JP3796031B2 - Duct directly connected water heater and water heater exhaust system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water heater installed in a kitchen or the like. More particularly, the present invention relates to a water heater of a duct direct connection type in which an exhaust port is directly connected to an exhaust duct, and can reduce the amount of dilution air by lowering the exhaust temperature. Moreover, it is related with the water heater exhaust apparatus containing such a water heater.
[0002]
[Prior art]
FIG. 2 is a schematic front view showing an outline of the configuration of a conventional duct-directly connected water heater. A gas burner 125 that is a combustor is disposed in the lower part of the water heater main body 105. The gas burner 125 is supplied with city gas or propane gas from a gas supply pipe (not shown), and a combustion flame 123 is formed. On the gas burner 125, a water pipe 119 with fins 121 is disposed. Tap water is supplied to the water pipe 119 from an upper water inlet 118. The water pipe 119 is heated by the radiant heat of the flame 123 of the gas burner 125 or the heat transfer from the combustion exhaust gas of the burner. Therefore, the water that enters from the water inlet 118 comes out of the water pipe water outlet 122 as hot water. Combustion exhaust gas goes up in the water heater body.
[0003]
An exhaust hood 104 is installed on the upper part of the water heater main body 105, and the combustion exhaust gas rises in the hood 104. A large number of dilution air suction ports 111 are opened in the exhaust hood unit 104, and a large amount of ambient air is sucked from the ports 111. A branch duct 103 is connected on the exhaust hood 104. A kitchen exhaust duct 101 is connected to the end of the branch duct 103. A fan (not shown) is installed in the exhaust duct 101, and the branch duct 103 and the exhaust hood 104 are at negative pressure.
[0004]
The thermal efficiency of the water heater is approximately 80%, and the exhaust temperature when entering the exhaust hood is 230 to 250 ° C. although it depends on the air ratio.
In the direct water heater connected to the duct, it is necessary to lower the exhaust temperature when entering the exhaust hood to 40 to 50 ° C. In the above-described water heater, the temperature is realized by sucking a large amount of diluted air with the suction force on the duct side in the exhaust hood.
This temperature of 40 to 50 ° C. is required for preventing duct fire and preventing malfunction due to the temperature fuse of the fireproof damper installed in the exhaust duct. In order to make the water heater a product that can be directly connected to the kitchen exhaust duct, it is necessary to obtain special approval from the Minister of Construction in the first place, but achieving the exhaust temperature is also a condition at that time. ing.
[0005]
The dilution air amount is 20 to 30 times the theoretical exhaust gas amount of the water heater (the absolute amount varies depending on the rated (maximum) combustion amount of the water heater). While the exhaust temperature is regulated, the dilution air temperature must be assumed to be high in the summer or in the kitchen room (about 40 ° C.), and this value is also expected in view of the safety factor.
The pressure loss at the exhaust hood that sucks in a large amount of diluted air is as large as around 10 mmAq (current product No. 16-24).
[0006]
[Problems to be solved by the invention]
In order to install a conventional duct-directly connected water heater, a large capacity (necessary displacement and static pressure (lift)) is required on the exhaust duct side for dilution air suction, resulting in the following problems. .
(1) Since the required capacity is large, there are many cases where the conditions are not satisfied. In this case, it is necessary to increase the capacity of the duct. However, since it is a modification of the equipment, it takes a lot of time and money, and in some cases it cannot be handled. Equipment remodeling items may include increasing the capacity of exhaust fans, expanding the duct diameter, installing and adjusting the air volume adjustment damper, and changing the layout of the hood / branch duct. However, in properties such as underground malls and tenant buildings, it is extremely difficult to carry out these operations that affect other tenants when installing a water heater in one tenant. On the other hand, it is these properties that have to use duct-connected water heaters.
[0007]
{Circle around (2)} Before installing the water heater, it is necessary to make a measurement for determining whether the capacity of the duct at the installation location satisfies the installation conditions, which is troublesome and expensive.
Although the measurement is performed at the installation location, the conditions are different from the installation state, and it is found that the required conditions are not satisfied after the water heater is installed, which may result in the problem described in the first section. What is currently being tried is to make a hole in the outlet diameter of the water heater exhaust hood in the kitchen exhaust duct, and connect a branch duct as a measuring jig, and the suction flow velocity and pressure at the opening are heated. This is a method in which measurement is performed with a type anemometer / manometer, and the determination is made based on the correlation between the measurement method obtained in advance by laboratory measurement and the installation state.
At present, since there is no accurate method for measuring duct capacity in advance, the above-described actual measurement determination is essential.
[0008]
(3) Even if it is impossible to satisfy the set installation conditions, the installation / use is likely to be performed at the discretion of the operator or user, which is a serious safety issue.
[0009]
The present invention has been made in view of such problems, and is a duct-directly connected water heater in which an exhaust port is directly connected to an exhaust duct, and can reduce the amount of diluted air by lowering the exhaust temperature. The purpose is to provide a water heater. It is another object of the present invention to provide a duct-directly connected water heater capable of directly connecting an exhaust port to an exhaust duct having a limited exhaust capacity. Furthermore, it aims at providing the water heater exhaust apparatus containing such a water heater.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, a duct directly connected water heater according to the present invention is a duct directly connected water heater that is directly connected to a collective kitchen exhaust duct and directly exhausts, and includes a combustor, a water pipe heated by the combustor, A latent heat recovery heat exchanger that recovers the latent heat in the exhaust gas of the combustor, and a negative pressure that opens the diluted air suction port through which the exhaust gas that has become 100 ° C. or less passes through the latent heat recovery heat exchanger. The exhaust hood part, and a branch duct connected to the tip of the exhaust hood part and having a negative pressure. The exhaust gas passing through the latent heat recovery heat exchanger is diluted with the dilution in the exhaust hood part. Diluted air is sucked and mixed from the air suction port and exhausted to the exhaust duct.
A water heater exhaust apparatus according to the present invention is a water heater exhaust apparatus including a collective kitchen exhaust duct having a negative pressure for sucking exhaust gas, and a duct directly connected water heater that is directly connected to the exhaust duct and exhausts directly. The duct-directly connected water heater is composed of a combustor, a water pipe heated by the combustor, a latent heat recovery heat exchanger that recovers latent heat in the exhaust gas of the combustor, and the latent heat recovery heat exchanger. An exhaust hood portion having a negative pressure through which the exhaust gas having a temperature of ℃ or less passes, and a negative air suction port is opened. Between the exhaust duct and the exhaust hood portion of the water heater, a negative pressure is provided. A branch duct that is in pressure is connected, and the exhaust gas that has passed through the latent heat recovery heat exchanger is mixed with the diluted air sucked from the diluted air suction port in the exhaust hood, and exhausted into the exhaust duct. To do And it features.
[0011]
In other words, the hot water heater is made to recover latent heat so as to be highly efficient, and the exhaust temperature is lowered in advance. Therefore, it requires only a small amount rather dilution air Gago, the required capacity of the kitchen exhaust duct small. Here, the higher the thermal efficiency, the better. If it is assumed to be 100%, the exhaust temperature is theoretically the ambient temperature. However, if the current technology is to be realized, the heat transfer area of the latent heat recovery heat exchanger is limited by the size of the equipment and the manufacturing cost, so the thermal efficiency is about 90 to 95%, and further about 92 to 93%. It is practical. Even in this case, the exhaust gas temperature is 100 ° C. or less, and the amount of diluted air that is sucked and mixed into the exhaust gas that has passed through the latent heat recovery heat exchanger from the diluted air suction port in the exhaust hood portion is 2 to 3 of the theoretical exhaust gas amount or 4 times, 0.5 to 1.5 of the water heater combustion fan and the like minus Oh Ru of about 1.5 min given from the main body, i.e., the theoretical amount of exhaust gas as combustion air itself or 2. About 5 times is enough. [0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it demonstrates, referring drawings.
FIG. 1 is a schematic front view showing an outline of the configuration of a duct-directly connected water heater according to one embodiment of the present invention. A gas burner 25 that is a combustor is disposed in the lower part of the water heater main body 5. City gas and propane gas are supplied to the gas burner 25 from a gas supply pipe (not shown), and a combustion flame 23 is formed in the gas burner 25. A water pipe 19 with fins 21 is disposed on the gas burner 25. Tap water is supplied to the water pipe 19 from an upper water inlet 18 through a water pipe 15 of a latent heat recovery heat exchanger 13 described later. The tap water is preheated to some extent by the latent heat recovery heat exchanger 13. The water pipe 19 is heated by radiant heat of the flame 23 of the gas burner 25 or heat transfer from the combustion exhaust gas of the burner. Therefore, the water entered from the water inlet 18 becomes hot water and comes out from the water pipe water outlet 22. Combustion exhaust gas goes up in the water heater body.
As for the direction of water flow, the counterflow type as in this embodiment is more advantageous in terms of heat transfer, but it may be in the opposite direction (cocurrent type).
[0013]
A latent heat recovery heat exchanger 13 is incorporated in the upper part of the water heater body 5. The latent heat recovery heat exchanger 13 is provided with a water pipe 15 with fins 17 connected in series to the water pipe 19 described above. The latent heat recovery heat exchanger water pipe 15 is supplied with tap water from a water inlet 18. The flue gas (temperature 230-250 degreeC) which gave the heat to the water pipe 19 of the above-mentioned kettle part, and fell in temperature to some extent passes the water pipe 15 outside. At this time, the heat of the exhaust gas gives further heat to the cold latent heat recovery heat exchanger water pipe 15 just filled with tap water, and the temperature at the outlet of the heat exchanger 13 becomes 100 ° C. or less. In the heat exchanger 13, the moisture in the exhaust gas (the hydrogen combusted in the gas is condensed) becomes water and releases latent heat. For this reason, the thermal efficiency of the water heater main body 5 as a whole is extremely high at 90 to 95%.
[0014]
An exhaust hood 4 is installed further above the latent heat recovery heat exchanger 13. The combustion exhaust gas rises in the exhaust hood 4. Several exhaust air suction ports 11 are opened in the exhaust hood 4, and ambient air is sucked through the ports 11 to a certain amount (same amount as combustion air or slightly larger).
A branch duct 3 is connected on the exhaust hood 4. A kitchen exhaust duct 1 is connected to the end of the branch duct 3. A fan (not shown) is installed in the exhaust duct 1, and the branch duct 3 and the exhaust hood portion 4 have a negative pressure.
The temperature of the exhaust gas mixed with the diluted air is further lowered to 40 to 50 ° C. or less.
[0015]
Thus, in the duct direct connection type water heater of the present embodiment, the exhaust gas temperature can be lowered to the exhaust gas temperature at which the exhaust gas can be directly exhausted to the duct with a dilution air amount of about 1/10 of the conventional one. Therefore, a duct direct connection type water heater can be realized without requiring an excessive load on the duct.
[0016]
【The invention's effect】
As is clear from the above description, the duct direct-coupled water heater and the water heater exhaust device of the present invention exhibit the following effects.
(1) Since the temperature of the exhaust gas is essentially low, it can be assured that a duct fire or a thermal fuse blown of a fireproof damper does not occur in principle. Therefore, essential safety can be ensured.
(2) Since the capacity required for the kitchen exhaust duct is very small, it can be additionally installed at most sites. For this reason, it is possible to increase the range of objects that can be installed and prevent illegal installation of kitchen hoods, which improves safety.
[0017]
(3) In principle, it is not necessary to measure duct capacity in advance and determine whether or not it can be used. Therefore, the installation property of the duct direct connection type water heater is improved.
(4) Energy saving, running cost reduction and CO ₂ reduction can be realized by increasing the efficiency of the water heater.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing an outline of a configuration of a duct direct-coupled water heater according to an embodiment of the present invention.
FIG. 2 is a schematic front view showing an outline of the configuration of a conventional duct-directly connected water heater.
[Explanation of symbols]
1 kitchen exhaust duct 3 branch duct 4 exhaust hood portion 5 water heater body 11 dilution air suction port 13 latent heat recovery heat exchanger 15 water tube 17 off fin <br/> 19 water tubes 21 off fin 22 water outlet 23 flame 25 Gas burner 101 kitchen exhaust duct 103 branch duct 104 exhaust hood 105 water heater body 111 dilution air suction port 118 the water inlet 119 of water tube 121 off fin <br/> 122 water outlet 123 flame 125 gas burner

Claims (6)

A duct-connected water heater that is directly connected to the collective kitchen exhaust duct and exhausts directly,
A combustor,
A water pipe heated by the combustor;
A latent heat recovery heat exchanger that recovers latent heat in the exhaust gas of the combustor;
An exhaust hood having a negative pressure, through which the exhaust gas that has become 100 ° C. or less passes through the latent heat recovery heat exchanger, the dilution air suction port being opened, and
A branch duct connected to the tip of the exhaust hood and having a negative pressure;
Comprising
A duct directly connected water heater, wherein the exhaust gas that has passed through the latent heat recovery heat exchanger is mixed with the diluted air sucked from the diluted air suction port in the exhaust hood and exhausted to the exhaust duct.   The diluted exhaust gas that has passed through the latent heat recovery heat exchanger is mixed with 0.5 to 2.5 times the theoretical exhaust gas amount from the diluted air suction port in the exhaust hood section. Item 2. A direct water heater connected to a duct according to item 1. The direct duct type hot water heater according to claim 1 or 2 , wherein the thermal efficiency of the direct duct type hot water heater is 90 to 95%. A water heater exhaust device comprising a collective kitchen exhaust duct that is negative pressure for sucking exhaust, and a duct directly connected water heater that is directly connected to the exhaust duct and exhausts directly,
The duct directly connected water heater
A combustor,
A water pipe heated by the combustor;
A latent heat recovery heat exchanger that recovers latent heat in the exhaust gas of the combustor;
An exhaust hood having a negative pressure, through which the exhaust gas that has become 100 ° C. or less passes through the latent heat recovery heat exchanger, the dilution air suction port being opened, and
Comprising
A branch duct having a negative pressure is connected between the exhaust duct and the exhaust hood of the water heater,
A hot water heater exhaust system, wherein the exhaust gas that has passed through the latent heat recovery heat exchanger is sucked and mixed with diluted air from the diluted air suction port in the exhaust hood section and exhausted to the exhaust duct.   The diluted exhaust gas that has passed through the latent heat recovery heat exchanger is mixed with 0.5 to 2.5 times the theoretical exhaust gas amount from the diluted air suction port in the exhaust hood section. Item 5. A water heater exhaust device according to Item 4.   The water heater exhaust device according to claim 4 or 5, wherein the duct-directly connected water heater has a thermal efficiency of 90 to 95%.

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