JP2015117884A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater capable of uniformly, sufficiently heating or cooling a high-temperature side surface and a low-temperature side surface of a thermoelectric module, and attaining high generation efficiency.SOLUTION: A water heater includes a heat exchanger 11 transferring heat to feedwater W by combustion gas G via a power generation unit 3 including a thermoelectric module 2. The power generation unit 3 includes a feedwater channel member 4 that contacts a low-temperature side surface of the thermoelectric module 2 and that has an opposite surface to the thermoelectric module 2 in which the feedwater W flows; and a combustion gas passage member 6 that contacts a high-temperature side surface of the thermoelectric module 2 and that has an opposite surface to the thermoelectric module 2 in which a combustion gas passage path 7 through which the combustion gas G passes is formed. The high-temperature side surface of the thermoelectric module 2 and the combustion gas passage path 7 are formed along a flow direction of the combustion gas G, and a plurality of heat receiving fins formed upright into a comb shape from the thermoelectric module 2-side toward the combustion gas passage path 7 is provided in the combustion gas passage member 6 with an attitude along the flow direction of the combustion gas G.

Description

  The present invention relates to a power generation unit including a thermoelectric module using a combustion gas generated by burning fuel as a high-temperature source and a water supply as a low-temperature source, and heat exchange for transferring heat from the combustion gas passing through the power generation unit to the water supply The present invention relates to a water heating device provided with a vessel.

As a conventional water heating device, Patent Document 1 below includes a thermoelectric module that uses combustion gas as a high-temperature source and water supply as a low-temperature source in a casing in which combustion gas generated by burning fuel with a burner flows. There is disclosed a water heating device including a power generation unit and a heat exchanger for transferring heat to combustion water from combustion gas that has passed through the power generation unit.
In this housing | casing, the pipe member through which water supply flows is provided, and the heat exchanger and the thermoelectric module are provided in the outer periphery of the pipe member. In the pipe member, a heat exchanger is provided on the upstream side of the flow of feed water from the thermoelectric module, and relatively high temperature feed water after being heated by heat exchange with the combustion gas in the heat exchanger is supplied to the thermoelectric module. It is comprised so that.
This thermoelectric module is formed in a hollow cylindrical shape along the axial direction of the tube member with the tube member as the center, and its outer peripheral surface is a high temperature side surface heated by the combustion gas flowing in the housing, and its inner peripheral surface is the tube As a low temperature side surface cooled by the feed water flowing through the member, power is generated by a temperature difference between the high temperature side surface and the low temperature side surface.

Japanese Patent No. 4908777

  In the conventional water heating apparatus disclosed in Patent Document 1, since the thermoelectric module is arranged with its axial direction perpendicular to the flow direction of the combustion gas, it is upstream of the flow direction of the combustion gas. The heat transfer coefficient is relatively high at the outer peripheral surface portion, but the heat transfer coefficient is extremely low at the outer peripheral surface portion on the downstream side. For this reason, it has been difficult to uniformly increase the temperature of the outer peripheral surface as the high temperature side surface of the thermoelectric module. Furthermore, since the thermoelectric module is formed in a hollow cylindrical shape, the area of the inner peripheral surface is smaller than the area of the outer peripheral surface. For this reason, it has been difficult to sufficiently reduce the temperature of the inner peripheral surface which is the low temperature side surface. For these reasons, the conventional water heating apparatus disclosed in Patent Document 1 has a problem that the temperature difference between the outer peripheral surface and the inner peripheral surface of the thermoelectric module is reduced, and the power generation efficiency of the thermoelectric module is reduced.

  The present invention has been made paying attention to such a point, and its purpose is to sufficiently expand the temperature difference between the high temperature side surface and the low temperature side surface of the thermoelectric module and obtain a high power generation efficiency. Is to provide.

The water heating apparatus according to the present invention for achieving this object is as follows:
A power generation unit including a thermoelectric module using a combustion gas generated by burning fuel as a high-temperature source and a water supply as a low-temperature source, and a heat exchanger for transferring heat from the combustion gas passing through the power generation unit to the water supply Water heater, and its characteristic configuration is
A water supply channel member that forms a water supply channel through which the water supply flows on a surface opposite to the thermoelectric module and that contacts the low temperature side surface of the thermoelectric module, and a high temperature side surface of the thermoelectric module. And a combustion gas passage member that forms a combustion gas passage through which the combustion gas passes on a surface opposite to the thermoelectric module;
Forming the hot side of the thermoelectric module and the combustion gas passage along the flow direction of the combustion gas generated from a burner;
The combustion gas passage member is provided with a plurality of heat receiving fins standing in a comb shape from the thermoelectric module side toward the combustion gas passage in a posture along the flow direction of the combustion gas. .

According to the characteristic configuration of the water heating device, by providing the water supply flow path member, the low-temperature side surface of the thermoelectric module can be uniformly and sufficiently cooled with relatively low-temperature water supply to lower the temperature.
On the other hand, by providing the combustion gas passage member, the high temperature side surface of the thermoelectric module can be uniformly heated by the combustion gas and the temperature can be raised. A combustion gas passage formed in the combustion gas passage member is formed along the flow direction of the combustion gas, and a plurality of heat receiving fins are erected in a comb-tooth shape along the flow direction of the combustion gas. Therefore, it is possible to pass between the heat receiving fins without hindering the flow of the combustion gas. Therefore, the heat of the combustion gas can be recovered satisfactorily by the heat receiving fin while suppressing an increase in the pressure loss of the combustion gas. And since the high temperature side surface of the thermoelectric module is also formed along the flow direction of the combustion gas, the heat recovered from the combustion gas can uniformly and sufficiently heat the high temperature side surface of the thermoelectric module to increase its temperature. .
Therefore, the temperature difference between the high temperature side surface and the low temperature side surface of the thermoelectric module can be sufficiently expanded to obtain high power generation efficiency.

A further characteristic configuration of the water heating device according to the present invention is as follows:
The water supply channel member is formed in a flat shape along the flow direction of the combustion gas, and a pair of the thermoelectric modules and a pair of combustion gas passage members are provided on both sides of the water supply channel member. It is in.

  According to the characteristic configuration of the water heating device, since the feed water flow path member is formed in a flat shape along the flow direction of the combustion gas, the flow of the combustion gas is hindered from increasing the pressure loss. be able to. Furthermore, since a pair of thermoelectric modules are provided on both outer sides of the water supply flow path member, and further, a pair of combustion gas passage members are provided on both outer sides of the pair of thermoelectric modules, the cooling side surfaces of the pair of thermoelectric modules and It is possible to expand the power generation output by making the high temperature side as wide as possible and cooling or heating the wide cooling side and the high temperature side well.

A further characteristic configuration of the water heating device according to the present invention is as follows:
The burner is provided with a plurality of flame holes in the transverse direction of the combustion gas flow path, and a partial output operation in which a flame is formed only in a central flame hole located in a central portion in the transverse direction of the plurality of flame holes. Configured to run,
The power generation unit is located above the central portion.

  According to the characteristic configuration of the water heating device, in the partial output operation, a flame is formed only in the central flame hole of the central portion in the transverse direction of the combustion gas flow path, and the combustion gas of the burner rises in the central portion. Thus, the power generation unit arranged in the upper central portion is reached. The combustion gas that has moved up the central portion and reached the power generation unit is evenly distributed to the pair of combustion gas passage members disposed on both outer sides of the water flow path member, and the pair of combustion gas passage members. It flows into the combustion gas passage formed in each. Therefore, the combustion gas passing through each combustion gas passage way passes well along the high temperature side surface of the thermoelectric module on the inside, so that the high temperature side surface of the thermoelectric module is more uniformly and sufficiently heated. Can do.

A further characteristic configuration of the water heating device according to the present invention is as follows:
The combustion gas passage member has an outer wall on the outer side of the combustion gas passage, and a gap is formed between the front end side of the heat receiving fin and the outer wall.

  According to the characteristic configuration of the water heating device, the combustion gas passing between the heat receiving fins of the combustion gas passageway flows out of the combustion gas passageway by the outer wall provided outside the combustion gas passageway. Can be prevented. In addition, since a gap is formed between the front end side of the heat receiving fin and the outer wall, the heat recovered by the heat receiving fin is outside by the gap formed between the front end side of the heat receiving fin and the outer wall. It is possible to prevent the heat from being transferred to the wall and dissipated, and the high temperature side surface of the thermoelectric module can be sufficiently heated by the heat recovered by the heat receiving fins.

A further characteristic configuration of the water heating device according to the present invention is as follows:
The power generation unit is provided with a plurality of connection bolts that are distributed around the thermoelectric module and fasten the water supply flow path member and the combustion gas passage member.

  According to the characteristic configuration of the water heating device, since the plurality of connecting bolts that fasten the water supply flow path member and the combustion gas passage member are distributed around the thermoelectric module, the thermoelectric module that is sandwiched by these members. The high temperature side surface and the low temperature side surface can be uniformly adhered to the feed water flow path member and the combustion gas passage member. Thereby, the high temperature side surface and low temperature side surface of the thermoelectric module can be heated and cooled more uniformly.

A further characteristic configuration of the water heating device according to the present invention is as follows:
On the cooling side wall of the water supply flow path member and the heating side wall of the combustion gas passage member, an accommodation recess for accommodating the thermoelectric module is formed,
A gap is formed between the inner peripheral side surface of the housing recess and the thermoelectric module.

  According to the characteristic configuration of the water heating device, the thermoelectric module is housed in the respective housing recesses formed in the cooling side wall of the feed water flow path member and the heating side wall of the combustion gas passage member, so that the thermoelectric module is converted into combustion gas. Direct contact can be prevented. Thereby, the temperature rise of the low temperature side surface of a thermoelectric module can be suppressed. Furthermore, by forming a gap between the inner peripheral side surface of the housing recess and the thermoelectric module, the inner peripheral surface of the housing recess of the water supply flow path member and the combustion gas passage member is prevented from coming into contact with the thermoelectric module. The temperature decrease on the high temperature side of the module and the temperature increase on the low temperature side can be suppressed. As a result, a decrease in power generation efficiency due to a reduction in temperature difference between the high temperature side surface and the low temperature side surface of the thermoelectric module can be suppressed.

A further characteristic configuration of the water heating device according to the present invention is as follows:
The area of the heat receiving surface of the heat receiving fin is that the area gradually increases from the upstream side to the downstream side in the flow direction of the combustion gas.

  According to the characteristic configuration of the water heating device, a decrease in the amount of heat received due to a decrease in the temperature of the combustion gas on the downstream side in the flow direction of the combustion gas can be compensated by increasing the area of the heat receiving surface of the heat receiving fin. The hot side of the module can be heated more uniformly in the direction of combustion gas flow.

A further characteristic configuration of the water heating device according to the present invention is as follows:
As the thermoelectric module, a high temperature thermoelectric module and a low temperature thermoelectric module having a lower operating temperature than the high temperature thermoelectric module are provided,
In the power generation unit, the high-temperature thermoelectric module and the low-temperature thermoelectric module are arranged side by side in order from the upstream side along the flow direction of the combustion gas.

  According to the characteristic configuration of the water heating device, in the power generation unit, the operating temperature of the high temperature side surface is increased upstream in the flow direction of the combustion gas in response to the temperature of the combustion gas decreasing from the upstream side toward the downstream side. Since a relatively high temperature thermoelectric module is provided and a low temperature thermoelectric module having a lower operating temperature than the high temperature thermoelectric module is provided on the downstream side, a plurality of thermoelectrics are generated by the combustion gas whose temperature decreases from the upstream side to the downstream side. Higher power generation efficiency can be obtained using the module.

Schematic configuration diagram of a water heating apparatus according to the present invention Schematic configuration diagram of a thermoelectric module according to the present invention The disassembled perspective view of the electric power generation unit which concerns on this invention Side view of power generation unit according to the present invention Cross-sectional view of a power generation unit according to the present invention The longitudinal cross-sectional view of the water supply flow path member which concerns on this invention

Hereinafter, an embodiment of a water heating device according to the present invention will be described based on the drawings.
The water heating apparatus 1 shown in FIG. 1 includes a burner 8 that generates a combustion gas G by burning a gas fuel F (an example of fuel, for example, a natural gas city gas 13A) at a lower end of a housing 10. The combustion gas G generated by the burner 8 flows upward through the combustion gas passage 40 formed in the housing 10.
The combustion gas flow path 40 is supplied to the feed water W from the power generation unit 3 including the thermoelectric module 2 using the combustion gas G as a high temperature source and the feed water W as a low temperature source, and the combustion gas G passing through the power generation unit 3. Heating heat exchangers 11 are sequentially arranged from the burner 8 side upward.

  A discharge port 9 for discharging the combustion gas G to the outside is provided in the upper part of the housing 10. Therefore, the combustion gas G generated in the burner 8 flows through the combustion gas passage 40, passes through the power generation unit 3 and the heat exchanger 11, and is discharged from the discharge port 9 to the outside of the housing 10. Further, the power generation unit 3 is disposed in the central portion in the transverse direction of the combustion gas flow path 40, and a part of the combustion gas flowing through the central portion of the combustion gas G flowing through the combustion gas flow path 40. G passes through the combustion gas passage 7 formed in the power generation unit 3, and the remaining combustion gas G passing through the outside passes through the outer passage 40 a formed outside the power generation unit 3.

The water supply W is relatively low-temperature water supplied from the outside, and is, for example, room temperature tap water. The water supply channel 5 through which this water supply W circulates includes a water supply channel 5 a of the power generation unit 3 and a water supply channel 5 b of the heat exchanger 11. Then, the water supply W supplied from the outside passes through the water supply passage 5 a of the power generation unit 3 arranged on the upstream side in the water supply passage 5, and then the heat exchanger 11 arranged on the downstream side in the water supply passage 5. By passing through the water supply flow path 5b, the heated water supply W is heated by heat exchange with the combustion gas G, and the heated water supply W is supplied to a hot water supply section connected to the downstream side of the water supply flow path 5 and used. .
The heat exchanger 11 is arranged in a state where a plurality of heat transfer tubes in which the water supply flow path 5b is formed are folded back, and a plurality of fins 11a are arranged on the surface of the heat transfer tubes along the flow of the combustion gas G. It is comprised as what is called a fin tube type heat exchanger.

The burner 8 is supplied with gas fuel F from a gas plug or the like via a gas fuel supply path 12 and supplied with combustion air A from a sirocco fan 14 via an air supply path 13.
The burner 8 is configured by sequentially arranging three burner portions of a first burner portion 8 a, a second burner portion 8 b, and a third burner portion 8 c along the transverse direction of the combustion gas flow path 40. That is, in the transverse direction of the combustion gas flow path 40, the second burner portion 3b is disposed at the center portion, and the first burner portion 8a and the third burner portion 8c are disposed on both sides thereof. And the gas fuel F supplied via the gas fuel supply path 12 is distributed and supplied to each burner part 8a, 8b, 8c. Each of the burner portions 8a, 8b, and 8c is formed in a longitudinal shape extending in a direction perpendicular to the paper surface in FIG. 1, and the flame hole 20 provided in each of the burner portions 8a, 8b, and 8c is also formed in a longitudinal shape. Has been. Further, two flame holes 20 having a longitudinal shape are provided side by side in the left-right direction in FIG. 1 in each of the burner portions 8a, 8b, 8c. That is, on the upper surface of the burner 8, six longitudinally shaped flame holes 20 arranged in the transverse direction of the combustion gas flow path 40 are arranged.

The gas fuel supply path 12 to which the gas fuel F is supplied is provided with an original gas electromagnetic valve 17 that interrupts the flow of the gas fuel F and a gas amount adjustment valve 18 that adjusts the supply amount of the gas fuel F. A gas fuel supply regulating valve 15a capable of intermittently adjusting the supply of gas fuel F to each burner portion 8a, 8b, 8c in each gas fuel supply passage 12 branched from the burner portions 8a, 8b, 8c. , 15b, 15c are provided.
Further, the combustion air A supplied through the air supply path 13 is also distributed and supplied to the burner portions 8a, 8b, and 8c, and the burner portions 8a and 8b are supplied to the branched air supply paths 13 respectively. , 8c are provided with air supply regulating valves 16a, 16b and 16c capable of intermittently adjusting the supply of combustion air A to 8c.
The control device S performs the opening / closing operation of the gas fuel supply adjustment valves 15a, 15b, 15c and the air supply adjustment valves 16a, 16b, 16c, and the operation of the original gas electromagnetic valve 17 and the gas amount adjustment valve 18. Further, the operation of the sirocco fan 14 is also controlled by the control device S.
Therefore, the control device S can control the combustion state of the burner 8 by controlling the open / closed state of each valve. When the combustion amount in the burner 8 is reduced, the gas fuel supply adjustment valves 15a and 15c and the air supply adjustment valves 16a and 16c are closed, and the gas fuel supply adjustment valve 15b and the air supply adjustment valve 16b are opened. At the same time, the flow rate of the gas fuel F is reduced by the gas amount adjusting valve 18 to reduce the amount of air supplied to the sirocco fan 14. Then, the burner 8 has only the flame hole 20 of the second burner portion 8b, in other words, the central flame hole 20a located at the central portion in the transverse direction among the plurality of flame holes 20 arranged in the transverse direction of the combustion gas flow path 40. Only a partial output operation in which a flame is formed is executed.

The control device S operates by taking in the electric power generated by the thermoelectric module 2 through the electric wire 28 and using it as a power source.
The generated power of the thermoelectric module 2 is also used as power necessary for the operation of the valves 13a to 13c, 15a to 15c, 17, 18 and the sirocco fan 14. The surplus of the generated power of the thermoelectric module 2 is temporarily stored in the storage battery 19, and the stored power of the storage battery 19 is used as insufficient power when the thermoelectric module 2 does not generate power. Thereby, the water heating apparatus 1 can be operated with a minimum or omitted power supply from the commercial power supply system, and can be operated, for example, during a power failure.

Next, the power generation unit 3 will be described.
As shown in FIGS. 1 and 3, the power generation unit 3 has a pair of thermoelectric modules 2 disposed on both sides of a water supply channel member 4 having a water supply channel 5 a, and further, both outer sides of the pair of thermoelectric modules 2. A pair of combustion gas passage members 6 are arranged on the top. And the electric power generation unit 3 is arrange | positioned in the center part in the cross direction of the combustion gas flow path 40, and is located above the center flame hole 20a. Below, the thermoelectric module 2, the water supply flow path member 4, and the combustion gas passage member 6 of the power generation unit 3 will be described in detail.

  As shown in FIG. 2, the thermoelectric module 2 is formed by electrically connecting a plurality of thermoelectric element pairs composed of a P-type thermoelectric element 31 and an N-type thermoelectric element 32 in series with metal electrodes 33, and positioned at both ends of this series circuit. The thermoelectric elements 31 and 32 are configured by providing output terminal electrodes 34 connected to the electric wires 28. Further, the plurality of thermoelectric elements 31 and 32 are fixed by being sandwiched between insulating plates 35 and 36 formed to have a substantially square and smooth surface by a material (for example, alumina) having electrical insulation and good thermal conductivity. Has been. In the present embodiment, the P-type thermoelectric element 31 and the N-type thermoelectric element 32 are made of a bismuth-tellurium-based (Bi-Te-based) semiconductor material.

The insulating plates 35 and 36 are mounted so as to be parallel to each other. For example, the smooth surface of the insulating plate 35 is used as the high temperature side surface 2b, and the smooth surface of the insulating plate 36 is used as the low temperature side surface 2a. A thermoelectromotive force is generated by the Seebeck effect in the thermoelectric element pair composed of the P-type thermoelectric element 31 and the N-type thermoelectric element 32 due to a temperature difference between the low temperature side surface 2a and the low temperature side surface 2a, and a current in the direction of the arrow shown in FIG. 2 is generated. . Here, the number and arrangement of the thermoelectric element pairs incorporated in the thermoelectric module 2 are not limited to those shown in FIG. 2, and may be changed as appropriate according to necessary generated power and the like.
Then, the power generation unit 3 is provided in the water heating device 1 so that the high temperature side surface 2b of the thermoelectric module 2 takes a posture along the flow direction of the combustion gas G generated from the burner 8 and flowing through the combustion gas passage 40. (See FIG. 1).

As shown in FIGS. 3 and 5, the water supply channel member 4 is in contact with the low-temperature side contact surface 4 a of the thermoelectric module 2 in close contact with the low-temperature side contact surface 4 a and is in contact with the thermoelectric module 2. A water supply channel 5a through which the water supply W flows is formed on the water supply channel surface 4b, which is the surface on the opposite side. Further, the water supply flow path member 4 is formed in a flat shape along the flow direction of the combustion gas G in the combustion gas flow path 40. Specifically, the water supply channel member 4 is formed so that the outer shape thereof is formed in a substantially rectangular parallelepiped shape, and the surface having the largest area is disposed along the flow direction of the combustion gas G in the combustion gas channel 40. ing.
5 and 6, the water supply pipe 25 and the drain pipe 26 are connected to the water supply flow path member 4, and the water supply W is formed in the water supply flow path member 4 by the water supply pipe 25. The water supply W introduced into the flow path 5a and passing through the water supply flow path 5a flows out to the drain pipe 26. Moreover, the water supply flow path 5a formed inside the water supply flow path member 4 is formed as a folded flow path that proceeds in the lateral direction while being folded back and forth between the upper part and the lower part.

  The feed water channel member 4 has a cooling member through hole 4c through which a connecting bolt 30 connecting the feed water channel member 4 and the combustion gas passage member 6 passes, and a low temperature side contact surface 4a to which the low temperature side surface 2a of the thermoelectric module 2 is in close contact. Are provided in a distributed manner around. Further, a low-temperature side accommodation recess 4 e in which the thermoelectric module 2 is accommodated is formed in the cooling side wall 4 d provided with the low-temperature side contact surface 4 a of the water supply flow path member 4.

As shown in FIGS. 3 and 4, the combustion gas passage member 6 is in contact with the high temperature side contact surface 6 a in close contact with the high temperature side surface 2 b of the thermoelectric module 2 and the high temperature side contact surface 6 a in contact with the thermoelectric module 2. A combustion gas passage 7 through which the combustion gas G passes is formed on the combustion gas passage surface 6b that is the opposite surface.
The combustion gas passage 7 is formed along the flow direction of the combustion gas G generated from the burner 8 and flowing through the combustion gas passage 40. The combustion gas passage 7 is provided with a plurality of comb-like standing shapes extending from the high-temperature side contact surface 6 a side in contact with the thermoelectric module 2 toward the combustion gas passage 7 in a posture along the flow direction of the combustion gas G. Heat receiving fins 27 are provided.
Further, the combustion gas passage member 6 is provided with heating member through-holes 6c through which the connecting bolts 30 are distributed and arranged around the high temperature side contact surface 6a where the high temperature side surface 2b of the thermoelectric module 2 is in close contact. In addition to this, at four corners of the combustion gas passage member 6, fixing through holes 6 g through which fixing bolts 50 for fixing the combustion gas passage members 6 pass are provided.
In addition, a high temperature side accommodation recess 6 e in which the thermoelectric module 2 is accommodated is formed on the heating side wall 6 d provided with the high temperature side contact surface 6 a of the combustion gas passage member 6.

The combustion gas passage member 6 has an outer wall 21 outside the combustion gas passage 7 (at the front end side of the heat receiving fins 27). The outer wall 21 is fixed to the combustion gas passage member 6 in a state where a tip end gap E is formed between the tip of the heat receiving fin 27 and the outer wall 21. Due to the tip end gap E, particularly in the partial output operation in which a flame is formed only in the central flame hole 20a of the burner 8, the high-temperature combustion gas G flows into the combustion gas passage 7 more intensively than the outer passage 40a. Therefore, it is possible to prevent the heat received by the heat receiving fins 27 of the combustion gas passage 7 from being transferred to the outer wall 21 and dissipated to the combustion gas passage 40 side.
Further, the outer wall through hole 21 a provided in the outer wall 21 is closed by the through hole closing plate 23. A through hole closing plate gasket 24 is provided between the through hole closing plate 23 and the outer wall 21. Thereby, the combustion gas G flowing through the combustion gas passage 7 can be prevented from flowing out of the outer wall through hole 21a.

As shown in FIGS. 3 to 5, in order to connect the thermoelectric module 2, the water supply flow path member 4, and the combustion gas passage member 6 to form the power generation unit 3, the thermoelectric module 2 is dispersedly arranged around the thermoelectric module 2. A plurality of connecting bolts 30 for fastening the flow path member 4 and the combustion gas passage member 6 are provided. The connection bolts 30 are provided in a distributed manner around the thermoelectric module 2 with the pair of thermoelectric modules 2 sandwiched between the water supply channel member 4 and the pair of combustion gas passage members 6. Each cooling member through-hole 4c of the member 4 and each heating member through-hole 6c of the pair of combustion gas passage members 6 are penetrated and connected and fixed. At this time, the tightening pressures of the respective connecting bolts 30 are adjusted so that the low temperature side surface 2a and the high temperature side surface 2b of the thermoelectric module 2 are connected to the low temperature side contact surface 4a of the feed water passage member 4 and the combustion gas passage member 6 respectively. The high temperature side contact surface 6a and the entire surface are connected and fixed so as to be in uniform contact.
Further, the fixing bolts 50 are passed through the fixing through holes 6g provided at the four corners of the combustion gas passage member 6 to fix the combustion gas passage members 6 to each other. At that time, the gasket 22 is passed through and fixed between the pair of combustion gas passage members 6.

  When connected and fixed in this way, the low temperature side inner peripheral side surface 4f of the low temperature side accommodating recess 4e and the high temperature side inner peripheral side surface 6f of the high temperature side accommodating concave portion 6e are configured to coincide with each other. The thermoelectric module 2 is in close contact with the low temperature side contact surface 4a of the low temperature side accommodation recess 4e and the high temperature side contact surface 6a of the high temperature side accommodation recess 6e in the space formed by the recess 4e and the high temperature side accommodation recess 6e. It is accommodated in the state that is done. In the state of being accommodated in this way, a side surface gap H is formed between the inner peripheral side surfaces 4f and 6f of the low temperature side accommodation recess 4e and the high temperature side accommodation recess 6e and the side surface 2c of the thermoelectric module 2. This side surface gap H prevents the side surface 2 c of the thermoelectric module 2 from being cooled and heated by the water supply flow path member 4 and the combustion gas passage member 6.

[Another embodiment]
Finally, another embodiment of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of other embodiments as long as no contradiction occurs.
(A) In the above-described embodiment, the area of the heat receiving surface of the heat receiving fin 27 is a constant area from the upstream side to the downstream side in the flow direction of the combustion gas G. The area of the surface may be gradually increased from the upstream side to the downstream side in the flow direction of the combustion gas G.

(B) In the above embodiment, the thermoelectric module 2 is provided in the power generation unit 3 along the flow direction of the combustion gas G. However, the thermoelectric module 2 is not limited to this, and the thermoelectric module 2 and the thermoelectric module for high temperature are used. A low-temperature thermoelectric element having a lower operating temperature than the element, and in the power generation unit 3, the high-temperature thermoelectric element and the low-temperature thermoelectric element are arranged in parallel along the flow direction of the combustion gas G from the upstream side. Also good.

(C) In the above embodiment, in the thermoelectric module 2, as shown in FIG. 2, the plurality of thermoelectric elements 31, 32 are arranged so as to be substantially square as a whole, and the insulating plate 35 is also formed in a substantially square shape. However, the present invention is not limited to this, and the number and arrangement of the plurality of thermoelectric elements 31 and 32 in the thermoelectric module 2 and the shape of the insulating plates 35 and 36 are necessary. It can be changed accordingly.

(D) In the said embodiment, although the heat exchanger 11 was set as the fin tube type heat exchanger 11 which has the fin 11a, not only this but the heat exchanger 11 is the multipipe which does not have the fin 11a, for example. It may be composed of a type heat exchanger or the like.

(E) In the said embodiment, although only the storage battery 19 was provided as a power supply of the water heating apparatus 1, not only this but the water heating apparatus 1 may be connected with the commercial power supply system | strain.

(F) In the above embodiment, the P-type thermoelectric element 31 and the N-type thermoelectric element 32 are made of a bismuth-tellurium-based (Bi-Te-based) material. The mold thermoelectric element 32 can also be composed of another metal-based thermoelectric material. An oxide-based thermoelectric material can also be used.

(G) In the above embodiment, a part of the combustion gas G generated in the burner 8 is configured to pass through the combustion gas passage 7 of the power generation unit 3, but this is not limiting, and the entire amount of the combustion gas G is combusted. You may comprise so that it may flow in into the gas passage 7.

  As described above, it is possible to provide a water heating apparatus capable of obtaining high power generation efficiency by uniformly or sufficiently heating or cooling the high temperature side surface and the low temperature side surface of the thermoelectric module.

DESCRIPTION OF SYMBOLS 1 Water heater 2 Thermoelectric module 2a Low temperature side 2b High temperature side 3 Power generation unit 4 Water supply flow path member 4d Cooling side wall 4e Low temperature side accommodation recessed part (accommodation recessed part)
4f Low temperature side inner peripheral side (inner peripheral side)
5a Water supply channel 6 Combustion gas passage member 6d Heating side wall 6e High temperature side accommodation recess (accommodation recess)
6f High temperature side inner peripheral side (inner peripheral side)
7 Combustion gas passage 7a Combustion gas flow path 8 Burner 11 Heat exchanger 20 Flame hole 20a Central flame hole 21 Outer wall 27 Heat receiving fin 30 Connection bolt 31 P-type thermoelectric element (thermoelectric element)
32 N-type thermoelectric element (thermoelectric element)
40 Combustion gas flow path E Tip clearance (gap)
G Combustion gas H Side surface gap (gap)
W water supply

Claims (8)

A power generation unit including a thermoelectric module using a combustion gas generated by burning fuel as a high-temperature source and a water supply as a low-temperature source, and a heat exchanger for transferring heat from the combustion gas passing through the power generation unit to the water supply Water heater,
A water supply channel member that forms a water supply channel through which the water supply flows on a surface opposite to the thermoelectric module and that contacts the low temperature side surface of the thermoelectric module, and a high temperature side surface of the thermoelectric module. And a combustion gas passage member that forms a combustion gas passage through which the combustion gas passes on a surface opposite to the thermoelectric module;
Forming the hot side of the thermoelectric module and the combustion gas passage along the flow direction of the combustion gas generated from a burner;
A water heating apparatus in which the combustion gas passage member is provided with a plurality of heat receiving fins standing in a comb-like shape from the thermoelectric module side toward the combustion gas passage in a posture along the flow direction of the combustion gas. .   The water supply channel member is formed in a flat shape along the flow direction of the combustion gas, and a pair of the thermoelectric modules and a pair of combustion gas passage members are provided on both sides of the water supply channel member. Item 2. A water heating apparatus according to Item 1. The burner is provided with a plurality of flame holes in the transverse direction of the combustion gas flow path, and a partial output operation in which a flame is formed only in a central flame hole located in a central portion in the transverse direction of the plurality of flame holes. Configured to run,
The water heating apparatus according to claim 2, wherein the power generation unit is disposed above the central portion.   4. The combustion gas passage member according to claim 1, wherein the combustion gas passage member has an outer wall outside the combustion gas passage, and a gap is formed between a front end side of the heat receiving fin and the outer wall. The water heating apparatus according to item.   5. The power generation unit according to claim 1, further comprising a plurality of connection bolts that are distributed around the thermoelectric module and fasten the water supply flow path member and the combustion gas passage member. Water heating device. On the cooling side wall of the water supply flow path member and the heating side wall of the combustion gas passage member, an accommodation recess for accommodating the thermoelectric module is formed,
The water heating apparatus according to any one of claims 1 to 5, wherein a gap is formed between an inner peripheral side surface of the housing recess and the thermoelectric module.   The water heating apparatus according to any one of claims 1 to 6, wherein an area of a heat receiving surface of the heat receiving fin is gradually increased from an upstream side to a downstream side in a flow direction of the combustion gas. The thermoelectric module includes a high temperature thermoelectric module and a low temperature thermoelectric module having a lower operating temperature than the high temperature thermoelectric module,
8. The power generation unit according to claim 1, wherein the high-temperature thermoelectric module and the low-temperature thermoelectric module are arranged side by side in order from the upstream side along the flow direction of the combustion gas. Water heating device.

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