JP5501120B2 - Water heater - Google Patents

Description

  The present invention is a water heater provided with a combustor of liquid fuel or gaseous fuel, which has not only a heat exchanger that recovers sensible heat but also a heat exchanger that recovers latent heat, a sensible heat recovery heat exchanger and latent heat The present invention relates to a water heater provided with a heat exchanger that is indirectly heated inside a heat exchanger for recovery.

  Conventionally, as a water heater equipped with a combustor of liquid fuel or gas fuel and exchanging heat between the combustion gas of the combustor and the water in the heat exchanger to change to hot water, the recovery of latent heat for the purpose of improving the heat exchange rate There were known hot water heaters that could. The hot water heater capable of recovering latent heat has two heat exchangers, a sensible heat recovery heat exchanger and a latent heat recovery heat exchanger, and the combustion gas combusted by the fuel is exchanged with the sensible heat recovery heat exchanger. The heat exchange was performed by contacting the vessel, and the combustion gas after depriving sensible heat was brought into contact with the latent heat recovery heat exchanger to deprive the latent heat. Further, the combustion gas flows through the sensible heat recovery heat exchanger and then the latent heat recovery heat exchanger.

  The latent heat recovery heat exchanger needs to supply water at a temperature as low as possible in order to recover the latent heat. Therefore, tap water of about 5 ° C. to 30 ° C. is first supplied to the latent heat recovery heat exchanger, although it varies depending on the season. And the tap water heated by passing through the latent heat recovery heat exchanger was then supplied to the sensible heat recovery heat exchanger.

  The water heater is provided with a heat exchanger that is indirectly heated inside the heat exchanger for hot water supply. As a so-called dual-structure heat exchanger, the internal heat exchanger is used as a heat source for chasing and heating. There was what was used (refer to FIG. 1 of Patent Document 1). In Patent Document 1, a reheating bath (heating) heat exchanger is provided inside the hot water storage can body by one heating means, and the hot water for the hot water supply in the hot water storage can body is used for the bath ( Heating) Heat exchanger was indirectly heated. This is because there is a low possibility that the reheating or heating on the side to be heated indirectly is always used, and there is often no problem even if the temperature is lower than that of hot water supply.

  Prior to the present application, the present applicant has proposed the one shown in FIG. That is, when a latent heat exchanger is provided in addition to the hot water storage can that is a sensible heat exchanger, it is necessary to consider the latent heat recovery during reheating. Since the sensible heat exchanger has a double structure, the structure of the latent heat exchanger can also be simplified if the latent heat exchanger has a double structure. In this case, a heat exchanger inside the sensible heat exchanger (hereinafter referred to as “sensible heat secondary heat exchanger”) and a heat exchanger inside the latent heat exchanger (hereinafter referred to as “latent heat secondary heat exchange”). Are connected in series, but in the same way as the relationship between the sensible heat exchanger and the latent heat exchanger described above, in order to make it easier to recover the latent heat, the circulating water such as reheating is latent heat. After passing through the secondary heat exchanger, it was necessary to be configured to pass through the sensible heat secondary heat exchanger.

  In the case of a dual-structure heat exchanger, in order for the internal heat exchanger to be indirectly heated, rather than the temperature of the fluid passing through the sensible heat secondary heat exchanger or the latent heat secondary heat exchanger, The temperature of the external fluid that indirectly heats the sensible heat secondary heat exchanger or the latent heat secondary heat exchanger needs to be higher. Conversely, if the temperature of the fluid passing through the sensible heat secondary heat exchanger or latent heat secondary heat exchanger is higher than the temperature of the external fluid, the sensible heat secondary heat exchanger or latent heat secondary heat exchange The temperature of the fluid passing through the vessel is not heated, but conversely, the fluid passing through the sensible heat secondary heat exchanger and the latent heat secondary heat exchanger radiates heat to the external fluid.

  Moreover, since the circulating water which passes a sensible heat secondary heat exchanger or a latent heat secondary heat exchanger is used for reheating or heating, it is connected with a bathtub or a hot water heater by circulation piping. This circulation pipe needs to assume various cases depending on the installation conditions of the hot water heater and the bathtub or hot water heater. Then, in order to respond to various installation conditions of the circulation piping, the water heater installation company prepares the circulation piping, and the extension distance and heat insulation state of the circulation piping will change depending on the construction method constructed by the installation contractor. There was a possibility that heat was radiated from the circulation piping when the extension distance of the piping was long or when the temperature of the circulation piping was poor. Furthermore, since the ambient temperature outside the circulation pipe changes depending on the season, it is necessary to expect that a certain amount of heat is generated from the circulation pipe in the cold season.

JP 2009-210203 A Japanese Patent Application No. 2010-112969

  However, it is provided with a sensible heat exchanger and a latent heat exchanger, and indirectly heated inside the sensible heat secondary heat exchanger and the latent heat exchanger that is indirectly heated inside the sensible heat exchanger. In a water heater provided with a latent heat secondary heat exchanger to be used, the sensible heat exchanger and the latent heat exchanger are used for hot water, and the sensible heat secondary heat exchanger and the latent heat secondary heat exchanger are tracked. It will be used for heating. Since the sensible heat secondary heat exchanger and the latent heat secondary heat exchanger used for reheating and heating are normally used in a circulating manner, the latent heat secondary heat is radiated after being radiated in a bathtub or hot water heater. Although the temperature of the fluid to be heated returning to the heat exchanger is dissipating heat, it is generally higher than the temperature of tap water.

  And in the water heater which has a hot-water supply function, a reheating function, or a heating function, the case where a hot-water supply function and a reheating function are used simultaneously, and the case where a hot-water supply function and a heating function are used simultaneously are also considered. When used at the same time, the water supplied to the latent heat exchanger for hot water supply is tap water, and the temperature of the circulating fluid returned to the latent heat secondary heat exchanger by reheating or heating is higher than that of tap water. In the latent heat secondary heat exchanger, the amount of heat of the circulating fluid is lost to the tap water of the latent heat exchanger or water close to tap water, and the circulating fluid is used in the latent heat secondary heat exchanger. There was a problem that the temperature dropped.

  Of course, when the hot water supply function is used, a method of stopping the reheating function or the heating function only while the hot water supply function is used is also conceivable. A problem arises that the convenience of the user is impaired because the room temperature of the room where the hot water heater is installed is lowered.

  In order to solve the above problems, the following technical means are taken in the present invention.

A water heater according to a first aspect of the present invention includes a latent heat exchanger, a sensible heat exchanger, a combustor that generates combustion gas, and the combustion gas further passes through the sensible heat exchanger and further performs the latent heat exchange. The first heated fluid passes through the latent heat exchanger and enters the sensible heat exchanger, and inside the latent heat exchanger A latent heat secondary heat exchanger that is indirectly heated, a sensible heat secondary heat exchanger that is indirectly heated inside the sensible heat exchanger, and a second fluid to be heated are the latent heat secondary heat. A second heat exchange channel passing through the exchanger and entering the sensible heat secondary heat exchanger, a bypass channel bypassing the latent heat secondary heat exchanger, the bypass channel and the latent heat secondary heat exchange Switching means for switching the flow path of the vessel, and switching control means for judging the switching condition of the switching means.
A water heater according to a second aspect of the present invention is the water heater of the first aspect, wherein the switching control means is provided with a time measuring means, and the judgment of the switching control means is performed in the first heat exchange flow path. When water flow is detected by the water flow detection means, the flow path of the second heated fluid is switched to the bypass flow path side, and water flow is not detected by the water flow detection means. Then, the time is started by the time measuring means, and after a predetermined time has elapsed, the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger side.
A water heater according to a third aspect of the present invention is the water heater of the first aspect, wherein the switching control means determines the sensible heat exchange detected by a sensible heat exchange temperature detector provided in the sensible heat exchanger. The temperature obtained by subtracting the temperature of the first heated fluid in the latent heat exchanger detected by the latent heat exchanger temperature detector provided in the latent heat exchanger from the temperature of the first heated fluid in the vessel When the difference is equal to or higher than the predetermined temperature, the flow path of the second heated fluid is switched to the bypass flow path side. When the difference is lower than the predetermined temperature, the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger. Switching to the side.
According to a fourth aspect of the present invention, there is provided a water heater according to the first aspect of the present invention, wherein the determination of the switching control means is performed by a latent heat heat exchanger detected by a latent heat heat exchanger temperature detector provided in the latent heat exchanger. A temperature difference obtained by subtracting the second heated fluid temperature detected by the latent heat secondary heat exchange temperature detector provided on the inlet side of the latent heat secondary heat exchanger from the temperature of the one heated fluid is a predetermined temperature. If the temperature is less than the predetermined temperature, the flow path of the second heated fluid is switched to the bypass flow path side. If the temperature is equal to or higher than the predetermined temperature, the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger side. ing.

By taking the technical means as described above, the following effects are obtained.
According to the first aspect of the present invention, the bypass flow path for bypassing the latent heat secondary heat exchanger, the switching means for switching the bypass flow path and the flow path of the latent heat secondary heat exchanger, and the switching condition of the switching means are determined. Since the switching control means is provided, there is a condition that the temperature of the second heated fluid of the latent heat secondary heat exchanger is higher than the temperature of the first heated fluid of the latent heat exchanger. Even if it does, it has the effect that the temperature of a 2nd to-be-heated fluid does not fall by switching to a bypass flow path.
According to the second invention, when the water flow detecting means provided in the first heat exchange channel is used and water flow is detected by the water flow detecting means, the second heated object is used. The fluid flow path is switched to the bypass flow path side, and when the water flow detection means no longer detects water flow, the time measuring means starts measuring time, and after a predetermined time has passed, the second heated fluid flow path passes through the latent heat 2 By switching to the secondary heat exchanger side, the temperature of the second heated fluid of the latent heat secondary heat exchanger is likely to be higher than the temperature of the first heated fluid of the latent heat exchanger. It is possible to switch to a bypass flow path for a certain period when hot water is used, and the first invention can be more reliably realized with a simple configuration.
According to the third invention, from the temperature of the first fluid to be heated in the sensible heat exchanger detected by the sensible heat exchanger temperature detector provided in the sensible heat exchanger using the first invention. If the temperature difference obtained by subtracting the temperature of the first heated fluid in the latent heat exchanger detected by the latent heat exchanger temperature detector provided in the latent heat exchanger is equal to or higher than a predetermined temperature, the second heated The flow path of the fluid is switched to the bypass flow path side. When the temperature is lower than the predetermined temperature, the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger side. When the temperature difference of the first heated fluid in the latent heat exchanger is large with reference to the temperature of the heated fluid, it is determined that the first heated fluid supplied into the latent heat exchanger is close to tap water Therefore, the first invention can be realized more reliably with a simple configuration.
According to the fourth invention, the latent heat secondary is obtained from the temperature of the first heated fluid in the latent heat exchanger detected by the latent heat exchanger temperature detector provided in the latent heat exchanger using the first invention. If the temperature difference obtained by subtracting the second heated fluid temperature detected by the latent heat secondary heat exchanger temperature detector provided on the inlet side of the heat exchanger is less than a predetermined temperature, the second heated fluid When the flow path is switched to the bypass flow path side and the temperature is equal to or higher than the predetermined temperature, the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger side, so that the second heated fluid is cooled to the first temperature lower. By not exchanging heat with the heated fluid, the first invention can be realized more reliably.

It is a schematic block diagram of the water heater for demonstrating Example 1 which concerns on this invention. It is a conceptual diagram for demonstrating the hot water supply driving | operation of Example 1. FIG. FIG. 3 is a conceptual diagram for explaining a chasing operation according to the first embodiment. It is a conceptual diagram for demonstrating the case where this invention is not implemented by the case where the hot water supply driving | operation and chasing operation of Example 1 are performed simultaneously. It is a conceptual diagram for demonstrating the case where this invention is performed by the case where the hot water supply driving | operation of Example 1 and a chasing operation are performed simultaneously. It is a schematic block diagram of the water heater for demonstrating Example 2 which concerns on this invention. It is a schematic block diagram of the water heater for demonstrating Example 3 which concerns on this invention. It is a schematic block diagram of the water heater for demonstrating Example 4 which concerns on this invention.

  Embodiments for carrying out the invention will be specifically described with reference to the drawings.

  An outline of the water heater of the present invention will be described with reference to FIG. The water heater 1 burns liquid fuel such as kerosene and heavy oil or gaseous fuel such as LPG and city gas in the combustor 9 and heats the water passed through the heat exchanger using the combustion gas generated by the combustion. To do. In order to improve the heat exchange rate, not only the sensible heat exchanger 20, but also the latent heat heat exchanger 30 that can improve the heat exchange rate by raising the feed water temperature to the upper part of the sensible heat exchanger 20, that is, the exhaust side. have. A sensible heat secondary heat exchanger 25 is provided inside the sensible heat exchanger 20, and a latent heat secondary heat exchanger 35 is provided inside the latent heat heat exchanger 30. The sensible heat exchanger 20 and the latent heat exchanger 30 are used for the hot water supply function, and the sensible heat secondary heat exchanger 25 and the latent heat secondary heat exchanger 35 track the bathtub 7 provided outside the water heater 1. It is used for the tracking function. In the present embodiment, an example in which the sensible heat secondary heat exchanger 25 and the latent heat secondary heat exchanger 35 of the water heater 1 are used for the reheating function will be described.

  The flow path of the 1st to-be-heated fluid which exhibits the hot_water | molten_metal supply function of the water heater 1 is demonstrated. In the water heater 1, tap water, which is the first fluid to be heated, is connected by a water supply pipe 11 and supplied through a pressure reducing valve 12. The depressurized tap water enters from the latent heat exchange inlet 31 at the bottom of the latent heat exchanger 30, passes through the inside of the latent heat exchanger 30, and the latent heat exchange outlet at the top of the latent heat exchanger 30. 32. As a result, the tap water is further deprived of heat from the combustion gas that has been largely deprived of heat by the sensible heat exchanger 20, and the temperature is raised. The latent heat exchange port 32 is an internal pipe 14 and is connected to the sensible heat exchange connection port 21 at the intermediate portion in the height direction of the sensible heat exchanger 20. The tap water heated slightly in the latent heat exchanger 30 enters the sensible heat inlet port 21 through the internal pipe 14, passes through the sensible heat exchanger 20, and passes through the upper part of the sensible heat exchanger 20. Is connected to a hot water tap 6 such as a bathroom by a hot water supply pipe 15. As a result, the tap water slightly heated in the latent heat exchanger 30 is heated to the set desired temperature by the combustion gas in the sensible heat exchanger 20 and used in the hot water tap 6. The water supply pipe 11 and the hot water supply pipe 15 are provided with a relief valve (not shown) for the purpose of protecting the sensible heat exchanger 20 and the latent heat exchanger 30 from excessive pressure.

  In the flow path of the first heated fluid, a water flow detector 13 is provided in the vicinity of the latent heat input port 31 on the water supply pipe 11. The water flow detector 13 detects the flow of water in the water supply pipe 11 and transmits it to the control device 70 by a change in voltage or a pulse. A sensible heat exchange temperature detector 23 is provided above the sensible heat exchanger 20 and in the vicinity of the sensible heat exchange connection port 22 to detect the temperature of the first heated fluid. The temperature detected by the sensible heat exchange temperature detector 23 is transmitted to the control device 70 by voltage.

  The flow path of the 2nd to-be-heated fluid which exhibits the chasing function of the water heater 1 is demonstrated. A bathtub 7 is provided outside the water heater 1, and the bathtub 7 is filled with hot water filled with hot water by the hot water supply function of the water heater 1 as a second heated fluid. A circulation port 8 is attached to the bathtub 7, and a circulation return pipe 17 and a circulation forward pipe 18 are attached to the circulation port 8 in communication with each other. When a circulation pump 19 provided in the middle of the circulation forward pipe 18 is driven, hot water in the bathtub 7 flows from the suction port of the circulation port 8 to the circulation return pipe 17. The circulation return pipe 17 is connected to the latent heat secondary input connection port 36 of the latent heat secondary heat exchanger 35, and is indirectly heated by the latent heat secondary heat exchanger 35 to reach the latent heat secondary output connection port 37. The latent heat secondary outlet port 37 is connected to the sensible heat secondary inlet port 26 of the sensible heat secondary heat exchanger 25 via the secondary heat exchange internal pipe 16, and indirectly through the sensible heat secondary heat exchanger 25. Heated to the sensible heat secondary outlet 27. The circulation outlet pipe 18 is connected to the sensible heat secondary outlet connection port 27 and reaches the discharge side of the circulation port 8. The circulation return pipe 17 and the circulation return pipe 18 have a part provided inside the water heater 1 and a part provided outside the water heater 1, and a part provided outside the water heater 1 It is selected according to the separation distance from the water heater 1. In addition, the circulation return pipe 17 and the circulation forward pipe 18 are kept warm so as to cover the pipe outside the water heater 1, and inside the water heater 1, the inside of the water heater 1 is kept warm as a whole. ing.

  A three-way valve 40 is provided in the vicinity of the latent heat secondary input connection port 36 in the middle of the circulation return pipe 17, and the three-way valve 40 communicates with the bypass flow path 41 in addition to the flow path toward the latent heat secondary input connection port 36. Has been. The bypass passage 41 communicates with the secondary heat exchange internal pipe 16 in the vicinity of the latent heat secondary outlet connection port 37. Thereby, the bypass flow path 41 is provided in parallel with the latent heat secondary heat exchanger 35. By switching the three-way valve 40, the latent heat secondary heat exchanger 35 and the bypass passage 41 can be switched.

  In the flow path of the second heated fluid, in the vicinity of the circulation return pipe 17 before entering the three-way valve 40, in order to detect the temperature of the second heated fluid, the latent heat secondary heat entry temperature detection is performed. A container 38 is provided. The temperature detected by the latent heat secondary heat input temperature detector 38 is transmitted to the control device 70 by voltage.

  Explaining in terms of the flow of combustion gas, the combustion gas generated by the combustion of the combustor 9 is directed upward through a plurality of smoke tubes (simply shown as a single smoke tube) inside the sensible heat exchanger 20. Move. Each of the plurality of smoke pipes is provided with a rectifying plate (not shown) that bends the flow of the combustion gas in order to increase the thermal efficiency of the sensible heat exchanger 20. Thereby, in the sensible heat exchanger 20, the tap water slightly heated in the latent heat exchanger 30 is heat-exchanged to a desired temperature.

  When the combustion gas comes into contact with the latent heat exchanger 30, the latent heat is taken away, and the temperature of the combustion gas further decreases. In this case, since the combustion gas contains water vapor generated by the combustion of the hydrogen component contained in the fuel, condensed water is generated on the surface of the latent heat exchanger 30. The amount of condensed water generated varies depending on the type of fuel, the amount of combustion, the feed water temperature, the humidity of the outside air, etc. and is not constant, but more or less condensed water is generated, and the condensed water contains nitrogen oxides generated by combustion. It becomes a strongly acidic liquid because sulfur oxides dissolve.

  And keeping strong acidic condensate inside the hot water heater 1 causes deterioration of the product, etc., so the strong acid condensate generated in the latent heat exchanger 30 is the latent heat exchanger 30. Is collected by a condensate tray 50 that is a condensate recovery device provided at the lower part of the water, neutralized in a neutralization tank 55, and then discharged to external sewage.

  The water heater 1 is provided with a control device 70 and electrically controls the water heater 1. The control device 70 detects the situation in the water heater 1 obtained from the water flow detector 13, the sensible heat heat temperature detector 23, the latent heat secondary heat input temperature detector 38, and the like by an electrical signal, and combustor 9. Control is performed by supplying power to the circulation pump 19, the three-way valve 40, and the like. The control device 70 includes a processing device of a CPU (central processing unit), and a storage device such as a ROM and a RAM, and electrically processes and controls the various controls.

  The control device 70 is provided with a switching control means 71 for controlling the switching direction of the three-way valve 40 under a predetermined condition. In the switching control means 71, timing is started under a predetermined condition, and at a predetermined time. In this case, it has time measuring means 72 for sending a signal to the switching control means 71. In the water heater 1, the combustor 9, the water flow detector 13, the secondary heat exchange internal piping 16, the circulation pump 19, the sensible heat exchanger 20, the sensible heat secondary heat exchanger 25, the latent heat exchanger 30, The latent heat secondary heat exchanger 35, the latent heat secondary heat input temperature detector 38, the three-way valve 40, the bypass passage 41, the condensate tray 50, the neutralization tank 55, the control device 70 and the like can be housed in one housing. It is in the state.

(During hot water operation)
An example of the heating situation of the water heater 1 during the hot water supply operation will be described with reference to FIG. When the combustor 9 is driven by the control device 70, the combustor 9 generates combustion gas. The combustion gas first heats the sensible heat exchanger 20, and the latent heat heat exchanger 30 is heated by the combustion gas from which most of the sensible heat after heating the sensible heat exchanger 20 is deprived. Therefore, the temperature of the combustion gas in FIG. 2 decreases from the right to the left. The controller 70 measures the temperature measured by the sensible heat exchanger temperature detector 23 and the temperature set by a hot water supply temperature setting unit (not shown) of a remote control device provided outside the hot water heater 1 (assuming that the temperature is 70 ° C.). To control the combustor 9.

  The heated sensible heat exchanger 20 and the latent heat exchanger 30 are applied with tap water pressure reduced by the pressure reducing valve 12, and tap water is supplied when the hot water tap 6 is opened. The temperature of the tap water varies depending on the season, but if tap water of 15 ° C. is supplied from the water supply pipe, in the vicinity of the latent heat exchange port 32 after being heated by the latent heat exchanger 30, The temperature is about 30 ° C., which is supplied to the sensible heat exchange 20, reaches about 70 ° C. equal to the set temperature in the vicinity of the sensible heat heat exchange connection port 22, and is supplied to the outside from the hot water tap 6.

(During driving)
An example of the heating state of the water heater 1 during the chasing operation will be described with reference to FIG. In this case, the hot water supply operation is not performed. Further, the state of the combustion gas is almost the same as that in the hot water supply operation, and thus the description thereof is omitted. At the time of chasing, if the control device 70 is operated to perform chasing operation with a remote control device, the temperature detected by the sensible heat exchange temperature detector 23 reaches the maximum temperature (assuming 70 ° C.). Thus, the combustor 9 is controlled. This is because it is advantageous to make the hot water supply side set temperature higher because it is indirectly heated by the sensible heat secondary heat exchanger 25 and the latent heat secondary heat exchanger 35 during reheating.

  When the circulation pump 19 is driven by the control device 70 in a state where the sensible heat exchanger 20 and the latent heat exchanger 30 are heated, the hot water (temporarily 35 ° C.) in the bathtub 7 starts to circulate. The hot water in the bathtub 7 flows into the circulation return pipe 17 from the suction side 8a of the circulation port 8 (the circulation port 8 is divided for the sake of clarity) and enters the latent heat secondary heat exchanger 35. The first heated fluid of the latent heat exchanger 30 remains stationary, but becomes constant because the temperature of the combustion gas is low after the first heated fluid rises to about 38 ° C., and the second heated The fluid is slightly heat-exchanged and reaches a temperature slightly higher than 35 ° C. near the latent heat secondary outlet 32. The first heated fluid of the sensible heat exchanger 20 remains stationary and becomes constant after rising to about 70 ° C., whereby the sensible heat secondary heat exchanger 25 is indirectly heated and the sensible heat 2 In the vicinity of the next connection port 27, the temperature rises to about 50 ° C. and returns to the bathtub 7 via the circulation forward pipe 18 and the discharge side 8 b of the circulation port 8. Since the bathtub 7 stores about 200 liters of hot water, even if the hot water heated to 50 ° C. returns, the hot water in the bathtub 7 rises slightly as a whole. By repeating this, the hot water in the bathtub 7 rises. When the reheating temperature is set to 42 ° C. by the reheating temperature setting unit (not shown) of the remote control device, the temperature circulating in the bathtub 7 by the latent heat secondary heat input temperature detector 38 When the temperature reaches the set temperature, the control device 70 stops the chasing operation.

(When hot water operation and chasing operation are performed simultaneously)
An example of the heating situation of the water heater 1 when the present invention is not carried out when the hot water supply operation and the chasing operation are performed simultaneously will be described with reference to FIG. When the hot water supply operation and the chasing operation are performed at the same time, the latent heat exchanger 30 is continuously supplied with tap water as the first heated fluid. Therefore, in this state, the hot water in the bathtub 7 that is the second heated fluid is 35 ° C., and the tap water that is the first heated fluid is 15 ° C. By passing through the heat exchanger 35, it is cooled, and even if it passes through the sensible heat secondary heat exchanger 25, it becomes 38 ° C., which is slightly higher than the temperature 35 ° C. of the original hot water in the bathtub 7. Thereby, although the warm water of the bathtub 7 rises slowly, since it is a little high temperature, it will take a long time until it will be 42 degreeC which is suitable temperature. When the extension distance between the circulation return pipe 17 and the circulation forward pipe 18 is long, the heat insulation performance of the heat insulating material of the circulation return pipe 17 and the circulation forward pipe 18 is poor, and the outside air temperature of the circulation return pipe 17 and the circulation forward pipe 18 is low. When the temperature is low in the cold season, a large heat dissipation loss occurs from the circulation return pipe 17 and the circulation forward pipe 18, and the temperature of the original hot water in the bathtub 7 may be 35 ° C. or less.

  An example of the heating situation of the water heater 1 in which the present invention is implemented when the hot water supply operation and the chasing operation are performed simultaneously will be described with reference to FIG. When the hot water supply operation and the reheating operation are performed simultaneously, the water flow detector 13 detects the flow of water, and when the switching control means 71 determines that the tap water has been supplied to the latent heat exchanger 30, the three-way valve 40 Is switched from a flow path that connects the circulation return pipe 17 and the latent heat secondary heat exchanger 35 to a flow path that connects the circulation return pipe 17 and the bypass flow path 41. Thus, the hot water in the bathtub 7 enters the sensible heat secondary heat exchanger 25 and rises to about 50 ° C. in the vicinity of the sensible heat secondary outlet 27 to follow the hot water in the bathtub 7.

  When the hot water supply operation is stopped as a result of closing of the hot water tap 6 during reheating, the water flow detector 13 detects that the flow of water has disappeared, and the switching control means 71 determines that the hot water supply operation has been stopped. Then, from the determined time, the time measuring means 72 of the switching control means 71 starts to measure a predetermined time. When the counting of the predetermined time by the time measuring means 72 is completed, the switching control means 71 starts the flow path circulation return pipe 17 and the latent heat 2 from the flow path connecting the circulation return pipe 17 and the bypass flow path 41 through the flow path of the three-way valve 40. It switches to the flow path which connects the next heat exchanger 35. The reason for not switching at the same time as the hot water supply operation is completed is to consider the time when the tap water, which is the first heated fluid in the latent heat exchanger 30, rises, and the capacity of the latent heat exchanger 30 and the combustor 9 Varies depending on the amount of combustion per hour. When the time for waiting for the switching of the three-way valve 40 is short or when the temperature of the hot water in the bathtub 7 decreases for a short time, the water flow detector 13 detects that the water flow has ceased. At the same time, the three-way valve 40 may be switched.

  A second embodiment will be described with reference to FIG. In the hot water heater 2, the determination of the switching control means 71 a of the three-way valve 40 when the hot water supply operation and the reheating operation are performed at the same time is performed by the detection of the sensible heat exchanger temperature detector 23 and the latent heat exchanger temperature detector 33. The difference from the first embodiment is that the water flow detector 13 is not provided, and the latent heat exchanger 30 is provided with a latent heat exchange temperature detector 33. The temperature detected by the latent heat heat exchanger temperature detector 33 is transmitted to the control device 70a by voltage. Since other configurations are the same as those of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  When the hot water supply operation and the reheating operation are performed at the same time, the switching control means 71a has a temperature difference obtained by subtracting the temperature detected by the latent heat heat exchanger temperature detector 33 from the temperature detected by the sensible heat heat exchanger temperature detector 23. When it becomes above, it is judged that the hot water supply operation is started and the tap water is supplied to the latent heat exchanger 30. The predetermined temperature can be determined by the temperature of the first fluid to be heated in the latent heat exchanger 30 being lowered when the hot water supply operation is started and the tap water is supplied. The temperature is determined by the mounting position of the heat exchanger 30 and the thermal efficiency of the latent heat exchanger 30 and can be determined to be that tap water has been supplied to the latent heat exchanger 30. If it is determined that the hot water is supplied by the switching control means 71a, the circulation return pipe 17 and the bypass flow path 41 are connected to the flow path of the three-way valve 40 from the flow path that connects the circulation return pipe 17 and the latent heat secondary heat exchanger 35. Switch to a flow path that allows communication. Thus, the hot water in the bathtub 7 enters the sensible heat secondary heat exchanger 25 and rises to about 50 ° C. in the vicinity of the sensible heat secondary outlet 27 to follow the hot water in the bathtub 7.

  When the hot water supply operation is stopped as a result of closing of the hot water tap 6 during reheating, the temperature of the first heated fluid of the latent heat exchanger 30 detected by the latent heat exchange temperature detector 33 is changed to the tap water. If the temperature difference from the temperature detected by the sensible heat exchanger temperature detector 23 becomes less than a predetermined temperature, the switching control means 71a determines that the hot water supply operation has been stopped. Then, the flow path of the three-way valve 40 is switched from the flow path connecting the circulation return pipe 17 and the bypass flow path 41 to the flow path connecting the circulation return pipe 17 and the latent heat secondary heat exchanger 35.

  A third embodiment will be described with reference to FIG. In the water heater 3, the determination of the switching control means 71 b of the three-way valve 40 when the hot water supply operation and the reheating operation are performed at the same time is performed by detection of the latent heat heat exchange temperature detector 33 and the latent heat secondary heat input temperature detector 38. What is different from the first embodiment is that the water flow detector 13 is not provided, and the latent heat exchanger 30 is provided with a latent heat exchange temperature detector 33. The temperature detected by the latent heat exchange temperature detector 33 is transmitted to the control device 70b by voltage. Since other configurations are the same as those of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the case where the hot water supply operation and the reheating operation are performed simultaneously, the switching control means 71b has a temperature difference obtained by subtracting the temperature detected by the latent heat secondary heat input temperature detector 38 from the temperature detected by the latent heat heat exchange temperature detector 33. When the temperature is lower than the predetermined temperature, the hot water supply operation is started, and it is determined that the latent heat secondary heat exchanger 35 cannot be heated by supplying tap water to the latent heat exchanger 30. The predetermined temperature is the first temperature if the second heated fluid in the latent heat secondary heat exchanger 35 is at a lower temperature than the first heated fluid outside the latent heat secondary heat exchanger 35. The temperature is determined by enabling heat transfer from the heated fluid to the second heated fluid. When the switching control means 71b determines that the hot water supply has been performed, the flow path connecting the circulation return pipe 17 and the latent heat secondary heat exchanger 35 through the flow path of the three-way valve 40 is defined as the circulation return pipe 17 and the bypass flow path 41. Switch to a flow path that allows communication. As a result, the hot water in the bathtub 7 directly enters the sensible heat secondary heat exchanger 25, and rises to about 50 ° C. near the sensible heat secondary outlet 27 so that the hot water in the bathtub 7 can be tracked.

  When the hot water supply operation is stopped as a result of closing of the hot water tap 6 during reheating, the temperature of the first heated fluid of the latent heat exchanger 30 detected by the latent heat exchange temperature detector 33 is supplied by the tap water. If the temperature difference from the temperature detected by the latent heat secondary heat input temperature detector 38 exceeds a predetermined temperature, the switching control means 71b changes the first heated fluid from the first heated fluid. It is determined that heat transfer to the second fluid to be heated is possible, and the circulation return pipe 17 and the latent heat secondary heat are passed from the flow path connecting the circulation return pipe 17 and the bypass flow path 41 through the flow path of the three-way valve 40 The flow path is switched to communicate with the exchanger 35.

  A fourth embodiment will be described with reference to FIG. The water heater 4 is an embodiment in which the three-way valve 40 of the first embodiment is replaced with a two-way valve 42, and the other components are the same as those of the first embodiment. Are given the same reference numerals and their description is omitted.

  The two-way valve 42 is provided in the middle of the bypass flow path 41 so that the bypass flow path 41 can be opened and closed. A bypass passage 41 that branches the circulation return pipe 17 communicates with the place where the three-way valve 40 of the first embodiment is provided.

  When the hot water supply operation and the reheating operation are simultaneously performed in the water heater 4, the water flow detector 13 detects the flow of water and the switching control means 71c determines that the tap water has been supplied to the latent heat exchanger 30. The two-way valve 42 is opened. When the two-way valve 42 is in the closed state, the bypass passage 41 is blocked and the second heated fluid flows in the direction of the latent heat secondary heat exchanger 35, but the two-way valve 42 is in the open state. Then, the latent heat secondary heat exchanger 35 is bent in order to increase the heat exchange rate of the latent heat secondary heat exchanger 35 and has a long passage distance. Since it is larger than 41, the second heated fluid hardly flows to the latent heat secondary heat exchanger 35, and the flow path can be switched. As a result, the hot water in the bathtub 7 enters the sensible heat secondary heat exchanger 25 via the bypass channel 41 and rises to about 50 ° C. in the vicinity of the sensible heat secondary outlet 27 to follow the hot water in the bathtub 7. I will whisper.

  When the hot water supply operation is stopped as a result of closing of the hot water tap 6 during reheating, the water flow detector 13 detects that the flow of water has disappeared, and the switching control means 71c determines that the hot water supply operation has been stopped. Then, from the determined time, the time measuring means 72 of the switching control means 71c starts measuring a predetermined time. When the timing of the predetermined time of the time measuring means 72 is finished, the two-way valve 42 is moved to the closed state by the switching control means 71c to shut off the bypass passage 41, and the second heated fluid is transferred to the latent heat secondary heat exchanger 35. Flow in the direction. The reason why the two-way valve 42 is not moved to the closed state at the same time as the hot water supply operation is finished is to consider the time during which the temperature of the tap water that is the first heated fluid in the latent heat exchanger 30 rises, It varies depending on the capacity of the latent heat exchange 30 and the amount of combustion per hour of the combustor 9. In addition, when the time which waits to move the two-way valve 42 to a closed state is short, or when the time when the temperature of the hot water of the bathtub 7 falls is short, the water flow detector 13 loses the flow of water. At the same time, the two-way valve 42 may be moved to the closed state.

  Although the example in which the three-way valve 40 is changed to the two-way valve 42 has been described based on the first embodiment, the three-way valve 40 is similarly changed to the two-way valve 42 in the second or third embodiment. It is possible to implement.

1, 2, 3, 4: Hot water heater 6: Hot water tap 7: Bathtub 8: Circulation port 9: Combustor 11: Water supply pipe 12: Pressure reducing valve 13: Water flow detector 14: Internal pipe 15: Hot water supply pipe 16: Secondary Heat exchange internal pipe 17: Circulation return pipe 18: Circulation return pipe 19: Circulation pump 20: Sensible heat exchanger 21: Sensible heat heat inlet port 22: Sensible heat heat outlet port 23: Sensible heat heat exchanger temperature Detector 25: Sensible heat secondary heat exchanger 26: Sensible heat secondary inlet 27: Sensible heat secondary outlet 30: Latent heat exchanger 31: Latent heat inlet 32: Latent heat outlet connection Port 33: Latent heat heat exchange temperature detector 35: Latent heat secondary heat exchanger 36: Latent heat secondary input connection port 37: Latent heat secondary output connection port 38: Latent heat secondary heat input temperature detector 40: Three-way valve 41: Bypass channel 42: Two-way valve 50: Condensate tray 55: Neutralization tank 70, 70a, 70b, 70c: Control devices 71, 71a, 71 , 71c: switching control means 72: timer means

Claims (4)

  A latent heat exchanger, a sensible heat exchanger, a combustor that generates combustion gas, and the combustion gas passes through the sensible heat exchanger and further passes through the latent heat exchanger. And a first heat exchange fluid that passes through the latent heat exchanger and enters the sensible heat exchanger, and latent heat 2 that is indirectly heated inside the latent heat exchanger. A secondary heat exchanger, a sensible heat secondary heat exchanger heated indirectly inside the sensible heat exchanger, and a second heated fluid passing through the latent heat secondary heat exchanger, and the sensible heat A second heat exchange channel entering the secondary heat exchanger, a bypass channel bypassing the latent heat secondary heat exchanger, and a switching means for switching between the bypass channel and the channel of the latent heat secondary heat exchanger And a water heater provided with switching control means for determining switching conditions of the switching means.   The switching control means is provided with a timing means, and the switching control means uses the water flow detection means provided in the first heat exchange flow path to detect water flow with the water flow detection means. In such a case, the flow path of the second heated fluid is switched to the bypass flow path side, and when the water flow detecting means stops detecting water flow, the time measuring means starts measuring time, and after a predetermined time has passed, The hot water heater according to claim 1, wherein the flow path of the second fluid to be heated is switched to the latent heat secondary heat exchanger side.   The determination of the switching control means is the latent heat exchange from the temperature of the first heated fluid in the sensible heat exchanger detected by a sensible heat exchange temperature detector provided in the sensible heat exchanger. When the temperature difference obtained by subtracting the temperature of the first heated fluid in the latent heat exchanger detected by the latent heat exchange temperature detector provided in the chamber is equal to or higher than a predetermined temperature, the second heated fluid The hot water heater according to claim 1, wherein the flow path is switched to the bypass flow path side, and the flow path of the second heated fluid is switched to the latent heat secondary heat exchanger side when the temperature is lower than a predetermined temperature. The determination of the switching control means is based on the temperature of the first heated fluid in the latent heat exchanger detected by the latent heat exchange temperature detector provided in the latent heat exchanger. When the temperature difference obtained by subtracting the second heated fluid temperature detected by the latent heat secondary heat exchanger temperature detector provided on the inlet side is less than a predetermined temperature, the flow path of the second heated fluid is The hot water heater according to claim 1, wherein the flow path of the second fluid to be heated is switched to the latent heat secondary heat exchanger side when switching to the bypass flow path side and above a predetermined temperature.

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