EP4148343A1

EP4148343A1 - Heat source system, heat source machine, and control device

Info

Publication number: EP4148343A1
Application number: EP19833973.1A
Authority: EP
Inventors: Noriomi OKAZAKI; Yuji Matsumoto
Original assignee: Toshiba Carrier Corp
Current assignee: Toshiba Carrier Corp
Priority date: 2018-07-09
Filing date: 2019-04-18
Publication date: 2023-03-15
Also published as: WO2020012750A1; JP2023161037A; KR20210013126A; JPWO2020012750A1; EP4148343A4; KR102519815B1

Abstract

A heat source system 1 of an embodiment includes an inlet-side pressure gauge 17 that is provided on an inlet side where water flows from a condensate return pipe into a water refrigerant heat-exchanger 9 and detects pressure of water flowing through the condensate return pipe on an upstream side of an inlet pump 10 for feeding water to the water refrigerant heat-exchanger 9, an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger 9 to the water feed pipe 5 and detects pressure of water flowing through the water feed pipe 5, and a control device 16 for executing processing of controlling a bypass valve 2 provided in a bypass pipe 7 based on the difference between the pressure on the inlet side detected by the inlet-side pressure gauge 17 and the pressure on the outlet side detected by the outlet-side pressure gauge.

Description

Technical Field

An embodiment of the present invention relates to a heat source system in which a heat source machine and a load device are connected to each other by a water feed pipe and a condensate return pipe, and a heat source machine and a control device used in the same.

Background Art

Conventionally, a heat source system configured by connecting a heat source machine and a load device with a water feed pipe and a condensate return pipe is used in a wide range of fields, for example, for air conditioning of buildings and the like, industrial use such as painting, drying, washing or the like, agricultural use such as cultivation, etc.
Such a heat source system has a simplex pump type configuration in which a pump is provided only on the heat source machine side, or a duplex pump type configuration in which a pump is provided on a load device side as well. In both configurations, various kinds of sensors such as a differential pressure gauge, a flow rate sensor, and a temperature sensor are installed in a water feed pipe, a condensate return pipe, or the like in order to acquire data necessary for control (for example, see Patent Literatures 1 and 2).

Citation List

Patent Literature

Patent Literature 1: Japanese Patent Laid-Open No. 2006-38379
Patent Literature 2: Japanese Patent Laid-Open No. 2014-35090

Summary of Invention

Technical Problem

If the types and number of sensors to be installed increase as in Patent Literatures 1 and 2, the amount of data to be acquired would increase, which is considered to be useful for control of the heat source system. On the other hand, if the types and number of sensors to be installed increase, not only the cost simply increases, but also there is a risk that a great deal of labor may be required at the time of start-up of the heat source system or during operation of the heat source system.
Therefore, there are provided a heat source system, a heat source machine, and a control device that can reduce the types and number of sensors to be installed and also improve the convenience at the time of start-up and during operation.

Solution to Problem

A heat source system of an embodiment includes an inlet-side pressure gauge that is provided on an inlet side where water flows from a condensate return pipe into a water refrigerant heat-exchanger and detects pressure of water flowing through the condensate return pipe on an upstream side of an inlet pump for feeding water to the water refrigerant heat-exchanger, an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to a water feed pipe and detects pressure of water flowing through the water feed pipe, and a control device for executing processing of controlling a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with a load device based on a difference between the pressure on the inlet side detected by the inlet-side pressure gauge and the pressure on the outlet side detected by the outlet-side pressure gauge.

Brief Description of Drawings

[Figure 1] Figure 1 is a diagram schematically showing a configuration of a simplex pump type heat source system according to a first embodiment and a second embodiment.
[Figure 2] Figure 2 is a diagram schematically showing another configuration of the simplex pump type heat source system according to a third embodiment.
[Figure 3] Figure 3 is a diagram schematically showing a configuration of a duplex pump type heat source system according to a fourth embodiment.
[Figure 4] Figure 4 is a diagram schematically showing another configuration of the duplex pump type heat source system according to a fifth embodiment.
[Figure 5] Figure 5 is a diagram schematically showing a piping mode of a heat source system according to a sixth embodiment.

Description of Embodiments

A plurality of embodiments will be described hereunder. Note that the details will be described later, but first to third embodiments are examples of a simplex pump type, fourth and fifth embodiments are examples of a duplex pump type, and a sixth embodiment is a modification thereof. Further, for simplification of description, the respective heat source systems of the embodiments are designated by the same reference signs.

(First Embodiment)

In a first embodiment, an example in which a bypass valve 2 (see Figure 1) is controlled based on the differential pressure between the pressure on an inlet side and the pressure on an outlet side of a heat source machine 3 (see Figure 1) in a simplex pump type heat source system 1 (see Figure 1) will be described. Here, the simplex pump type may be paraphrased as, for example, a primary pump system.
As shown in Figure 1, the heat source system 1 includes heat source machines 3, load devices 4, a water feed pipe 5 and a condensate return pipe 6 for circulating water between the heat source machines 3 and the load devices 4, and the like, and is configured such that water whose temperature has been adjusted to a predetermined temperature by the heat source machine 3 is sent to various load device 4 sides such as an air conditioner for air-conditioning a building and a cleaning device and a drying device installed in a factory via the water feed pipe 5, and also water from the load device 4 side is circulated through the condensate return pipe 6 to the heat source machine 3 side. Note that in Figure 1, a water flowing direction is indicated by using outlined arrows for convenience.
Further, the heat source system 1 is provided with a bypass pipe 7 for connecting the water feed pipe 5 and the condensate return pipe 6 in parallel with the load device 4, and the bypass valve 2 for adjusting the flow of water in the bypass pipe 7. By controlling the bypass valve 2, more specifically, by adjusting the opening degree of the bypass valve 2, the amount of water flowing through the bypass pipe 7 is adjusted. Further, an expansion tank 8 for applying pressure to the water flowing through the condensate return pipe 6 is connected to the condensate return pipe 6, and an outlet of the expansion tank 8 is connected to the condensate return pipe 6.
A plurality of heat source machines 3, for example, about two to ten-odd heat source machines 3 are installed based on a required specification and so that backup can be performed in the event of a failure. Each heat source machine 3 includes a water refrigerant heat-exchanger 9 for exchanging heat between water and a refrigerant, an inlet pump 10 for feeding water to the water refrigerant heat-exchanger 9 at a predetermined pressure, a water-side inlet pressure gauge 12 provided in an inlet pipe 11 from which water flows into the water refrigerant heat-exchanger 9, a water-side outlet pressure gauge 14 provided in an outlet pipe 13 into which water flows out from the water refrigerant heat-exchanger 9, a unit controller 15, and the like.
As is well known, the water refrigerant heat-exchanger 9 exchanges heat between water and a refrigerant. For example, a double-pipe heat-exchanger having a double-pipe structure of a water pipe and a refrigerant pipe, a plate heat-exchanger partitioned by a plurality of plates, a configuration in which a refrigerant pipe is arranged in a meandering manner in a water container, and the like can be appropriately adopted. In this embodiment, a plurality of water refrigerant heat-exchangers 9 described above are provided in each heat source machine 3. Note that a so-called hot-water generable type, a so-called cold-water generable type or a hot-water and cold-water generable type may be appropriately adopted as the water refrigerant heat-exchanger 9 according to the purpose.
The inlet pump 10 is controlled by an inverter (not shown), and it is provided between the condensate return pipe 6 and the water refrigerant heat-exchanger 9 in the inlet pipe 11 of the water refrigerant heat-exchanger 9. The inlet pump 10 adjusts the pressure of water flowing through the condensate return pipe 6 to a predetermined pressure and then feeds the water to the water refrigerant heat-exchanger 9, and water is fed to the water refrigerant heat-exchanger 9 at a constant pressure. The inlet pump 10 also functions as a drive source for feeding water to the load device 4 side. The type of feeding water to the load device 4 side by the pump provided in the heat source machine 3 in this way is called the simplex pump type.
The water-side inlet pressure gauge 12 is provided between the water refrigerant heat-exchanger 9 and the inlet pump 10, and detects the pressure of water which has been adjusted to a predetermined pressure by the inlet pump 10. Therefore, the pressure of water detected by the water-side inlet pressure gauge 12 is higher than the pressure of water flowing through the condensate return pipe 6. In other words, the water-side inlet pressure gauge 12 does not measure the pressure of water flowing through the condensate return pipe 6.
In the outlet pipe 13 of the water refrigerant heat-exchanger 9, the water-side outlet pressure gauge 14 detects the pressure of water which has been heat-exchanged in the water refrigerant heat-exchanger 9 to be adjusted to a predetermined temperature and flows out therefrom. At this time, since the outlet pipe 13 is directly connected to the water feed pipe 5, it can be considered that the pressure of the water detected by the water-side outlet pressure gauge 14 is substantially coincident with the pressure of the water flowing through the water feed pipe 5. In other words, the water-side outlet pressure gauge 14 can substantially detect the pressure of water flowing through the water feed pipe 5 on the upstream side of a branch point with respect to the bypass pipe 7. The water-side outlet pressure gauge 14 corresponds to an outlet-side pressure gauge.
The unit controller 15 controls the heat source machine 3 individually, and for example, the unit controller 15 controls each heat source machine 3 to perform processing of determining the flow rate of water flowing through the water refrigerant heat-exchanger 9 (hereinafter referred to as a chiller flow rate) based on the difference in water pressure detected by the water-side inlet pressure gauge 12 and the water-side outlet pressure gauge 14, etc. This unit controller 15 is connected to a control device 16 for controlling the entire heat source system 1.
In the present embodiment, the control device 16 is incorporated in one of the plurality of installed heat source machines 3, and it outputs a control command for controlling the heat source system 1 to each heat source machine 3 and also acquires information indicating an operation state such as the chiller flow rate described above from each heat source machine 3. Further, the control device 16 is directly connected to the load device 4 or indirectly connected to the load device 4 via a controller of the load device 4, and is enabled to acquire information indicating the operation state of the load device 4, etc. Hereinafter, the heat source machine 3 including the control device 16 therein will also be referred to as a representative machine for convenience.
Further, the control device 16 is also connected to the bypass valve 2 and the expansion tank 8, and allowed to perform processing of adjusting the opening degree of the bypass valve 2 provided in the bypass pipe 7, and processing of acquiring pressure (control pressure) to be applied to water flowing from the expansion tank 8 to the condensate return pipe 6. Note that the control pressure may be, for example, a pressure value itself to be set in the expansion tank 8 from the control device 16, or may be a control value with which a pressure value to be set can be specified.
The heat source machine 3 provided with the control device 16 is provided with an inlet-side pressure gauge 17. This inlet-side pressure gauge 17 is provided on an upstream side of the inlet pump 10 with respect to the flow of water flowing into the water refrigerant heat-exchanger 9, and detects the pressure of water to be taken into the inlet pump 10. More specifically, the inlet-side pressure gauge 17 is provided on a suction port side which is directly connected to the condensate return pipe 6. Therefore, unlike the water inlet pressure gauge described above, the inlet-side pressure gauge 17 can detect the pressure of water flowing through the condensate return pipe 6.
In the case of the present embodiment, the inlet-side pressure gauge 17 is incorporated in the heat source machine 3 serving as a representative machine. This representative machine has a connection mode in which inflow water branches from the condensate return pipe 6 at a position closest to the load device 4 side and outflow water joins the water feed pipe 5 at a position closest to the load device 4 side. Further, the heat source machines 3 other than the representative machine have a connection mode in which water branching from the condensate return pipe 6 on a downstream side of the representative machine flows therein, and water flows out therefrom to the water feed pipe 5 on an upstream side of the representative machine. Note that a connection portion 18 is provided between each heat source machine 3 and the water feed pipe 5 and the condensate return pipe 6.
Next, an operation of the above-described configuration will be described.
The inlet pump 10 serves to feed water to the water refrigerant heat-exchanger 9 under a predetermined pressure, but it also functions as a drive source for feeding water to the load device 4 side as described above. At this time, when a shutoff valve 4a on the load device 4 side is closed, for example, due to the operation of the load device 4 being stopped or the like, the flow of water on the discharge side of the inlet pump 10, that is, in the water feed pipe 5 is blocked or obstructed.
If the flow of water in the water feed pipe 5 is blocked or obstructed, there is a risk that the inlet pump 10 may fall into a so-called shut-off operation state, which increases the temperature to cause a failure or induce noise or vibration. This is also the case when the water flow on the suction side of the inlet pump 10, that is, in the condensate return pipe 6 is blocked or obstructed.
Therefore, it has been conventionally performed that various sensors such as a flow meter, a temperature sensor, or a differential pressure gauge installed between the water feed pipe 5 and the condensate return pipe 6 are provided, and for example, for the bypass valve 2, PID control is performed based on the differential pressure between the pressure of water in the water feed pipe 5 and the pressure of water in the condensate return pipe 6 so that the flow of water becomes appropriate.
By the way, although the control of the bypass valve 2 itself can be performed based on the differential pressure, there exists a problem that is difficult to be solved only by acquiring the differential pressure when the heat source system 1 is actually operated. This is a problem in which, as is well known, as the pressure to be applied is smaller, it is easier for water to boil, and thus if the pressure of water flowing through the condensate return pipe 6 decreases to be smaller than a reference value such as atmospheric pressure, cavitation or the like would occur to cause a failure.
Therefore, actually, there is a circumstance that a pressure gauge for detecting the pressure of water flowing through the condensate return pipe 6 is provided in addition to the differential pressure gauge for different control purposes. In other words, since individual sensors have been conventionally provided for different control operations such as acquisition of differential pressure and monitoring of pressure on the condensate return pipe 6, so that the types and number of sensors have tended to increase.
However, as the types and number of sensors to be installed increase, adjustment is required for each of the sensor in addition to mere increase of the cost and the like, so that a great deal of labor is required not only at the time of start-up of the heat source system 1, but also during operation of the heat source system 1. Further, since sensors to be installed in pipes are generally installed by a contractor side, the installed sensors differ from those of specifications, which causes defects for the heat source machine 3 side and thus causes a risk that unexpected troubles occur.
Therefore, as described above, the heat source system 1 is provided with the inlet-side pressure gauge 17 for detecting the pressure of water flowing in the condensate return pipe 6 on the front stage side of the inlet pump 10 of the heat source machine 3 serving as the representative machine, and the bypass valve 2 is controlled based on the difference between the inlet-side pressure gauge 17 and the outlet-side pressure gauge which is provided at the water-side outlet of the water refrigerant heat-exchanger 9 and substantially detects the pressure of water flowing through the water feed pipe 5.
This eliminates the need for the differential pressure gauge which has been conventionally provided. Further, since the outlet-side pressure gauge has been already installed for the water refrigerant heat-exchanger 9, the number of sensors does not increase. Therefore, it is possible to reduce the types and number of sensors. If the types and number of sensors to be installed can be reduced, the convenience at the time of start-up, or during operation or maintenance will be improved.
At this time, for example, a detection value of the outlet-side pressure gauge provided in the heat source machine 3 serving as the representative machine can be used as the pressure of water flowing through the water feed pipe 5, or any of a maximum value, a minimum value, an average value and a representative value of detected values of the outlet-side pressure gauges of the plurality of heat source machines 3 in operation may be used.
Further, in the heat source system 1, the inlet-side pressure gauge 17 will be prepared by a manufacturer side of the heat source machine 3 because the inlet-side pressure gauge 17 is provided in the heat source machine 3. As a result, it is possible to reduce the possibility of such a problem that the installed sensors are different from those of the specifications as in the conventional case. Further, unlike the conventional differential pressure gauge, it is not necessary to extend wirings to the piping side, so that the installation cost can be reduced.
As described above, in the heat source system 1, the heat source machine 3, and the control device 16, the types and number of sensors to be installed can be reduced, and the convenience at the time of start-up and during operation is improved. Of course, since the pressure of water flowing through the condensate return pipe 6 itself can be detected by the inlet-side pressure gauge 17, it is also possible to perform control of applying pressure to the expansion tank 8 when the pressure of the water is smaller than, for example, the atmospheric pressure.
According to the heat source system 1, the heat source machine 3, and the control device 16 described above, the following effects can be obtained.
The heat source system 1 includes the inlet-side pressure gauge 17 for detecting the pressure of water flowing through the condensate return pipe 6 on the upstream side of the inlet pump 10, the outlet-side pressure gauge which is provided on the outlet side where water flows out from the water refrigerant heat-exchanger 9 to the water feed pipe 5 and detects the pressure of water flowing through the water feed pipe 5, and the control device 16 for executing the processing of controlling the bypass valve 2 provided in the bypass pipe 7 connecting the water feed pipe 5 and the condensate return pipe 6 in parallel with the load device 4 based on the difference between the inlet-side pressure detected by the inlet-side pressure gauge 17 and the outlet-side pressure detected by the outlet-side pressure gauge.
This makes it possible to control the bypass valve 2 based on the detection results of the inlet-side pressure gauge 17 and the outlet-side pressure gauge, which eliminates the need to install the differential pressure gauge which has been conventionally provided, and the inlet-side pressure gauge 17 can be used for monitoring the pressure on the condensate return pipe 6 side, so that the types and number of sensors to be installed can be reduced.
Since the bypass valve 2 is controlled based on the differential pressure, it is possible to prevent occurrence of the above-mentioned shut-off operation and reduce the risk of failure. Further, since the inlet-side pressure gauge 17 is provided in the heat source machine 3, the manufacturer of the heat source machine 3 will prepare the inlet-side pressure gauge 17. Therefore, it is possible to avoid the above-described unexpected troubles and the like, so that it is possible to improve the convenience at the time of start-up and during operation.
Further, the heat source machine 3 used in the heat source system 1 includes the water refrigerant heat-exchanger 9, and the control device 16 for executing the processing of controlling the bypass valve 2 provided in the bypass pipe 7 connecting the water feed pipe 5 and the condensate return pipe 6 in parallel with the load device 4 based on the difference between the pressure of water detected by the inlet-side pressure gauge 17 and the pressure of water detected by the outlet-side pressure gauge, that is, the difference in pressure between the inlet side and the outlet side of the heat source machine 3 or the water refrigerant heat-exchanger 9. Like the heat source system 1 described above, such a heat source machine 3 can also reduce the types and number of sensors to be installed, and also improve the convenience at the time of start-up and during operation. In addition, it is possible to shorten the construction period and reduce the cost when constructing the heat source system.
The control device 16 for controlling the heat source system 1 executes the processing of controlling the bypass valve 2 provided in the bypass pipe 7 connecting the water feed pipe 5 and the condensate return pipe 6 in parallel with the load device 4 based on the difference between the pressure of water on the inlet side and the pressure of water on the outlet side. Like the heat source system 1 described above, such a control device 16 can also reduce the types and number of sensors to be installed, and also can improve convenience at the time of start-up and during operation.

(Second Embodiment)

In a second embodiment, processing of determining the amount of water flowing to the load device 4 side in the simplex pump type heat source system 1 will be described. Note that the configuration of the heat source system 1 is the same as that of the first embodiment, and thus it will be described with reference to Figure 1.
The heat source system 1 of the present embodiment has a configuration common to that of the first embodiment, and includes the foregoing heat source machines 3, the load devices 4, the water feed pipe 5, the condensate return pipe 6, the inlet-side pressure gauge 17, the water-side outlet pressure gauge 14 corresponding to the outlet-side pressure gauge, and the control device 16.
When the heat source system 1 is operated, it is necessary to appropriately control the amount of water flowing on the load device 4 side. Hereinafter, a portion of the water feed pipe 5 that is closer to the load device 4 side than a branch point between the water feed pipe 5 and the bypass pipe 7 is referred to as a load-side water feed portion 5a for convenience, and the amount of water flowing through the load-side water feed portion 5a is referred to as a load flow rate (F2; see Figure 1). Further, a portion of the condensate return pipe 6 that is closer to the load device 4 side than a branch point between the condensate return pipe 6 and the bypass pipe 7 is referred to as a load-side condensate return portion 6a for convenience.
Therefore, it has been conventionally performed that a flow meter is provided in the load-side condensate return portion 6a to directly acquire the load flow rate (F2), or each of the load-side water feed portion 5a and the load-side condensate return portion 6a is provided with a thermometer for detecting the temperature of water to estimate the load flow rate (F2) based on the temperature difference therebetween.
On the other hand, in the heat source system 1 of the present embodiment, the load flow rate (F2) is determined based on the difference in pressure detected by the inlet-side pressure gauge 17 and the outlet-side pressure gauge, and the opening degree and mechanical characteristic of the bypass valve 2.
First, the control device 16 determines the total amount of water supplied from the heat source machine 3 side. Hereinafter, the total amount of water supplied from the heat source machine 3 side is referred to as a total flow rate (F1; see Figure 1). At this time, the total flow rate (F1) is considered to be the total amount of water (chiller flow rate) supplied from each heat source machine 3 in operation.
At this time, the chiller flow rate of each heat source machine 3 in operation is controlled by each unit controller 15. Therefore, the control device 16 can acquire respective chiller flow rates from the unit controllers 15, and sum up the acquired chiller flow rates to determine the total flow rate (F1).
Next, the control device 16 determines the amount of water flowing through the bypass pipe 7 from the opening degree and mechanical characteristic of the bypass valve 2. Hereinafter, the amount of water flowing through the bypass pipe 7 is referred to as a bypass flow rate (F3; see Figure 1). Here, the amount of water that can pass through the bypass valve 2 is represented by f, the valve opening degree of the bypass valve 2 is represented by v, the flow rate when the bypass valve 2 is fully opened is represented by Cv, the rangeability indicating an adjustment range is represented by r, the density of water is represented by ρ, a gravitational acceleration is represented by G, and the differential pressure between the inlet side and the outlet side of the water refrigerant heat-exchanger 9 is represented by ΔP.
The amount of water (f) that can pass through the bypass valve 2 can be determined as follows according to whether the valve type has an equal percent characteristic or a linear characteristic. Note that "●" indicates multiplication, "/" indicates division, and "^" indicates a power.

In the case of the equal percent characteristic $f = Cv • r^{\land} (v / 100 - 1)$
In the case of the linear characteristic $f = Cv • (1 / r + (1 - 1 / r) • (v / 100))$

At this time, the bypass flow rate (F3) is determined as follows. $F 3 = f / (0.07 • {(ρ / (G • Δ P))}^{\land} 0.5)$
When the total flow rate (F1) and the bypass flow rate (F3) are determined in this way, the load flow rate (F2) can be determined as follows. $F 2 = F 1 - F 3$
The control device 16 controls the heat source system 1 so that the determined load flow rate (F2) falls within an appropriate range.
As described above, the heat source system 1 of the present embodiment can determine the load flow rate (F2) based on the difference in pressure detected by the inlet-side pressure gauge 17 and the outlet-side pressure gauge, and the opening degree and mechanical characteristic of the bypass valve 2, so that it is unnecessary to install a conventional flow meter or thermometer. Therefore, the types and number of sensors to be installed can be reduced.
Since the inlet-side pressure gauge 17 is provided in the heat source machine 3, the manufacturer of the heat source machine 3 will prepare the inlet-side pressure gauge 17, so that it is possible to avoid the unexpected troubles described above and the like, and thus it is possible to improve the convenience at the time of start-up and during operation.
Further, the heat source machine 3 used in the heat source system 1 includes the water refrigerant heat-exchanger 9, and the control device 16 for executing the processing of determining the load flow rate (F2) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side and the pressure of water on the outlet side. Like the heat source system 1 described above, such a heat source machine 3 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation. In addition, it is possible to shorten the construction period and reduce the cost when the heat source system is constructed.
The control device 16 for controlling the heat source system 1 executes the processing of determining the load flow rate (F2) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side and the pressure of water on the outlet side. Like the heat source system 1 described above, such a control device 16 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.
The heat source system 1 can execute both the processing of determining the load flow rate (F2) described above and the processing of controlling the bypass valve 2 described with respect to the first embodiment. In other words, the heat source machine 3 may be configured so as to execute either the processing of controlling the bypass valve 2 or the processing of determining the load flow rate (F2), or execute both of the processing of controlling the bypass valve 2 and the processing of determining the load flow rate (F2).
Further, the control device 16 also may be configured so as to execute either the processing of controlling the bypass valve 2 or the processing of determining the load flow rate (F2), or execute both of the processing of controlling the bypass valve 2 and the processing of determining the load flow rate (F2).

(Third Embodiment)

In a third embodiment, the configuration for acquiring the pressure on the inlet side of the heat source machine 3 in the simplex pump type heat source system 1 is different from those in the first embodiment and the second embodiment.
As shown in Figure 2, unlike the first embodiment and the second embodiment described above, the heat source system 1 of the present embodiment does not include the inlet-side pressure gauge 17 (see Figure 1), but is configured to acquire the pressure of water flowing through the condensate return pipe 6 from a control pressure set in the expansion tank 8.
Specifically, the control device 16 constituting the heat source system 1 is connected to the expansion tank 8 as described in the first embodiment, and is capable of controlling the expansion tank 8 to apply pressure to the water flowing through the condensate return pipe 6, etc. In other words, the control device 16 grasps either a pressure to be applied to water flowing through the condensate return pipe 6 from the expansion tank 8 or a control value with which the pressure to be applied can be specified.
At this time, since the outlet of the expansion tank 8 is connected to the condensate return pipe 6, it can be considered that the pressure applied to water flowing through the condensate return pipe 6 from the expansion tank 8 is substantially coincident with the pressure of water flowing through the condensate return pipe 6.
Therefore, the control device 16 acquires or specifies the pressure of water flowing through the condensate return pipe 6 from the control pressure set in the expansion tank 8, and executes at least one or both of the processing of controlling the bypass valve 2 described in the first embodiment and the processing of determining the load flow rate (F2) described in the second embodiment based on the difference in pressure detected by the control pressure and the water-side outlet pressure gauge 14 which is the outlet-side pressure gauge.
As a result, it is possible to control the bypass valve 2 and determine the load flow rate (F2) without providing the inlet-side pressure gauge 17, so that it is possible to reduce the types and number of sensors to be installed and improve the convenience at the time of start-up and during operation.
Further, the heat source machine 3 used in the heat source system 1 includes the water refrigerant heat-exchanger 9, and the control device 16 for executing the processing of determining the load flow rate (F2) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side of the water refrigerant heat-exchanger 9 and the pressure of water on the outlet side of the water refrigerant heat-exchanger 9. Like the heat source system 1 described above, such a heat source machine 3 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.
Further, the control device 16 for controlling the heat source system 1 executes the processing of determining the load flow rate (F2) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side of the water refrigerant heat-exchanger 9 and the pressure of water on the outlet side of the water refrigerant heat-exchanger 9. Like the heat source system 1 described above, such a control device 16 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.

(Fourth Embodiment)

In a fourth embodiment, an example in which the load flow rate (F12; see Figure 3) is determined based on the differential pressure between the pressure on the inlet side of the heat source machine 3 and the pressure on the outlet side of the heat source machine 3 and the resistance coefficient of a free bypass pipe 20 (see Figure 3) in a duplex pump type heat source system 1 (see Figure 3) will be described. Note that the configurations common to each embodiment will be described while represented by the same reference signs. Here, the duplex pump type may be paraphrased as, for example, a secondary pump type.
As shown in Figure 3, the heat source system 1 of the present embodiment includes the heat source machines 3, the load devices 4, the water feed pipe 5, the condensate return pipe 6, the inlet-side pressure gauge 17, the water-side outlet pressure gauge 14 corresponding to the outlet-side pressure gauge, the control device 16, and the like. Further, the water feed pipe 5 is provided with a water feed side header 21 between the heat source machine 3 side and the load device 4 side, and the condensate return pipe 6 is provided with a condensate return side header 22 between the heat source machine 3 side and the load device 4 side.
The water feed side header 21 includes an upstream side header 23 located on the heat source machine 3 side, a downstream side header 24 located on the load device 4 side, one or more secondary pumps 25 provided between the upstream side header 23 and the downstream side header 24, and a control valve 26 for allowing excessive water to circulate to the upstream side header 23. The secondary pump 25 is controlled by an inverter (not shown). In this way, a configuration in which pumps are provided on the heat source machine 3 side and the load device 4 side respectively is called a duplex pump type.
Since the operation of such a duplex pump type is well known, detailed description thereof is omitted. However, water fed from the heat source machine 3 side is stored in the upstream side header 23, the water stored in the upstream side header 23 is fed to the load device 4 side by the secondary pump 25, and the water that has passed through the load device 4 is circulated to the heat source machine 3 via the condensate return side header 22.
In the case of the duplex pump type, the free bypass pipe 20 is provided to connect a portion of the water feed pipe 5 closer to the heat source machine 3 side than the water feed side header 21 and a portion of the condensate return pipe 6 closer to the heat source machine 3 side than the condensate return side header 22. The free bypass pipe 20 is a piping member provided with no valve body, and it is configured so that water flows from the water feed pipe 5 to the condensate return pipe 6 when the pressure of water flowing through the water feed pipe 5 is higher than the pressure of water flowing through the condensate return pipe 6 as indicated by outlined arrows, whereas water flows from the condensate return pipe 6 to the water feed pipe 5 when the pressure of water flowing through the water feed pipe 5 is lower than the pressure of water flowing through the condensate return pipe 6.
As described in the above-described second embodiment, it can be considered that the total amount of water fed from the heat source machine 3 side is the total of respective chiller flow rates of the heat source machines 3 in operation. The amount of water flowing through the free bypass pipe 20 can be determined from the difference in water pressure between the water feed pipe 5 side and the condensate return pipe 6 side and the resistance coefficient of the free bypass pipe 20 because no valve is provided. Hereinafter, the total amount of water fed from the heat source machine 3 side is referred to as a water leakage amount (F11), and the amount of water flowing through the free bypass pipe 20 is referred to as a free bypass flow rate (F13).
At this time, a method of determining the free bypass flow rate (F13) itself is a general method based on Bernoulli's theorem, and thus detailed description thereof is omitted. However, it may be determined by multiplying the flow velocity determined from the difference in water pressure between the water feed pipe 5 side and the condensate return pipe 6 side and the cross-sectional area of the free bypass pipe 20, and then adding a resistance coefficient determined by the mechanical characteristic of the free bypass pipe 20 and the like to a multiplication result.
The load flow rate (F12) can be determined by subtracting the free bypass flow rate (F13) from the total amount of water (F11) when water flows from the water feed pipe 5 to the condensate return pipe 6, and by adding the free bypass flow rate (F13) to the total water amount (F11) when water flows from the condensate return pipe 6 to the water feed pipe 5.
As described above, the control device 16 can determine the load flow rate (F12) based on the differential pressure between the pressure on the inlet side of the heat source machine 3 and the pressure on the outlet side of the heat source machine 3 and the resistance coefficient of the free bypass pipe 20. As a result, as described in the second embodiment, the flow meter, the thermometer and the like which have been conventionally provided are unnecessary, and the types and number of sensors to be installed can be reduced.
Further, since the inlet-side pressure gauge 17 is provided in the heat source machine 3, it is possible to avoid unexpected troubles and the like, and thus it is possible to obtain such an effect as improving the convenience at the time of start-up and during operation.
The heat source machine 3 used in the heat source system 1 includes the water refrigerant heat-exchanger 9, and the control device 16 for executing the processing determining the load flow rate (F12) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side and the pressure of water on the outlet side. Like the heat source system 1 described above, such a heat source machine 3 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.
The control device 16 for controlling the heat source system 1 executes the processing of determining the load flow rate (F12) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side and the pressure of water on the outlet side. Like the heat source system 1 described above, such a control device 16 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.

(Fifth Embodiment)

In a fifth embodiment, in the duplex pump type heat source system 1, the configuration for acquiring the pressure on the inlet side of the heat source machine 3 is different from that in the fourth embodiment. Note that the configurations common to the fourth embodiment will be described while represented by the same reference signs.
As shown in Figure 4, the heat source system 1 of the present embodiment does not include the inlet-side pressure gauge 17 (see Figure 3) unlike the fourth embodiment described above, and is configured to acquire the pressure of water flowing through the condensate return pipe 6 from the control pressure set in the expansion tank 8. In other words, the heat source system 1 of the present embodiment executes processing similar to that of the third embodiment described above in the duplex pump type.
The control device 16 constituting the heat source system 1 is connected to the expansion tank 8, and is capable of controlling the expansion tank 8 to apply pressure to the water flowing through the condensate return pipe 6, etc. In other words, the control device 16 grasps either a pressure to be applied to water flowing through the condensate return pipe 6 from the expansion tank 8 or a control value with which the pressure to be applied can be specified.
At this time, since the outlet of the expansion tank 8 is connected to the condensate return pipe 6, it can be considered that the pressure applied to water flowing through the condensate return pipe 6 from the expansion tank 8 is the pressure of water flowing through the condensate return pipe 6. The control device 16 acquires or specifies the pressure of water flowing through the condensate return pipe 6 from the control pressure set in the expansion tank 8, and executes the processing of determining the load flow rate (F12) of a flow to the load device 4 side described in the fourth embodiment based on the difference in pressure detected by the control pressure and the water-side outlet pressure gauge 14 which is the outlet-side pressure gauge.
As a result, it is possible to determine the load flow rate (F12) without providing the inlet-side pressure gauge 17, so that the types and number of sensors to be installed can be reduced and the convenience at the time of start-up and during operation can be improved.
The heat source machine 3 used in the heat source system 1 includes the water refrigerant heat-exchanger 9, and the control device 16 for executing the processing of determining the load flow rate (F12) of a flow to the load device 4 side based on the difference between the control pressure of the expansion tank 8 and the pressure of water detected by the outlet-side pressure gauge, that is, based on the difference between the pressure of water on the inlet side of the water refrigerant heat-exchanger 9 and the pressure of water on the outlet side of the water refrigerant heat-exchanger 9. Like the heat source system 1 described above, such a heat source machine 3 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.
Further, the control device 16 for controlling the heat source system 1 executes the processing of determining the load flow rate (F2) of a flow to the load device 4 side based on the difference between the pressure of water on the inlet side of the water refrigerant heat-exchanger 9 and the pressure of water on the outlet side of the water refrigerant heat-exchanger 9. Like the heat source system 1 described above, such a control device 16 can also reduce the types and number of sensors to be installed, and can improve the convenience at the time of start-up and during operation.

(Sixth Embodiment)

In a sixth embodiment, the arrangement mode of the bypass pipe 7 or the free bypass pipe 20 is different from that of the other embodiments.
In the first embodiment and the like, the example in which the bypass pipe 7 is provided outside the heat source machine 3 in the simplex pump type is shown, but as shown as part 1 of a built-in pipe example in Figure 5, the bypass pipe 7 and the bypass valve 2 may be configured to be arranged inside the heat source machine 3. As a result, the bypass valve 2 can be prepared by the manufacturer side of the heat source machine 3, and occurrence of the unexpected troubles described above can be prevented. Further, since the bypass pipe 7 is incorporated in the heat source machine 3, pipes which match the specifications can be used. Therefore, the heat source machine 3 and the heat source system 1 can be appropriately controlled, and a work of laying the bypass pipe 7 on the load device 4 side is unnecessary, so that the installation cost can be reduced.
Note that a plurality of heat source machines 3 each including a built-in bypass pipe 7 may be provided, or only a representative machine may be provided.
Further, as shown as part 2 of the built-in pipe example of Figure 5, the free bypass pipe 20 may be configured to be arranged inside the heat source machine 3 in the duplex pump type. As a result, the free bypass pipe 20 can be prepared by the manufacturer side of the heat source machine 3, and mechanical elements such as the cross-sectional area, the resistance coefficient, and the like can be surely grasped. Therefore, the calculation for determining the load flow rate can be appropriately performed, the heat source system 1 can be operated appropriately, and the work of laying the free bypass pipe 20 on the load device 4 side becomes unnecessary, so that the installation cost can be reduced.
Note that a plurality of heat source machines 3 each including a built-in free bypass pipe 20 may be provided, or only a representative machine may be provided.

(Other Embodiments)

In the embodiments, the example in which the control device 16 is incorporated in the heat source machine 3 is shown, but the control device 16 may be attached to the surface of the heat source machine 3, or installed in the neighborhood of the heat source machine 3, for example, at a remote place such as a control room.
In the embodiments, the example in which the inlet-side pressure gauge 17 is incorporated in the heat source machine 3 serving as a representative machine is shown, but the inlet-side pressure gauges 17 may be installed in all of the installed heat source machines 3 or in a plurality of heat source machines 3 out of the installed heat source machines 3. In other words, one or more inlet-side pressure gauges 17 may be provided. At this time, when the inlet-side pressure gauges 17 are provided in the plurality of heat source machines 3, the embodiments may be configured so that the inlet-side pressure gauges 17 communicate with the control device 16, for example, via the unit controllers 15.
In the embodiments, the example in which the inlet-side pressure gauge 17 is incorporated in the heat source machine 3 is shown, but when the inlet pump 10 is provided outside the heat source machine 3, the inlet-side pressure gauge 17 is also provided outside the heat source machine 3. In that case, when a pressure gauge has been already installed in the inlet pump 10 provided outside, the embodiments may be configured so that the pressure gauge is used as the inlet-side pressure gauge 17.
In the embodiments, the example in which the control pressure is acquired based on the control command from the control device 16 is shown, but when the expansion tank 8 is provided with a pressure gauge, the embodiments may be configured so that the detection value of the pressure gauge is acquired as the set control pressure in the expansion tank 8.
Although some embodiments of the present invention have been described above, these embodiments are presented as examples, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other modes, and can be subjected to various omissions, replacements, and alterations without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the inventions recited in claims and the scope of the equivalents thereof.

Claims

A simplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe and one inlet pump is provided for one heat source machine, comprising:
an inlet-side pressure gauge that is provided on an inlet side where water flows from the condensate return pipe into the water refrigerant heat-exchanger and detects pressure of water flowing through the condensate return pipe on an upstream side of the inlet pump for feeding water to the water refrigerant heat-exchanger;

an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of controlling a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device based on a difference between the pressure on the inlet side detected by the inlet-side pressure gauge and the pressure on the outlet side detected by the outlet-side pressure gauge of the heat source machine in operation.
A simplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe and one inlet pump is provided for one heat source machine, comprising:
an inlet-side pressure gauge that is provided on an inlet side where water flows from the condensate return pipe into the water refrigerant heat-exchanger and detects pressure of water flowing through the condensate return pipe on an upstream side of the inlet pump for feeding water to the water refrigerant heat-exchanger;

an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of determining a load flow rate of a flow to a side of the load device based on a difference between the pressure on the inlet side detected by the inlet-side pressure gauge and the pressure on the outlet side detected by the outlet-side pressure gauge, an opening degree of a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device, and a mechanical characteristic of the bypass valve.
A simplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe and one inlet pump is provided for one heat source machine, comprising:
an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of controlling a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device based on a difference between a control pressure set in an expansion tank for applying a predetermined pressure to water flowing through the condensate return pipe and the pressure on the outlet side detected by the outlet-side pressure gauge.
A simplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe and one inlet pump is provided for one heat source machine, comprising:
an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of determining a load flow rate of a flow to a side of the load device based on a difference between a control pressure set in an expansion tank for applying a predetermined pressure to water flowing through the condensate return pipe and the pressure on the outlet side detected by the outlet-side pressure gauge, an opening degree of a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device, and a mechanical characteristic of the bypass valve.
A duplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe, one inlet pump is provided for one heat source machine, and the water feed pipe is provided with a secondary pump, comprising:
an inlet-side pressure gauge that is provided on an inlet side where water flows from the condensate return pipe into the water refrigerant heat-exchanger and detects pressure of water flowing through the condensate return pipe on an upstream side of the inlet pump for feeding water to the water refrigerant heat-exchanger;

an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of determining a load flow rate of a flow to a side of the load device based on a difference between the pressure on the inlet side detected by the inlet-side pressure gauge and the pressure on the outlet side detected by the outlet-side pressure gauge, and a resistance coefficient of a free bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device.
A duplex pump type heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe, one inlet pump is provided for one heat source machine, and the water feed pipe is provided with a secondary pump, comprising:
an outlet-side pressure gauge that is provided on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe and detects pressure of water flowing through the water feed pipe; and

a control device for executing processing of determining a load flow rate of a flow to a side of the load device based on a difference between a control pressure set in an expansion tank for applying a predetermined pressure to water flowing through the condensate return pipe and the pressure on the outlet side detected by the outlet-side pressure gauge, and a resistance coefficient of a free bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device.
The heat source system according to any one of claims 1 to 6, wherein a pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device is provided in the heat source machine.
A heat source machine used for a heat source system in which the heat source machine and a load device are connected to each other by a water feed pipe and a condensate return pipe, comprising:
a water refrigerant heat-exchanger for performing heat-exchange between water and a refrigerant; and

a control device for executing both or at least one of processing of controlling a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device based on a difference between pressure of water on an inlet side where water flows from the condensate return pipe into the water refrigerant heat-exchanger and pressure of water on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe, and processing of determining a load flow rate of a flow to a side of the load device.
A control device for controlling a heat source system in which a heat source machine having a water refrigerant heat-exchanger and a load device are connected to each other by a water feed pipe and a condensate return pipe, executing both or at least one of processing of controlling a bypass valve provided in a bypass pipe connecting the water feed pipe and the condensate return pipe in parallel with the load device based on a difference between pressure of water on an inlet side where water flows from the condensate return pipe into the water refrigerant heat-exchanger and pressure of water on an outlet side where water flows out from the water refrigerant heat-exchanger to the water feed pipe, and processing of determining a load flow rate of a flow to a side of the load device.