methods can be adopted regardless of whether the flow rate Q in the load device is directly detected or indirectly detected. The flow rate detecting means used in the implementation of the first characteristic configuration may be used, or may be a separate one.

The third feature configuration of the present invention specifies an embodiment suitable for the implementation of the second feature configuration.
The pump control means, as the pump output control,
Based on the detection information of the pressure detection means for detecting the heat medium supply pressure to the load device, the output of at least one heat medium pump of the operation heat medium pumps is adjusted to supply the heat medium to the load device. Feed pressure control that adjusts the feed pressure to the target pressure;
The target change control for changing the target pressure of the supply pressure control according to the change of the load flow rate based on the detection information of the flow rate detecting means is configured.

  That is, in this configuration, as the pump output control for adjusting the output of at least one of the operating heat medium pumps according to the change in the load flow rate Q, one of the operating heat medium pumps is at least one of the operating heat medium pumps. By adjusting the output of one heat medium pump, the supply pressure control for adjusting the heat medium supply pressure P to the load device to the target pressure Pm is executed.

  And as another one, the target change control which changes the target pressure Pm in feed pressure control according to the change of the load flow rate Q is performed, and the target pressure Pm is changed according to the change of the load flow rate Q in this way. By executing the above-mentioned supply pressure control in the form, as a whole, the output of at least one heat medium pump among the operation heat medium pumps is adjusted according to the change in the load flow rate Q.

  That is, according to the above configuration, although the output of the operation heat medium pump is adjusted according to the change of the load flow rate Q as a whole, the output of the operation heat medium pump is adjusted substantially according to the change of the load flow rate Q, as in the control of the number of operating pumps. Unlike the pump operation number control according to the change in the load flow rate Q, the output adjustment of the operation heat medium pump in the pump output control is performed according to the heat medium supply pressure P. The independence of the pump operation number control and the pump output control can be increased to improve the stability of system operation.

  In the implementation of this configuration, the heat medium supply pressure P adjusted by the supply pressure control, the target pressure Pm of the supply pressure control changed by the target change control, and the heat medium supply pressure P detected by the pressure detection means are: The pressure is not limited to the discharge pressure of the entire operating heat medium pump, and may be the inlet heat medium pressure of the load device, the inlet / outlet heat medium differential pressure of the entire operating heat medium pump, or the like.

The fourth feature configuration of the present invention specifies an embodiment suitable for the implementation of the third feature configuration.
The pump control means, as the target change control,
When the number of operating heat medium pumps is decreased by one in the pump operation number control, the pump control is performed with respect to the target flow rate of the supply pressure control with respect to the threshold flow rate that is an index of the decrease in the number of operation at that time. Change to the corresponding pressure value on or near the line,
In addition, when the number of operating heat medium pumps is increased by one in the control of the number of operating pumps, the target pressure of the supply pressure control is one step higher than the threshold flow rate that is an index of the increase in the operating number at that time. In the form of changing to the pressure value corresponding to the pump control line or the pressure value in the vicinity thereof with respect to the threshold flow rate on the large flow rate side only,
The target pressure of the supply pressure control is configured to be changed step by step whenever the number of operating heat medium pumps is changed.

  That is, (see FIG. 2), when the threshold flow rate Qs, which is an index of the decrease in the number of operating units when the number N of operating heat medium pumps is decreased, and when the number N of operating heat medium pumps is increased by one. In short, the threshold flow rate Qs on the large flow rate side by one step from the threshold flow rate Qs that is an index of the increase in the number of operating units is simply the threshold flow rate Qs on the upper limit side in the heat medium pump operation with each operating number N. (In other words, it corresponds to the threshold flow rate Qs that serves as the number change index on the side that increases the number of operating heat pumps by one from the current number N of operating heat pumps).

  Therefore, in the above-described configuration, the pressure value Ps (Ps1 to Ps3) corresponding to the upper limit side threshold flow rate Qs in the heat medium pump operation with each operation number N or the pressure value near the pressure control line M is sent. The target pressure Pm for the supply pressure control is changed step by step every time the number of operating heat medium pumps is changed in the form of the target pressure Pm for the supply pressure control.

  That is, if the target pressure Pm of the supply pressure control is changed stepwise in this way, as the pump output control, the load flow rate Q is higher than the upper limit side threshold flow rate Qs in the heat medium pump operation with each operation number N. In the reduced state, the output of at least one operation heat medium pump is adjusted to be lower than the maximum output so that the output of the entire operation heat medium pump is reduced by the amount of the decrease in the flow rate. Energy consumption of the pump as a whole can be reduced, and energy saving can be further promoted.

  Further, in the above configuration, the target pressure Pm for the feed pressure control is changed only when the number of operating heat pumps is changed, and the target pressure Pm for the feed pressure control is maintained constant in other steady operation states. (In other words, it becomes the individual discharge pressure constant control for each number N of heat medium pumps operated), so the system operation is stabilized when there are many small changes in load flow rate Q that do not lead to changes in the number of heat medium pumps operated. It is effective to do.

The fifth feature configuration of the present invention specifies an embodiment suitable for the implementation of the third feature configuration.
The pump control means, as the target change control,
Based on the detection information of the flow rate detecting means, the pressure value corresponding to the load flow rate at each time point on the pump control line or a pressure value in the vicinity thereof is set as the target pressure of the supply pressure control,
The target pressure of the supply pressure control is configured to be continuously changed as the load flow rate changes.

  That is, according to this configuration, the pressure value P corresponding to the load flow rate Q (current flow rate) at each time point on the pump control line M or a pressure value in the vicinity thereof is set as the target pressure Pm for the feed pressure control. In the embodiment, the target pressure Pm of the supply pressure control is continuously changed with the change of the load flow rate Q. Therefore, in the heat medium pump operation with each operation number N, the load flow rate Q is the upper limit side threshold flow rate Qs (current state) In the state where the operating number of the heat medium pump is decreased from the threshold flow rate Qs), which is the number change index on the side where the operating number of the heat medium pump is increased by one, the decrease in the flow rate and the pressure decrease corresponding to the decrease in flow rate The output of at least one operating heat medium pump is adjusted to be lower than the maximum output so that the output of the entire operating heat medium pump is reduced, and the energy consumption of the entire operating heat medium pump is reduced accordingly. To do And be can promote energy saving more effectively.

The sixth characteristic configuration of the present invention specifies an embodiment suitable for implementation of any of the third to fifth characteristic configurations,
The pump control means, as the pump operation number control,
In the state where the heat medium supply pressure detected by the pressure detection means is within the target pressure setting allowable range in the supply pressure control, when the load flow rate decreases below the threshold flow rate, the number of operating heat medium pumps is reduced. When the load is reduced and the load flow rate is increased above the threshold flow rate, the number of operating heat medium pumps is increased by one.

  In other words, in this configuration, a situation in which the heat medium supply pressure P to the load device is out of the set allowable range of the target pressure Pm in the supply pressure control, that is, an appropriate heat medium supply pressure P is ensured. In such a situation, even when the load flow rate Q decreases from the threshold flow rate Qs (lower limit side threshold flow rate) or the load flow rate Q increases from the threshold flow rate Qs (upper limit side threshold flow rate), the operation of the heat medium pump is performed. The current number of heat medium pumps is maintained without changing the number.

  Therefore, according to this configuration, in order to change the number N of operating heat medium pumps in a situation where an appropriate heat medium supply pressure P is not secured, the heat medium supply pressure P for the load device is more inappropriate. In this respect, the stability of system operation can be improved.

The seventh feature configuration of the present invention specifies an embodiment suitable for the implementation of the first feature configuration.
Provide a short circuit reflux path that short-circuits the downstream part and the upstream part of the heat medium pump parallel arrangement group in the heat medium supply path, and a short circuit flow rate adjustment valve is interposed in the short circuit reflux path,
The pump control means, together with the pump operation number control, as a short circuit reflux amount control,
A short circuit that adjusts the opening of the short-circuit flow rate adjustment valve based on detection information of pressure detection means for detecting the heat medium supply pressure to the load device to adjust the heat medium supply pressure to the load device to a target pressure. Supply pressure control of the type,
When the number of operating heat medium pumps is decreased by one in the pump operation number control, the pump control is performed with respect to the target flow rate of the supply pressure control with respect to the threshold flow rate that is an index of the decrease in the number of operation at that time. Change to the corresponding pressure value on or near the line,
In addition, when the number of operating heat medium pumps is increased by one in the control of the number of operating pumps, the target pressure of the supply pressure control is one step higher than the threshold flow rate that is an index of the increase in the operating number at that time. In the form of changing to the pressure value corresponding to the pump control line or the pressure value in the vicinity thereof with respect to the threshold flow rate on the large flow rate side only,
The target pressure of the supply pressure control is configured to execute target change control that changes step by step every time the number of operating heat medium pumps is changed.

  That is, as described above (see FIG. 2), the threshold flow rate Qs that is an index of the decrease in the number of operating medium pumps when the operating medium pump operating number N is decreased by one, and the operating number N of the heat medium pumps are one. In short, the threshold flow rate Qs on the large flow rate side by one step from the threshold flow rate Qs, which is an index of the increase in the number of operating units when increased, is simply the upper limit side in the heat medium pump operation with each operating number N. Is equivalent to a threshold flow rate Qs (that is, a threshold flow rate Qs that serves as a number change index for increasing the number of operating heat medium pumps by one from the current operating number N).

  Therefore, in the above configuration, the pressure value Ps (Ps1 to Ps3) corresponding to the upper limit side threshold flow rate Qs in the heat medium pump operation with each operation number N on the pump control line M or the nearby pressure value is short-circuited. The target pressure Pm for the supply pressure control is changed step by step every time the number N of operating heat medium pumps is changed.

  That is, if the target pressure Pm in the short-circuit type supply pressure control is changed stepwise in this way, even when a fixed output type pump is used for each of the plurality of heat medium pumps, In a state where the load flow rate Q is lower than the upper limit side threshold flow rate Qs in the pump operation, the surplus of the heat medium supply flow rate as a whole of the operation heat medium pump generated by the decrease of the load flow rate Q is short-circuited supply pressure. By adjusting the opening degree of the short-circuit flow rate adjustment valve by control, it is possible to escape through the short-circuit reflux path, and for each of the heat medium pump operations at each operation number N, the heat medium supply pressure P to the load device is set to the number of heat medium pump operations. It is possible to stably maintain the target pressure Pm for each N, thereby stabilizing the operation of the system.

[First Embodiment]
FIG. 1 shows a heat source system for air conditioning. This system is provided with a plurality of refrigerators R capable of output adjustment (ie capacity control) by an inverter device INV as heat source units, and each of the refrigerators R has a cooling water circulation path 1. The cooling towers CT are individually connected to each other.

  2a is a primary header that receives chilled water C supplied from each refrigerator R in parallel through the primary chilled water outbound path 3a, and 2b is supplied with chilled water C from the primary header 2a through a plurality of chilled water relay paths 3b. It is a secondary header, and each load is supplied in parallel by supplying cold water C as a heating medium from the secondary header 2b to a plurality of load devices U such as air conditioners through a secondary cold water forward path 3c. In the device U, the cold heat stored in the supplied cold water C is consumed for a required purpose such as cooling.

  Reference numeral 2c denotes a return header that receives the chilled water C that has been heated by cold consumption from each load device U through the secondary chilled water return path 3d, and returns the received chilled water C to each refrigerator R through the primary chilled water return path 3e. The chilled water circulation system connecting the refrigerator R and the load device U is connected to the primary side (in other words, the heat source side) and the load device U on the refrigerator R side with the primary header 2a and the return header 2c as a boundary. To the secondary side (in other words, the load side).

  In addition to the refrigerator R, the cooling tower CT, and the load device U, the components constituting the heat source system include a primary pump JA and a secondary chilled water outbound path 3c interposed in the primary chilled water return path 3e to each chiller R. And a secondary pump JB interposed in each of the parallel chilled water relay paths 3b constituting the heat medium supply path to the load device U, a cooling water pump JC interposed in each cooling water circulation path 1, etc., and these pumps JA , JB, and JC are variable pumps capable of continuously adjusting the pump output by adjusting the rotational speed of the pump motor by frequency control using the inverter device INV provided in each of the motors.

  Note that each of the cooling tower CT, the cooling water pump JC, and the primary pump JA is started and stopped according to the start and stop of the corresponding refrigerator R, and the secondary pump JB is a load that is a required cooling water flow rate on the load device U side. The number of operating units is controlled and the output is controlled according to the flow rate Q.

  Va is an opening / closing valve provided in each of the primary side cold water outbound paths 3a, and these opening / closing valves Va are opened when the corresponding refrigerator R and primary pump JA are operated.

  Vb is a flow rate adjusting valve provided in each load device U. Under the chilled water circulation by the primary pump JA and the secondary pump JB, the flow rate adjusting valve Vb causes the cold water flow rate q (that is, the load device) of each load device U. U individual load flow rate) is adjusted in accordance with the thermal load g of each load device U (that is, the required amount of cooling energy of each load device U).

  Vs is a short-circuit flow rate adjusting valve for adjusting a flow rate balance provided in a short-circuit reflux path 3f extending between the primary header 2a and the secondary header 2b, and this short-circuit flow rate adjusting valve Vs is detected by a pressure sensor PS described later. The opening degree is adjusted so as to keep the chilled water supply pressure P at an appropriate value in accordance with the chilled water supply pressure P to the load device U (the chilled water pressure in the secondary header 2b in this example).

  Reference numeral 4 denotes a bypass path that short-circuits the primary header 2a and the return header 2c, and the cold water flow through the bypass path 4 absorbs the difference in the chilled water flow rate between the primary side and the secondary side. That is, in the state where the flow rate of the chilled water on the primary side is larger than that on the secondary side, the difference chilled water C flows from the primary side header 2a to the return side header 2c through the bypass path 4, and conversely than the primary side. In the state where the secondary side cold water flow rate is large, the difference of the cold water C flows from the return side header 2c through the bypass 4 toward the primary side header 2a.

As sensors for detecting the flow rate, temperature, pressure, etc. of each part, in addition to the pressure sensor PS for detecting the chilled water supply pressure P to the load device U, the load flow rate Q on the load device U side (that is, each load device U) A flow rate sensor FS for detecting the total flow rate Q = Σq) of the return chilled water C from the chiller, a temperature sensor TS for detecting the supply chilled water temperature Ti to the load unit U and the return chilled water temperature To to the refrigerator R, and Flow rate / water supply pressure of each primary pump JA, outlet cold water temperature / inlet cooling water temperature / outlet cooling water temperature of each refrigerator R, inlet cold water pressure / outlet cold water pressure of each load device U, flow rate of each cooling water pump JC A sensor S for detecting the temperature and humidity of the outside air is also provided.

  Reference numeral 5 denotes a system controller. The system controller 5 is configured to execute the following control for each of the primary side and the secondary side based on the detection information of each sensor.

The chilled water flow rate q of each load device U is adjusted by the flow rate adjustment valve Vb according to the thermal load g of each load device U, whereas the primary side is supplied to the load device U detected by the temperature sensor TS. Based on the temperature difference between the supplied cold water temperature Ti and the return cold water temperature To to the refrigerator R and the load flow rate Q (= Σq) on the load device U side detected by the flow sensor FS, the thermal load on the load device U side The total G (= Σg) is calculated sequentially.

  And the heat load side operation number control which changes the operation number of the refrigerator R according to the change of the heat load total G with respect to the heat load total G changing with the change of the heat load g in each load apparatus U. And the output control on the heat source side that continuously adjusts the output of each of the operating refrigerator R and the primary pump JA and the cooling water pump JC with the inverter INV according to the change of the heat load total G, Thus, the amount of generated cold heat on the primary side is balanced with respect to the total heat load G.

On the other hand, on the secondary side, the load flow rate Q (= Σq) changes due to the adjustment of the cooling flow rate q by the flow rate adjustment valve Vb, whereas the load of the secondary pump JB is based on the detected load flow rate Q by the flow rate sensor FS. Pump output control is performed to control the number of operating pumps N to change the operating number N according to the change in the load flow rate Q, and to continuously adjust the output of the operating secondary pump JB by the inverter device INV as the load flow rate Q changes. Do.

  More specifically, in order to execute the above pump operation number control and pump output control for the secondary pump JB which is an example of the heat medium pump interposed in parallel in the heat medium supply path to the load device U, Specifically, the following control modes (A) to (F) are employed (see FIGS. 2 and 3).

  (A) In the secondary pump operation with each operation number N, each of the operation secondary pumps JB is operated at the maximum output, and the correlation between the chilled water supply flow rate Q and the chilled water supply pressure P is shown for each operation number N. Set pump performance curves L1 to L3.

In consideration of piping resistance and the like, a pump control line M indicating a correlation between the load flow rate Q and the supply pressure P necessary to supply the cold water C of the load flow rate Q to each load device U is set. .
Each of the flow rate values Qs (Qs1 to Qs3) at the intersections X1 to K3 between the pump performance curves L1 to L3 and the pump control line M for each number N of operating units is set as a threshold flow rate.

  In this example, the threshold flow rate Qs (Qs1 to Qs3) set in this way is stored in the system controller 5 as the pump control means by the initial setting, and the pump control line M is similarly set as a function expression by the initial setting. It is stored in the system controller 5.

  In this example, an approximate quadratic curve obtained by simulation or calculation is used as the pump control line M after being corrected based on actual measurement data at the time of system test operation.

  (B) And, as the pump operation number control, based on the detection information of the flow rate sensor FS that detects the load flow rate Q, when the load flow rate Q decreases below the threshold flow rate Qs for each of the threshold flow rates Qs (Qs1 to Qs3). When the operating number N of the secondary pumps JB is decreased by one and when the load flow rate Q increases beyond the threshold flow rate Qs, the operating number N of the secondary pumps JB is increased by one.

  That is, in FIG. 2, when the load flow rate Q is in the flow rate range of Qs3 to Qs2, all three secondary pumps JB are operated, and in the state where the load flow rate Q is in the flow rate range of Qs2 to Qs1, two 2 The secondary pump JB is operated, and one secondary pump JB is operated in a state where the load flow rate Q is in a flow rate range of Qs1 or less.

  That is, by controlling the number of operating pumps, the situation where the operating number N of the secondary pumps JB becomes excessive is avoided, and the operating number N of the secondary pumps JB is surely minimized to the extent possible at each time point. Turn into.

  (C) On the other hand, as the pump output control for adjusting the output of the operating secondary pump JB with the change of the load flow rate Q, based on the detection information of the pressure sensor PS that detects the chilled water supply pressure P to the load device U, In the secondary pump operation at each operation number N (N = 1, 2, 3) by pump operation number control, the output of each of the operation secondary pumps JB is adjusted by the inverter device INV, and the heat medium is sent to the load device U A target change is performed in which the supply pressure control for adjusting the supply pressure P to the target pressure Pm is executed, and the target pressure Pm for the supply pressure control is changed according to the change in the load flow rate Q based on the detection information of the flow rate sensor FS. Execute control.

  (D) With regard to this target change control, when the number N of operating secondary pumps JB is decreased by one in the pump operation number control, the target pressure Pm of the feed pressure control is decreased, and the number of operating pumps at that time decreases. Is changed to a pressure value Ps (Ps1 to Ps3) corresponding to the threshold flow rate Qs, which is an index of.

  Further, when the number N of secondary pumps JB is increased by one in the operation number control, the target pressure Pm of the feed pressure control is set to be smaller than the threshold flow rate Qs that is an index of the increase in the number of operations at that time. The pressure value Ps (Ps1 to Ps3) corresponding to the threshold flow rate Qs on the large flow rate side on the pump control line M is changed by the level.

  In other words, the threshold flow rate Qs on the upper limit side in the secondary pump operation with each operation number N (the threshold flow rate serving as the number change index on the side where the number of operation of the secondary pump JB is increased by one from the current operation number N) Qs) is set so that the pressure value Ps (Ps1 to Ps3) corresponding to the pump control line M on the pump control line M is set as the target pressure Pm for the feed pressure control, and the target pressure Pm for the feed pressure control is set to the number N of secondary pumps operated. Change in stages for each change.

  That is, in the pump output control in which the supply pressure control is performed under this target change control, the chilled water supply pressure P to the load device U changes along the pressure change line PLm in FIG. .

  In the state where the load flow rate Q is reduced below the upper limit threshold flow rate Qs in the secondary pump operation with each operation number N, the operation 2 is performed so that the output of the entire operation secondary pump is reduced by the decrease in the flow rate. By adjusting the output of each of the secondary pumps JB to a lower side than the maximum output, the energy consumption of the secondary pump operation is further reduced in combination with the minimization of the number N of secondary pumps operated by the above-mentioned pump operation number control.

  (E) In this example, the chilled water supply pressure detected by the pressure sensor PS in the secondary pump operation at each operation number N is used to change the operation number N of the secondary pumps JB by the pump operation number control. Only when P is within the set allowable range of the target pressure Pm (Ps1 to Ps3) in the feed pressure control, if the load flow rate Q decreases below the threshold flow rate Qs, the number N of operating secondary pumps JB is reduced to one. Decrease.

  Similarly, the chilled water supply pressure P detected by the pressure sensor PS in the secondary pump operation with each operation number N is within the set allowable range of the target pressure Pm (Ps1 to Ps3) in the supply pressure control. Only in the state, when the load flow rate Q increases above the threshold flow rate Qs, the number N of operating secondary pumps JB is increased by one.

  That is, by allowing only the change in the number of secondary pumps operating in a situation where an appropriate cold water supply pressure P is ensured in this way, the secondary pump can be used in a situation where the appropriate heat medium supply pressure P is not ensured. In order to change the number N of operating JBs, it is possible to prevent the cold water supply pressure P for the load device U from becoming inappropriate.

  (F) Moreover, in this example, as the opening degree control of the short circuit flow rate adjustment valve Vs equipped in the short circuit reflux path 3f, the cold water to the load device U is also obtained by performing the short circuit flow rate adjustment valve Vs based on the detection information of the pressure sensor PS. The target pressure Pm of the feed pressure control in the secondary pump operation with each operation number N of the supply pressure P (that is, the target pressures Ps1 to Ps3 that are changed every time the number of secondary pump operation number N is changed by the target change control) It is intended to adjust to.

  In other words, the opening degree control of the short circuit flow rate adjusting valve Vs that adjusts the opening degree of the short circuit flow rate adjusting valve Vs based on the detection information of the pressure sensor PS to adjust the cold water supply pressure P to the load device U to the target pressure Pm. , The target pressure Pm is changed stepwise for each change of the number N of secondary pumps operated by the target change control.

  That is, in the output control in which the output of the operation secondary pump JB is adjusted in accordance with the change in the load flow rate Q in the secondary pump operation with each operation number N, the output of the operation secondary pump JB reaches the lower limit of the adjustment range, Even if the output of the operating secondary pump JB cannot be adjusted to a lower side beyond that, the chilled water supply pressure P to the load device U is controlled by the number N of operating units by controlling the opening degree of the short-circuit flow rate adjusting valve Vs. The target pressure Pm (Ps1 to Ps3) in the secondary pump operation can be adjusted.

[Second Embodiment]
In the first embodiment described above, for the target pressure Pm of the feed pressure control in the output control of the secondary pump JB, the target pressure Pm of the feed pressure control is changed by the target change control every time the number of secondary pumps N is changed. However, instead of this, in the second embodiment, the target pressure Pm of the feed pressure control is continuously changed as the load flow rate Q changes.

  That is, in the second embodiment, the target pressure control is executed by the system controller 5 in the following control form (D ′) (see FIG. 4).

(D ') Based on the detection information of the flow sensor FS, the pressure value P corresponding to the load flow Q (current flow) at each time point on the pump control line M is used as the target pressure Pm of the feed pressure control. The target pressure Pm for the feed pressure control is continuously changed as the load flow rate Q changes.

  That is, in the output control of the secondary pump JB that performs the supply pressure control under the target change control, the chilled water supply pressure P to the load device U with respect to the change of the load flow rate Q is the pressure change line PLm in FIG. Varies along.

  In the state where the load flow rate Q is reduced below the upper limit threshold flow rate Qs in the secondary pump operation with each operation number N, the operation secondary pump is operated with respect to the flow rate decrease and the pressure decrease corresponding to the flow rate decrease. The output of each of the operating secondary pumps JB is adjusted to be lower than the maximum output so that the output as a whole is reduced, and the secondary pumps are coupled with the minimization of the number N of secondary pumps operated by the above operation number control. The energy consumption of driving is further effectively reduced.

  In the second embodiment, as in the case of the first embodiment, the number N of secondary pumps JB is changed by the operation number control. The load flow rate Q decreases (or increases) from the threshold flow rate Qs only when the cold water supply pressure P detected by the pressure sensor PS is within the set allowable range of the target pressure Pm at each time point of the supply pressure control. Then, it is desirable to decrease (or increase) the number N of operating secondary pumps JB.

  Further, similarly to the first embodiment described above, the chilled water supply pressure P to the load device U is set to the target at each time point in the supply pressure control by performing the short-circuit flow rate adjustment valve Vs based on the detection information of the pressure sensor PS. It is desirable to adjust to the pressure Pm (that is, the target pressure continuously changed with the change of the load flow rate Q by the target change control).

  About others, it is the same as 1st Embodiment.

[Third Embodiment]
In both the first and second embodiments described above, an example in which the output of the operating secondary pump JB is adjusted by the inverter device INV in accordance with the change in the load flow rate Q has been shown. An example in which the output control of the pump JB is not performed will be shown.

  That is, in the third embodiment, a fixed output type pump is used for each secondary pump JB. Then, instead of the output control of the secondary pump JB, the system controller 5 executes short-circuit recirculation amount control which is substantially the same control as the opening degree control of the short-circuit flow rate adjustment valve Vs shown in the first embodiment. It is configured to do.

  Specifically, as short-circuit recirculation amount control, short-circuit type supply pressure control and target change control for changing the target pressure Pm of the supply pressure control according to the change of the load flow rate Q are executed. In the supply pressure control, the opening degree of the short-circuit flow rate adjustment valve Vs is adjusted based on the detection information of the pressure sensor PS that detects the chilled water supply pressure P to the load device U to target the chilled water supply pressure P to the load device U. Adjust to pressure Pm.

  On the other hand, in the target change control, when the operation number N of the secondary pumps JB is decreased by one in the operation number control, the target pressure Pm in the short-circuit type supply pressure control is set as an index for the decrease in the operation number at that time. The pressure value Ps (Ps1 to Ps3) corresponding to the threshold flow rate Qs on the pump control line M is changed.

  Further, when the number N of secondary pumps JB is increased by one in the operation number control, the target pressure Pm in the short-circuit type supply pressure control is set to the threshold flow rate Qs that is an index of the increase in the number of operations at that time. The pressure value Ps (Ps1 to Ps3) corresponding to the threshold flow rate Qs on the large flow rate side on the pump control line M is changed by one step.

  In other words, the threshold flow rate Qs on the upper limit side in the secondary pump operation with each operation number N (the threshold flow rate serving as the number change index on the side where the number of operation of the secondary pump JB is increased by one from the current operation number N) Qs) is set so that the pressure value Ps (Ps1 to Ps3) corresponding to the pump control line M on the pump control line M is the target pressure Pm in the short-circuit type supply pressure control, and the target pressure Pm of the short-circuit type supply pressure control is 2 Each time the next pump operation number N is changed, it is changed in stages.

  That is, while using a fixed output pump as the secondary pump JB, by performing short-circuit feed pressure control under the above target change control, chilled water feed to the load device U in response to changes in the load flow rate Q The supply pressure P changes along the pressure change line PLm in FIG. 2 as in the case of the first embodiment.

  That is, in the state where the load flow rate Q is decreased from the upper limit side threshold flow rate Qs in the secondary pump operation with each operation number N, the heat medium as the entire fixed output operation secondary pump generated by the decrease of the load flow rate Q is obtained. The surplus portion of the feed flow rate is released through the short-circuit recirculation path 3f by adjusting the opening of the short-circuit flow rate adjustment valve Vs by short-circuit feed pressure control, so that the load device is used for each secondary pump operation with each operating number N The cold water supply pressure P to U is stably maintained at the target pressure Pm (Ps1 to Ps3) for each number N of secondary pumps operating.

  In the third embodiment, as in the case of the first embodiment, the operation number N of the secondary pumps JB is changed by the operation number control. When the load flow rate Q decreases (or increases) from the threshold flow rate Qs only in a state where the cold water supply pressure P detected by the pressure sensor PS is within the set allowable range of the target pressure Pm in the short-circuit type supply pressure control. It is desirable to decrease (or increase) the number N of operating secondary pumps JB.

  Others are the same as in the first embodiment.

[Another embodiment]
The first and second embodiments described above show a case where all of the plurality of heat medium pumps (secondary pumps JB) are variable output pumps, and the third embodiment described above includes a plurality of heat medium pumps. Although all the (secondary pumps JB) are fixed output type pumps, the present invention is that some of the plurality of heat medium pumps are variable output type pumps and others are fixed output type pumps. It can also be applied in some cases.

  In this case, when there is a variable output type pump among the operation heat medium pumps in the heat medium pump operation in each operation number N by the pump operation number control, the variable output type operation pump is described above. When the pump output control is performed and all of the operating heat medium pumps become fixed output type pumps by changing the number N of operation, the above-described short-circuit delivery pressure control may be performed.

  In each of the above-described embodiments, an example in which the cold water C cooled by the refrigerator R is used as the heat medium is shown. However, the heat medium is not limited to the cold water C, and may be brine, hot water, or the like. Alternatively, the heat source device to be heated is not limited to a refrigerator, and may be any device such as a cold / hot water generator, a boiler, or a heat exchanger.

  In each of the above-described embodiments, the example in which the secondary pump is the heat medium pump of the present invention in the heat medium circulation system including the primary pump JA and the secondary pump JB has been described. In the heat medium circulation system including the heat medium pump that also serves as the heat medium pump, the present invention may be applied to the heat medium pump, and the heat medium is supplied to the load device by a plurality of heat medium pumps other than the heat medium circulation system. The present invention can also be applied to cases.

  The present invention is not limited to a heat source system of an air conditioner, and can be applied to a heat source system for various purposes in various fields as long as the heat source system includes a plurality of heat medium pumps that supply a heat medium to a load device.

System configuration diagram showing the first embodiment The graph explaining the pump control system of 1st Embodiment The flowchart explaining the pump control system of 1st Embodiment. The graph explaining the pump control system of 2nd Embodiment Graph explaining the conventional pump control system

Explanation of symbols

R Heat source machine C Heat medium U Load device 3b Heat medium feed path JB Heat medium pump Q Load flow rate N Number of operating units 5 Pump control means P Pressure L1 to L3 Pump performance curve for each operating unit M Pump control line X1 to X3 Intersection Qs1 ~ Qs3 Threshold flow rate (Qs)
FS Flow rate detection means PS Pressure detection means Pm Target pressure 3f Short-circuit return path Vs Short-circuit flow rate adjustment valve

Claims (7)

While interposing a plurality of heat medium pumps in parallel arrangement in the heat medium feed path for supplying the heat medium cooled or heated by the heat source machine to the load device,
A heat source system equipped with pump control means for changing the number of operating heat medium pumps according to a change in load flow rate that is a heat medium flow rate required by the load device,
Set the pump performance curve for each number of operating units that shows the correlation between the heat medium supply flow rate and the heat medium supply pressure when each of the operating heat medium pumps is operated at the maximum output in the operation of the heat medium pump with each operating number. With
Setting a pump control line indicating the correlation between the load flow rate and the supply pressure required to supply the load medium with the heat medium of the load flow rate,
Each of the flow rate value at each intersection of the pump performance curve and the pump control line for each number of operating units or its neighboring flow rate value is set as the threshold flow rate,
With respect to these settings, the pump control means, based on the detection information of the flow rate detection means for detecting the load flow rate, as the pump operation number control,
For each of the threshold flow rates, when the load flow rate decreases below the threshold flow rate, the number of operating heat medium pumps decreases by one, and when the load flow rate increases above the threshold flow rate, the number of operating heat medium pumps decreases by one. Heat source system configured to increase.   The pump control means outputs the output of at least one heat medium pump of the operation heat medium pumps according to the change of the load flow rate based on the detection information of the flow rate detection means for detecting the load flow rate together with the pump operation number control. The heat source system according to claim 1, wherein the pump output control to be adjusted is executed. The pump control means, as the pump output control,
Based on the detection information of the pressure detection means for detecting the heat medium supply pressure to the load device, the output of at least one heat medium pump of the operation heat medium pumps is adjusted to supply the heat medium to the load device. Feed pressure control that adjusts the feed pressure to the target pressure;
The heat source system according to claim 2, wherein target change control is executed to change a target pressure of the supply pressure control according to a change in load flow rate based on detection information of the flow rate detection means. The pump control means, as the target change control,
When the number of operating heat medium pumps is decreased by one in the pump operation number control, the pump control is performed with respect to the target flow rate of the supply pressure control with respect to the threshold flow rate that is an index of the decrease in the number of operation at that time. Change to the corresponding pressure value on or near the line,
In addition, when the number of operating heat medium pumps is increased by one in the control of the number of operating pumps, the target pressure of the supply pressure control is one step higher than the threshold flow rate that is an index of the increase in the operating number at that time. In the form of changing to the pressure value corresponding to the pump control line or the pressure value in the vicinity thereof with respect to the threshold flow rate on the large flow rate side only,
The heat source system according to claim 3, wherein the target pressure of the supply pressure control is changed step by step every time the number of operating heat medium pumps is changed. The pump control means, as the target change control,
Based on the detection information of the flow rate detecting means, the pressure value corresponding to the load flow rate at each time point on the pump control line or a pressure value in the vicinity thereof is set as the target pressure of the supply pressure control,
The heat source system according to claim 3, wherein the target pressure of the supply pressure control is continuously changed as the load flow rate changes. The pump control means, as the pump operation number control,
In the state where the heat medium supply pressure detected by the pressure detection means is within the target pressure setting allowable range in the supply pressure control, when the load flow rate decreases below the threshold flow rate, the number of operating heat medium pumps is reduced. The heat source system according to any one of claims 3 to 5, wherein the number of operating heat medium pumps is increased by one when the load is reduced and the load flow rate is higher than a threshold flow rate. Provide a short circuit reflux path that short-circuits the downstream part and the upstream part of the heat medium pump parallel arrangement group in the heat medium supply path, and a short circuit flow rate adjustment valve is interposed in the short circuit reflux path,
The pump control means, together with the pump operation number control, as a short circuit reflux amount control,
A short circuit that adjusts the opening of the short-circuit flow rate adjustment valve based on detection information of pressure detection means for detecting the heat medium supply pressure to the load device to adjust the heat medium supply pressure to the load device to a target pressure. Supply pressure control of the type,
When the number of operating heat medium pumps is decreased by one in the pump operation number control, the pump control is performed with respect to the target flow rate of the supply pressure control with respect to the threshold flow rate that is an index of the decrease in the number of operation at that time. Change to the corresponding pressure value on or near the line,
In addition, when the number of operating heat medium pumps is increased by one in the control of the number of operating pumps, the target pressure of the supply pressure control is one step higher than the threshold flow rate that is an index of the increase in the operating number at that time. In the form of changing to the pressure value corresponding to the pump control line or the pressure value in the vicinity thereof with respect to the threshold flow rate on the large flow rate side only,
The heat source system according to claim 1, wherein the target pressure of the supply pressure control is configured to execute target change control that changes step by step every time the number of operating heat medium pumps is changed.

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