Heating system

Abstract

To provide a technique capable of suppressing the occurrence of deviation in frequency of executing heating among a plurality of heat source machines.SOLUTION: The heating system includes a heating circuit through which a heat medium flows, a plurality of heat source machines provided in parallel with the heating circuit and each capable of executing a first heating operation for heating the heat medium flowing through the heating circuit, a plurality of heat source control units provided for each of the plurality of heat source machines and each of which controls the heat source machine, a heating terminal that performs heating by heat dissipation from the heat medium flowing through the heating circuit, a request generation unit that generates a heating execution request for execution of the heating by the heating terminal, a request transmission unit that transmits the heating execution request generated by the request generation unit to a predetermined heat source control unit among the plurality of heat source control units, and a selection unit that selects the heat source machine to execute the first heating operation from among the plurality of heat source machines. When the heating execution request is transmitted to a predetermined heat source control unit, the heat source unit selected by the selection unit executes the first heating operation.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology disclosed herein relates to heating systems. [Background technology]

[0002] Patent Document 1 discloses a heating system including a heating circuit through which a heat medium flows, a heat source unit provided in the heating circuit and capable of performing a first heating operation to heat the heat medium flowing in the heating circuit, a heat source control unit provided in the heat source unit and controlling the heat source unit, a heating terminal that performs heating by radiating heat from the heat medium flowing in the heating circuit, a request generation unit that generates a heating execution request for the heating terminal to perform heating, and a request transmission unit that transmits the heating execution request generated by the request generation unit to the heat source control unit. In the heating system, the heat source control unit to which the heating execution request is transmitted is configured to cause the corresponding heat source unit to perform the first heating operation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-163001 Summary of the Invention [Problem to be solved by the invention]

[0004] In the heating system of Patent Document 1, the heat source control unit is linked to the request generation unit via the request transmission unit. Specifically, "linking" here refers to the transmission of the heating request generated by the request generation unit to the heat source control unit via the request transmission unit. However, when a heating system is constructed with multiple heat source units in a heating circuit, the multiple heat source control units provided for each heat source unit may include a heat source control unit linked to the request generation unit and a heat source control unit not linked to the request generation unit. In this case, the heat source control unit linked to the request generation unit may cause the heat source unit to perform the first heating operation in preference to a heat source control unit not linked to the request generation unit. In other words, the heat source unit controlled by the heat source control unit linked to the request generation unit may perform the first heating operation in preference to a heat source unit controlled by a heat source control unit not linked to the request generation unit. This may result in a bias in the frequency of heating operations among the multiple heat source units. This specification provides a technology that can prevent imbalances in the frequency of heating among a plurality of heat source units. [Means for solving the problem]

[0005] In a first aspect of the present technology, a heating system may include a heating circuit through which a heat medium flows, a plurality of heat source units arranged in parallel to the heating circuit and each capable of performing a first heating operation to heat the heat medium flowing in the heating circuit, a plurality of heat source control units arranged for each of the heat source units and each controlling the heat source unit, a heating terminal that performs heating by heat radiation from the heat medium flowing in the heating circuit, a request generation unit that generates a heating execution request for performing heating by the heating terminal, a request transmission unit that transmits the heating execution request generated by the request generation unit to a predetermined heat source control unit among the plurality of heat source control units, and a selection unit that selects a heat source unit to perform the first heating operation from the plurality of heat source units. When the heating execution request is transmitted to the predetermined heat source control unit, the heat source unit selected by the selection unit may perform the first heating operation.

[0006] In the heating system of Patent Document 1, when a heating execution request is generated, a heat source control unit linked to the request generation unit causes the corresponding heat source unit to perform the first heating operation. In contrast, with the above configuration, when a heating execution request is generated, the heat source unit selected by the selection unit performs the first heating operation. For example, when a heating execution request is generated, a different heat source unit can be caused to perform the first heating operation each time. This makes it possible to prevent bias in the frequency of heating execution among multiple heat source units.

[0007] In a second aspect of the present technology, in the first aspect, the plurality of heat source control units may include one parent unit control unit and at least one child unit control unit configured to be able to communicate with the parent unit control unit, and the parent unit control unit may function as the selection unit.

[0008] According to the above configuration, there is no need to install a control device that functions as a selection unit in the heating system separately from the plurality of heat source control units, which simplifies the configuration of the heating system.

[0009] In a third aspect of the present technology, in the first or second aspect, the heating system may further include a pump that sends the heat medium flowing in the heating circuit to the heating terminal. When the heating execution request is transmitted to the predetermined heat source control unit, the predetermined heat source control unit may operate the pump.

[0010] In order to send a heat medium to a heating terminal when a heating execution request is generated, a heating system may be provided with a control device (also referred to as a pump control device) that operates a pump when a heating execution request is generated. According to the above configuration, when a heating execution request is generated, the heat source control unit to which the heating execution request is transmitted (i.e., the heat source control unit that is linked to the request generation unit) can operate the pump. In other words, the heat source control unit that is linked to the request generation unit can function as a pump control device. This eliminates the need to install a separate pump control device in the heating system, thereby simplifying the configuration of the heating system.

[0011] In a fourth aspect of the present technology, in the second aspect, the heating system may further include a pump that sends the heat medium flowing in the heating circuit to the heating terminal. When the heating execution request is transmitted to the predetermined heat source control unit, the parent device control unit may operate the pump.

[0012] The master unit control unit can communicate with each of the multiple heat source control units, and therefore can grasp the operating status of each heat source unit (i.e., whether or not the first heating operation is being performed in each heat source unit). According to the above configuration, the master unit control unit controls the operation / stop of the pump, and therefore the master unit control unit can also grasp the operating status of the pump (i.e., whether or not the pump is operating). This allows the master unit control unit to aggregate information about the heating system.

[0013] In a fifth aspect of the present technology, in the third or fourth aspect, when the first heating operation cannot be performed in at least one of the plurality of heat source machines, operation of the pump may be prohibited.

[0014] If the first heating operation cannot be performed in at least one of the multiple heat source machines, the heat medium flowing through the heating circuit may not be heated to the temperature required for heating. In this case, even if the pump is operated to send the heat medium to the heating terminal, the heat medium may be wasted. According to the above configuration, if the first heating operation cannot be performed in at least one of the multiple heat source machines, the pump is prohibited from operating. This makes it possible to prevent the pump from being operated unnecessarily in a situation where the heat medium cannot be heated to the temperature required for heating.

[0015] In a sixth aspect of the present technology, in any one of the first to fifth aspects, the heating system may further include a hot water supply circuit through which water flows. Each of the plurality of heat source machines may be configured to be further capable of executing a second heating operation that heats the water flowing through the hot water supply circuit. In each of the plurality of heat source machines, the first heating operation may be disabled while the second heating operation is being executed.

[0016] According to the above configuration, by causing at least one of the multiple heat source machines to perform the second heating operation, it is possible to heat the water flowing through the hot water supply circuit. However, when causing at least one of the multiple heat source machines to perform the second heating operation, the heat source machine performing the second heating operation is unable to perform the first heating operation, and therefore the heat medium flowing through the heating circuit may not be heated to the temperature required for heating. In this case, even if the pump is operated to send the heat medium to the heating terminal, the heat medium may be wasted. Furthermore, according to the above configuration, when the first heating operation is unable to be performed in at least one of the multiple heat source machines, the pump is prohibited from operating. This makes it possible to prevent the pump from being operated unnecessarily in situations where the heat medium cannot be heated to the temperature required for heating.

[0017] In a seventh aspect of the present technology, in the first to sixth aspects, the heating system may include a plurality of the heating terminals, a plurality of the request generation units provided for each of the plurality of heating terminals, and a plurality of the request transmission units provided for each of the plurality of the request generation units.

[0018] According to the above configuration, a plurality of heating terminals can be arranged in a plurality of spaces to heat the plurality of spaces, or a single space can be heated by a plurality of heating terminals. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic configuration diagram of a heating system 2 according to an embodiment. [Figure 2] 4 is a diagram showing the flow of the heat medium when a first heating operation is performed in the heat source unit 100 of the heating system 2 according to the embodiment. FIG. [Figure 3] 5 is a diagram showing the flow of the heat medium when a second heating operation is performed in the heat source apparatus 100 of the heating system 2 according to the embodiment. FIG. [Figure 4]10 is a diagram showing an example of whether the first heating operation can be performed for each of the heat source units 100, 200, 300, 400, and 500, and an example of the priorities assigned to the heat source units 100, 200, 300, 400, and 500, in the heating system 2 according to the embodiment. FIG. [Figure 5] 10 is a flowchart of a heat source selection process executed by a master unit control unit 102 of a heating system 2 according to the embodiment. [Figure 6] 10 is a flowchart of a set value increasing process executed by a master unit control unit 102 of a heating system 2 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] (Example) As shown in FIG. 1, the heating system 2 includes a hot water supply circuit 4 (some parts not shown), a heating circuit 6, five heat source units 100, 200, 300, 400, and 500, and three heating terminals 8a, 8b, and 8c. Water flows through the hot water supply circuit 4. A heat medium (e.g., water or antifreeze) flows through the heating circuit 6. The heat source units 100, 200, 300, 400, and 500 are provided in parallel with the heating circuit 6 and the hot water supply circuit 4, respectively. The heat source units 100, 200, 300, 400, and 500 heat the water flowing through the hot water supply circuit 4 and the heat medium flowing through the heating circuit 6. A faucet and a bathtub (not shown) are provided in the hot water supply circuit 4. The heating circuit 6 includes heating terminals 8a, 8b, and 8c provided in parallel with each other. The heating terminals 8a, 8b, and 8c include, for example, floor heating devices and panel heaters. Heating terminals 8a, 8b, and 8c provide heating by heat radiation from the heat medium flowing in heating circuit 6. Heating system 2 can supply water heated by heat source units 100, 200, 300, 400, and 500 to a faucet or a bathtub via hot water supply circuit 4. Heating system 2 can also cause heating terminals 8a, 8b, and 8c to provide heating by sending the heat medium heated by heat source units 100, 200, 300, 400, and 500 to heating terminals 8a, 8b, and 8c via heating circuit 6.

[0021] The heating circuit 6 includes a primary forward flow path 12 through which the heat medium is sent from each of the heat source units 100, 200, 300, 400, and 500, a primary return flow path 14 that sends the heat medium to each of the heat source units 100, 200, 300, 400, and 500, a secondary forward flow path 16 that sends the heat medium to each of the heating terminals 8a, 8b, and 8c, and a secondary return flow path 18 through which the heat medium is sent from each of the heating terminals 8a, 8b, and 8c. Fluid mixers 20 are provided between the downstream end of the primary forward flow path 12, the upstream end of the primary return flow path 14, the upstream end of the secondary forward flow path 16, and the downstream end of the secondary return flow path 18. By providing the fluid mixer 20, it is possible for a difference to occur between the flow rate of the heat medium flowing in the primary forward flow path 12 and the primary return flow path 14 (i.e., the total flow rate of the heat medium flowing in the heat source units 100, 200, 300, 400, 500) and the flow rate of the heat medium flowing in the secondary forward flow path 16 and the secondary return flow path 18 (i.e., the total flow rate of the heat medium flowing in the heating terminals 8a, 8b, 8c).

[0022] The heating circuit 6 further includes terminal flow paths 22a, 22b, and 22c corresponding to the heating terminals 8a, 8b, and 8c, respectively. The upstream ends of the terminal flow paths 22a, 22b, and 22c are connected to the secondary forward flow path 16. The downstream ends of the terminal flow paths 22a, 22b, and 22c are connected to the secondary return flow path 18. Terminal pumps 24a, 24b, and 24c are provided in the terminal flow paths 22a, 22b, and 22c. The terminal pumps 24a, 24b, and 24c draw the heat medium from the secondary forward flow path 16 into the terminal flow paths 22a, 22b, and 22c, and deliver the heat medium from the terminal flow paths 22a, 22b, and 22c to the secondary return flow path 18. By operating the terminal pumps 24a, 24b, and 24c, the heat medium is delivered to the heating terminals 8a, 8b, and 8c, and heating is performed by the heating terminals 8a, 8b, and 8c.

[0023] The heating system 2 includes thermostats 26a, 26b, and 26c corresponding to the heating terminals 8a, 8b, and 8c. The thermostats 26a, 26b, and 26c detect the temperature of the space in which the corresponding heating terminals 8a, 8b, and 8c are installed, i.e., the space heated by the heating terminals 8a, 8b, and 8c (e.g., the interior of a house). When the detected temperature falls below a predetermined heating ON threshold (e.g., 20°C), the thermostats 26a, 26b, and 26c output a heating ON signal to start heating by the heating terminals 8a, 8b, and 8c. When the detected temperature exceeds a predetermined heating OFF threshold (e.g., 25°C), the thermostats 26a, 26b, and 26c output a heating OFF signal to end heating by the heating terminals 8a, 8b, and 8c. In this specification, the heating ON signal and the heating OFF signal are collectively referred to as "heating signals."

[0024] The heat source machine 100 includes a burner 32, a first heat exchanger 34 that heats a heat medium using the combustion heat of the burner 32, a primary return branch path 36 that connects the fluid inlet of the first heat exchanger 34 and the primary return flow path 14, a primary forward branch path 38 that connects the fluid outlet of the first heat exchanger 34 and the primary forward flow path 12, a heat source pump 40 provided in the primary return branch path 36, a bypass path 42 that bypasses the first heat exchanger 34 and the heat source pump 40 and connects the primary return branch path 36 and the primary forward branch path 38, a second heat exchanger 44 that heats water flowing in the hot water supply circuit 4 by heat exchange with the heat medium flowing in the bypass path 42, and a three-way valve 46 provided at the connection between the primary forward branch path 38 and the bypass path 42. The three-way valve 46 is switchable between a first state (see FIG. 2 ) in which the heat medium flowing out of the first heat exchanger 34 is sent to the primary forward flow path 12 via the primary forward branch path 38, and a second state (see FIG. 3 ) in which the heat medium flowing out of the first heat exchanger 34 is sent to the bypass path 42 via the primary forward branch path 38. The three-way valve 46 can switch the destination of the heat medium flowing out of the first heat exchanger 34 between the bypass path 42 and the primary forward flow path 12. In addition, the primary return branch path 36 is provided with a primary return thermistor 48 that detects the temperature of the heat medium immediately before it is heated in the first heat exchanger 34. The primary forward branch path 38 is provided with a primary forward thermistor 50 that detects the temperature of the heat medium immediately after it is heated in the first heat exchanger 34.

[0025] As shown in Fig. 2, the heat source apparatus 100 is configured to be able to perform a first heating operation in which the heat medium flowing in the heating circuit 6 is heated by setting the three-way valve 46 to the first state, firing the burner 32, and operating the heat source pump 40. When the first heating operation is performed, the heat medium in the primary return flow path 14 passes through the primary return branch path 36, the first heat exchanger 34, and the primary forward branch path 38 in this order, and is then sent to the primary forward flow path 12. The heat medium is heated by the combustion heat of the burner 32 as it passes through the first heat exchanger 34.

[0026] As shown in Fig. 3, the heat source apparatus 100 is configured to be able to perform a second heating operation in which the water flowing in the hot water supply circuit 4 is heated by setting the three-way valve 46 to the second state, firing the burner 32, and operating the heat source pump 40. When the second heating operation is performed, a heat medium is circulated between the primary return branch path 36, the first heat exchanger 34, the primary forward branch path 38, and the bypass path 42 (i.e., the second heat exchanger 44). When passing through the first heat exchanger 34, the heat medium is heated by the heat of combustion of the burner 32, and when passing through the second heat exchanger 44, the heat medium is released to the water flowing in the hot water supply circuit 4. As a result, the water flowing in the hot water supply circuit 4 is heated.

[0027] The heat source device 100 further includes a heat source control unit 102 including a CPU, a ROM, a RAM, etc. The ROM stores various operating programs. The RAM temporarily stores various signals input to the heat source control unit 102 and various data generated in the process of the CPU executing processing. The heat source control unit 102 controls each component of the heat source device 100 by the CPU executing processing based on information stored in the ROM and RAM. The heat source control unit 102 can set a setting value (also referred to as an "output setting value") related to the output of the burner 32. The output setting value is set to one of five levels, for example, "1," "2," "3," "4," and "5." The heat source control unit 102 controls the output of the burner 32 based on the output setting value when burning the burner 32 (for example, when performing the first heating operation). The heat source control unit 102 increases the output of the burner 32 as the output setting value increases.

[0028] 1 include the same components as the heat source unit 100. For example, the heat source control units 202, 302, 402, 502 included in the heat source units 200, 300, 400, 500 are components corresponding to the heat source control unit 102, and control the components of the heat source units 200, 300, 400, 500. For simplification, the other components included in the heat source units 200, 300, 400, 500 are not labeled with reference numerals.

[0029] A first signal line 62a for communication with the thermostat 26a and a second signal line 64a for communication with the terminal pump 24a are connected to the heat source control unit 102 of the heat source device 100. A heating signal output by the thermostat 26a is transmitted to the heat source control unit 102 via the first signal line 62a. The heat source control unit 102 also controls the operation of the terminal pump 24a by sending instructions to the terminal pump 24a via the second signal line 64a. For example, when a heating ON signal is transmitted from the thermostat 26a, the heat source control unit 102 operates the terminal pump 24a. This starts the supply of heat medium to the heating terminal 8a corresponding to the thermostat 26a, and heating by the heating terminal 8a begins. Thereafter, when a heating OFF signal is transmitted from the thermostat 26a, the heat source control unit 102 stops the terminal pump 24a. This stops the supply of heat medium to the heating terminal 8a corresponding to the thermostat 26a, and heating by the heating terminal 8a ends.

[0030] A first signal line 62b for communicating with thermostat 26b and a second signal line 64b for communicating with terminal pump 24b are connected to the heat source control unit 202 of the heat source apparatus 200. The relationship between the heat source control unit 202, thermostat 26b, terminal pump 24b, and heating terminal 8b is similar to the relationship between the heat source control unit 102, thermostat 26a, terminal pump 24a, and heating terminal 8a described above. Furthermore, a first signal line 62c for communicating with thermostat 26c and a second signal line 64c for communicating with terminal pump 24c are connected to the heat source control unit 302 of the heat source apparatus 300. The relationship between the heat source control unit 302, thermostat 26c, terminal pump 24c, and heating terminal 8c is similar to the relationship between the heat source control unit 102, thermostat 26a, terminal pump 24a, and heating terminal 8a described above.

[0031] In this embodiment, of the heat source control units 102, 202, 302, 402, and 502, the heat source control unit 102 functions as a parent unit control unit, and the remaining heat source control units 202, 302, 402, and 502 function as child unit control units that can communicate with the parent unit control unit. Hereinafter, the heat source control unit 102 will also be referred to as the "parent unit control unit 102," and the heat source control units 202, 302, 402, and 502 will also be referred to as the "child unit control units 202, 302, 402, and 502." The parent unit control unit 102 and the child unit control units 202, 302, 402, and 502 cooperate with each other to control the heating system 2.

[0032] As shown in Fig. 4, the master unit control unit 102 manages whether the first heating operation can be performed in each of the heat source units 100, 200, 300, 400, and 500. For example, the first heating operation cannot be performed in a heat source unit that is performing the second heating operation. Alternatively, the first heating operation cannot be performed in a heat source unit in which an error has occurred. An error here refers to, for example, an ignition failure of the burner 32 or a detection failure of the thermistors 48 and 50.

[0033] 1 prohibits the operation of the terminal pump 24a when the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500 (for example, when the second heating operation is being performed in all of the heat source units 100, 200, 300, 400, and 500). Furthermore, when the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, the master unit control unit 102 transmits an instruction to the slave unit control units 202 and 302 to prohibit the operation of the terminal pumps 24b and 24c. As a result, when the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, the operation of the terminal pumps 24a, 24b, and 24c is prohibited. If the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, the heat medium flowing through the heating circuit 6 may not be heated to the temperature required for heating. In this case, even if the terminal pumps 24a, 24b, and 24c are operated to send the heat medium to the heating terminals 8a, 8b, and 8c, the heat medium may be wasted. In this embodiment, if the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, the operation of the terminal pumps 24a, 24b, and 24c is prohibited, thereby preventing the terminal pumps 24a, 24b, and 24c from being operated unnecessarily.

[0034] As shown in Fig. 4, the master unit control unit 102 assigns a priority (1, 2, 3, 4) to each of the heat source units 100, 200, 300, 400, and 500 when the first heating operation is to be performed. The master unit control unit 102 of this embodiment manages the combustion frequency (e.g., cumulative number of ignitions, cumulative combustion time) of the burner 32 for each of the heat source units 100, 200, 300, 400, and 500, and is configured to assign higher priorities in order of lowest combustion frequency of the burner 32. Furthermore, if there is a heat source unit for which the first heating operation cannot be performed, the master unit control unit 102 assigns priorities excluding that heat source unit. For this reason, a priority is not assigned to a heat source unit for which the first heating operation cannot be performed (heat source unit 500 in the example of Fig. 4).

[0035] The master unit control unit 102 shown in FIG. 1 stores the heating signal most recently transmitted to the master unit control unit 102 (i.e., the heating signal most recently output by the thermostat 26a). The master unit control unit 102 also acquires and stores the heating signal most recently transmitted to the slave unit control units 202 and 302 (i.e., the heating signal most recently output by the thermostats 26b and 26c) through communication with the slave unit control units 202 and 302. This allows the master unit control unit 102 to know the heating signal most recently output by the thermostats 26a, 26b, and 26c. The heating signals most recently output by the thermostats 26a, 26b, and 26c indicate whether heating is being performed at the heating terminals 8a, 8b, and 8c, respectively. If the heating signal most recently output by the thermostats 26a, 26b, 26c is a heating ON signal, heating is performed at the heating terminals 8a, 8b, 8c corresponding to the thermostats 26a, 26b, 26c. If the heating signal most recently output by the thermostats 26a, 26b, 26c is a heating OFF signal, heating is not performed at the heating terminals 8a, 8b, 8c corresponding to the thermostats 26a, 26b, 26c.

[0036] (Heat source selection process; Figure 5) If at least one of thermostats 26a, 26b, 26c has recently output a heating ON signal, heating is being performed by at least one of heating terminals 8a, 8b, 8c, and therefore at least one of heat source units 100, 200, 300, 400, 500 should be caused to perform the first heating operation (see FIG. 2) in order to supply heated heat medium to heating terminals 8a, 8b, 8c. If at least one of thermostats 26a, 26b, 26c has recently output a heating ON signal, parent unit control unit 102 executes the heat source selection process shown in FIG. 5 in order to cause at least one of heat source units 100, 200, 300, 400, 500 to perform the first heating operation.

[0037] In S2, the master unit control unit 102 determines whether the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500. If the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500 (if YES), the processing shown in Fig. 5 ends. If the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, that is, if the first heating operation can be performed in at least one of the heat source units 100, 200, 300, 400, and 500 (if NO), the processing proceeds to S4.

[0038] In S4, the parent unit control unit 102 identifies the number of heat source units that will perform the first heating operation (i.e., the number of operating units). For example, if the detection value of a flow rate sensor (not shown) that detects the flow rate of the heat medium flowing through the secondary forward flow path 16 is small, the parent unit control unit 102 identifies the number of operating units as a small number (e.g., 1 unit). If the detection value of the flow rate sensor is large, the parent unit control unit 102 identifies the number of operating units as a large number (e.g., 2 units). After S4, the process proceeds to S6.

[0039] In S6, the parent unit control unit 102 selects the heat source unit with the highest priority from among the heat source units capable of performing the first heating operation, for the number of operating units identified in S4. In the example of Fig. 4, if the number of operating units is identified as one, the heat source unit 100 with the highest priority is selected from among the heat source units 100, 200, 300, and 400 that are capable of performing the first heating operation. After S6, the process proceeds to S8.

[0040] In S8, the parent unit control unit 102 causes the heat source units selected in S6 to perform the first heating operation. Note that if the heat source units 200, 300 controlled by the child unit control units 202, 302 are included among the heat source units selected in S6, the parent unit control unit 102 sends an instruction to the child unit control units 202, 302 to perform the first heating operation. In response to the instruction from the parent unit control unit 102, the child unit control units 202, 302 cause the heat source units 200, 300 that they control to perform the first heating operation. After S8, the processing shown in FIG. 5 ends.

[0041] (Advantages of heat source selection processing) In this embodiment, the heat source device 100 is linked to the thermostat 26a via a first signal line 62a. The heat source device 200 is linked to the thermostat 26b via a first signal line 62b. The heat source device 300 is linked to the thermostat 26c via a first signal line 62c. According to conventional thinking, these links are typically used to cause the heat source device 100 to perform the first heating operation when the thermostat 26a outputs a heating ON signal, to cause the heat source device 200 to perform the first heating operation when the thermostat 26b outputs a heating ON signal, and to cause the heat source device 300 to perform the first heating operation when the thermostat 26c outputs a heating ON signal. However, in this embodiment, when at least one of the thermostats 26a, 26b, and 26c outputs a heating ON signal, a heat source device selected regardless of the above links performs the first heating operation. Specifically, the heat source unit selected in accordance with the priority order (see FIG. 4) set by the parent unit control unit 102 executes the first heating operation. As described above, the priority order in this embodiment is assigned in ascending order of the combustion frequency of the burner 32. Therefore, the heat source unit with the low combustion frequency of the burner 32 executes the first heating operation with priority over the heat source unit with the high combustion frequency of the burner 32. This makes it possible to prevent imbalances in the combustion frequency of the burner 32 among the heat source units 100, 200, 300, 400, and 500.

[0042] (Setting value increase process; Figure 6) While the heating system 2 is powered on, the master unit control section 102 repeatedly executes the process shown in FIG.

[0043] In S22, the master unit control unit 102 determines whether the thermostat 26a has output a heating ON signal. As described above, when the thermostat 26a outputs a heating ON signal, the master unit control unit 102 operates the terminal pump 24a, thereby starting heating by the heating terminal 8a. Therefore, in S22, it can be said that the master unit control unit 102 determines whether heating by the heating terminal 8a has started. If the thermostat 26a has not output a heating ON signal (NO), the process repeats S22. If the thermostat 26a has output a heating ON signal (YES), the process proceeds to S24.

[0044] In S24, the master unit control unit 102 acquires the operating status of the heat source unit 100 that it controls. The master unit control unit 102 also communicates with the slave unit control units 202, 302, 402, 502 to acquire the operating status of the first heating operation in the heat source units 200, 300, 400, 500. Thereafter, the master unit control unit 102 determines whether the first heating operation is being performed in at least one of the heat source units 100, 200, 300, 400, 500, based on the acquired operating status of the heat source units 100, 200, 300, 400, 500. For example, if the second heating operation (see FIG. 3) is being performed in all of the heat source units 100, 200, 300, 400, 500, the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, 500. In this case, even if the thermostat 26a outputs a heating ON signal, the first heating operation may not be performed (i.e., NO in S24) in any of the heat source units 100, 200, 300, 400, and 500. If the first heating operation is not being performed in any of the heat source units 100, 200, 300, 400, and 500 (NO), the process proceeds to S26.

[0045] In S26, the master unit control unit 102 determines whether the thermostat 26a has output a heating OFF signal. As described above, if the thermostat 26a outputs a heating OFF signal, the master unit control unit 102 stops the terminal pump 24a, thereby ending heating by the heating terminal 8a. Therefore, in S26, it can be said that the master unit control unit 102 determines whether heating by the heating terminal 8a has ended. If the thermostat 26a outputs a heating OFF signal (YES), the processing shown in FIG. 6 ends. If the thermostat 26a does not output a heating OFF signal (NO), the processing returns to S24.

[0046] In S24, if the first heating operation is being performed in at least one of the heat source units 100, 200, 300, 400, and 500 (YES), the process proceeds to S28. In S28, the parent unit control unit 102 starts timing. After S28, the process proceeds to S30.

[0047] In S30, the master unit control unit 102 determines whether the thermostat 26a has output a heating OFF signal. That is, the master unit control unit 102 determines whether heating by the heating terminal 8a has ended. If the thermostat 26a has not output a heating OFF signal (NO), the process proceeds to S32.

[0048] In S32, the parent device control unit 102 determines whether the time elapsed since the start of timing in S28, i.e., the timing period, is equal to or greater than a predetermined period. If the timing period is less than the predetermined period (NO), the process returns to S30. If the timing period is equal to or greater than the predetermined period (YES), the process proceeds to S34.

[0049] In S34, the parent unit control unit 102 increases the output setting values ​​of all of the heat source units 100, 200, 300, 400, and 500. Specifically, the parent unit control unit 102 increases the output setting value of the heat source unit 100 that it controls, and sends instructions to the child unit control units 202, 302, 402, and 502 to increase the output setting values ​​of the heat source units 200, 300, 400, and 500. The child unit control units 202, 302, 402, and 502 increase the output setting values ​​of the heat source units 200, 300, 400, and 500 that they control in response to the instructions from the parent unit control unit 102. As a result, the output setting values ​​of all of the heat source units 100, 200, 300, 400, and 500 increase.

[0050] After S34, or if the thermostat 26a outputs a heating OFF signal in S30 (if YES), the process proceeds to S36. The process also proceeds to S36 if the first heating operation is no longer being performed in any of the heat source units 100, 200, 300, 400, and 500 while the master unit control unit 102 is measuring time. In S36, the master unit control unit 102 ends measuring time. After S36, the process shown in FIG. 6 ends.

[0051] (Advantages of increasing the set value) As described above, thermostat 26a outputs a heating ON signal when the detected temperature (i.e., the temperature of the space heated by heating terminal 8a) falls below the heating ON threshold, and outputs a heating OFF signal when the detected temperature exceeds the heating OFF threshold. Therefore, while thermostat 26a alternately outputs the heating ON signal and the heating OFF signal, it can be seen that the temperature of the space heated by heating terminal 8a is maintained at an appropriate temperature (in this embodiment, a temperature equal to or greater than the heating ON threshold and equal to or less than the heating OFF threshold). On the other hand, if thermostat 26a does not output a heating OFF signal for a long period of time after outputting the heating ON signal, it is expected that the temperature of the space heated by heating terminal 8a will remain below the appropriate temperature.

[0052] The timing period in this embodiment can also be described as "a period during which the first heating operation is performed in at least one of the heat source units 100, 200, 300, 400, and 500 after the thermostat 26a outputs a heating ON signal without the thermostat 26a outputting a heating OFF signal." Therefore, if the timing period is long, it is expected that the temperature of the space heated by the heating terminal 8a will stagnate in a state lower than the optimum temperature, even though the heat medium heated by the heat source unit is supplied to the heating terminal 8a and heating is performed by the heating terminal 8a. According to the set value increase process, if the timing period is equal to or longer than a predetermined period (i.e., if the timing period is long), the output set values ​​of all the heat source units 100, 200, 300, 400, and 500 are increased. This makes it possible to increase the heating capacity (i.e., the output of burner 32) of the heat source unit performing the first heating operation, increase the amount of heat that the heat source unit gives to the heat medium, and increase the amount of heat radiated by the heat medium at heating terminal 8a, thereby raising the temperature of the space heated by heating terminal 8a. This makes it possible to overcome a situation in which the temperature of the space heated by heating terminal 8a remains lower than the optimum temperature.

[0053] Furthermore, in the set value increase process, the output set values ​​of all the heat source units 100, 200, 300, 400, and 500 are increased, rather than only the output set values ​​of some of the heat source units being increased. This makes it possible to prevent differences from occurring between the output set values ​​of the heat source units 100, 200, 300, 400, and 500.

[0054] 6 may be executed as processing corresponding to heating terminals 8b and 8c other than heating terminal 8a. Therefore, in the above description of the setting value increasing processing, thermostat 26a may be read as thermostat 26b (or thermostat 26c), terminal pump 24a may be read as terminal pump 24b (or terminal pump 24c), and heating terminal 8a may be read as heating terminal 8b (or heating terminal 8c).

[0055] (Variation) The number of heat source machines included in the heating system 2 is not limited to five, but may be two, three, four, six or more.

[0056] The number of heating terminals included in the heating system 2 is not limited to three, but may be one, two, or four or more.

[0057] (See FIG. 1) The heating system 2 does not have to include the hot water supply circuit 4. In this case, each of the heat source units 100, 200, 300, 400, 500 may be configured not to perform the second heating operation.

[0058] (See FIG. 1) Each of the terminal flow paths 22a, 22b, and 22c may be provided with an on-off valve that opens and closes the terminal flow path 22a, 22b, and 22c. When the thermostats 26a, 26b, and 26c output a heating ON signal, the on-off valves provided in the corresponding terminal flow paths 22a, 22b, and 22c may be opened, thereby allowing the supply of heat medium to the corresponding heating terminals 8a, 8b, and 8c. When the thermostats 26a, 26b, and 26c output a heating OFF signal, the on-off valves provided in the corresponding terminal flow paths 22a, 22b, and 22c may be closed, thereby prohibiting the supply of heat medium to the corresponding heating terminals 8a, 8b, and 8c.

[0059] (See FIG. 1) The heating system 2 may include a remote control operable by a user instead of or in addition to the thermostats 26a, 26b, and 26c. The user may be able to input an operation to the remote control to start / stop heating in the heating terminals 8a, 8b, and 8c. The remote control may output a heating ON signal when an input operation to start heating is performed in the heating terminals 8a, 8b, and 8c. The remote control may output a heating OFF signal when an input operation to stop heating is performed in the heating terminals 8a, 8b, and 8c. The heating ON signal / heating OFF signal output by the remote control may be transmitted to the heat source control units 102, 202, and 302 via first signal lines 62a, 62b, and 62c corresponding to the heating terminals 8a, 8b, and 8c.

[0060] (See FIG. 1) Even if the first heating operation cannot be performed in all of the heat source units 100, 200, 300, 400, and 500, the operation of the terminal pumps 24a, 24b, and 24c may be permitted.

[0061] (See Figure 1) Operation of terminal pumps 24a, 24b, 24c may be prohibited not only when the first heating operation cannot be performed in all heat source units 100, 200, 300, 400, 500, but also when the first heating operation cannot be performed in at least one (e.g., a majority) of heat source units 100, 200, 300, 400, 500.

[0062] (See FIG. 4) The priority order when the first heating operation is performed may be assigned in a manner different from that of the embodiment. For example, the priority order may be assigned so that it rotates periodically (for example, every 24 hours) among the heat source units 100, 200, 300, 400, and 500.

[0063] (See FIG. 1) The heating system 2 may further include a control device (hereinafter referred to as a "system control unit") separate from the heat source control units 102, 202, 302, 402, 502 and configured to be able to communicate with the heat source control units 102, 202, 302, 402, 502. The system control unit may execute at least a part of the heat source selection process shown in FIG. 5 in place of the master unit control unit 102. For example, the system control unit may determine whether the first heating operation is not executable in all of the heat source units 100, 200, 300, 400, 500 (see S2). The system control unit may specify the number of heat source units that are to execute the first heating operation (see S4). The system control unit may select the heat source unit that is to execute the first heating operation (see S6). Furthermore, the system control unit may execute at least a part of the set value increase process shown in FIG. 6 in place of the master unit control unit 102. For example, the system control unit may determine whether the first heating operation is being performed in at least one of the heat source units 100, 200, 300, 400, and 500 (see S24). The system control unit may measure time and determine whether the measured time period is equal to or longer than a predetermined period (see S28, S30, S32, and S36).

[0064] In S34 of the set value increase process, the master unit control unit 102 may increase the output set value of some of the heat source units 100, 200, 300, 400, and 500 (see FIG. 6).

[0065] (See FIG. 6) In the set value increase process, after S22, S24 may be skipped and S26 may be started. As a result, after the thermostat 26a outputs the heating ON signal, timing may be started regardless of whether the first heating operation is being performed in at least one of the heat source units 100, 200, 300, 400, and 500. As a result, if the thermostat 26a does not output a heating OFF signal for a long period of time, the output set value of the heat source units 100, 200, 300, 400, and 500 may be increased regardless of whether the heat source units 100, 200, 300, 400, and 500 are performing the first heating operation.

[0066] (See FIG. 1) The master unit control unit 102 may instruct the operation / stop of the terminal pumps 24a, 24b, and 24c. Specifically, when the thermostats 26a, 26b, and 26c output a heating ON signal, the master unit control unit 102 may operate the corresponding terminal pumps 24a, 24b, and 24c. When the thermostats 26a, 26b, and 26c output a heating OFF signal, the master unit control unit 102 may stop the corresponding terminal pumps 24a, 24b, and 24c. In this example, the master unit control unit 102 can easily grasp the operating status of the terminal pumps 24a, 24b, and 24c.

[0067] (Correspondence) In the embodiments, the hot water supply circuit 4 is an example of a "hot water supply circuit." The heating circuit 6 is an example of a "heating circuit." The heating terminals 8a, 8b, and 8c are examples of a "heating terminal." The heat source units 100, 200, 300, 400, and 500 are examples of "multiple heat source units." The heat source control units 102, 202, 302, 402, and 502 are examples of "multiple heat source control units." The thermostats 26a, 26b, and 26c are examples of a "request generation unit." The heating ON signal is an example of a "heating execution request." The first signal lines 62a, 62b, and 62c are examples of a "request transmission unit." The heat source control units 102, 202, and 302 are examples of a "predetermined heat source control unit." The heat source control unit 102 is an example of a "selection unit." The heat source control unit 102 is an example of a "parent unit control unit." The heat source control units 202, 302, 402, and 502 are examples of "slave control units." The terminal pumps 24a, 24b, and 24c are examples of "pumps."

[0068] The technical elements described in this specification or drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations set forth in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful. [Explanation of symbols]

[0069] 2: heating system, 4: hot water supply circuit, 6: heating circuit, 8a, 8b, 8c: heating terminal, 12: primary forward flow path, 14: primary return flow path, 16: secondary forward flow path, 18: secondary return flow path, 20: fluid mixer, 22a, 22b, 22c: terminal flow path, 24a, 24b, 24c: terminal pump, 26a, 26b, 26c: thermostat, 32: burner, 34: first heat exchanger, 36: primary return flow path Branch, 38: Primary forward branch, 40: Heat source pump, 42: Bypass path, 44: Second heat exchanger, 46: Three-way valve, 48: Primary return thermistor, 50: Primary forward thermistor, 62a, 62b, 62c: First signal line, 64a, 64b, 64c: Second signal line, 100, 200, 300, 400, 500: Heat source unit, 102: Parent unit control unit, 202, 302, 402, 502: Child unit control units

Claims

1. a heating circuit through which a heat transfer medium flows; a plurality of heat source units provided in parallel in the heating circuit, each capable of performing a first heating operation to heat the heat medium flowing in the heating circuit; A plurality of heat source control units provided for the plurality of heat source units, each controlling a heat source unit; a heating terminal that heats by radiating heat from the heat medium flowing in the heating circuit; a request generation unit that generates a heating execution request for performing heating by the heating terminal; a request transmission unit that transmits the heating execution request generated by the request generation unit to a predetermined heat source control unit among the plurality of heat source control units; a selection unit that selects a heat source machine that is to perform the first heating operation from among the plurality of heat source machines, A heating system in which, when the heating execution request is transmitted to the predetermined heat source control unit, the heat source machine selected by the selection unit executes the first heating operation.

2. the plurality of heat source control units include one parent unit control unit and at least one child unit control unit configured to be able to communicate with the parent unit control unit, The heating system according to claim 1 , wherein the master control unit functions as the selection unit.

3. The heating system further includes a pump that sends the heat medium flowing through the heating circuit to the heating terminal, The heating system according to claim 1 , wherein when the heating execution request is transmitted to the predetermined heat source control unit, the predetermined heat source control unit operates the pump.

4. The heating system further includes a pump that sends the heat medium flowing through the heating circuit to the heating terminal, The heating system according to claim 2 , wherein the master controller operates the pump when the heating execution request is transmitted to the predetermined heat source controller.

5. The heating system according to claim 3 or 4, wherein operation of the pump is prohibited when the first heating operation cannot be performed in at least one of the plurality of heat source machines.

6. The heating system further includes a hot water circuit through which water flows; each of the plurality of heat source machines is further configured to be able to perform a second heating operation to heat the water flowing through the hot water supply circuit; The heating system according to claim 5 , wherein the first heating operation cannot be performed while the second heating operation is being performed in each of the plurality of heat source machines.

7. A plurality of the heating terminals; A plurality of the request generation units provided for each of the plurality of heating terminals; The heating system according to claim 1 or 2, further comprising: a plurality of the request transmitters, each of which is provided for each of the plurality of request generators.

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