JPS6251381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims at high efficiency and relates to a combustion device that can be applied to a water heater or a hot water heater using a condensing heat exchanger.

In recent years, there has been a call for energy conservation, and a highly efficient combustion device is required. Conventionally, the efficiency of combustion appliances has been around 80% at most, and if the efficiency exceeds that, condensed water will adhere to the heat exchanger, so designs have been made to suppress condensed water to the extent that it does not adhere to the heat exchanger due to durability and other issues. was. However, considering the recent trend towards energy conservation, there is a movement to increase efficiency to over 90% by not only extracting sensible heat from combustion exhaust gas as in the past, but also recovering latent heat.

That is, conventionally, as shown in FIG. 3, a condensing heat exchanger 2 for latent heat recovery is placed above the primary heat exchanger 1, and the condensing heat exchanger 2 is placed above the primary heat exchanger 1 and A condensed water receiver 3 is provided below the exchanger 2 to receive the condensed water discharged from the secondary heat exchanger 2 and prevent it from falling into the primary heat exchanger 1. At this time, the combustion exhaust gas is made to exit through the path shown by arrow A in FIG. The configuration shown in Figure 3 can be made relatively easily by attaching a condensed water heat exchanger on top of a conventional device, but with the aim of achieving high efficiency, it is necessary to ensure heat exchange of over 90%. In order to do so, it was necessary to consider changes in the environment. This is based on the fact that the heat exchange efficiency decreases as the humidity of the combustion air decreases, as shown in FIG.

SUMMARY OF THE INVENTION An object of the present invention is to take into account the influence of the humidity of combustion air so that even if the outside air is dry, a reduction in efficiency will not occur.

In order to achieve the above object, the present invention has a basic configuration in which condensed water discharged from a condensing heat exchanger is passed through an air supply path through which air to be supplied to a burner passes, without passing through the inside of the heat exchanger. , With this configuration, water vapor latent heat of the combustion air is supplied.

An embodiment of the present invention will be described below with reference to FIG.

4 is a burner, and 5 is an air supply path for supplying air to the burner 4, which is provided outside the heat exchanger. Near the entrance of the air supply path 5, condensed water coming out of the condensing heat exchanger 2 An outlet of the receiver 3 is arranged, and the condensed water flows through the air supply path 5. Further, a condensed water outlet 6 is provided at the lower part of the air supply path 5. 7 is a fan that supplies combustion air.

Next, the operation will be explained.

Combustion air supplied from the fan 7 is supplied to the burner 4 in the direction of the arrow, and combustion is performed. The heat obtained by combustion is exchanged between the primary heat exchanger 1 and the condensing heat exchanger 2 and used as a water heater or hot water heater. At this time, the condensing heat exchanger 2 The water vapor in the combustion exhaust gas condenses, and the condensed water passes through the condensed water receiver 3.
The air is guided to the air supply path 5. Here, the above condensed water is
It is mixed with combustion air and supplied to the burner 4 again. At this time, the combustion air has a considerably high degree of saturation, and the water vapor content in the combustion air has increased. Therefore, the dew point temperature of the combustion exhaust gas is almost determined by the temperature of the water passing through the condensing heat exchanger 2 (water pipes etc. are not shown here), so if the amount of water vapor in the combustion air increases, Indeed, the amount of condensed water increases, the amount of latent heat recovered increases, and efficiency improves.

As is clear from the above description, the combustion appliance of the present invention provides the following effects.

(1) In conventional combustion devices that aim for high efficiency and recover latent heat, the efficiency differs depending on the water vapor content during combustion. Therefore, efficiency decreases on days with low humidity. In contrast, according to the present invention, the combustion air is supplied with condensed water after the combustion gas undergoes heat exchange and is discharged and discarded from the condensing heat exchanger, so there is no condensed water in the combustion air. In order to supply this air to the burner, the heat of the condensed water is recovered, and combustion air with a high degree of steam saturation is constantly supplied to the burner, which is dependent on the outside air environment. This enables stable and highly efficient heat exchange.

Moreover, since the condensed water does not pass through the inner surfaces of the primary heat exchanger 1 and the condensing heat exchanger 2, but passes through the outside, the condensed water is exposed to high-temperature combustion air and evaporates, making it difficult to humidify the combustion air. There is no fear that a sufficient amount will not be obtained, and stable heat exchange can be obtained.

(2) Conventional latent heat recovery type combustion devices discard the heat of condensed water, but in the present invention, the heat of the condensed water can be recovered as latent heat, thereby improving combustion efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a combustion appliance according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between combustion efficiency and humidity of combustion air, and FIG. 3 is a schematic diagram of a conventional combustion apparatus. 2... Condensing heat exchanger, 4... Burner, 5...
...Air supply path.

Claims (1)

[Claims] 1 has a burner, a condensing heat exchanger that exchanges heat with the combustion gas of the burner, and an air supply path through which air to be supplied to the burner passes, and the condensed water discharged from the condensing heat exchanger is passed through the air supply path. A combustion appliance with a structure that allows it to pass through.