HEAT SOURCE UNIT COUPLING SYSTEM

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This application claims priority to Japanese Patent Application No. 2024-116960 filed on Jul. 22, 2024. The entire content of the priority application is incorporated herein by reference.

TECHNICAL FIELD

[0002]The technology disclosed herein relates to heat source unit coupling systems.

BACKGROUND ART

[0003]Japanese Patent Application Publication No. 2016-125690 describes a heat source unit coupling system. The heat source unit coupling system includes a heat medium circulation channel including a heat medium outgoing pipe and a heat medium return pipe; a water distribution channel including a water supply pipe and a hot water outlet pipe; a plurality of heat source units connected in parallel to the heat medium circulation channel and the water distribution channel; and a coupling controller communicable with each of the plurality of heat source units. Each of the plurality of heat source units is configured to perform a space heating operation for heating a heat medium supplied from the heat medium return pipe and supplying it to the heat medium outgoing pipe and a hot water supplying operation for heating water supplied from the water supply pipe and supplying it to the hot water outlet pipe.

SUMMARY

[0004]In heat source unit coupling systems such as the one described above, it is determined, for each of the heat source units, whether to cause the heat source unit to perform the space heating operation, to perform the hot water supplying operation, or to stand by without performing the space heating operation nor the hot water supplying operation, usually based on heat loads required for space heating and hot water supply. However, in heat source unit coupling systems such as the one described above, one or more heat source units among the plurality of heat source units may be configured to perform only the space heating operation or only the hot water supplying operation, which leads to a difference between the number of heat source devices capable of performing the hot water supplying operation and the number of heat source units capable of performing the space heating operation. In this case, among the plurality of heat source units, heat source units capable of performing both the space heating operation and the hot water supplying operation may be more frequently used in some circumstances, which leads to more severe deterioration in these heat source units compared to the other ones. The disclosure herein provides a technology for suppressing imbalance in usage frequencies for space heating and hot water supply among heat source units in a heat source unit coupling system including one or more heat source units capable of performing only a space heating operation or only a hot water supplying operation.

[0005]In a first aspect of the disclosure herein, a heat source unit coupling system may comprise a heat medium circulation channel including a heat medium outgoing pipe and a heat medium return pipe; a water distribution channel including a water supply pipe and a hot water outlet pipe; one or more multifunctional heat source units connected in parallel to the heat medium circulation channel and the water distribution channel; one or more single-function heat source units connected in parallel to the heat medium circulation channel; and a coupling controller communicable with each of the one or more multifunctional heat source units and the one or more single-function heat source units. The one or more multifunctional heat source units may be configured to perform a space heating operation for heating a heat medium supplied from the heat medium return pipe and supplying it to the heat medium outgoing pipe; and a hot water supplying operation for heating water supplied from the water supply pipe and supplying it to the hot water outlet pipe. The one or more single-function heat source units may be configured to perform the space heating operation. The coupling controller may be configured to: instruct each of the one or more multifunctional heat source units to start or stop the hot water supplying operation based on priorities of the one or more multifunctional heat source units for the hot water supplying operation; and instruct each of the one or more multifunctional heat source units and each of the one or more single-function heat source units to start or stop the space heating operation based on priorities of the one or more multifunctional heat source units for the space heating operation and priorities of the one or more single-function heat source units for the space heating operation. The priorities of the one or more single-function heat source units for the space heating operation may be higher than the priorities of the one or more multifunctional heat source units for the space heating operation.

[0006]In the heat source unit coupling system above, the single-function heat source units preferentially perform the space heating operation when space heating is requested, and thus the one or more multifunctional heat source units are less frequently used for the space heating operation. This configuration suppresses imbalance of the usage frequencies for the space heating operation and the hot water supplying operation among the plurality of heat source units.

[0007]In a second aspect according to the first aspect, the priorities of the one or more multifunctional heat source units for the hot water supplying operation may be at least partially different from the priorities of the one or more multifunctional heat source units for the space heating operation.

[0008]If the priorities of the one or more multifunctional heat source units for the hot water supplying operation were the same as the priorities of the one or more multifunctional heat source units for the space heating operation, multifunctional heat source units more frequently used for the hot water supplying operation would also be more frequently used for the space heating operation, which may lead to imbalance of the usage frequencies among the multifunctional heat source units. In contrast, the above configuration suppresses such imbalance since the priorities of the one or more multifunctional heat source units for the hot water supplying operation are at least partially different from the priorities of the one or more multifunctional heat source units for the space heating operation.

[0009]In a third aspect according to the first or second aspect, the one or more multifunctional heat source units may comprise a first multifunctional heat source unit and a second multifunctional heat source unit. When a priority of the first multifunctional heat source unit for the hot water supplying operation is higher than a priority of the second multifunctional heat source unit for the hot water supplying operation, a priority of the first multifunctional heat source unit for the space heating operation may be lower than a priority of the second multifunctional heat source unit for the space heating operation. When the priority of the first multifunctional heat source unit for the hot water supplying operation is lower than the priority of the second multifunctional heat source unit for the hot water supplying operation, the priority of the first multifunctional heat source unit for the space heating operation may be higher than the priority of the second multifunctional heat source unit for the space heating operation.

[0010]In the configuration above, multifunctional heat source units having higher priorities for the hot water supplying operation (i.e., multifunctional heat source units more frequently used for the hot water supplying operation) have lower priorities for the space heating operation (i.e., are less frequently used for the space heating operation). In contrast, multifunctional heat source units having higher priorities for the space heating operation (i.e., multifunctional heat source units more frequently used for the space heating operation) have lower priorities for the hot water supplying operation (i.e., are less frequently used for the hot water supplying operation). This configuration suppresses imbalance of the usage frequencies among the multifunctional heat source units.

[0011]In a fourth aspect according to one of the first to third aspects, the coupling controller may treat a multifunctional heat source unit that is in a state of being unable to normally perform the hot water supplying operation among the one or more multifunctional heat source units as a single-function heat source unit.

[0012]Even when the one or more multifunctional heat source units are in the state of being unable to normally perform the hot water supplying operation, they may still be able to normally perform the space heating operation. The configuration above secures more heat source units to be used for the space heating operation by utilizing multifunctional heat source device(s) unable to normally perform the hot water supplying operation as single-function heat source unit(s).

[0013]In a fifth aspect according to one of the first to fourth aspects, the one or more single-function heat source units may comprise a plurality of single-function heat source units. The coupling controller may be further configured to perform a rotation to rotate priorities of the plurality of single-function heat source units for the space heating operation when a predetermined heating rotation condition is met.

[0014]The configuration above suppresses imbalance of the usage frequencies among the single-function heat source units.

[0015]In a sixth aspect according to the fifth aspect, the heating rotation condition may be based on a number of times the heat source unit coupling system has been used for space heating.

[0016]If the heat source unit coupling system were repeatedly used for space heating without the rotation of the priorities for the space heating operation, single-function heat source units having higher priorities for the space heating operation would continuously be used at higher frequencies. The configuration above suppresses imbalance of the usage frequencies among the single-function heat source units, since the priorities for the space heating operation are rotated based on the number of times the heat source unit coupling system has been used for space heating.

[0017]In a seventh aspect according to the fifth aspect, the heating rotation condition may be based on a time period during which the heat source unit coupling system has been used for space heating.

[0018]If the heat source unit coupling system were used for space heating for a long time without the rotation of the priorities for the space heating operation, single-function heat source units having higher priorities for the space heating operation would continuously be used at higher frequencies. The configuration above suppresses imbalance of the usage frequencies among the single-function heat source units, since the priorities for the space heating operation is rotated based on the time period during which the heat source unit coupling system has been used for space heating.

[0019]In an eighth aspect according to one of the fifth to seventh aspects, the coupling controller may be further configured to determine post-rotation priorities of the plurality of single-function heat source units for the space heating operation based only on pre-rotation priorities of the plurality of single-function heat source units for the space heating operation.

[0020]The configuration above allows the coupling controller to perform a simpler process for the rotation of the priorities of the plurality of single-function heat source units for the space heating operation.

[0021]In a ninth aspect according to one of the first to eighth aspects, the one or more multifunctional heat source units may comprise a plurality of multifunctional heat source units. The coupling controller may be further configured to perform, when a predetermined hot water supplying rotation condition is met, a rotation to rotate priorities of the plurality of multifunctional heat source units for the hot water supplying operation and simultaneously perform a rotation to rotate priorities of the plurality of multifunctional heat source units for the space heating operation.

[0022]Compared to rotating the priorities for the hot water supplying operation and the priorities for the space heating operation based on different conditions, the configuration above allows the coupling controller to perform the rotations in a simpler manner.

[0023]In a tenth aspect according to the ninth aspect, the hot water supplying rotation condition may be based on a number of times the heat source unit coupling system has been used for hot water supply.

[0024]If the heat source unit coupling system were repeatedly used for hot water supply without the rotation of the priorities for the hot water supplying operation, multifunctional heat source units having higher priorities for the hot water supplying operation would continuously be used at higher frequencies. The configuration above suppresses imbalance of the usage frequencies among the multifunctional heat source units since the priorities for the hot water supplying operation is rotated based on the number of times the heat source unit coupling system has been used for hot water supply.

[0025]In an eleventh aspect according to the ninth aspect, the hot water supplying rotation condition may be based on a time period during which the heat source unit coupling system has been used for hot water supply.

[0026]If the heat source unit coupling system were used for hot water supply for a long time without the rotation of the priorities for the hot water supplying operation, multifunctional heat source units having higher priorities for the hot water supplying operation would continuously be used at higher frequencies. The configuration above suppresses imbalance of the usage frequencies among the multifunctional heat source units since the priorities for the hot water supplying operation is rotated based on the time period during which the heat source unit coupling system has been used for hot water supply.

[0027]In a twelfth aspect according to the ninth to eleventh aspects, the coupling controller may be further configured to determine post-rotation priorities of the plurality of multifunctional heat source units for the hot water supplying operation based only on pre-rotation priorities of the plurality of multifunctional heat source units for the hot water supplying operation.

[0028]The configuration above allows the coupling controller to perform a simpler process for the rotation of the priorities of the multifunctional heat source units for the hot water supplying operation.

[0029]In a thirteenth aspect, a heat source unit coupling system may comprise a heat medium circulation channel including a heat medium outgoing pipe and a heat medium return pipe; a water distribution channel including a water supply pipe and a hot water outlet pipe; one or more multifunctional heat source units connected in parallel to the heat medium circulation channel and the water distribution channel; one or more single-function heat source units connected in parallel to the water distribution channel; and a coupling controller communicable with each of the one or more multifunctional heat source units and each of the one or more single-function heat source units. The one or more multifunctional heat source units may be configured to perform a space heating operation for heating a heat medium supplied from the heat medium return pipe and supplying it to the heat medium outgoing pipe; and a hot water supplying operation for heating water supplied from the water supply pipe and supplying it to the hot water outlet pipe. The one or more single-function heat source units may be configured to perform the hot water supplying operation. The coupling controller may be configured to instruct each of the one or more multifunctional heat source units and each of the one or more single-function heat source units to start or stop the hot water supplying operation based on priorities of the one or more multifunctional heat source units for the hot water supplying operation and priorities of the one or more single-function heat source units for the hot water supplying operation; and instruct each of the one or more multifunctional heat source units to start or stop the space heating operation based on priorities of the one or more multifunctional heat source units for the space heating operation. The priorities of the one or more single-function heat source units for the hot water supplying operation may be higher than the priorities of the one or more multifunctional heat source units for the hot water supplying operation.

[0030]In the heat source unit coupling system above, the single-function heat source units preferentially perform the hot water supplying operation when hot water supply is requested, and thus the one or more multifunctional heat source units are less frequently used for the hot water supplying operation. This configuration suppresses imbalance of the usage frequencies for the space heating operation and the hot water supplying operation among the plurality of heat source units.

BRIEF DESCRIPTION OF DRAWINGS

[0031]FIG. 1 shows a configuration of a heat source unit coupling system 1 according to an embodiment.

[0032]FIG. 2 shows how single-function heat source units 100, 200, 300 are switched between starting and stopping a space heating operation and how multifunctional heat source units 400, 500, 600 are switched between starting and stopping a hot water supplying operation and the space heating operation in the heat source unit coupling system 1 according to the embodiment.

[0033]FIG. 3 shows a procedure performed by a parent controller 602 when the multifunctional heat source unit 500 is unable to normally perform the hot water supplying operation in the heat source unit coupling system 1 according to the embodiment.

[0034]FIG. 4 shows how priorities for the space heating operation are rotated among the single-function heat source units 100, 200, 300 in the heat source unit coupling system 1 according to the embodiment.

[0035]FIG. 5 shows how priorities for the hot water supplying operation and the space heating operation are rotated among the multifunctional heat source units 400, 500, 600 in the heat source unit coupling system 1 according to the embodiment.

[0036]FIG. 6 shows a configuration of a heat source unit coupling system 2 according to a variant.

DETAILED DESCRIPTION

[0037]Representative, non-limiting examples of the present disclosure will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved heat source unit coupling system, as well as methods for using and manufacturing the same.

[0038]Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the present disclosure in the broadest sense, and are instead taught merely to particularly describe representative examples of the present disclosure. Furthermore, various features of the above-described and below-described representative examples, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

[0039]All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

Embodiment

[0040]As shown in FIG. 1, a heat source unit coupling system 1 according to an embodiment comprises a heat medium circulation channel 30, a water distribution channel 34, three single-function heat source units 100, 200, 300, three multifunctional heat source units 400, 500, 600, and a fluid mixer 20. The heat medium circulation channel 30 comprises a heat medium return pipe 31 and a heat medium outgoing pipe 33. The water distribution channel 34 comprises a water supply pipe 35 and a hot water outlet pipe 36. The single-function heat source unis 100, 200, 300 and the multifunctional heat source units 400, 500, 600 are connected in parallel to the heat medium circulation channel 30. The multifunctional heat source units 400, 500, 600 are connected in parallel to the water distribution channel 34. A flow sensor 40 is disposed in the water supply pipe 35, and the flow sensor 40 is configured to detect a flow rate of water flowing in the water supply pipe 35. To heat one or more spaces by using the heat source unit coupling system 1, a heat medium for space heating (e.g., water or an antifreeze liquid) is delivered from the fluid mixer 20 through the heat medium return pipe 31 into at least one of the single-function heat source units 100, 200, 300 and the multifunctional heat source units 400, 500, 600 and heated therein, and then the heated heat medium flows back to the fluid mixer 20 through the heat medium outgoing pipe 33. The heat medium for space heating then flows from the fluid mixer 20 into space heating terminals (not shown) through a space heating terminal outgoing channel 43 and is used for space heating therein, and then this cooled heat medium flows back to the fluid mixer 20 through a space heating terminal return channel 41. To supply hot water by using the heat source unit coupling system 1, water is delivered from the water supply pipe 35 into at least one of the multifunctional heat source units 400, 500, 600 and heated therein, and then the heated water flows out to the hot water outlet pipe 36.

[0041]The single-function heat source unit 100 comprises a burner 101, a controller 102, a first heat exchanger 103 at which the heat medium is heated by the burner 101, a branched heat medium return pipe 121 branched off from the heat medium return pipe 31 and connected to an inlet of the first heat exchanger 103, a branched heat medium outgoing pipe 123 extending from an outlet of the first heat exchanger 103 and connected to the heat medium outgoing pipe 33, and a pump 107 disposed in the branched heat medium return pipe 121.

[0042]The controller 102 comprises a CPU, a ROM, a RAM, etc. and controls the burner 101 and the pump 107 of the single-function heat source unit 100. In order for the single-function heat source unit 100 to perform a space heating operation, the controller 102 activates the pump 107. Consequently, the heat medium flows through the heat medium return pipe 31 and the branched heat medium return pipe 121 and then flows into the first heat exchanger 103. After flowing out from the first heat exchanger 103, the heat medium flows through the branched heat medium outgoing pipe 123 and then flows into the heat medium outgoing pipe 33. The controller 102 turns on the burner 101. The heat medium flowing through the first heat exchanger 103 is thereby heated and the heated heat medium is supplied to the heat medium outgoing pipe 33.

[0043]The single-function heat source units 200 and 300 each have the same configuration as the heat source unit 100. Thus, the same components of the single-function heat source units 200 and 300 are labeled with 200 and 300 numbering systems, respectively, and their detailed descriptions are not repeated. The single-function heat source units 100, 200, 300 are configured to perform only the space heating operation.

[0044]The multi-functional heat source unit 400 comprises a burner 401, a controller 402, a first heat exchanger 403 at which the heat medium is heated by the burner 401, a branched heat medium return pipe 421 branched off from the heat medium return pipe 31 and connected to an inlet of the first heat exchanger 403, a branched heat medium outgoing pipe 423 extending from an outlet of the first heat exchanger 403 and connected to the heat medium outgoing pipe 33, a pump 407 disposed in the branched heat medium return pipe 421, a bypass pipe 409 connecting the branched heat medium outgoing pipe 423 to a portion of the branched heat medium return pipe 421 located upstream of the pump 407, a three-way valve 411 located at a position where the branched heat medium outgoing pipe 423 is connected to the bypass pipe 409 and configured to direct the heat medium flowing out from the first heat exchanger 403 to the bypass pipe 409 or the heat medium outgoing pipe 33, a second heat exchanger 430 located on the bypass pipe 409, a water heating circuit 425 for supplying water from the water supply pipe 35 to the hot water outlet pipe 36 via the second heat exchanger 430, and an on-off valve 415 configured to flow or stop the water in the water heating circuit 425. At the second heat exchanger 430, the water flowing in the water heating circuit 425 is heated by exchanging heat with the heat medium flowing in the bypass pipe 409.

[0045]The controller 402 comprises a CPU, a ROM, a RAM, etc. and controls the burner 401, the pump 407, the three-way valve 411, and the on-off valve 415 of the multifunctional heat source unit 400. In order for the multifunctional heat source unit 400 to perform the space heating operation, the controller 402 controls the three-way valve 411 to direct the heat medium flowing out from the first heat exchanger 403 to the heat medium outgoing pipe 33 and also activates the pump 407. Consequently, the heat medium flows through the heat medium return pipe 31 and the branched heat medium return pipe 421 and then flows into the first heat exchanger 403. After flowing out from the first heat exchanger 403, the heat medium flows through the branched heat medium outgoing pipe 423 and then flows into the heat medium outgoing pipe 33. The controller 402 turns on the burner 401. The heat medium flowing through the first heat exchanger 403 is thereby heated and the heated heat medium is supplied to the heat medium outgoing pipe 33.

[0046]In order for the multifunctional heat source unit 400 to perform a hot water supplying operation, the controller 402 controls the three-way valve 411 to direct the heat medium flowing out from the first heat exchanger 403 to the bypass pipe 409 and also activates the pump 407. This causes the heat medium to circulate between the first heat exchanger 403 and the second heat exchanger 430. The controller 402 also opens the on-off valve 415 and turns on the burner 401. Consequently, the heat medium flowing through the first heat exchanger 403 is heated, and the heated heat medium is supplied to the second heat exchanger 430, thereby heating the water flowing through the water heating circuit 425 and supplying the heated water to the hot water outlet pipe 36.

[0047]The multifunctional heat source units 500 and 600 each have the same configuration as the multifunctional heat source unit 400. Thus, the same components of the multifunctional heat source units 500 and 600 are labeled with 500 and 600 numbering systems, respectively, and their detailed descriptions are not repeated. The multifunctional heat source units 400, 500, 600 are configured to perform both the space heating operation and the hot water supplying operation.

[0048]In the heat source unit coupling system 1, the controllers 102, 202, 302, 402, 502, 602 are communicable with each other. In the heat source unit coupling system 1, one of the controllers 102, 202, 302, 402, 502, 602 (e.g., the controller 602) functions as a parent controller for controlling the overall operation of the heat source unit coupling system 1, while the other controllers function as child controllers that operate according to instructions from the parent controller. When functioning as the parent controller, the controller 602 determines, for each of the single-function heat source units 100, 200, 300, whether to cause the single-function heat source unit to perform the space heating operation or to stand by without performing the space heating operation and also determines, for each of the multifunctional heat source units 400, 500, 600, whether to cause the multifunctional heat source unit to perform the space heating operation, to perform the hot water supplying operation, or to stand by without performing the space heating operation nor the hot water supplying operation, based on amounts of heat required for hot water supply and/or space heating. When functioning as the child controllers, the controllers 102, 202, 302 cause the single-function heat source units 100, 200, 300 to perform the space heating operation or to stand by without performing the space heating operation according to instructions from the parent controller 602. When functioning as the child controllers, the controllers 402, 502 cause the multifunctional heat source units 400, 500 to perform the space heating operation, to perform the hot water supplying operation, or to stand by without performing the space heating operation nor the hot water supplying operation according to instructions from the parent controller 602. The parent controller 602 causes the multifunctional heat source unit 600 to perform the space heating operation, to perform the hot water supplying operation, or to stand by without performing the space heating operation nor the hot water supplying operation according to an instruction from itself.

[0049]As shown in FIG. 2, priorities for the hot water supplying operation and priorities for the space heating operation are assigned in advance to the single-function heat source units 100, 200, 300 and the multifunctional heat source units 400, 500, 600. In the example shown in FIG. 2, the priorities for the space heating operation are assigned such that the single-function heat source units 100, 200, 300 have higher priorities than the multifunctional heat source units 400, 500, 600. Among the multifunctional heat source units, 400, 500, and 600, the priorities for the hot water supplying operation and the priorities for the space heating operation are assigned such that multifunctional heat source units having higher priorities for the hot water supplying operation are lower in the priorities for the space heating operation and multifunctional heat source units having lower priorities for the hot water supplying operation are higher in the priorities for the space heating operation.

[0050]As shown in (A) in FIG. 2, when space heating and hot water supply are requested in the heat source unit coupling system 1, the parent controller 602 causes the single-function heat source unit 100 having the highest priority for the space heating operation to start the space heating operation and also causes the multifunctional heat source unit 600 having the highest priority for the hot water supplying operation to start the hot water supplying operation. As the amounts of heat required for the space heating and hot water supply increase, the controller 602 causes the single-function heat source unit 200 having the second highest priority for the space heating operation to start the space heating operation and also causes the multifunctional heat source unit 500 having the second highest priority for the hot water supplying operation to start the hot water supplying operation, as shown in (B) in FIG. 2. As the amount of heat required for the space heating further increases, the controller 602 causes the single-function heat source unit 300 and the multifunctional heat source unit 400 having the third and fourth highest priorities for the space heating operation to start the space heating operation as shown in (C) in FIG. 2. In this embodiment, when the amount of heat required for the hot water supply further increases while all of the single-function heat source units 100, 200, 300 and the multifunctional heat source units 400, 500, 600 are performing the hot water supplying operation or the space heating operation as shown in (C) in FIG. 2, the controller 602 causes the multifunctional heat source unit 400 having the third highest priority for the hot water supplying operation to stop the space heating operation and start the hot water supplying operation as shown in (D) in FIG. 2. Thus, in the heat source unit coupling system 1 according to this embodiment, the hot water supplying operation is prioritized over the space heating operation when the hot water supplying operation and the space heating operation are requested in one heat source unit.

[0051]Referring to FIG. 3, a process performed by the parent controller 602 when the multifunctional heat source unit 500 is unable to normally perform the hot water supplying operation in the heat source unit coupling system 1 according to this embodiment is described. In (A) in FIG. 3, the single-function heat source units 100, 200 are performing the space heating operation and the multifunctional heat source units 500, 600 are performing the hot water supplying operation. When the multifunctional heat source unit 500 becomes unable to normally perform the hot water supplying operation, the controller 602 changes the preassigned priorities for the hot water supplying operation and the space heating operation as shown in (B) in FIG. 3. Specifically, the controller 602 treats the multifunctional heat source unit 500 as a single-function heat source unit so that the priority of the multifunctional heat source unit 500 for the hot water supplying operation is cancelled and the priority of the multifunctional heat source unit 500 for the space heating operation is changed to the second highest priority. Further, the priorities of the single-function heat source units 200, 300 and the multifunctional heat source unit 400 for the space heating operation are lowered by one. After changing the priorities as above, the controller 602 causes the single-function heat source unit 200 to stop the space heating operation, cause the multifunctional heat source unit 400 to start the hot water supplying operation, and causes the multifunctional heat source unit 500 to start the space heating operation. Thereafter, when the multifunctional heat source unit 500 becomes able to normally perform the hot water supplying operation, as shown in (C) in FIG. 3, the controller 602 changes the priorities for the hot water supplying operation and the space heating operation back to those shown in (A) in FIG. 3. Then, the controller 602 causes the single-function heat source unit 200 to start the space heating operation, causes the multifunctional heat source unit 400 to stop the hot water supplying operation, and causes the multifunctional heat source unit 500 to restart the hot water supplying operation.

[0052]Referring to FIG. 4, how the priorities of the single-function heat source units 100, 200, 300 for the space heating operation are rotated in the heat source unit coupling system 1 according to this embodiment is described. In the heat source unit coupling system 1 according to this embodiment, the priorities of the single-function heat source units 100, 200, 300 for the space heating operation are rotated in response to a time period during which the heat source unit coupling system 1 has been used for space heating (this time period is termed “space heating period” hereinafter) reaching a predetermined period (e.g., 24 hours). For example, as shown in (A) in FIG. 4, the single-function heat source unit 100 having the highest priority for the space heating operation is performing the space heating operation in the heat source unit coupling system 1. When the space heating period of the heat source unit coupling system 1 reaches the predetermined period, the parent controller 602 rotates the priorities of the single-function heat source units 100, 200, 300 for the space heating operation, so that the priority of the single-function heat source unit 300 having the lowest priority for the space heating operation among the single-function heat source units is changed to the highest priority for the space heating operation and the priorities of the other single-function heat source units 100, 200 for the space heating operation are lowered by one as shown in (B) in FIG. 4. As a result of this rotation, the parent controller 602 causes the single-function heat source unit 100 to stop the space heating operation, causes the single-function heat source unit 300 to start the space heating operation, and causes the single-function heat source unit 200 to keep standing by.

[0053]When the space heating period of the heat source unit coupling system 1 reaches the predetermined period again, the parent controller 602 rotates the priorities of the single-function heat source units 100, 200, 300 for the space heating operation, so that the priority of the single-function heat source unit 200 having the lowest priority for the space heating operation is changed to the highest priority for the space heating operation and the priorities of the other single-function heat source units 100, 300 for the space heating operation are lowered by one as shown in (C) in FIG. 4. As a result of this rotation, the parent controller 602 causes the single-function heat source unit 100 to keep standing by, causes the single-function heat source unit 300 to stop the space heating operation, and cases the single-function heat source unit 200 to start the space heating operation.

[0054]Referring to FIG. 5, how the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation are rotated in the heat source unit coupling system 1 according to this embodiment is described. In the heat source unit coupling system 1 according to this embodiment, the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation are rotated in response to a time period during which the heat source unit coupling system 1 has been used for hot water supply (this time period is termed “hot water supplying period” hereinafter) reaching a predetermined period (e.g., 24 hours). For example, as shown in (A) in FIG. 5, the multifunctional heat source unit 600 having the highest priority for the hot water supplying operation is performing the hot water supplying operation in the heat source unit coupling system 1. When the hot water supplying period of the heat source unit coupling system 1 reaches the predetermined period, the parent controller 602 rotates the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation, so that the priority of the multifunctional heat source unit 600 for the hot water supplying operation is changed from the highest priority to the lowest priority and the priorities of the other multifunctional heat source units 400, 500 for the hot water supplying operation are raised by one as shown in (B) in FIG. 5. The parent controller 602 also changes the priority of the multifunctional heat source unit 500 for the space heating, which now has the highest priority for the hot water supplying operation, to the lowest priority, lowers the priority of the multifunctional heat source unit 400 for the space heating by one, and raises the priority of the multifunctional heat source unit 600 for the space heating operation, which has the lowest priority for the hot water supplying operation, by two. As a result of this rotation, the parent controller 602 causes the multifunctional heat source unit 400 to keep standing by, causes the multifunctional heat source unit 500 to start the hot water supplying operation, and causes the multifunctional heat source unit 600 to stop the hot water supplying operation and stand by.

[0055]When the hot water supplying period of the heat source unit coupling system 1 reaches the predetermined period again, the parent controller 602 rotates the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation, so that the priority of the multifunctional heat source unit 500 for the hot water supplying operation is changed from the highest priority to the lowest priority and the priorities of the other multifunctional heat source units 400, 600 for the hot water supplying operation are raised by one as shown in (C) in FIG. 5. The parent controller 602 also changes the priority of the multifunctional heat source unit 400 for space heating operation, which has the highest priority for the hot water supplying operation, to the lowest priority, lowers the priority of the multifunctional heat source unit 600 for the space heating by one, and raises the priority of the multifunctional heat source unit 500 for the space heating operation, which has the lowest priority for the hot water supplying operation, by two. As a result of this rotation, the parent controller 602 causes the multifunctional heat source unit 600 to keep standing by, causes the multifunctional heat source unit 400 to start the hot water supplying operation, and causes the multifunctional heat source unit 500 to stop the hot water supplying operation and enter standby. In the heat source unit coupling system 1 according to this embodiment, the rotation of the priorities of the single-function heat source units 100, 200, 300 for the space heating operation and the rotation of the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation are performed separately.

Variants

[0056]The heat source unit coupling system 1 may use the number of times the heat source unit coupling system 1 has been used for hot water supply reaching a predetermined number (e.g., ten) as the rotation condition for the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation, instead of the hot water supplying time period of the heat source unit coupling system 1 reaching the predetermined period. Further, the heat source unit coupling system 1 may use a number of times the heat source unit coupling system 1 has been used for space heating reaching a predetermined number (e.g., ten) as the rotation condition for rotating the priorities of the single-function heat source units 100, 200, 300 for the space heating operation.

[0057]The heat source unit coupling system 1 may prioritize the space heating operation over the hot water supplying operation when these operations are requested in one heat source unit.

[0058]In the heat source unit coupling system 1, the priorities of the single-function heat source units 100, 200, 300 for the space heating operation and the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation may be rotated simultaneously based on the same condition.

[0059]In the heat source unit coupling system 1, the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supply operation and the priorities of the multifunctional heat source units 400, 500, 600 for the space heating operation may be rotated based on different conditions.

[0060]The heat source unit coupling system 1 may comprise another controller configured to function as a parent controller other than the controllers 102, 202, 302, 402, 502, 602.

[0061]The single-function heat source units 100, 200, 300 of the heat source unit coupling system 1 may be configured to perform only the hot water supplying operation. In this case, water heating circuits 125, 225, 325 may be connected to the first heat exchangers 103, 203, 303, respectively, as in a heat source unit coupling system 2 shown in FIG. 6. Water flowing through the first heat exchangers 103, 203, 303 may be directly heated by the burners 101, 201, 301. The priorities for the hot water supplying operation are assigned such that the priorities of the single-function heat source units 100, 200, 300 for the hot water supplying operation are higher than the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation. Among the multifunctional heat source units 400, 500, 600, their priorities for the hot water supplying operation and the space heating operation are assigned such that multifunctional heat source units having the higher priorities for the hot water supplying operation are lower in the priorities for the space heating operation and multifunctional heat source units having lower priorities for the hot water supplying operation are higher in the priorities for the space heating operation. When the hot water supplying period of the heat source unit coupling system 1 reaches a predetermined period (e.g., 24 hours), the priorities of the single-function heat source units 100, 200, 300 for the hot water supplying operation are rotated, and when the space heating period of the heat source unit coupling system 1 reaches a predetermined period (e.g., 24 hours), the priorities of the multifunctional heat source units 400, 500, 600 for the hot water supplying operation and the space heating operation are rotated.

[0062]The multifunctional heat source units 400, 500, 600 may each comprise another burner to heat water during the hot water supplying operation other than the burner 401, 501, 601 to heat the heat medium during the space heating operation. In this case, multifunctional heat source units 400, 500, 600 may be configured to simultaneously perform the hot water supplying operation and the space heating operation.

[0063]The three-way valves 411, 511, 611 of the heat source units 400, 500, 600 may be located at positions where the branched heat medium return pipes 421, 521, 621 are connected to the bypass pipes 409, 509, 609.

Correspondence Relationship

[0064]The parent controller 602 is an example of “coupling controller”.