Patent Publication Number: US-9416961-B2

Title: Boiler connection system

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to Japanese Patent Application No. 2014-264912 filed on Dec. 26, 2014, the contents of which are hereby incorporated by reference into the present application. 
     TECHNICAL FIELD 
     The present application relates to a boiler connection system which performs hot water supply and/or space heating with a heat medium heated by a plurality of heat sources. 
     DESCRIPTION OF RELATED ART 
     A hot water supply system is known which heats water with a plurality of heat source devices by means of combustion heat of burners and supplies the heated water. For example, JP2005-61666A discloses a parallel installation type hot water supply system including a plurality of water heaters. 
     JP2005-61666A merely describes a technique in which, in the parallel installation type hot water supply system including the plurality of water heaters, the use frequencies of the plurality of water heaters are made uniform. An object of the present application is to provide a boiler connection system which is able to supply water for hot water supply and to supply a heat medium for space heating. 
     BRIEF SUMMARY OF INVENTION 
     A boiler connection system disclosed in the present application includes: a heat medium circulating passage including a heat medium outgoing pipe and a heal medium return pipe; a water flow passage including a water supply pipe and a hot water supply pipe; a plurality of heat source devices connected in parallel to the heat medium circulating passage and the water flow passage; and a controller. Each of the plurality of heat source devices includes: a first heat exchanger configured to heat a heat medium by means of combustion heat of a burner; a heat medium heating circuit branching at one end thereof from the heat medium return pipe and connected at another end thereof to the heat medium outgoing pipe via the first heat exchanger; a bypass pipe connected to the heat medium heating circuit so as to bypass the first heat exchanger; a pressure-feed device provided on the heat medium heating circuit and at the first heat exchanger side with respect to a connection portion between the bypass pipe and the heat medium heating circuit; a flow passage switching valve provided at at least one side of the connection portion; a second heat exchanger provided on the bypass pipe and configured to exchange heat with the heat medium flowing through the bypass pipe to heat water supplied from the water supply pipe; and a water heating circuit branching at one end thereof from the water supply pipe and connected at another end thereof to the hot water supply pipe via the second heat exchanger. The controller executes, in each of the plurality of heat source devices: a space heating operation in which the flow passage switching valve is controlled such that a connection destination of a flow passage for the heat medium having passed through the first heat exchanger is the heat medium outgoing pipe, the pressure-feed device is operated, and the heat medium is heated by the first heat exchanger and supplied to the heat medium outgoing pipe; and a hot water supply operation in which the flow passage switching valve is controlled such that the connection destination of the flow passage for the heat medium having passed through the first heat exchanger is the bypass pipe, the pressure-feed device is operated, and the heat medium is heated by the first heat exchanger and supplied to the bypass pipe. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a configuration diagram of a boiler connection system according to an embodiment; 
         FIG. 2  is a configuration diagram of the boiler connection system according to the embodiment, illustrating an example of control during a space heating operation; and 
         FIG. 3  is a configuration diagram of the boiler connection system according to the embodiment, illustrating an example of control in which a hot water supply operation is performed during the space heating operation. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     In one or more embodiments, the boiler connection system includes, in each heat source device, the first heat exchanger which heats the heat medium, the heat medium heating circuit, the bypass pipe, the pressure-feed device, the flow passage switching valve, the second heat exchanger which heats the water, and the water heating circuit. The bypass pipe is connected to the heat medium heating circuit so as to bypass the first heat exchanger. The flow passage switching valve is provided at at least one side of the connection portion at which the heat medium heating circuit is connected to the bypass pipe. In the heat source device, when the controller controls the flow passage switching valve such that the connection destination of the flow passage for the heat medium having passed through the first heat exchanger is the heat medium outgoing pipe, the heat medium flows and circulates from the heat medium return pipe through the heat medium heating circuit including the first heat exchanger to the heat medium outgoing pipe. In a state where the flow passage is switched as described above, if the controller operates the pressure-feed device, the heat medium flowing from the heat medium return pipe into the heat source device can be heated by the first heat exchanger and returned to the heat medium outgoing pipe, whereby the space heating operation can be performed. In addition, in the heat source device, when the controller controls the flow passage switching valve such that the connection destination of the flow passage for the heat medium having passed through the first heat exchanger is the bypass pipe, the heat medium circulates through the first heat exchanger, the heat medium heating circuit, and the second heat exchanger provided on the bypass pipe. In a state where the flow passage is switched as described above, if the controller heats the heat medium with the first heat exchanger and operates the pressure-feed device, the water flowing from the water supply pipe into the heat source device can be heated and returned to the hot water supply pipe, whereby the hot water supply operation can be performed. The controller can perform the space heating operation by controlling the flow passage switching valve in at least one of the plurality of heat source devices such that flow of the heat medium to the bypass pipe is blocked and the heat medium flows between the heat medium heating circuit and the heat medium circulating passage. In addition, the controller can perform the hot water supply operation by controlling the flow passage switching valve in at least one of the plurality of heat source devices such that flow of the heat medium between the heat medium heating circuit and the heat medium circulating passage is blocked and the heat medium flows to the bypass pipe. 
     In one or more embodiments of the boiler connection system, the controller may determine whether to perform or stop the space heating operation or the hot water supply operation of each of the plurality of heat source devices, on the basis of an amount of heat required for hot water supply and/or space heating. In this case, in the heat source device whose space heating operation has been determined to be performed, the controller may control the flow passage switching valve such that flow of the heat medium to the bypass pipe is blocked and the heat medium flows between the heat medium heating circuit and the heat medium circulating passage, and operates the pressure-feed device; and in the heat source device whose space heating operation has been determined to be stopped, the controller may control the flow passage switching valve such that flow of the heat medium between the heat medium heating circuit and the heat medium circulating passage is blocked and the heat medium flows to the bypass pipe, and stops the pressure-feed device. According to this, only by controlling the flow passage switching valve which switches between the space heating operation and the hot water supply operation, it is possible to prevent the heat medium from flowing from the heat medium circulating passage into the first heat exchanger of the heat source device determined to be stopped. As a result, in the heat source device which does not need to heat the heat medium, a load is not applied to the pipe in the first heat exchanger, so that it is possible to suppress deterioration of the pipe. That is, it is not necessary to newly provide an open/close valve or the like in order to prevent the heat medium from flowing into the first heat exchanger of the heat source device determined to be stopped. 
     In one or more embodiments, the boiler connection system may further include: an open/close valve provided on the water heating circuit of each of the plurality of heat source devices; and a flow sensor capable of detecting a flow rate of water flowing through the water flow passage. In this case, the controller may perform control such that, in at least one of the heat source devices whose space heating operation has been determined to be stopped, the open/close valve is opened; and when the flow sensor detects flow of the water through the water flow passage, the controller may execute the hot water supply operation in the heat source device whose space heating operation has been determined to be stopped and whose open/close valve has been opened. According to this, when the flow sensor detects flow of the water through the water flow passage, all the heating capacities of the heat source devices whose space heating operation has been stopped can be used for heating the water, so that it is possible to quickly perform hot water supply. 
     Representative, non-limiting examples of the present invention 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 preferred aspects of the present teachings and is not intended to limit the scope of the invention. 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 boiler connection systems, as well as methods for using and manufacturing the same. 
     Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. 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. 
     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 
     As shown in  FIG. 1 , a boiler connection system  1  according to an embodiment includes a heat medium return pipe  31 , a heat medium outgoing pipe  33 , a water supply pipe  35 , a hot water supply pipe  36 , five heat source devices  100 ,  200 ,  300 ,  400 , and  500 , a water mixer  20 , and a controller  10 . The heat source devices  100 ,  200 ,  300 ,  400 , and  500  are connected in parallel between a heat medium circulating passage ( 31 ,  33 ) and a water flow passage ( 35 ,  36 ). On the water supply pipe  35 , a flow sensor  40  which is capable of detecting the flow rate of water flowing through the water supply pipe  35  is provided. 
     The heat source device  100  includes: a burner  101 ; a first heat exchanger  103  which heats a heat medium by means of combustion heat of the burner  101 ; a heat medium return branch pipe  121  which is connected to a fluid inlet of the first heat exchanger  103  and the heat medium return pipe  31 ; a heat medium supply branch pipe  123  which is connected to a fluid outlet of the first heat exchanger  103  and the heat medium outgoing pipe  33 ; and a pump  107  (an example of a pressure-feed device) which is provided on the heat medium return branch pipe  121 . The heat medium return branch pipe  121  and the heat medium supply branch pipe  123  are an example of a heat medium heating circuit. The heat medium return pipe  31  and the heat medium outgoing pipe  33  are an example of the heat medium circulating passage. In the heat medium heating circuit, the heat medium return branch pipe  121  branches from the heat medium return pipe  31  and is connected to the first heat exchanger  103 , and the first heat exchanger  103  is connected to the heat medium outgoing pipe  33  via the heat medium supply branch pipe  123 . 
     The heat source device  100  further includes a bypass pipe  109 , a second heat exchanger  130 , and a water heating circuit  125 . The bypass pipe  109  is connected to the heat medium return branch pipe  121  and the heat medium supply branch pipe  123  so as to bypass the first heat exchanger  103 . The second heat exchanger  130  is provided on the bypass pipe  109 . The water heating circuit  125  branches at one end thereof from the water supply pipe  35  and is connected at another end thereof to the hot water supply pipe  36  via the second heat exchanger  130 . The second heat exchanger  130  exchanges heat with the heat medium flowing through the bypass pipe  109 , to heat water supplied from the water supply pipe  35 . The pump  107  is provided at the first heat exchanger  103  side with respect to a connection portion between the bypass pipe  109  and the heat medium return branch pipe  121 . 
     The heat source device  100  further includes: an open/close valve  115  which is provided on the water heating circuit  125  and between the water supply pipe  35  and the second heat exchanger  130 ; and a three-way valve  111  which is provided on the heat medium heating circuit and at a connection portion between the heat medium supply branch pipe  123  and the bypass pipe  109 . By switching the three-way valve  111 , a destination of the heat medium flowing out from the first heat exchanger  103  can be switched to either the bypass pipe  109  or the heat medium outgoing pipe  33 . When the three-way valve  111  is controlled such that the destination of the heat medium flowing out from the first heat exchanger  103  is the heat medium outgoing pipe  33 , the heat medium flows from the heat medium return pipe  31  through the heat medium return branch pipe  121  into the first heat exchanger  103 . The heat medium flowing out from the first heat exchanger  103  flows through the heat medium supply branch pipe  123  into the heat medium outgoing pipe  33 . When the three-way valve  111  is controlled such that the destination of the heat medium flowing out from the first heat exchanger  103  is the bypass pipe  109 , the heat medium circulates through the first heat exchanger  103  and the second heat exchanger  130 . 
     The heat medium flows out from the water mixer  20  to the heat medium return pipe  31 , and flows from the heat medium return pipe  31  into the heat medium return branch pipe  121 . When: the three-way valve  111  is controlled such that the destination of the heat medium flowing out from the first heat exchanger  103  is the heat medium supply branch pipe  123 ; and the pump  107  is operating, the heat medium flows from the heat medium return branch pipe  121  into the first heat exchanger  103 . When the burner  101  is performing combustion, the heat medium is heated at the first heat exchanger  103  and flows out through the heat medium supply branch pipe  123  to the heat medium outgoing pipe  33 . 
     When the open/close valve  115  is opened, water for hot water supply flows from the water supply pipe  35  into the second heat exchanger  130 . When: the three-way valve  111  is controlled such that the destination of the heat medium flowing out from the first heat exchanger  103  is the bypass pipe  109 ; and the pump  107  is operating, the heat medium circulates between the first heat exchanger  103 , the three-way valve  111 , and the bypass pipe  109 . When the burner  101  is performing combustion, the heat medium heated at the first heat exchanger  103  flows into the second heat exchanger  130  provided on the bypass pipe  109 . By means of the heat medium flowing through the second heat exchanger  130 , the water supplied from the water supply pipe  35  can be heated. The water heated at the second heat exchanger  130  flows out to the hot water supply pipe  36 . 
     Each of the heat source devices  200 ,  300 ,  400 , and  500  has the same configuration as the heat source device  100 . Thus, for each of the configurations of the heat source devices  200 ,  300 ,  400 , and  500 , the reference numeral of 100s for each component of the heat source device  100  is replaced with a reference numeral of 200s, 300s, 400s, or 500s, and the description thereof is omitted. 
     The heat medium flows out from the water mixer  20  to the heat medium return pipe  31 , flows from the heat medium return pipe  31  through the heat medium return branch pipes  121 ,  221 ,  321 ,  421 , and  521  into the heat source devices  100 ,  200 ,  300 ,  400 , and  500 , flows through the first heat exchangers  103 ,  203 ,  303 ,  403 , and  503 , and flows out through the heat medium supply branch pipes  123 ,  223 ,  323 ,  423 , and  523  to the heat medium outgoing pipe  33 . When any of the heat source devices  100 ,  200 ,  300 ,  400 , and  500  is in a space heating operation state, the temperature of the heat medium flowing from the heat medium outgoing pipe  33  into the water mixer  20  is higher than that of the heat medium flowing out from the water mixer  20  to the heat medium return pipe  31 . A heat medium circulating through a heating terminal flows through a heating terminal return pipe  41  into the water mixer  20 , passes through the water mixer  20 , and flows out through a heating terminal outgoing pipe  43 . In the water mixer  20 , the heat medium circulating through the heating terminal is heated by the heat medium circulating through the heat source devices  100 ,  200 ,  300 ,  400 , and  500 . 
     The controller  10  determines whether to perform or stop a space heating operation or a hot water supply operation of each of the heat source devices  100 ,  200 ,  300 ,  400 , and  500 , on the basis of an amount of heat required for hot water supply and/or space heating. In the present embodiment, control performed by the controller  10  when the heat source devices  100  and  200  are stopped and the heat source devices  300 ,  400 , and  500  are operated to perform the space heating operation, and control performed by the controller  10  when a demand for hot water supply occurs in this state, will be described. 
     When the controller  10  determines to stop the heat source devices  100  and  200  and to operate the heat source devices  300 ,  400 , and  500  on the basis of an amount of heat required for the space heating operation, the controller  10  controls the three-way valves  311 ,  411 , and  511  of the heat source devices  300 ,  400 , and  500  determined to be operated, to connect the first heat exchangers  303 ,  403 , and  503  of the heat source devices  300 ,  400 , and  500  to the heat medium outgoing pipe  33  via the heat medium supply branch pipes  323 ,  423 , and  523  such that a destination of the heat medium flowing out from each of the first heat exchangers  303 ,  403 , and  503  is the heat medium outgoing pipe  33  as shown in  FIG. 2 . In addition, the controller  10  operates the pumps  307 ,  407 , and  507  and ignites the burners  301 ,  401 , and  501  to cause the burners  301 ,  401 , and  501  to perform combustion. Accordingly, the heat medium flows from the heat medium return pipe  31  through the heat medium return branch pipes  321 ,  421 , and  521  into the first heat exchangers  303 ,  403 , and  503  and is heated by the burners  301 ,  401 , and  501 . The heated heat medium flows out through each of the heat medium supply branch pipes  323 ,  423 , and  523  to the heat medium outgoing pipe  33 . The heated heat medium flows from the heat medium outgoing pipe  33  into the water mixer  20  and heats the heat medium circulating through the heating terminal. In addition, the controller  10  controls the open/close valves  315 ,  415 , and  515  such that the open/close valves  315 ,  415 , and  515  are in a closed state. 
     The controller  10  controls the three-way valves  111  and  211  of the heat source devices  100  and  200  determined to be stopped, such that the destinations of the heat medium flowing out from the first heat exchangers  103  and  203  of the heat source devices  100  and  200  are the bypass pipes  109  and  209 . The pumps  107  and  207  are in a stop state, and no heat medium flows out and in between: the heat medium return pipe  31  and the heat medium outgoing pipe  33 ; and the heat source devices  100  and  200 . In addition, no heat medium circulates through the pipes within the heat source devices  100  and  200 . Moreover, the controller  10  controls the open/close valves  115  and  215  such that the open/close valves  115  and  215  are in an opened state. 
     Next, the control performed by the controller  10  when a demand for hot water supply occurs in this state will be described with reference to  FIG. 3 . For example, when a faucet is opened, the water for hot water supply flows through the water supply pipe  35  and the hot water supply pipe  36 . Since the open/close valves  115  and  215  are in an opened state, the water flowing through the water supply pipe  35  flows through the water heating circuits  125  and  225 , on which the open/close valves  115  and  215  are provided, into the second heat exchangers  130  and  230  as shown in  FIG. 3 . When the flow sensor  40  detects flow of the water through the water supply pipe  35  (e.g., when a detection value indicating a water flow rate equal to or higher than a predetermined value is inputted from the flow sensor  40 ), the controller  10  operates the pumps  107  and  207  and ignites the burners  101  and  201  to cause the burners  101  and  201  to perform combustion. Accordingly, the heat medium circulates between the first heat exchanger  103 , the three-way valve  111 , and the bypass pipe  109  in the heat source device  100 . The heat medium is heated at the first heat exchanger  103  by means of combustion heat of the burner  101  and flows through the second heat exchanger  130  provided on the bypass pipe  109 . By means of the heat medium flowing through the second heat exchanger  130 , the water supplied from the water supply pipe  35  is heated. In addition, the heat medium circulates between the first heat exchanger  203 , the three-way valve  211 , and the bypass pipe  209  in the heat source device  200 . The heat medium is heated at the first heat exchanger  203  by means of combustion heat of the burner  201  and flows through the second heat exchanger  230  provided on the bypass pipe  209 . By means of the heat medium flowing through the second heat exchanger  230 , the water supplied from the water supply pipe  35  is heated. The water heated by the second heat exchangers  130  and  230  flows out through the downstream sides of the water heating circuits  125  and  225  to the hot water supply pipe  36 . According to the boiler connection system  1 , when a demand for hot water supply occurs during space heating, all the heating capacities of the currently stopped heat source devices  100  and  200  can be used for heating the water, so that it is possible to quickly perform hot water supply. 
     As described above, the boiler connection system  1  according to the embodiment includes the three-way valve ( 111 , etc.) which is capable of switching the destination of the heat medium flowing out from the first heat exchanger ( 103 , etc.) to either the heat medium outgoing pipe ( 33 ) or the bypass pipe ( 109 , etc.). When the three-way valve ( 111 , etc.) is controlled such that the destination of the heat medium flowing out from the first heat exchanger ( 103 , etc.) is the heat medium outgoing pipe ( 33 ), the heat medium circulates through the first heat exchanger ( 103  etc.), the heat medium return pipe  31 , and the heat medium outgoing pipe  33 . When the three-way valve ( 111 , etc.) is controlled such that the destination of the heat medium flowing out from the first heat exchanger ( 103 , etc.) is the bypass pipe ( 109 , etc.), the heat medium circulates through the first heat exchanger ( 103 , etc.) and the second heat exchanger ( 130 , etc.). The controller  10  controls the three-way valves  111  and  211  such that the destinations of the heat medium flowing out from the first heat exchangers ( 103 , etc.) are the bypass pipes  109  and  209  in the heat source devices  100  and  200  whose space heating operation has been determined to be stopped. Accordingly, in the heat source devices  100  and  200  determined to be stopped, the heat medium circulates through the first heat exchangers  103  and  203  and the second heat exchangers  130  and  230 , and flow of the heat medium from the heat medium return branch pipes  121  and  221  to the first heat exchangers  103  and  203  is stopped. According to the above-described boiler connection system  1 , only by controlling the three-way valves  111  and  211  which are used in switching between the space heating operation and the hot water supply operation, it is possible to stop flow of the heat medium from the heat medium return pipe  31  into the first heat exchangers  103  and  203  in the heat source devices  100  and  200  determined to be stopped. As a result, in the heat source devices  100  and  200  which do not need to heat the heat medium, a load is not applied to the pipes in the first heat exchangers  103  and  203 , so that it is possible to suppress deterioration of the pipes. In the above-described boiler connection system  1 , it is not necessary to newly provide an open/close valve in order to prevent the heat medium from flowing into each of the first heat exchangers  103  and  203  of the heat source devices  100  and  200  determined to be stopped. 
     In the above-described boiler connection system  1 , the controller  10  performs control such that: in the heat source devices  300 ,  400 , and  500  determined to be operated, the open/close valves  315 ,  415 , and  515  thereof are closed; and in the heat source devices  100  and  200  determined to be stopped, the open/close valves  115  and  215  thereof are opened. When a demand for hot water supply occurs in this state and the water flows through the water supply pipe  35 , while the water flows through the water heating circuits  125  and  225 , the water does not flow through the water heating circuits  325 ,  425 , and  525 . When the flow sensor  40  detects flow of the water through the water supply pipe  35 , the controller  10  performs control to operate the pumps  107  and  207  and to ignite the burners  101  and  201  to cause the burners  101  and  201  to perform combustion, whereby it is possible to quickly perform hot water supply by using the heat source devices  100  and  200 . 
     In the above-described embodiment, the pump ( 107 , etc.) as the pressure-feed device is provided at the first heat exchanger ( 103 , etc.) side with respect to the connection portion between the bypass pipe  109  and the heat medium return branch pipe  121 . However, the pressure-feed device may be provided at the first heat exchanger ( 103 , etc.) side with respect to the connection portion between the bypass pipe  109  and the heat medium supply branch pipe  123 . In addition, in the above-described embodiment, the three-way valve ( 111 , etc.) is a three-way valve ( 111 , etc.) which is provided at the connection portion between the heat medium supply branch pipe ( 123 , etc.) and the bypass pipe ( 109 , etc.) and is capable of switching the destination of the heat medium flowing out from the first heat exchanger  103  to either the heat medium outgoing pipe ( 33 ) or the bypass pipe ( 109 , etc.), but is not limited thereto. The three-way valve may be provided at the connection portion between the heat medium return branch pipe ( 121 , etc.) and the bypass pipe ( 109 , etc.), and the destination of the heat medium flowing out from the first heat exchanger  103  may be switched to either the heat medium outgoing pipe ( 33 , etc.) or the bypass pipe ( 109 , etc.) by the three-way valve ( 111 , etc.). Moreover, in the above-described embodiment, the open/close valve ( 115 , etc.) is provided between the water heating circuit ( 125 , etc.) and the water supply pipe ( 35 ), but the position of the open/close valve is not limited thereto. For example, the open/close valve may be provided between the water heating circuit ( 125 , etc.) and the hot water supply pipe ( 36 ). 
     Specific examples of the present invention has been described in detail, however, these are mere exemplary indications and thus do not limit the scope of the claims. The art described in the claims include modifications and variations of the specific examples presented above. Technical features described in the description and the drawings may technically be useful alone or in various combinations, and are not limited to the combinations as originally claimed. Further, the art described in the description and the drawings may concurrently achieve a plurality of aims, and technical significance thereof resides in achieving any one of such aims.