JPH04254105A - Hot water supply device - Google Patents

Abstract

PURPOSE:To supply hot water with a high concentration of carbon dioxide and, at the same time, make the exhaust gas clean, and reduce the fuel cost by providing a hot water supply device in which the combustion gas and water exchange heat by an indirect contact type heat exchanger and then hot water is made by exchanging heat by a direct contact type heat exchanger. CONSTITUTION:After the combustion gas that is generated by a combustion means 7 exchanges heat by an indirect contact type heat exchanger 12, the combustion gas exchanges heat by a direct contact type heat exchanger 10. On the other hand, the water exchanges heat by a direct contact type heat exchanger 10, and then exchanges heat by an indirect contact type heat exchanger 12. The combustion gas and water come, therefore, in contact in the state of low temperature so that the solubility of the carbon dioxide in the hot water becomes large and hot water with a high carbon dioxide concentration can be obtained, and, at the same time, it is possible to reduce the concentrations of the carbon dioxide and nitrogen dioxide contained in the exhaust gas. And, the thermal efficiency can be made high so that the fuel cost can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water heater for home use, etc., which uses combustion means as a heating source.

0002

2. Description of the Related Art Conventionally, there has been a water heater of this type as shown in FIG. The solid arrows in the figure indicate the flow direction of hot water, and the broken lines indicate the flow direction of exhaust gas.

[0003] A combustion chamber 1 whose vertically upper end is open to the atmosphere, a combustion means 2 provided on the side of the combustion chamber 1 and forming a flame f in the horizontal direction, and a combustion chamber 1 connected below the combustion means 2. A hot water storage chamber 3 for storing hot water, a water supply pipe 4 for supplying water from the upper part to the lower part of the combustion chamber 1, and a water supply pipe 4 connected to the hot water storage chamber 3 for supplying the hot water stored in the hot water storage chamber 3 to a predetermined location. It consists of a hot water supply pipe 5. The water is then discharged into the combustion chamber 1 through the water supply pipe 4, comes into direct contact with the flame f formed by the combustion means 2, undergoes heat exchange, and becomes hot water. After the hot water falls vertically downward and is stored in a hot water storage section 3, it is supplied to a predetermined location via a hot water supply pipe 5.

0004

However, in the above structure, the water and the flame f come into direct contact, so that the atmospheric temperature when carbon dioxide dissolves becomes extremely high. As shown in FIG. 3, when the temperature is high, the solubility of carbon dioxide decreases, making it impossible to increase the concentration of carbon gas dissolved in water. Furthermore, since only heat exchange is performed through direct contact, there is a problem in that high thermal efficiency cannot be obtained.

[0005] The present invention solves such conventional problems, and the temperature of the combustion gas to be heat exchanged is first lowered by exchanging heat in an indirect contact heat exchanger, and then the temperature of the combustion gas is lowered.
By exchanging heat in a direct contact heat exchanger, the temperature of the combustion gas when carbon dioxide is dissolved is lowered, and furthermore, by first contacting the water to be heat exchanged with the combustion gas in a direct contact heat exchanger, the temperature of the combustion gas is reduced. By keeping the temperature of water at which carbon dissolves low, the solubility of carbon dioxide can be increased, and by connecting a direct contact heat exchanger and an indirect contact heat exchanger, thermal efficiency can be improved. The first priority is to reduce the amount of carbon dioxide and nitrogen dioxide emitted into the atmosphere.
The purpose is to

[0006] The second purpose is to make the exhaust passage into a trap shape, and by making the bottom of the trap-shaped exhaust passage a hot water storage tank, the combustion gas is drained into the water stored in the hot water storage tank at the bottom of the trap-shaped exhaust passage. When passing through the water, it pushes down the water level at the entrance of the hot water storage tank and then passes through the water in the form of bubbles, creating a high pressure and large contact area when dissolving carbon dioxide, increasing the solubility and thermal efficiency of carbon gas, and further The aim is to reduce the amount of carbon dioxide and nitrogen dioxide emitted into the atmosphere.

[0007]

[Means for Solving the Problems] In order to achieve the first object, the water heater of the present invention includes a combustion fan that supplies combustion air, and a combustion fan that adjusts the air and fuel supplied by the combustion fan. a combustion means for guiding the combustion gas generated by the combustion means, an exhaust passage for guiding the combustion gas generated by the combustion means, a hot water storage tank provided in the middle of the exhaust passage, and a combustion gas generated by the combustion means in the exhaust passage downstream from the hot water storage tank. A direct contact heat exchanger that exchanges heat through direct contact between combustion gas and water, a water supply pipe that supplies water to this direct contact heat exchanger, and an indirect contact between combustion gas and water in an exhaust path upstream of the hot water storage tank. an indirect contact heat exchanger that exchanges heat with the direct contact heat exchanger; a connecting pipe that supplies the hot water that has been heat exchanged with the direct contact heat exchanger to the indirect contact heat exchanger; It is equipped with hot water pipes that supply hot water.

In order to achieve the second object, the present invention provides a hot water storage tank with a trap shape so that the combustion gas passing through the exhaust passage passes through the hot water stored in the hot water storage tank.

[0009]

According to the present invention, the air supplied by the combustion fan is mixed with fuel by the combustion means and then combusted. The combustion gas generated by the combustion means undergoes heat exchange in an indirect contact heat exchanger, further undergoes heat exchange in a direct contact heat exchanger, and is discharged into the atmosphere. On the other hand, water is supplied to a direct contact heat exchanger via a water supply pipe, and after heat exchange, is stored in a hot water storage tank. The stored hot water is supplied to an indirect contact heat exchanger via a connecting pipe, and after further heat exchange,
It is supplied to a predetermined location via hot water pipes. The hot water stored in the hot water storage tank is transported by a transport means provided midway through the hot water supply pipe. In a direct contact heat exchanger, direct contact between combustion gas and water causes carbon dioxide and nitrogen dioxide contained in the combustion gas to dissolve in water, and the concentration of carbon dioxide and nitrogen dioxide components in the combustion gas decreases to a level lower than that of water. It decreases by the amount dissolved in. The temperature of the exhaust gas when released into the atmosphere is approximately the same temperature as the water supplied from the water supply pipe.

[0010]Furthermore, the combustion gas is pushed down by a combustion fan to lower the water level at the entrance of the trap-shaped hot water storage tank, and then passes through the hot water in the form of bubbles. The combustion gas comes into contact with the hot water stored in the hot water storage tank under pressure, and the combustion gas passes through the hot water in the form of bubbles with a large contact area, so carbon dioxide and nitrogen dioxide in the combustion gas dissolve in the hot water. In addition, when the combustion gas passes through the hot water stored in the hot water tank in a bubble state, it comes into direct contact with the stored hot water and exchanges heat with it.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. The solid line arrows in the figure indicate the flow direction of hot water, the broken line arrows indicate the flow direction of exhaust gas, and the broken lines mean signal lines. Also, the same components are given the same reference numerals.

FIG. 1 is a schematic explanatory diagram of an embodiment of a water heater according to the present invention. Reference numeral 7 denotes a combustion means for adjusting and combusting the air and fuel supplied by the combustion fan 6 which supplies combustion air, and is provided at the lowest part of the combustion chamber 7a. An exhaust path 8 for guiding the combustion gas generated by the combustion means 7 is provided so as to be connected to the combustion chamber 7a on the downstream side of the combustion means 7. The exhaust passage 8 is bent horizontally at right angles above the combustion chamber 7a, and the other end of the exhaust passage 8 is bent vertically at right angles to be open to the atmosphere. Further, a hot water storage tank 9 is provided in a side exhaust passage 8a located in the middle of the exhaust passage 8, leaving an exhaust space 8b above.

A direct contact heat exchanger 10 is provided in the middle of the vertical exhaust passage 8c on the side of the hot water storage tank 9 that is open to the atmosphere, for exchanging heat by bringing the combustion gas into direct contact with water. A water supply pipe 11 that supplies water to the direct contact heat exchanger 10 is connected to the direct contact heat exchanger 10.

Also, an exhaust passage 8 on the side of the combustion means 7 from the hot water storage tank 9
An indirect contact heat exchanger 12 is provided in the combustion chamber 7a that is connected to the combustion chamber 7a in the middle of the combustion chamber 7a. A connecting pipe 1 is provided between the direct contact heat exchanger 10 and the indirect contact heat exchanger 12 to supply the hot water exchanged with the direct contact heat exchanger 10 to the indirect contact heat exchanger 12.
3 is provided, and a hot water supply pipe 14 is connected to the outlet of the indirect contact heat exchanger 12 to supply hot water to a predetermined location.

Further, a conveying device 15 is provided in the middle of the hot water supply pipe 14 for conveying hot water, and a control means 16 is provided for controlling the combustion fan 6, the combustion means 7, and the conveying device 15 in order to supply stable hot water. There is.

In the above configuration, the air supplied by the combustion fan 6 is mixed with fuel by the combustion means 7, and then combustion is performed. After the combustion gas generated by the combustion means 7 undergoes heat exchange in the indirect contact heat exchanger 12,
It flows through the horizontal exhaust passage 8b and the vertical exhaust passage 8c, undergoes further heat exchange in the direct contact heat exchanger 10, and is discharged to the atmosphere. On the other hand, water is supplied to the direct contact heat exchanger 10 via the water supply pipe 11 and is stored in the hot water storage tank 9 after heat exchange. The stored hot water is supplied to an indirect contact heat exchanger 12 via a communication pipe 13, and after further heat exchange, is supplied to a predetermined location via a hot water supply pipe 14.

During the water supplied from the water supply pipe 11, the combustion gas and water come into direct contact with each other in the direct contact heat exchanger 10, so that carbon dioxide and nitrogen dioxide contained in the combustion gas are dissolved in the water. At the same time, the concentration of carbon dioxide and nitrogen dioxide components in the combustion gas decreases by the amount dissolved in water.

In this embodiment, the temperature of the combustion gas to be heat exchanged is determined by first exchanging heat in the indirect contact heat exchanger 12 to lower the temperature, and then exchanging heat in the direct contact heat exchanger 10. By lowering the temperature of the combustion gas when carbon dioxide dissolves, and by first bringing the water to be heat exchanged into contact with the combustion gas in the direct contact heat exchanger 10, the temperature of the water when carbon dioxide dissolves is lowered. Therefore, the solubility of carbon dioxide can be increased as shown in FIG.

Hot water with dissolved carbon dioxide has the effect of increasing blood flow, and when used for bathing, it does not easily raise blood pressure, so even the elderly can take a bath with peace of mind.It also has warming and heat retention properties due to the effect of increasing blood flow. This allows bathers to feel hotter than the actual temperature, and it is difficult for the bathwater to cool down after bathing, so the temperature for reheating or keeping warm can be kept low, reducing fuel costs. In addition, by connecting the direct contact heat exchanger 10 and the indirect contact heat exchanger 12 with the connecting pipe 13, thermal efficiency can be improved and fuel costs can be reduced. Furthermore, fuel efficiency is reduced by increasing efficiency, and fuel efficiency is reduced by lowering the set temperature by heat retention and warming effects, and by reducing carbon dioxide and nitrogen dioxide in the combustion gas.
The amount of carbon dioxide and nitrogen dioxide emitted can be reduced.

FIG. 2 shows another embodiment of the present invention, which differs from the above embodiment in that the exhaust space 8 above the side exhaust passage 8a is
The middle part of b is removed, and the combustion gas passing through the exhaust path 8 is transferred to the hot water storage tank 9.
The hot water storage tank 9 is shaped like a trap so that the hot water stored therein passes through. The structure other than this is the same as the above embodiment.

In the above structure, the combustion gas is pushed down by the combustion fan 6 to lower the water surface at the entrance 9a of the trap-shaped hot water storage tank 9, and then passes through the hot water in the form of bubbles. Hot water tank 9
Since the combustion gas comes into contact with the hot water stored in the hot water storage chamber 9 under pressure, carbon dioxide and nitrogen dioxide in the combustion gas are easily dissolved in the hot water, and they pass through the hot water stored in the hot water storage chamber 9 in the form of bubbles. During this process, the combustion gas once again comes into direct contact with the stored hot water to exchange heat.

[0022] Therefore, the combustion gas is brought into contact with the hot water stored in the hot water storage tank 9 under high pressure and a large contact area, which makes it possible to further increase the solubility of carbon dioxide and nitrogen dioxide, as well as to increase the thermal efficiency. Costs can also be reduced further. Furthermore, by increasing the solubility of carbon dioxide and nitrogen dioxide, the amount of carbon dioxide and nitrogen dioxide discharged into the atmosphere can be reduced.

[0023]

[Effects of the Invention] As described above, the water heater of the present invention provides the following effects.

(1) After heat exchange with an indirect contact heat exchanger, heat exchange is performed with a direct contact heat exchanger to lower the temperature of the combustion gas when it comes into direct contact with water. Since the solubility of carbon dioxide and nitrogen dioxide contained in water can be increased, hot water with a high carbon gas concentration can be obtained. Furthermore, the amount of carbon dioxide and nitrogen dioxide emitted into the atmosphere can be significantly reduced.

[0025] Furthermore, by connecting the direct contact heat exchanger and the indirect contact heat exchanger with a connecting pipe, it is possible to obtain high thermal efficiency, reduce fuel costs, and suppress the amount of combustion that is emitted into the atmosphere. It is possible to suppress emissions of carbon dioxide and nitrogen dioxide.

Furthermore, hot water containing dissolved carbon dioxide has the effect of increasing blood flow and does not easily raise blood pressure when bathing, so even elderly people can bathe with peace of mind. In addition, due to the action of increasing blood flow, it can exert a warming effect, a heat retaining effect, a fatigue recovery effect, or a healing effect.

[0027]Furthermore, because the bather feels hotter than the actual temperature due to the warming effect and heat retention effect, it is difficult for the bather to cool down after bathing, so the temperature can be kept low, reducing fuel costs and reducing the amount of combustion. This makes it possible to reduce the amount of carbon dioxide and nitrogen dioxide emitted into the atmosphere.

(2) Since the hot water storage tank installed in the middle of the exhaust path is shaped like a trap, the combustion gas is kept under high pressure.
Moreover, the hot water stored in the hot water storage tank is brought into contact with a large contact area, and the solubility of carbon dioxide and nitrogen dioxide can be further increased, thermal efficiency can be increased, and fuel costs can be further reduced. Furthermore, by increasing the solubility of carbon dioxide and nitrogen dioxide, the amount of carbon dioxide and nitrogen dioxide discharged into the atmosphere can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a water heater according to an embodiment of the present invention.

[Fig. 2] Schematic configuration diagram when the hot water storage tank is shaped like a trap in the same embodiment.

[Figure 3] Solubility characteristic diagram of carbon dioxide

[Fig. 4] Schematic configuration diagram of a conventional water heater

[Explanation of symbols]

6 Combustion fan 7 Combustion means 8 Exhaust path 9 Hot water tank 10 Direct contact heat exchanger 11 Water supply pipe 12 Indirect contact heat exchanger 13 Connecting pipe 14 Hot water pipe 15 Conveyance device 16 Control means

Claims (2)

[Claims] 1. A combustion fan that supplies combustion air, a combustion means that adjusts and burns the air and fuel supplied by the combustion fan, and an exhaust path that guides combustion gas generated by the combustion means. a hot water storage tank provided in the middle of the exhaust path, and a direct contact heat exchanger that directly contacts and exchanges heat between the combustion gas generated by the combustion means and water in the exhaust path downstream of the hot water storage tank; a water supply pipe that supplies water to the direct contact heat exchanger; an indirect contact heat exchanger that brings combustion gas and water into indirect contact to exchange heat in the exhaust path upstream of the hot water storage tank; and the direct contact heat exchanger. A hot water supply device comprising a communication pipe that supplies hot water heat-exchanged by the indirect contact heat exchanger to the indirect contact heat exchanger, and a hot water supply pipe that supplies hot water from the indirect contact heat exchanger to a predetermined location. 2. The water heater according to claim 1, wherein the hot water storage tank is shaped like a trap so that the combustion gas passing through the exhaust passage passes through hot water stored in the hot water storage tank.