WO2023176207A1

WO2023176207A1 - Heat source system

Info

Publication number: WO2023176207A1
Application number: PCT/JP2023/004129
Authority: WO
Inventors: 有亮朝田; 浩中山; 明弘稲生; 嵩俊中神
Original assignee: ダイキン工業株式会社
Priority date: 2022-03-18
Filing date: 2023-02-08
Publication date: 2023-09-21
Also published as: JP2023137404A

Abstract

A heat source system (100) includes a plurality of heat source devices (101) provided in parallel, a plurality of pumps (102) provided in parallel, a collecting pipe (103) that unifies flow paths between the plurality of heat source devices (101) and the plurality of pumps (102), and a controller (150). The controller (150) determines the required flow rate on the basis of at least the minimum required flow rate set for each heat source device (101) and the operating state of each heat source device (101), determines the current water supply amount or maximum water supply amount on the basis of the flow rate set for each pump (102) and the operation state of each pump (102), compares the required flow rate with the current water supply amount or maximum water supply amount, and controls the operation of the plurality of heat source devices (101) or the plurality of pumps (102) according to the comparison result.

Description

heat source system

The present disclosure relates to a heat source system.

Patent Document 1 discloses a heat source system in which a plurality of heat source machines connected in parallel and a plurality of pumps connected in parallel are connected in series via manifold piping. In a manifold piping type heat source system, even if a specific pump or heat source device breaks down, other pumps or heat source devices can be started to continue operation.

In conventional manifold piping type heat source systems, the required minimum flow rate of each heat source device is secured by fixing the minimum number of pumps to start and the lower limit of the VFD command value for pumps with VFD (variable frequency drive) function. There is.

JP 2021-17995 Publication

However, in conventional manifold piping type heat source systems, if the number of heat source machines and the number of pumps are different, or if pumps of different capacities are mixed, it may not be possible to secure the required minimum flow rate of the heat source machines. . Further, if one or more pumps malfunctions, the number of operable pumps becomes insufficient, and it may become impossible to secure the required minimum flow rate of the heat source equipment. Furthermore, when a pump with a VFD function is used, if the VFD command value becomes low, it may become impossible to ensure the required minimum flow rate of the heat source device.

As described above, in the conventional manifold piping type heat source system, it may become impossible to secure the required minimum flow rate of the heat source equipment, and there is a risk that stable control may not be possible.

An object of the present disclosure is to enable stable control in a manifold piping type heat source system.

A first aspect of the present disclosure includes a plurality of heat source devices (101) provided in parallel with each other, a plurality of pumps (102) provided in parallel with each other, and a plurality of heat source devices (101) and a plurality of pumps provided in parallel with each other. a control unit that controls the operation of a collection pipe (103) arranged so as to integrate flow paths between the pump (102), the plurality of heat source devices (101), and the plurality of pumps (102); (150) is a manifold piping type heat source system. The control unit (150) [A] determines the required flow rate based on at least the required minimum flow rate set for the plurality of heat source devices (101) and the operating state of the plurality of heat source devices (101). , [B] Based on the flow rate set for the plurality of pumps (102) and the operating status of the plurality of pumps (102), determine the current water flow rate or the maximum water flow rate, and [C] determine the required flow rate and , the current water supply amount or the maximum water supply amount is compared, and depending on the result, the operation of the plurality of heat source devices (101) or the plurality of pumps (102) is controlled.

In the first aspect, the required flow rate according to the operating state of each heat source device (101) and the current water supply amount or maximum water supply amount according to the operating state of each pump (102) are constantly compared, and as needed. It is possible to adjust the increase/decrease stage of the heat source device (101) or the pump (102), etc. Therefore, the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed.

A second aspect of the present disclosure is that in the first aspect, at least one of the plurality of heat source machines (101) and the plurality of pumps (102) is configured with a plurality of different capacities.

In the second aspect, unlike the conventional manifold piping type heat source system, even if heat source devices (101) and pumps (102) of different capacities are mixed, the required minimum flow rate of each heat source device (101) can be ensured. This allows stable control to be performed.

In a third aspect of the present disclosure, in the first or second aspect, the control unit (150) controls the number of operating units of the plurality of heat source devices (101) or the number of operating units of the plurality of pumps (102). Increase or decrease.

In the third aspect, stable control can be performed by ensuring the required minimum flow rate of each heat source device (101) by increasing/decreasing stages of the heat source device (101) or the pump (102).

In a fourth aspect of the present disclosure, in any one of the first to third aspects, the control unit (150) controls the flow rate variation in each piping (105) connected to the plurality of heat source devices (101). The required flow rate is determined based on the flow rate obtained by multiplying the required minimum flow rate by a coefficient that takes into account the flow rate, and the operating state of the plurality of heat source devices (101).

In the fourth aspect, the required flow rates for the plurality of heat source devices (101) can be determined more accurately, so more stable control can be performed.

In a fifth aspect of the present disclosure, in any one of the first to fourth aspects, the control unit (150) compares the requested flow rate and the current water supply amount, and determines that the requested flow rate is higher. If it is larger, the pump (102) to be started is selected from among the plurality of pumps (102) so that the current water flow rate satisfies the required flow rate and the change in the current water flow rate is the smallest.

In the fifth aspect, by increasing the number of pumps (102), the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed. Further, since the pump (102) is increased in stages so that the change in the current water supply amount is minimized, the influence on the system load due to the increase in the pump (102) stages can be suppressed to the lowest possible extent.

In a sixth aspect of the present disclosure, in any one of the first to fourth aspects, the control unit (150) uses information about a pump (102) scheduled to be stopped from among the plurality of pumps (102). Based on the above-mentioned current water supply amount, calculate the water supply amount after stage reduction from the current water supply volume, compare the water transmission volume after stage reduction with the required flow rate, and, depending on the result, permit or prohibit the operation stoppage of the pump (102). .

In the sixth aspect, by reducing the stages of the pump (102), the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed.

In a seventh aspect of the present disclosure, in any one of the first to fourth aspects, at least one of the plurality of pumps (102) is a VFD type pump (102), and the control unit (150) updates the VFD command value for the VFD type pump (102) in operation based on the difference between the requested flow rate and the current water supply amount.

In the seventh aspect, by adjusting the VFD command value of the VFD type pump (102), the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed.

In an eighth aspect of the present disclosure, in the seventh aspect, the control unit (150) controls the difference between the pressure of the piping (107, 116) connected to the VFD pump (102) and the set value of the pressure. Based on this, determine the VFD command value of the VFD type pump (102), determine the current water supply amount by multiplying the flow rate set in the VFD type pump (102) in operation by the rotation rate, and determine the required flow rate. and the current water supply amount, and if the required flow rate is larger, calculate the lower limit value of the VFD command value so as to compensate for the difference between the required flow rate and the current water supply amount, and When the lower limit value is larger than the VFD command value, the VFD command value is updated by the lower limit value.

In the eighth aspect, the VFD command value of the VFD pump (102) can be adjusted so that the required minimum flow rate of each heat source device (101) can be ensured.

A ninth aspect of the present disclosure is that in any one of the first to fourth aspects, the control unit (150) compares the required flow rate and the maximum water supply amount, and determines that the required flow rate is higher. If it is larger, a heat source device (101) to be shut down is selected from the plurality of heat source devices (101) so that the maximum amount of water fed satisfies the required flow rate.

In the ninth aspect, by reducing the stages of the heat source device (101), the required minimum flow rate of the other heat source devices (101) in operation can be ensured, and stable control can be performed.

In a tenth aspect of the present disclosure, in the ninth aspect, the control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, the control unit (150) control and second control are selectively performed, and in the first control, a heat source device (101) is stopped from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate. is selected, and in the second control, a heat source device (101) is stopped from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate and the change in the required flow rate is minimized. 101).

In the tenth aspect, by reducing the stages of the heat source device (101), the required minimum flow rate of the other heat source devices (101) in operation can be ensured, and stable control can be performed. In addition, in the second control, the heat source equipment (101) is reduced in stage so that the change in the required flow rate is minimized, so the impact on the system load due to the reduction in the stage of the heat source equipment (101) is suppressed as much as possible. can do.

In an eleventh aspect of the present disclosure, in any one of the first to fourth aspects, the control unit (150) controls a heat source device (101) scheduled to start operation among the plurality of heat source devices (101). Based on the information, calculate the required flow rate after increasing the stage from the required flow rate, compare the required flow rate after increasing the stage with the maximum water supply amount, and according to the result, permit the start of operation of the heat source equipment (101). or prohibit.

In the eleventh aspect, the number of heat source devices (101) is increased while ensuring the required minimum flow rate of each heat source device (101) during operation, so stable control can be performed.

A twelfth aspect of the present disclosure is that in any one of the first to fourth aspects, the control unit (150) compares the required flow rate and the maximum water supply amount, and determines that the required flow rate is higher. If it is large, the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is limited.

In the twelfth aspect, by limiting the capacity of the heat source machines (101) during operation, the required minimum flow rate of each heat source machine (101) can be ensured and stable control can be performed.

A thirteenth aspect of the present disclosure is that in any one of the first to fourth aspects, the control unit (150) compares the required flow rate and the maximum water supply amount, and determines that the required flow rate is higher. If the amount is large, a third control and a fourth control are selectively performed, and in the third control, one of the plurality of heat source devices (101) is operated so that the maximum water supply amount satisfies the required flow rate. A heat source device (101) to be stopped is selected, and in the fourth control, the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is limited.

In the thirteenth aspect, the required minimum flow rate of each heat source device (101) is ensured by selectively reducing the stages of the heat source device (101) or limiting the capacity of the heat source device (101) during operation. , stable control can be performed.

A fourteenth aspect of the present disclosure is that in the thirteenth aspect, the control unit (150) performs the fourth control when the required flow rate is larger than the maximum water supply amount.

In the fourteenth aspect, it is possible to avoid the influence on the system load due to the step reduction of the heat source device (101).

A fifteenth aspect of the present disclosure is that in the thirteenth or fourteenth aspect, the control unit (150) determines that the required flow rate is larger than the maximum water supply amount and that one of the plurality of heat source devices (101) When the capacity of the heat source device (101) in operation is lower than the predetermined lower limit value, the third control is performed.

In the fifteenth aspect, when the capacity of the heat source device (101) in operation cannot be restricted, the required minimum flow rate of the other heat source device (101) in operation is ensured by reducing the stages of the heat source device (101). This allows stable control to be performed.

In a sixteenth aspect of the present disclosure, in any one of the thirteenth to fifteenth aspects, the control unit (150) is configured such that the required flow rate is larger than the maximum water supply amount and the plurality of heat source units (101), when the capacity of the heat source device (101) in operation is lower than a predetermined lower limit value, the fifth control and the sixth control are selectively performed as the third control, and the fifth control is performed selectively as the third control. In the control, a heat source device to be shut down is selected from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate, and in the sixth control, the maximum water supply amount satisfies the required flow rate. A heat source device (101) to be shut down is selected from among the plurality of heat source devices (101) so that the following equation is satisfied and the change in the required flow rate is the smallest.

In the 16th aspect, when the capacity of the heat source device (101) in operation cannot be restricted, the required minimum flow rate of the other heat source device (101) in operation is ensured by reducing the stages of the heat source device (101). This allows stable control to be performed. In addition, in the sixth control, the stages of the heat source equipment (101) are reduced so that the change in the required flow rate is minimized, so the impact on the system load due to the stage reduction of the heat source equipment (101) is suppressed as much as possible. can do.

FIG. 1 is a configuration diagram schematically showing a heat source system according to an embodiment. FIG. 2 is a flowchart illustrating control of the number of pumps in the heat source system shown in FIG. 1. FIG. 3 is a schematic diagram showing the details of pump stage increasing processing in the heat source system shown in FIG. 1. FIG. 4 is a schematic diagram showing the details of the pump stage reduction process in the heat source system shown in FIG. 1. FIG. 5 is a flow diagram illustrating pump VFD control in the heat source system shown in FIG. 1. FIG. 6 is a flow diagram illustrating control of the number of heat source devices in the heat source system shown in FIG. 1. FIG. 7 is a schematic diagram showing the details of the heat source functional power limitation process in the heat source system shown in FIG. FIG. 8 is a schematic diagram showing the details of the heat source equipment stage reduction process in the heat source system shown in FIG. 1. FIG. 9 is a schematic diagram showing the details of the heat source equipment stage increasing process in the heat source system shown in FIG. 1.

(Embodiment)
Embodiments of the present disclosure will be described below with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications, or its uses. Further, since each drawing is for conceptually explaining the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

<Heat source system>
As shown in FIG. 1, the heat source system (100) according to the present embodiment mainly includes a plurality of (three in this example) heat source devices (101) and a plurality of (four in this example) pumps (102). ) and a control section (150). In the heat source system (100) shown in FIG. 1, a heat medium such as cold water or hot water circulates in the direction of the arrow between each heat source device (101) and the system load. The system load is the load of air conditioning equipment, etc. The plurality of heat source devices (101) are, for example, chillers, heat pumps, etc., but below, a case where the plurality of heat source devices (101) are chillers will be described as an example. The plurality of pumps (102) are in this example primary pumps with a VFD (102a). The control unit (150) mainly controls the operation of the heat source device (101) and the pump (102).

A plurality of heat source machines (101) are arranged in parallel with each other. A plurality of pumps (102) are arranged in parallel with each other. The respective numbers of heat source machines (101) and pumps (102) are not particularly limited. Moreover, the respective numbers of heat source devices (101) and pumps (102) may be different as in this example, or may be the same. Furthermore, at least one of the plurality of heat source devices (101) and the plurality of pumps (102) may be configured with a plurality of different capacities.

In the heat source system (100), a collection pipe (103) is arranged so as to combine the flow paths between the plurality of heat source machines (101) and the plurality of pumps (102) into one. That is, the heat source system (100) is of a manifold piping type. The collective pipe (103) is connected to a plurality of pipes (105) communicating with each heat source device (101) via a first header (104). The collective pipe (103) is connected to a plurality of pipes (107) communicating with each pump (102) via a second header (106).

The cold water cooled by the plurality of heat source machines (101) is sent to the system load via the plurality of pipes (108) communicating with each heat source machine (101). The plurality of pipes (108) are connected to the water supply pipe (110) via a third header (109). The third header (109) may be provided with a sensor (T, P in FIG. 1) that measures the temperature and pressure of the cold water sent to the system load. A secondary pump may be placed between the water pipe (110) and the system load.

The heat medium (water in this example) used in the system load is sent to the heat source machine (101) via the return pipe (111). The return pipe (111) is connected to a measurement pipe (114) provided with a flow meter (113) via a fourth header (112). The fourth header (112) may be provided with a sensor (T in FIG. 1) that measures the temperature of the heat medium sent to the heat source device (101). The measurement pipe (114) is connected to a plurality of pipes (116) communicating with each pump (102) via a fifth header (115).

Note that a bypass pipe (117) that bypasses the plurality of heat source devices (101) and the plurality of pumps (102) is provided between the third header (109) and the fifth header (115). A valve (118) is provided in the bypass pipe (117).

<Control unit>
The control unit (150) includes, for example, a computer and its peripheral devices. The control unit (150) executes various functions described below using hardware such as a computer and programs executed by the computer.

The control unit (150) outputs a command signal to start or stop the heat source device (101) or the pump (102). The control unit (150) outputs a command signal to control the VFD (102a) of the pump (102). Measurement signals (temperature, pressure) from sensors provided in the third header (109) and fourth header (112) and measurement signals from the flowmeter (113) are input to the control unit (150). The control unit (150) controls the opening degree of the valve (118) provided in the bypass pipe (117).

The control unit (150) determines the required flow rate based on at least the required minimum flow rate set for the plurality of heat source devices (101) and the operating state of the plurality of heat source devices (101). The control unit (150) determines the current water supply amount or the maximum water supply amount based on the flow rates set for the plurality of pumps (102) and the operating states of the plurality of pumps (102). The control unit (150) compares the required flow rate with the current water supply amount or the maximum water supply amount, and controls the operation of the plurality of heat source devices (101) or the plurality of pumps (102) according to the result. Control. The control unit (150) may, for example, increase or decrease the number of operating heat source devices (101) or the number of operating pumps (102). Here, the "operating state" includes not only the ON/OFF states of the heat source device (101) and the pump (102) but also the VFD command values of the heat source device (101) and the pump (102). Moreover, "controlling operation" includes not only control of the ON/OFF state of the heat source device (101) and the pump (102) but also VFD control of the heat source device (101) and the pump (102).

If there is a difference in the length of the piping (105) connected to each of the plurality of heat source devices (101), the control unit (150) may, for example, The required flow rate may be determined based on the flow rate obtained by multiplying the required minimum flow rate by a coefficient that takes into account flow rate variations, and the operating status of the plurality of heat source devices (101). Specifically, the piping length L1 of the piping (105) from the first header (104) to the first heat source device (101), and the piping length L1 of the piping (105) from the first header (104) to the other heat source device (101). ) have different piping lengths L2, and when one heat source device (101) is used as a reference, the required minimum flow rate of the other heat source device (101) is the flow rate obtained by multiplying the predetermined required minimum flow rate by the coefficient L2/L1. You can set it to .

Hereinafter, details of the operation control of the heat source device (101) or the pump (102) by the control unit (150) will be explained with reference to FIGS. 2 to 9.

<Pump number control>
FIG. 2 is a flow diagram illustrating the control of the number of pumps by the control unit (150).

First, in step S101, the control unit (150) determines whether the flow rate at the system load (hereinafter referred to as load-side flow rate) exceeds the capacity of the total number of pumps (102) in operation. When the load-side flow rate is larger, the control unit (150) increases the number of pumps (102) by normal number control. Specifically, in step S102, the control unit (150) enables starting, for example, the pump (102) with the shortest cumulative operating time among the startable pumps (102), and in step S103, the control unit (150) enables starting the pump (102) with the shortest cumulative operating time. (102) will be increased.

On the other hand, if it is determined in step S101 that the load-side flow rate is not larger, the control unit (150) determines in step S104 that if the load-side flow rate is reduced by one from the number of pumps (102) in operation. Determine whether the capacity is smaller than the capacity of . If the load-side flow rate is not smaller, the control unit (150) determines in step S105 that the total required minimum flow rate set for each operating heat source device (101), that is, the required flow rate, is equal to or smaller than the required flow rate for each operating pump (101). 102) is larger than the total flow rate (rated flow rate), that is, the current water supply amount. If the required flow rate is larger, the control unit (150) forcibly increases the pump (102) in step S106, and if the required flow rate is not larger, the control unit (150) increases the pump (102) in step S107. Decided to maintain the current number of operating vehicles (102). Incidentally, when determining the required flow rate in step S105, as described above, variations in the flow rate in the pipes (105) connected to each heat source device (101) may be taken into consideration.

Hereinafter, the contents of the pump stage increasing process (processing in step S106 etc.) by the control unit (150) will be explained with reference to FIG. 3. If there is a pump (102) on standby whose current water supply amount after increasing the stage satisfies the required flow rate (standby pump case 1 in Figure 3 (pumps 2 and 3 apply)), the control unit (150) controls the standby pump (102) to Among the pumps (102) in the middle, the pump (102) with the smallest change in the current water supply amount (in other words, the smallest capacity) after stage increase (standby pump in Figure 3, Pump 2 in Case 1) can be activated. . On the other hand, in step S106, if there is no pump (102) on standby whose current water supply amount after stage increase satisfies the required flow rate (standby pump case 2 (no applicable pump) in FIG. 3), the control unit (150) The pump (102) with the largest capacity among the standby pumps (102) (pump 1 in standby pump case 2 in FIG. 3) can be activated. In this case, the pumps (102) can be started sequentially in descending order of capacity until a standby pump (102) whose current water supply amount after stage increase satisfies the required flow rate is found. If there are a plurality of pumps (102) that satisfy the condition in step S106, in step S102, the control unit (150) selects, for example, the pump with the shortest cumulative operating time from among the plurality of applicable pumps (102). (102) can be activated. Thereafter, in step S103, the control unit (150) increases the stage of the pump (102) that is enabled to start.

In step S104, if the control unit (150) determines that the load side flow rate is smaller, the control unit (150) performs stage reduction of the pumps (102) by normal number control. Specifically, in step S108, the control unit (150) determines that the "total required minimum flow rate set for each operating heat source device (101)", that is, the required flow rate, is equal to "the total required minimum flow rate set for each operating pump (102)". The sum of the rated flow rates (current water supply volume) minus the rated flow rate of the pump (102) scheduled to be shut down next, that is, the flow rate is determined to be smaller than the water supply volume after stage reduction. If the required flow rate is smaller, in step S109, the control unit (150) enables the pump (102) scheduled to be stopped, for example, the pump (102) with the longest cumulative operating time, to stop the pump (102), and in step S110, Perform stage reduction of the pump (102). Incidentally, when determining the required flow rate in step S108, as described above, variations in the flow rate in the piping (105) connected to each heat source device (101) may be taken into consideration.

In step S108, if the control unit (150) determines that the required flow rate is not smaller than the water supply amount after stage reduction, in step S111, the control unit (150) determines that the required flow rate is not smaller than the water supply amount after stage reduction, in addition to the pump (102) scheduled to be stopped. , it is determined whether there is a pump (102) in operation whose current water supply amount after stage reduction is larger than the required flow rate. The details of the pump stage reduction process by the control unit (150) will be described below with reference to FIG. 4. In FIG. 4, it is assumed that the pump (102) that is originally scheduled to be shut down (OFF) is pump 2. If there is no pump (102) in operation whose current water supply amount after step reduction satisfies the required flow rate (pump in operation in Figure 4 Case 1 (no corresponding pump including pump 2)), the control unit (150) performs step S107. In this step, it is decided to prohibit stage reduction of all pumps (102) and maintain the current number of operating pumps (102). On the other hand, if there is an operating pump (102) whose current water supply amount after stage reduction is larger than the required flow rate (operating pump case 2 (pump 1 applies) in Figure 4), the control unit (150) In S109, among the pumps (102) that can be stopped, for example, the pump (102) with the longest cumulative operating time (pump 1 in the running pump case 2 in FIG. 4) is made stopable, and in step S110, , perform stage reduction of the pump (102).

In the pump number control shown in FIG. 2, the processes of steps S101 to S111 described above may be repeatedly performed at predetermined time intervals.

<Pump VFD control>
When at least one of the plurality of pumps (102) has a VFD function, the control unit (150) controls the above-mentioned required flow rate instead of or in addition to the pump number control shown in FIG. The VFD command value for the pump with VFD function (102) in operation (hereinafter referred to as the VFD type pump (102)) may be updated based on the difference from the current water supply amount described above.

FIG. 5 is a flow diagram illustrating pump VFD control by the control unit (150).

First, in step S151, the control unit (150) controls the VFD pump (102) based on the difference between the pressure of the piping (107, 116) connected to the VFD pump (102) and the set value of the pressure. Determine the command value.

Next, in step S152, the control unit (150) determines the lower limit value of the VFD command value from the information of each heat source device (101) in operation and each pump (102) in operation. Specifically, for the VFD type pump (102) in operation, the current flow rate estimate is calculated by multiplying the flow rate set in the VFD type pump (102) by the rotation rate, and the estimated value is used to calculate the current flow rate. The above-mentioned current water flow rate is determined, and if the above-mentioned required flow rate is larger than the current water flow rate, the lower limit value of the VFD command value is set so as to compensate for the difference between the required flow rate and the current water flow rate. calculate.

Next, in step S153, the control unit (150) determines whether the lower limit value of the VFD command value determined in step S152 is larger than the VFD command value determined based on the pressure in step S151. When the lower limit value of the VFD command value is larger, in step S154, the control unit (150) increases the VFD command value to the lower limit value. That is, the VFD command value is updated by the lower limit value, and then, in step S155, the control unit (150) outputs the updated VFD command value as the VFD command value for the VFD type pump (102).

In step S153, if the control unit (150) determines that the lower limit of the VFD command value determined in step S152 is not larger than the VFD command value determined based on the pressure in step S151, in step S155, The control unit (150) directly outputs the VFD command value determined based on the pressure as a VFD command value for the VFD pump (102).

In the pump VFD control shown in FIG. 5, the processes of steps S151 to S155 described above may be repeatedly performed at predetermined time intervals. Furthermore, when a plurality of VFD pumps (102) are provided, the same VFD command value may be output to each VFD pump (102) in the pump VFD control shown in FIG.

<Control of number of heat source devices>
In place of the pump number control shown in FIG. 2 and/or the pump VFD control shown in FIG. 5, or in addition to the pump number control and/or the pump VFD control shown in FIG. The number of machines may be controlled.

FIG. 6 is a flow diagram illustrating the control of the number of heat source devices by the control unit (150).

First, in step S301, the control unit (150) determines whether the amount of heat in the system load (hereinafter referred to as load-side heat amount) exceeds the capacity of the total number of heat source devices (101) in operation. If the load-side heat amount is not larger, the control unit (150) determines in step S302 whether the load-side heat amount is smaller than the capacity when the number of pumps (102) in operation is reduced by one. Determine. When the load-side heat amount is smaller, the control unit (150) reduces the number of heat source devices (101) through normal number control. Specifically, in step S303, the control unit (150) enables the heat source device (101) with the longest cumulative operating time to be stopped, for example, from among the heat source devices (101) that can be stopped, and in step S304, Implement stage reduction of the heat source machine (101).

On the other hand, if it is determined in step S302 that the load-side heat amount is not smaller than It is determined whether the "total", that is, the requested flow rate, is larger than the "sum of the flow rates (rated flow rates) set for all pumps (102) that have not failed", that is, the maximum water flow rate. If the required flow rate has not become larger, the control unit (150) determines to maintain the current number of operating heat source devices (101) in step S306. Note that when determining the required flow rate in step S305, as described above, variations in flow rate in the piping (105) connected to each heat source device (101) may be taken into consideration.

In the case where it is determined in step S305 that the required flow rate is larger, if at least one of the plurality of heat source devices (101) has a VFD function or the like and capacity adjustment is possible, the control unit (150) performs heat source functional capacity restriction processing in steps S307 and S308, which will be described later.

Hereinafter, the details of the heat source functional power restriction processing by the control unit (150) will be explained with reference to FIG. 7. As shown in FIG. 7, when the compressor of the heat source machine (101) has a VFD function, even if the flow rate does not meet the required minimum flow rate of the heat source machine (101), the VFD command of the compressor of the heat source machine (101) By limiting the maximum value, operation can be continued with a low flow rate. For example, [1] assume that when the compressor of the heat source machine (101) is operating at 100% capacity, the required minimum flow rate is half the rated flow rate. After that, [2] it is assumed that the flow rate corresponding to the above-mentioned maximum water supply amount becomes 40% of the rated value, and the required minimum flow rate cannot be satisfied as it is. In this case, [3] If the upper limit of the VFD command value (that is, the capacity limit value) of the compressor of the heat source machine (101) is limited to 80%, operation will continue even if the flow rate is 40% of the original rating. It becomes possible. It should be noted that the capacity limit value of the heat source device (101) has a lower limit set according to specifications and the like.

Therefore, in step S307, the control unit (150) first calculates the capacity limit value of the heat source device (101) that allows continued operation, and then in step S308, the control unit (150) determines that the calculated capacity limit value is a predetermined lower limit value. If it is larger, in step S309, the capacity of the heat source machine (101) is limited to the capacity limit value while the number of heat source machines (101) in operation remains the same. On the other hand, if the capacity limit value of the heat source device (101) is not larger than the predetermined lower limit value, the control unit (150) performs forced stage reduction of the heat source device (101) from step S310 described later.

Note that the heat source functional capacity restriction processing in steps S307 and S308 described above can be selected, for example, by the user, and if it is determined in step S305 that the required flow rate is larger, the control unit (150) performs the processing in step S307. Alternatively, the heat source functional power limitation process in S308 may be omitted, and the heat source device (101) may be forced to be reduced in stage from step S310, which will be described later.

Hereinafter, the contents of the heat source device stage reduction process (processing in step S310 etc.) by the control unit (150) will be explained with reference to FIG. 8. In step S310, the control unit (150) determines whether there is an operating heat source unit (101) whose required flow rate after stage reduction is smaller than the maximum water supply amount (operating heat source unit in FIG. 8 Case 1 (heat source unit 2)). , heat source unit 3)), among the operating heat source units (101), the change in the required flow rate after stage reduction is the smallest (that is, the required minimum flow rate is the smallest) (the heat source unit (101) (operating in Figure 8) Medium heat source equipment (in case 1, heat source equipment 2) can be stopped. On the other hand, in step S310, if there is no heat source device (101) in operation for which the required flow rate after stage reduction is smaller than the maximum water supply amount (heat source device in operation in Fig. 8 Case 2 (no applicable heat source device)), the control The part (150) is capable of stopping the heat source device (101) with the largest required minimum flow rate among the operating heat source devices (101) (heat source device 1 in operation heat source device Case 2 in Figure 8). In this case, the heat source devices (101) can be stopped in order of decreasing required minimum flow rate until an operating heat source device (101) whose required flow rate after stage reduction is smaller than the maximum water supply amount is found. If there is a plurality of heat source devices (101) that satisfy the condition in step S310, in step S303, the control unit (150) selects the heat source device (101) with the highest total operating time, for example, from among the plurality of heat source devices (101). It is possible to stop a long heat source machine (101). After that, in step S304, the control unit (150) performs stage reduction of the heat source device (101) that can be stopped. Incidentally, when determining the required flow rate in step S310, as described above, variations in the flow rate in the piping (105) connected to each heat source device (101) may be taken into consideration.

The heat source equipment stage reduction process when it is determined in step S301 that the load-side heat amount does not exceed the capacity of the total number of operating heat source equipment (101) has been described. On the other hand, if it is determined in step S301 that the load-side heat amount exceeds the capacity of the total number of operating heat source devices (101), the control unit (150) controls the heat source devices ( 101). Specifically, first, in step S311, the control unit (150) adds "the total required minimum flow rate (required flow rate) set for each heat source device (101) in operation to the next scheduled start of operation. Determine whether the flow rate that is the sum of the required minimum flow rate of the heat source equipment (101), that is, the required flow rate after stage increase, is smaller than the sum of the rated flow rates of all non-faulty pumps (102), that is, the maximum water flow rate. do. If the required flow rate after increasing the stage is smaller, in step S312, the control unit (150) enables starting the heat source device (101) scheduled to start operation, for example, the heat source device (101) with the shortest cumulative operating time, In step S313, the number of stages of the heat source device (101) is increased. Note that when determining the required flow rate in step S311, as described above, variations in flow rate in the piping (105) connected to each heat source device (101) may be taken into consideration.

On the other hand, if it is determined in step S311 that the required flow rate after stage increase is not smaller than the maximum water supply amount, in step S314, the control unit (150) controls the increase It is determined whether there is a standby heat source device (101) whose required flow rate after the stage is smaller than the maximum water supply amount.

Hereinafter, the details of the heat source device stage increasing process by the control unit (150) will be explained with reference to FIG. 9. In FIG. 9, it is assumed that the heat source device (101) that is originally scheduled to start operation (ON) is the heat source device 2. If there is no standby heat source unit (101) whose required flow rate after increasing the stage is smaller than the maximum water supply rate (standby heat source unit in Figure 9 Case 1 (no applicable heat source unit including heat source unit 2)), the control unit (150) ) determines in step S306 to prohibit increasing the number of heat source devices (101) and maintain the current number of operating heat source devices (101). On the other hand, if there is a standby heat source unit (101) whose required flow rate after increasing the stage is smaller than the maximum water flow rate (standby heat source unit Case 2 (heat source unit 1 applies) in Figure 9), the control unit (150) In step S312, for example, the heat source device (101) with the shortest cumulative operating time is started from among the heat source devices (101) that can be started (in the standby heat source device case 2 of FIG. 9, the heat source device 1 corresponds to the heat source device). In step S313, the number of stages of the heat source device (101) is increased.

In controlling the number of heat source devices shown in FIG. 6, the processes of steps S301 to S313 described above may be repeatedly performed at predetermined time intervals.

<Features of the embodiment>
The heat source system (100) of this embodiment includes a plurality of heat source machines (101) arranged in parallel with each other, a plurality of pumps (102) arranged in parallel with each other, a plurality of heat source machines (101), and a plurality of heat source machines (101). A control unit (150) that controls the operation of a collection pipe (103) arranged to combine the flow paths between the pump (102) and the plurality of heat source devices (101) and the plurality of pumps (102). Equipped with.

According to the heat source system (100) of this embodiment, the required flow rate is determined according to the number of activated heat source devices (101), and the current water supply amount (current amount) is determined according to the number of activated pumps (102). (101) or the maximum amount of water that can be sent (the maximum amount of water that can be sent), and if necessary, increase or decrease the stages of the heat source device (101) or pump (102), or the pump (102) with VFD function. VFD setting values can be adjusted. Therefore, the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed.

Furthermore, according to the heat source system (100) of the present embodiment, even if the numbers of heat source devices (101) and pumps (102) are different, or a plurality of pumps (102) with different capacities are mixed, However, since the required minimum flow rate of each heat source device (101) can be always ensured, it is possible to correspond to various system configurations.

Furthermore, according to the heat source system (100) of the present embodiment, the number of activated heat source machines (101) can be limited according to the number of operable pumps (102). For example, when one or more pumps (102) are out of order, even if a start/stop command is output to the heat source equipment (101) during high load, the number of pumps (102) that can be operated is insufficient, and the required minimum There is a heat source device (101) whose flow rate cannot be ensured, and stable control may not be possible. In contrast, in the heat source system (100) of the present embodiment, the number of activated heat source devices (101) can be limited based on the amount of water supplied by the operable pumps (102).

Further, according to the heat source system (100) of the present embodiment, for the pump (102) with a VFD function, the current estimated flow rate is calculated according to the various operating information described above, and the required flow rate is calculated from the estimated flow rate. If is larger, the VFD command value of the pump (102) can be increased to cover the required flow rate. Furthermore, if the VFD command value becomes low, the flow rate may not be sufficient in the heat source device (101) and stable control may not be possible. The lower limit of the VFD command value may be determined.

Further, according to the heat source system (100) of the present embodiment, it is possible to reduce the number of man-hours required for trial run adjustment to ensure the required minimum flow rate of the heat source machine (101), and it is possible to provide stable quality even without being an expert. Therefore, it can contribute to resolving labor shortages and reducing adjustment costs.

In the heat source system (100) of the present embodiment, at least one of the plurality of heat source machines (101) and the plurality of pumps (102) may be configured with a plurality of different capacities. For example, when a plurality of pumps (102) with different capacities coexist, the current water supply amount changes depending on the capacity of the activated pump (102), so the flow rate in the heat source device (101) may become insufficient. On the other hand, in the heat source system (100) of the present embodiment, the pump (102) is increased or decreased depending on, for example, the number of activated heat source devices (101) or the rated flow rate of the activated pump (102). be able to. Therefore, unlike the conventional manifold piping type heat source system, even if heat source machines (101) and pumps (102) of different capacities are mixed, the required minimum flow rate of each heat source machine (101) can be secured and stable can be controlled.

In the heat source system (100) of this embodiment, the control unit (150) may increase or decrease the number of operating plural heat source machines (101) or the operating number of plural pumps (102). In this way, the required minimum flow rate of each heat source device (101) can be ensured by increasing/decreasing stages of the heat source device (101) or the pump (102), and stable control can be performed.

In the heat source system (100) of the present embodiment, the control unit (150) calculates the required minimum flow rate by multiplying it by a coefficient that takes into account flow rate variations in each pipe (105) connected to the plurality of heat source devices (101). The required flow rate may be determined based on the flow rate and the operating state of the plurality of heat source devices (101). In this way, the required flow rates for the plurality of heat source devices (101) can be determined more accurately, so that more stable control can be performed.

In the heat source system (100) of the present embodiment, the control unit (150) compares the requested flow rate with the current water supply amount, and if the requested flow rate is larger, the control unit (150) compares the requested flow rate with the current water supply amount. The pump (102) to be started may be selected from among the plurality of pumps (102) so that the flow rate is satisfied and the change in the current water supply amount is minimized. In this way, by increasing the number of pumps (102), the required minimum flow rate of each heat source device (101) can be ensured, and stable control can be performed. Further, since the pump (102) is increased in stages so that the change in the current water supply amount is minimized, the influence on the system load due to the increase in the pump (102) stages can be suppressed to the lowest possible extent.

In the heat source system (100) of the present embodiment, the control unit (150) calculates the post-reduced water supply amount from the current water supply amount based on information about the pump (102) scheduled to be shut down among the plurality of pumps (102). The pump (102) may be permitted or prohibited to stop operating according to the calculated result, and the water supply amount after stage reduction is compared with the required flow rate. In this way, by reducing the stages of the pump (102), the required minimum flow rate of each heat source device (101) can be ensured, and stable control can be performed.

In the heat source system (100) of the present embodiment, at least one of the plurality of pumps (102) is a VFD type pump (102), and the control unit (150) controls the difference between the requested flow rate and the current water supply amount. Based on this, the VFD command value for the VFD pump (102) in operation may be updated. In this way, by adjusting the VFD command value of the VFD type pump (102), the required minimum flow rate of each heat source device (101) can be ensured and stable control can be performed. In addition, in this case, the control unit (150) issues a VFD command for the VFD pump (102) based on the difference between the pressure of the piping (107, 116) connected to the VFD pump (102) and the set value of the pressure. The current water supply amount is determined by multiplying the flow rate set by the operating VFD pump (102) by the rotation rate, and the requested flow rate is compared with the current water supply amount. is larger, a lower limit value of the VFD command value is calculated so as to compensate for the difference between the required flow rate and the current water supply amount, and if the lower limit value is larger than the VFD command value, The VFD command value may be updated by the lower limit value. In this way, the VFD command value of the VFD pump (102) can be adjusted so that the required minimum flow rate of each heat source device (101) can be ensured.

In the heat source system (100) of the present embodiment, the control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, the control unit (150) determines that the maximum water supply amount is higher than the requested flow rate. The heat source device (101) whose operation is to be stopped may be selected from among the plurality of heat source devices (101) so as to satisfy the flow rate. In this way, by reducing the stage of the heat source device (101), the required minimum flow rate of the other heat source devices (101) in operation can be ensured, and stable control can be performed. Further, in this case, the control unit (150) compares the required flow rate with the maximum water supply amount, and if the required flow rate is larger, selectively performs the first control and the second control. In the first control, a heat source device (101) to be shut down is selected from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate, and in the second control, the maximum A heat source device (101) to be shut down may be selected from among the plurality of heat source devices (101) so that the water supply amount satisfies the required flow rate and the change in the required flow rate is the smallest. In this way, by reducing the stage of the heat source device (101), the required minimum flow rate of the other heat source devices (101) in operation can be ensured, and stable control can be performed. In addition, in the second control, the heat source equipment (101) is reduced in stage so that the change in the required flow rate is minimized, so the impact on the system load due to the reduction in the stage of the heat source equipment (101) is suppressed as much as possible. can do.

In the heat source system (100) of the present embodiment, the control unit (150) calculates the post-increase required flow rate from the required flow rate based on the information of the heat source device (101) scheduled to start operation among the plurality of heat source devices (101). is calculated, and the required flow rate after stage increase is compared with the maximum water supply amount, and depending on the result, the start of operation of the heat source device (101) may be permitted or prohibited. In this way, the number of heat source devices (101) is increased while ensuring the required minimum flow rate of each heat source device (101) during operation, so stable control can be performed.

In the heat source system (100) of the present embodiment, the control unit (150) compares the required flow rate with the maximum water supply amount, and if the required flow rate is larger, the control unit (150) controls the plurality of heat source devices (101). The capacity of the heat source device (101) that is in operation may be limited. In this way, the required minimum flow rate of each heat source device (101) can be ensured by limiting the capacity of the heat source device (101) in operation, and stable control can be performed.

In the heat source system (100) of the present embodiment, the control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, the control unit (150) performs a third control and a fourth control. In the third control, a heat source device (101) to be stopped from among the plurality of heat source devices (101) is selected so that the maximum water supply amount satisfies the required flow rate, and the third control In the 4-control, the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) may be limited. In this way, the required minimum flow rate of each heat source device (101) can be ensured by selectively reducing the stages of the heat source device (101) or limiting the capacity of the heat source device (101) during operation. Stable control can be performed. In this case, if the control unit (150) performs the fourth control when the requested flow rate is larger than the maximum water supply amount, the influence on the system load due to the stage reduction of the heat source device (101) will be reduced. can be avoided. Further, the control unit (150) determines that the requested flow rate is larger than the maximum water supply amount, and the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is lower than a predetermined lower limit value. In such cases, if the third control is performed, even if the capacity of the heat source machine (101) in operation cannot be restricted, the capacity of the other heat source machine (101) in operation can be reduced by reducing the stage of the heat source machine (101). It is possible to secure the required minimum flow rate and perform stable control. Furthermore, the control unit (150) determines that the required flow rate is larger than the maximum water supply amount and that the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is lower than a predetermined lower limit value. In this case, a fifth control and a sixth control are selectively performed as the third control, and in the fifth control, the plurality of heat source devices (101) are controlled so that the maximum water supply amount satisfies the required flow rate. A heat source device to be stopped is selected from among the plurality of heat source devices (101), and in the sixth control, the heat source device is selected from among the plurality of heat source devices (101) so that the maximum water flow rate satisfies the required flow rate and the change in the required flow rate is minimized. You may select the heat source device (101) whose operation is to be stopped from the list. In this way, if the capacity of the heat source machine (101) in operation cannot be restricted, the required minimum flow rate of the other heat source machine (101) in operation can be ensured by reducing the stages of the heat source machine (101). , stable control can be performed. In addition, in the sixth control, the heat source device (101) is reduced in stage so that the change in the required flow rate is minimized, so the effect on the system load due to the step reduction in the heat source device (101) is minimized. Can be suppressed.

(Other embodiments)
Although the embodiments and modifications have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. Further, the above embodiments and modifications may be combined or replaced as appropriate. Furthermore, the descriptions such as "first", "second", etc. mentioned above are used to distinguish the words to which these descriptions are given, and they also limit the number and order of the words. isn't it.

As explained above, the present disclosure is useful for heat source systems.

100 heat source system 101 heat source machine 102 pump 103 collective piping 105, 107, 116 piping 150 control section

Claims

A plurality of heat source machines (101) provided in parallel with each other,
a plurality of pumps (102) provided in parallel with each other;
a collective pipe (103) arranged so as to combine flow paths between the plurality of heat source devices (101) and the plurality of pumps (102);
A control unit (150) that controls the operation of the plurality of heat source devices (101) and the plurality of pumps (102),
The control unit (150) includes:
Determining the required flow rate based on at least the required minimum flow rate set for the plurality of heat source machines (101) and the operating state of the plurality of heat source machines (101),
Determining the current water supply amount or the maximum water supply amount based on the flow rate set for the plurality of pumps (102) and the operating state of the plurality of pumps (102),
A heat source system that compares the required flow rate with the current water supply amount or the maximum water supply amount, and controls the operation of the plurality of heat source devices (101) or the plurality of pumps (102) according to the result.
The heat source system according to claim 1,
A heat source system in which at least one of the plurality of heat source machines (101) and the plurality of pumps (102) has a plurality of different capacities.
The heat source system according to claim 1 or 2,
The control unit (150) is a heat source system that increases or decreases the number of operating units of the plurality of heat source devices (101) or the number of operating units of the plurality of pumps (102).
The heat source system according to any one of claims 1 to 3,
The control unit (150) calculates a flow rate obtained by multiplying the required minimum flow rate by a coefficient that takes into account flow variation in each pipe (105, 108) connected to the plurality of heat source devices (101), and (101) A heat source system that determines the required flow rate based on the operating state of the heat source system.
The heat source system according to any one of claims 1 to 4,
The control unit (150) compares the required flow rate and the current water supply amount, and if the required flow rate is larger, the current water supply amount satisfies the required flow rate and changes the current water supply amount. A heat source system that selects a pump (102) to start operation from among the plurality of pumps (102) so that
The heat source system according to any one of claims 1 to 4,
The control unit (150) calculates the water supply amount after stage reduction from the current water supply volume based on the information of the pump (102) scheduled to stop operation among the plurality of pumps (102), and calculates the water supply volume after stage reduction. A heat source system that compares the required flow rate with the required flow rate and, depending on the result, permits or prohibits the operation of the pump (102) to be stopped.
The heat source system according to any one of claims 1 to 4,
At least one of the plurality of pumps (102) is a VFD type pump (102),
The control unit (150) is a heat source system that updates a VFD command value for the VFD pump (102) in operation based on the difference between the required flow rate and the current water supply amount.
The heat source system according to claim 7,
The control unit (150) includes:
Determining a VFD command value for the VFD pump (102) based on the difference between the pressure of the pipe (107, 116) connected to the VFD pump (102) and the set value of the pressure;
determining the current water supply amount by multiplying the flow rate set by the VFD type pump (102) in operation by the rotation rate;
Comparing the required flow rate and the current water supply amount, and if the required flow rate is larger, calculating the lower limit value of the VFD command value so as to compensate for the difference between the required flow rate and the current water supply amount. death,
A heat source system that updates the VFD command value with the lower limit value when the lower limit value is larger than the VFD command value.
The heat source system according to any one of claims 1 to 4,
The control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, controls the plurality of heat sources so that the maximum water supply amount satisfies the required flow rate. A heat source system in which a heat source machine (101) to be shut down is selected from among machines (101).
The heat source system according to claim 9,
The control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, selectively performs first control and second control;
In the first control, a heat source device (101) to be stopped from among the plurality of heat source devices (101) is selected so that the maximum water supply amount satisfies the required flow rate,
In the second control, a heat source device (101) to be shut down is selected from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate and the change in the required flow rate is the smallest. heat source system.
The heat source system according to any one of claims 1 to 4,
The control unit (150) calculates the required flow rate after increasing the stage from the required flow rate based on the information of the heat source device (101) scheduled to start operation among the plurality of heat source devices (101), and calculates the required flow rate after increasing the stage from the required flow rate. A heat source system that compares the flow rate with the maximum water supply amount and, depending on the result, permits or prohibits the start of operation of the heat source device (101).
The heat source system according to any one of claims 1 to 4,
The control unit (150) compares the requested flow rate with the maximum water supply amount, and if the requested flow rate is larger, the control unit (150) selects the operating heat source device (101) from among the plurality of heat source devices (101). ) heat source system that limits the ability of
The heat source system according to any one of claims 1 to 4,
The control unit (150) compares the required flow rate and the maximum water supply amount, and if the required flow rate is larger, selectively performs a third control and a fourth control;
In the third control, a heat source device (101) to be stopped from among the plurality of heat source devices (101) is selected so that the maximum water supply amount satisfies the required flow rate,
In the fourth control, the heat source system limits the capacity of the heat source device (101) in operation among the plurality of heat source devices (101).
The heat source system according to claim 13,
The control unit (150) performs the fourth control when the required flow rate is larger than the maximum water supply amount.
heat source system.
The heat source system according to claim 13 or 14,
The control unit (150) determines that the required flow rate is larger than the maximum water supply amount, and that the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is lower than a predetermined lower limit value. In this case, a heat source system that performs the third control.
The heat source system according to any one of claims 13 to 15,
The control unit (150) determines that the required flow rate is larger than the maximum water supply amount, and that the capacity of the heat source device (101) in operation among the plurality of heat source devices (101) is lower than a predetermined lower limit value. In this case, the fifth control and the sixth control are selectively performed as the third control,
In the fifth control, a heat source device to be shut down is selected from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate,
In the sixth control, a heat source device (101) to be shut down is selected from among the plurality of heat source devices (101) so that the maximum water supply amount satisfies the required flow rate and the change in the required flow rate is the smallest. heat source system.