Heat source device

Abstract

A heat source device 2 disclosed in the present description comprises: a hot water storage tank 10; an internal heat source 20 for heating water in the hot water storage tank 10; a first temperature sensor 30 for detecting the temperature of the water in the hot water storage tank above the internal heat source 20; a circulation pipe 40 which is connected to a lower part and an upper part of the hot water storage tank 10; a circulation pump 50; and a controller 52. The controller 52 is configured so as to be capable of executing heating control for operating the internal heat source 20 in a state where the circulation pump 50 is stopped and circulation control for operating the circulation pump 50. The controller 52 executes switching between the heating control and the circulation control on the basis of the temperature detected by the first temperature sensor 30.

Description

heat source device

[0001] The technology disclosed herein relates to a heat source device.

[0002] International Publication No. 2007 / 068031 discloses a heat source device. The heat source device comprises a hot water storage tank, an internal heat source positioned above the bottom of the hot water storage tank for heating the water in the tank, a plurality of temperature sensors provided in the hot water storage tank for detecting the temperature of the water in the tank, circulation piping connected to the bottom and top of the hot water storage tank, a circulation pump that sends water from the bottom of the hot water storage tank to the circulation piping and from the circulation piping to the top of the hot water storage tank, and a control unit that controls the operation of the internal heat source and the circulation pump.

[0003] In the heat source system described above, when the circulation pump is operated, cold water from the bottom of the hot water storage tank may flow into the top of the tank via the circulation piping. In this case, the cold water may mix with the water at the top of the tank, potentially lowering the temperature of the hot water supplied from the top of the tank. This specification provides a technology that can raise the overall temperature of the water in the hot water storage tank while preventing the temperature of the water at the top of the tank from falling below a predetermined temperature.

[0004] The heat source device according to the first aspect disclosed in this specification may include a hot water storage tank, an internal heat source disposed above the bottommost part of the hot water storage tank in the hot water storage tank for heating the water in the hot water storage tank, a first temperature sensor provided in the hot water storage tank for detecting the temperature of the water in the hot water storage tank above the internal heat source, a circulation pipe connected to the lower and upper parts of the hot water storage tank, a circulation pump for sending water from the lower part of the hot water storage tank to the circulation pipe and sending water from the circulation pipe to the upper part of the hot water storage tank, and a control unit for controlling the operations of the internal heat source and the circulation pump. The control unit may be configured to be capable of executing heating control for operating the internal heat source with the circulation pump stopped and circulation control for operating the circulation pump. The control unit may execute switching between the heating control and the circulation control based on the detected temperature of the first temperature sensor.

[0005] According to the above configuration, in the heating control, due to the operation of the internal heat source, the water above the internal heat source is heated and its temperature rises, while the water below the internal heat source is not heated and is maintained at the original temperature. As a result, a temperature stratification is formed inside the hot water storage tank, where a layer of high-temperature water is stacked on top of a layer of low-temperature water. In the circulation control, the low-temperature water at the lower part of the hot water storage tank flows into the upper part of the hot water storage tank via the circulation pipe, and the low-temperature water from the circulation pipe mixes with the high-temperature water layer at the upper part of the hot water storage tank. Therefore, inside the hot water storage tank, the volume of the high-temperature water layer increases and the volume of the low-temperature water layer decreases, and at the same time, the temperature of the high-temperature water layer decreases. Therefore, during the execution of the circulation control, the temperature of the high-temperature water layer will decrease. According to the above configuration, by the control unit executing switching between the heating control and the circulation control based on the detected temperature of the first temperature sensor, it is possible to suppress the temperature of the water at the upper part of the hot water storage tank from falling below a predetermined temperature while raising the temperature of the water inside the hot water storage tank as a whole.

[0006] In the second aspect, in the heat source device according to the first aspect, the control unit may operate the internal heat source in the circulation control while the circulation pump is operating.

[0007] With the above configuration, it is possible to heat the water above the internal heat source while circulation control is in operation. This reduces the time required to raise the overall temperature of the water in the hot water storage tank.

[0008] In a third embodiment, the heat source device according to the first or second embodiment may further include a water supply pipe for supplying water to the hot water storage tank and a hot water supply pipe for supplying hot water from the hot water storage tank. The point where the hot water supply pipe connects to the hot water storage tank may be located above the point where the downstream end of the circulation pipe connects to the hot water storage tank.

[0009] When the heat source unit performs circulation control, even if the temperature of the water in the upper part of the hot water storage tank decreases as the lower-temperature water flows into the upper part of the hot water storage tank, the water above the point where the lower-temperature water flows into the hot water storage tank (i.e., the point where the downstream end of the circulation piping connects to the hot water storage tank) will not decrease in temperature as easily. With the above configuration, since the point where the hot water supply piping connects to the hot water storage tank is located above the point where the downstream end of the circulation piping connects to the hot water storage tank, it is possible to suppress the decrease in the temperature of the hot water supplied from the hot water supply piping.

[0010] In the fourth embodiment, in the heat source device according to any one of the first to third embodiments, the control unit may switch from the heating control to the circulation control when the first temperature sensor detects a temperature of a first switching temperature or higher during the execution of the heating control, or when the temperature detected by the first temperature sensor is lower than the first switching temperature, i.e., when the circulation control is being executed, the control unit may switch from the circulation control to the heating control when the temperature detected by the first temperature sensor is lower than or equal to a second switching temperature.

[0011] With the above configuration, the second switching temperature, which is the threshold temperature for switching from circulation control to heating control, is set lower than the first switching temperature, which is the threshold temperature for switching from heating control to circulation control. Therefore, frequent switching between heating control and circulation control can be suppressed.

[0012] In a fifth embodiment, the heat source device according to any one of the first to fourth embodiments may further include a second temperature sensor for detecting the temperature of the water sent from the hot water storage tank to the circulation piping. The control unit may terminate the heating control or the circulation control if the second temperature sensor detects a temperature above the heating termination temperature while the heating control or the circulation control is being performed.

[0013] With the above configuration, it is possible to heat up the entire volume of hot water in the hot water storage tank.

[0014] In the sixth embodiment, in the heat source device of the fifth embodiment, the second temperature sensor may be provided in the circulation piping and detect the temperature of the water inside the circulation piping.

[0015] With the above configuration, it is possible to more reliably raise the temperature of all the hot water in the storage tank.

[0016] In the seventh embodiment, in the heat source device of the first to sixth embodiments described above, the first temperature sensor may detect the temperature of the water in the hot water storage tank below the point where the downstream end of the circulation piping is connected to the hot water storage tank.

[0017] With the above configuration, when the heat source device performs circulation control, the first temperature sensor detects the temperature of the water in the hot water storage tank below the point where cold water flows into the hot water storage tank (i.e., the point where the downstream end of the circulation piping connects to the hot water storage tank). Therefore, the temperature drop at the top of the hot water storage tank due to the inflow of cold water can be accurately detected by the first temperature sensor.

[0018] In the eighth embodiment, the heat source device of any one of the first to seventh embodiments may further include a third temperature sensor provided in the hot water storage tank for detecting the temperature of the water in the hot water storage tank above the point where the downstream end of the circulation piping connects to the hot water storage tank. The control unit may switch from the circulation control to the heating control when the third temperature sensor detects a temperature below the circulation stop temperature while the circulation control is being executed.

[0019] With the above configuration, even if the water temperature above the point where the downstream end of the circulation piping connects to the hot water storage tank drops, the control switches from circulation to heating, thus preventing the temperature of the hot water supplied from the top of the hot water storage tank from dropping.

[0020] In the ninth embodiment, the heat source device of any one of the first to eight embodiments may further include an external heat source for heating the water flowing through the circulation piping.

[0021] With the above configuration, by operating the circulation pump and the external heat source, the water at the bottom of the hot water storage tank can be heated by the external heat source and returned to the top of the hot water storage tank, thereby heating the water inside the tank.

[0022] In the tenth embodiment, the external heat source in the heat source device of the ninth embodiment may include a heat pump heat source unit.

[0023] According to the above configuration, the energy efficiency when heating water in the hot water storage tank using an external heat source can be improved.

[0024] This is a diagram showing the configuration of the heat source device 2 of the embodiment. This is a flowchart of the processing performed by the controller 52 of the heat source device 2 of the embodiment. This is a diagram schematically showing the temperature distribution of the water in the hot water storage tank 10 when heating control is being performed in the heat source device 2 of the embodiment. This is a diagram schematically showing the temperature distribution of the water in the hot water storage tank 10 when circulation control is being performed in the heat source device 2 of the embodiment. This is a diagram showing the configuration of a modified heat source device 4. This is a diagram showing the configuration of another modified heat source device 6.

[0025] Representative and non-limiting examples of the present disclosure are described below in detail with reference to the drawings. This detailed description is intended simply to show those skilled in the art details for carrying out preferred examples of the teachings and is not intended to limit the scope of the present disclosure. In addition, the disclosed additional features and teachings may be used separately from or in conjunction with other features and teachings to provide further improved heat source devices and methods of using and manufacturing the same.

[0026] Furthermore, the combinations of features and processes disclosed in the following detailed description are not essential for implementing this disclosure in the broadest sense, and are included solely to illustrate typical examples of this disclosure. Moreover, the various features of the following typical examples, as well as the various features of the various independent and dependent claims, do not necessarily have to be combined in the same way as the examples described herein, or in the order listed, to provide additional and useful embodiments of this teaching.

[0027] All features described herein and / or in the claims are intended to be disclosed individually and independently of each other, as limitations to the specific matters described in the original disclosure and in the claims, separate from the features described in the examples and / or in the claims. Furthermore, all descriptions of numerical ranges and groups or clusters are intended to disclose intermediate configurations as limitations to the specific matters described in the original disclosure and in the claims.

[0028] (Example) As shown in Figure 1, the heat source device 2 according to this example comprises a hot water storage tank 10, an internal heat source 20, a first temperature sensor 30, a second temperature sensor 32, circulation piping 40, circulation pump 50, controller 52, hot water supply piping 60, and cold water supply piping 62. The hot water storage tank 10 is a sealed container that stores water inside and is covered on the outside with an insulating material (not shown). The capacity of the hot water storage tank 10 in this example is, for example, 100 liters.

[0029] The internal heat source 20 is installed in the middle section of the inside of the hot water storage tank 10 and is equipped with a heating element 22 that generates heat when electricity is supplied to it. The internal heat source 20 heats the water stored inside the hot water storage tank 10 by generating heat in the heating element 22. The first temperature sensor 30 is installed inside the hot water storage tank 10 above the internal heat source 20 and can detect the temperature of the water in the upper part of the hot water storage tank 10. The second temperature sensor 32 is installed inside the hot water storage tank 10 below the internal heat source 20 and can detect the temperature of the water in the lower part of the hot water storage tank 10.

[0030] The upstream end of the circulation pipe 40 is below the second temperature sensor 32 and connected to the bottom of the hot water storage tank 10. The downstream end of the circulation pipe 40 is above the first temperature sensor 30 and connected to the top of the hot water storage tank 10. The circulation pump 50 is installed in the circulation pipe 40 and pumps water in the circulation pipe 40 from the upstream side to the downstream side. When the circulation pump 50 operates, water flows from the bottom of the hot water storage tank 10 into the circulation pipe 40, and water also flows from the circulation pipe 40 to the top of the hot water storage tank 10.

[0031] The upstream end of the water supply pipe 62 is connected to a water source (not shown), such as a public water supply. The downstream end of the water supply pipe 62 is connected to the bottom of the hot water storage tank 10, below the connection point between the upstream end of the circulation pipe 40 and the hot water storage tank 10. Alternatively, the downstream end of the water supply pipe 62 may be connected to the bottom of the hot water storage tank 10, above or at the same height as the connection point between the upstream end of the circulation pipe 40 and the hot water storage tank 10. The upstream end of the hot water supply pipe 60 is connected to the top of the hot water storage tank 10, above the connection point between the downstream end of the circulation pipe 40 and the hot water storage tank 10. Alternatively, the upstream end of the hot water supply pipe 60 may be connected to the top of the hot water storage tank 10, below or at the same height as the connection point between the downstream end of the circulation pipe 40 and the hot water storage tank 10. The downstream end of the hot water supply pipe 60 is connected to a hot water supply point (not shown), such as a faucet or shower. When the heat source device 2 supplies hot water, high-temperature water is sent from the top of the hot water storage tank 10 to the hot water supply piping 60, and low-temperature water flows from the water supply piping 62 to the bottom of the hot water storage tank 10.

[0032] In this embodiment, the connection point between the upstream end of the circulation pipe 40 and the hot water storage tank 10, and the connection point between the downstream end of the water supply pipe 62 and the hot water storage tank 10, may be located above or below the bottom of the hot water storage tank 10. Also, the connection point between the downstream end of the circulation pipe 40 and the hot water storage tank 10, and the connection point between the upstream end of the hot water supply pipe 60 and the hot water storage tank 10, may be located below or above the top of the hot water storage tank 10.

[0033] The controller 52 includes a CPU, ROM, RAM, etc. The controller 52 controls the operation of the heat source device 2 by executing various processes according to the program stored in the ROM. When power is supplied to the heat source device 2, the controller 52 executes the process shown in Figure 2.

[0034] In S10, the controller 52 waits until the first temperature sensor 30 detects a temperature below a predetermined heating start temperature (for example, 55°C). When the first temperature sensor 30 detects a temperature below the heating start temperature (YES), the process proceeds to S12.

[0035] In S12, the controller 52 starts the operation of the internal heat source 20. As a result, the water in the hot water storage tank 10 is heated by the internal heat source 20. Note that the circulation pump 50 is stopped when the process in S12 is executed. This control, in which the controller 52 operates the internal heat source 20 with the circulation pump 50 stopped, is also called heating control.

[0036] Figure 3 illustrates the temperature distribution of the water inside the hot water storage tank 10 when the controller 52 is performing heating control. During heating control, the heating element 22 of the internal heat source 20 generates heat, causing the water above the internal heat source 20 to heat up and its temperature to rise. On the other hand, the water below the internal heat source 20 is not heated and remains at its original temperature. Through heating control, a temperature stratification is formed inside the hot water storage tank 10, in which a layer of high-temperature water is stacked on top of a layer of low-temperature water.

[0037] As shown in Figure 2, in S14, the controller 52 waits until the first temperature sensor 30 detects a predetermined first switching temperature (for example, 60°C) or higher. When the first temperature sensor 30 detects a temperature of YES or higher, the process proceeds to S16.

[0038] In S16, the controller 52 starts the operation of the circulation pump 50. As a result, water flows from the bottom of the hot water storage tank 10 into the circulation pipe 40, and water flows from the circulation pipe 40 to the top of the hot water storage tank 10. This control by the controller 52 to operate the circulation pump 50 is also called circulation control. In other words, in S16, the controller 52 switches from heating control to circulation control. In this embodiment, since the internal heat source 20 is operating when the process in S16 is executed, in circulation control, the controller 52 operates the internal heat source 20 while the circulation pump 50 is operating.

[0039] Figure 4 illustrates the temperature distribution of water inside the hot water storage tank 10 when the controller 52 is performing circulation control. During circulation control, the cold water at the bottom of the hot water storage tank 10 flows into the top of the tank via the circulation pipe 40, and the cold water from the circulation pipe 40 mixes with the layer of hot water at the top of the tank. As a result, the volume of the layer of hot water increases and the volume of the layer of cold water decreases inside the hot water storage tank 10, and the temperature of the layer of hot water decreases. In this embodiment, the water above the internal heat source 20 is continuously heated by the heat generated by the heating element 22 of the internal heat source 20, but the decrease in water temperature due to the inflow of cold water from the circulation pipe 40 is greater than the increase in water temperature due to heating by the internal heat source 20, so the temperature of the layer of hot water decreases while circulation control is being performed.

[0040] As shown in Figure 2, in S18, the controller 52 determines whether the first temperature sensor 30 detects a temperature below a predetermined second switching temperature (for example, 55°C). If the first temperature sensor 30 detects a temperature above the second switching temperature (NO), the process proceeds to S20.

[0041] In S20, the controller 52 determines whether the second temperature sensor 32 detects a temperature equal to or higher than a predetermined heating completion temperature (e.g., 60°C). If the second temperature sensor 32 detects a temperature below the heating completion temperature (NO), the process returns to S18.

[0042] In S18, when the first temperature sensor 30 detects a temperature below the second switching temperature (YES), the process proceeds to S22. In S22, the controller 52 stops the circulation pump 50. That is, in S22, the controller 52 executes the switching from circulation control to heating control. After S22, the process returns to S14.

[0043] By the processes of S14 - S22, the controller 52 alternately repeats the heating control and the circulation control. When the temperature of the water at the upper part of the hot water storage tank 10 becomes equal to or higher than the first switching temperature (e.g., 60°C) by the heating control, the controller 52 executes the switching from the heating control to the circulation control. Also, when the temperature of the water at the upper part of the hot water storage tank 10 becomes equal to or lower than the second switching temperature (e.g., 55°C) by the circulation control, the controller 52 executes the switching from the circulation control to the heating control. Thereby, while maintaining the temperature of the water at the upper part of the hot water storage tank 10 at or higher than the second switching temperature (e.g., 55°C), the heating of the water inside the hot water storage tank 10 can be continued until the temperature of the entire water in the hot water storage tank 10 becomes equal to or higher than the heating end temperature (e.g., 60°C).

[0044] In S20, when the second temperature sensor 32 detects a temperature equal to or higher than the heating end temperature (YES), the process proceeds to S24. In S24, the controller 52 determines whether the first temperature sensor 30 detects a temperature equal to or higher than the heating end temperature. Usually, a temperature stratification is formed inside the hot water storage tank 10, so the temperature detected by the first temperature sensor 30 should be higher than the temperature detected by the second temperature sensor 32. However, if the temperature stratification of the water inside the hot water storage tank 10 is disturbed for some reason, the temperature detected by the first temperature sensor 30 may be lower than the temperature detected by the second temperature sensor 32. For this reason, in this embodiment, in S24, a confirmation determination using the first temperature sensor 30 is also performed. When the first temperature sensor 30 detects a temperature below the heating end temperature (NO), the process returns to S18. When the first temperature sensor 30 detects a temperature equal to or higher than the heating end temperature (YES), the process proceeds to S26.

[0045] In S26, the controller 52 stops the operation of the circulation pump 50.

[0046] In S28, the controller 52 stops the operation of the internal heat source 20. After S28, the process of FIG. 2 ends.

[0047] (Modification) The heat source device 2 may be provided in the hot water storage tank 10 like the heat source device 4 shown in FIG. 5, and may include a third temperature sensor 34 that detects the temperature of the water in the hot water storage tank 10 above the connection point between the downstream end of the circulation pipe 40 and the hot water storage tank 10. In this case, in S18 of FIG. 2, when the first temperature sensor 30 detects a temperature equal to or lower than a predetermined second switching temperature (for example, 55°C), or when the third temperature sensor 34 detects a temperature equal to or lower than a predetermined circulation stop temperature (for example, 55°C), the process of S22 may be executed, and in other cases, the process of S20 may be executed.

[0048] In the example shown in FIG. 1, the first temperature sensor 30 and the second temperature sensor 32 may be installed inside the hot water storage tank 10 or outside the hot water storage tank 10.

[0049] In the example shown in FIG. 5, the second temperature sensor 32 may be installed inside the circulation pipe 40 or outside the circulation pipe 40. Also, in the example shown in FIG. 5, the third temperature sensor 34 may be installed inside the hot water storage tank 10 or outside the hot water storage tank 10.

[0050] The heat source device 2 may further include an external heat source 70 that heats the water flowing through the circulation pipe 40 like the heat source device 6 shown in FIG. 6. The external heat source 70 may be a heat pump heat source machine, a gas heat source machine, or a solar heat source machine.

[0051] The internal heat source 20 does not have to be configured to generate heat by power supply. For example, the internal heat source 20 may be a heat exchanger through which a high-temperature heat medium flows. In this case, the heat exchanger is arranged to pass through the inside of the hot water storage tank 10 and heats the water inside the hot water storage tank 10 by heat exchange with the high-temperature heat medium.

[0052] The heating start temperature in S10 in Figure 2 may be the same as or different from the second switching temperature in S18. Also, the heating end temperatures in S20 and S24 may be the same as or different from the first switching temperature in S14.

[0053] In step S16 of Figure 2, the controller 52 may start the operation of the circulation pump 50 and stop the operation of the internal heat source 20. In this case, in step S22 of Figure 2, the controller 52 may stop the circulation pump 50 and start the operation of the internal heat source 20. In other words, in circulation control, the controller 52 may operate the circulation pump 50 and stop the internal heat source 20.

[0054] (Relationship) Controller 52 is an example of a control unit.

Claims

1. A heat source device comprising: a hot water storage tank; an internal heat source positioned above the lowest part of the hot water storage tank for heating the water in the tank; a first temperature sensor provided in the hot water storage tank for detecting the temperature of the water in the tank above the internal heat source; circulation piping connected to the lower and upper parts of the hot water storage tank; a circulation pump that sends water from the lower part of the hot water storage tank to the circulation piping and from the circulation piping to the upper part of the hot water storage tank; and a control unit that controls the operation of the internal heat source and the circulation pump, wherein the control unit is configured to perform heating control, which operates the internal heat source while the circulation pump is stopped, and circulation control, which operates the circulation pump, and the control unit switches between the heating control and the circulation control based on the temperature detected by the first temperature sensor.

2. The heat source device according to claim 1, wherein the control unit operates the internal heat source while the circulation pump is operating in the circulation control.

3. The heat source device according to claim 1 or 2, further comprising a water supply pipe for supplying water to the hot water storage tank and a hot water supply pipe for supplying hot water from the hot water storage tank, wherein the location where the hot water supply pipe connects to the hot water storage tank is positioned above the location where the downstream end of the circulation pipe connects to the hot water storage tank.

4. The heat source device according to any one of claims 1 to 3, wherein the control unit switches from the heating control to the circulation control when the first temperature sensor detects a temperature of a first switching temperature or higher during the execution of the heating control, and switches from the circulation control to the heating control when the temperature detected by the first temperature sensor is lower than the first switching temperature, i.e., a second switching temperature or lower.

5. The heat source device according to any one of claims 1 to 4, further comprising a second temperature sensor for detecting the temperature of water sent from the hot water storage tank to the circulation piping, wherein the control unit terminates the heating control or the circulation control when the second temperature sensor detects a temperature above the heating termination temperature during the execution of the heating control or the circulation control.

6. The heat source device according to claim 5, wherein the second temperature sensor is provided in the circulation piping and detects the temperature of the water inside the circulation piping.

7. The heat source device according to any one of claims 1 to 6, wherein the first temperature sensor detects the temperature of the water in the hot water storage tank below the point where the downstream end of the circulation piping is connected to the hot water storage tank.

8. The heat source device according to any one of claims 1 to 7, further comprising a third temperature sensor provided in the hot water storage tank for detecting the temperature of the water in the hot water storage tank above the point where the downstream end of the circulation piping connects to the hot water storage tank, wherein the control unit switches from the circulation control to the heating control when the third temperature sensor detects a temperature below the circulation stop temperature while the circulation control is being executed.

9. The heat source device according to any one of claims 1 to 8, further comprising an external heat source for heating the water flowing through the circulation piping.

10. The heat source device according to claim 9, wherein the external heat source comprises a heat pump heat source unit.

Images