KR20060038814A - Device for control temperature of exhaust gas in proportional type gas boiler - Google Patents

Abstract

The present invention relates to an exhaust gas temperature maintaining apparatus of a proportional control gas boiler to control the air volume of the blower so that the exhaust gas can be maintained in a certain temperature range.

The present invention for realizing this, the heat exchanger for heating the heating water by using the heat burned by the burner, the exhaust gas temperature sensor for detecting the temperature of the exhaust gas discharged after being heat-exchanged by the heat exchanger, A controller of a proportional control gas boiler comprising a blower for supplying air necessary for gas combustion, and a controller for controlling the overall operation of the boiler including the burner and the exhaust gas temperature sensor and the blower, wherein the controller is configured to exhaust the exhaust gas. When it is determined that the temperature sensed by the gas temperature sensor falls below a reference temperature set to a temperature at which the condensation may occur in the heat exchanger, the blower is driven at the maximum rotation speed, thereby reducing the heat exchange time of the exhaust gas. To keep the exhaust gas within a certain range to prevent condensation By Jim Lim invented to save energy.

Gas Boiler, Heat Exchanger, Condensing, Semi-Condensing, Air Flow Control

Description

Device for control temperature of exhaust gas in proportional type gas boiler             

1 is a view showing an example of the configuration of a conventional general boiler,

2 is a view showing an example of the configuration of a conventional condensing heat exchanger,

3 is a view for explaining the structure of a heat exchanger according to the present invention;

Figure 4 is a graph showing the efficiency of the heat and boiler of the boiler and the condensing boiler according to the present invention,

5 is a flow chart for explaining the blower control action of the controller according to the present invention.

<Description of the symbols for the main parts of the drawings>

10-circulation pump, 11,31-heating heat exchanger,

12-exhaust gas temperature sensor, 13-burner,

19-blower, 20-burner,

22-sensible heat exchanger, 24-latent heat exchanger,

25-condensate, 32-controller.

The present invention relates to an exhaust gas temperature maintaining apparatus of a proportional control gas boiler for maintaining the exhaust gas temperature of a proportional control gas boiler having a means for measuring the temperature of the exhaust gas at a preset temperature. The present invention relates to an exhaust gas temperature maintaining apparatus of a proportional control gas boiler for controlling the air volume of the blower so that the exhaust gas can be maintained in a certain temperature range.

Boilers used for heating and hot water supply in general households can be divided into oil boilers and gas boilers according to the fuel used, and are divided into general boilers and condensing boilers according to the recovery method of combustion heat for heating heating water.

In general boilers, the water in the heat exchanger is heated using combustion heat generated when burning fuel, and the regenerated water is forced to circulate to the heating pipe to heat the room or circulate to the hot water pipe to use hot water in the bathroom or kitchen. To make it work.

1 is a view showing an example of the configuration of a conventional general boiler, forcibly circulating the internal water by the circulation pump 10 during heating to absorb the heat of combustion of the burner 13 in the heating heat exchanger 11 to increase the temperature, three way According to the operation of the side 14 to supply to the heating pipe 15 to be used for indoor heating while the hot water is used when the internal heat of the internal heat of the boiler directly supplied to the hot water outlet 16 or as shown in the heating heat exchanger The hot water absorbed by 11 is supplied to the hot water heat exchanger 17 so that the direct water introduced into the direct inlet 18 absorbs the heat that the hot water heat exchanger 17 has. It serves to supply. At this time, a predetermined amount of air and gas are supplied to the burner 13 by the blower 19 to burn the exhaust gas of high temperature, and the exhaust gas is heat-exchanged in the heating heat exchanger 11 and then the outside through the exhaust port. To be discharged. The exhaust port is provided with an exhaust gas temperature sensor 12 for measuring the temperature of the exhaust gas.

The heat exchanger, that is, the heating heat exchanger of the general boiler is generally made of copper material having excellent thermal conductivity, and is controlled so that heat exchange can be performed at an efficiency of 75 to 80% to prevent condensation.

2 is a view showing an example of a configuration of a conventional condensing heat exchanger, for example, a diagram showing an upward combustion condensing heat exchanger. Heat exchanger uses the latent heat of the exhaust gas which has passed through the sensible heat exchanger 22 together with the sensible heat exchanger 22 which directly heats the internal water in the heat exchange pipe 21 using the heat burned by the burner 20. It consists of a latent heat exchanger (24) which indirectly heats the internal water in the pipe (23). The condensate receiver 25 and the guide plate 26 are for guiding the flow of the exhaust gas so that the exhaust gas can transfer heat to the latent heat exchanger 24 for a sufficient time in the latent heat exchanger 24. The receiver 25 is for discharging condensate generated in the latent heat exchanger 24 to the outside. And the heating water and hot water are circulated in a similar manner to the ordinary boiler. As described above, the internal water pipe (hereinafter, referred to as 'heating water') heated by absorbing combustion heat of fuel in the heat exchanger of the boiler is heated to about 50 to 80 ° C, and is discharged through the outlet for heating and hot water use. . The sensible heat exchanger 22 is manufactured using a copper material having excellent thermal conductivity as in a general boiler, and the latent heat exchanger 24 is made of a corrosion resistant material such as aluminum or stainless steel to produce condensed water when it comes into contact with exhaust gas. To prevent it.

On the other hand, when the boiler is operated to heat or use hot water as described above, controlling the fire power of the boiler in proportion to the heating area or hot water consumption, that is, in proportion to the load, is called proportional control. The method of controlling the gas control valve in the above-described gas boiler includes an air proportional control method and a current proportional control method, and are controlled by a controller installed in the boiler to control the overall operation of the boiler.

The boiler controller has a function of controlling to provide a thermal power according to the load in order to supply the heating water of the temperature set by the user. For example, a gas boiler with a maximizing force of 20,000 kcal / h uses 5 liters of hot water at 40 ° C per minute (when the temperature of the direct water supplied through the tap water is 15 ° C and the gas boiler efficiency is 80%). The load, or required thermal power, is (40-15) × 5 × 60 / 0.8 = 9,375 kcal / h. Therefore, the gas volume is controlled to 46.88% of the maximum capacity of the gas boiler to provide a firepower suitable for the load. Typically, the proportional control range is widened by controlling the air supply required for gas combustion to achieve an optimal combustion state. In this case, controlling the gas amount in accordance with the required fire power and interlocking the air amount is called current proportional control, and controlling the air amount in accordance with the required fire power and interlocking the gas amount is called air proportional control.

In a boiler designed for heat exchange for maximum thermal power, when combustion is performed with minimum thermal power in proportional control range, the temperature of exhaust gas is lowered below 100 ℃, and water droplets form in the chimney and the heat exchanger surface as dew forms. And corrosion occurs in the heat exchanger. Therefore, the proportional control range should be limited until the exhaust gas temperature drops below 100 ℃.

The exhaust gas temperature is related to the efficiency of the boiler. When the thermal power obtained by combustion in the burner is sufficiently heat exchanged, the temperature of the exhaust gas going to the chimney will be low and vice versa. In general, in the proportional control gas boiler, the temperature of the exhaust gas is designed to be in the range of up to 180 ° C to at least 105 ° C, and thus there is a problem in that efficiency is lowered when supplying the maximum force.

The present invention has been invented in view of the above circumstances, by adding a heat exchanger made of the same material to a conventional heat exchanger having an efficiency of 80% to increase the heat transfer area to improve boiler efficiency, and heat transfer In order to prevent condensate from occurring at low thermal power by increasing the area, by controlling the air flow rate according to the temperature change of the exhaust gas, the exhaust gas is kept at a constant temperature, thereby improving the efficiency of the boiler and saving energy. It is an object of the present invention to provide an exhaust gas temperature maintaining apparatus of a proportionally controlled gas boiler that does not cause corrosion even when the heat exchanger is expanded to the same material in consideration of thermal conductivity, since condensate is not generated even when the heat transfer area is increased. .

The present invention for realizing the object as described above, the heat exchanger for heating the heating water using the heat burned by the burner, the exhaust is installed in the exhaust port to sense the temperature of the exhaust gas discharged after heat exchange by the heat exchanger In the control device of the proportional control gas boiler having a gas temperature sensor, a blower for supplying the air required to burn the gas, a controller for controlling the overall operation of the boiler including the burner and the exhaust gas temperature sensor and the blower, When the controller determines that the temperature sensed by the exhaust gas temperature sensor falls below a reference temperature set to a temperature at which condensation may occur in the heat exchanger, the controller is configured to drive the blower at the maximum rotational speed. Condensation by maintaining exhaust gas temperature within a certain range by reducing heat exchange time Characterized in that it is to prevent.

In the above, the heat exchanger is characterized in that designed with an efficiency of 85%.

Hereinafter, the configuration and operation according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view for explaining the structure of the heat exchanger according to the present invention, in which the heat transfer area of the heat exchanger 31 is enlarged than the heat transfer area of the heat exchanger 11 shown in FIG. Since different and other components are the same as those shown in FIG. 1, the same reference numerals are used to describe the same elements, and detailed descriptions thereof will be omitted to avoid overlapping descriptions.

In the heating heat exchanger 31 according to the present invention, the heat transfer area is enlarged so that the maximum efficiency is designed to be about 85%, whereas the conventional heat exchanger is designed to have a maximum efficiency of about 80%. The fin tube constituting) is shown in a state in which the fin tube is increased by one row compared with the conventional heating heat exchanger 11 shown in FIG. 1. The increase of the fin tube is just an example and is intended to indicate that the heat transfer area is increased compared with the conventional, and as described above, the maximum efficiency is designed to increase the efficiency by about 5% compared to the conventional, with the maximum efficiency of about 85%. It will be able to reap.

On the other hand, the controller 32 for controlling the overall operation of the boiler is to control the operation of the boiler aimed at the room temperature set value by the user, the heating heat exchanger 31 according to the present invention is the same as the conventional thermal power, but the heat transfer area In this expanded state, in a low thermal power state, condensation may occur at an upper end of the heating heat exchanger 31 to corrode the heating heat exchanger 31.

In order to prevent this, in the present invention, as shown in FIG. 4, when a condition in which the condensation may occur in the heating heat exchanger 31 is formed, the blower 19 is driven at the maximum rotation speed to increase the discharge rate of the exhaust gas. Doing. Increasing the exhaust velocity of the exhaust gas reduces the contact time between the heating heat exchanger 31 and the exhaust gas, that is, the heat exchange time, so that the heat transfer efficiency is reduced, but the exhaust gas does not drop to a temperature sufficient to condense.

Here, the condition that condensation may occur in the heating heat exchanger 31 is about when the temperature of the exhaust gas passing through the exhaust port is approximately 105 ° C. Therefore, the controller 32 drives the blower 19 at the maximum rotation speed when it is determined that the exhaust gas detected by the exhaust gas temperature sensor 12 decreases to about 105 ° C as the fire power by the burner 13 is lowered. To control it.

Figure 4 is a graph showing the efficiency of the boiler, the general boiler and the condensing boiler in accordance with the present invention.

As shown, for example, a typical boiler exhibits an efficiency of about 75% when the maximizing force is 30,000 [kW] and about 82% when the minimizing force is 15,000 [kPa], and the condensing boiler has a maximizing force of 30,000 [kW]. 85%, exhibits an efficiency of about 98% when the minimum force is 15,000 [5,000], the boiler according to the present invention is 80% when the maximum force is 30,000 [㎉], 82% when the minimum force is 15,000 [㎉] It is designed to show the degree of efficiency.

In particular, the boilers and condensing boilers have a relatively proportional increase in efficiency as heat is reduced from maximizing force to minimizing force, but in boilers according to the present invention, for example, the efficiency from 30,000 [kPa] to 25,000 [kPa] is maximized. It can be seen that it increases relatively proportionally and is constant at about 82% below 25,000 [㎉]. This is because the heat quantity is determined to be condensation from 25,000 [㎉] or less, and since the controller 32 drives the blower 19 at the maximum rotation speed, heat exchange time is reduced and efficiency is not increased. Here, the time of driving the blower is not specified as 25,000 [㎉], but is merely an example for description, and it will be apparent to those skilled in the art that it may be changed according to the specifications of the boiler.

5 is a flow chart for explaining the blower control action of the controller according to the present invention.

When the controller 32 detects the operation of the burner 13, the controller 32 periodically receives a detection temperature signal from the exhaust gas temperature sensor 12, and compares it with a preset reference temperature to determine whether the controller 32 is lower than the reference temperature. Perform the steps. The reference temperature is a temperature corresponding to a critical temperature at which the condensation is expected to occur during the heat exchange in the heating heat exchanger 31 when the exhaust gas temperature drops below a certain temperature by observing the exhaust gas temperature passing through the exhaust port. .

In the determination step, the controller 31 drives the blower 19 at the maximum rotational speed at the moment when it is determined that the exhaust gas temperature falls below the reference temperature.

Accordingly, the exhaust gas is discharged to the exhaust port while performing heat exchange with the heating heat exchanger 11 at a speed faster than the normal heat exchange time. That is, the exhaust gas is discharged to the exhaust port in a state in which the temperature does not drop enough to cause condensation because the heat exchange time is not sufficiently exchanged. Therefore, as described on the basis of Figure 4, the low thermal power does not improve the efficiency sufficiently, but as a whole it is possible to achieve an energy saving effect by showing a higher efficiency than a general boiler.

As described above, the present invention can save energy by increasing the heat transfer area of the heat exchanger to have a boiler efficiency of 85%, which does not improve the efficiency of the boiler by more than 80% due to the generation of condensate in a general boiler. In addition, by eliminating the possibility of condensate generated by increasing the heat transfer area, there is an advantage that the heat exchanger can be made of a copper material having good thermal conductivity.

Claims (2)

Heat exchanger that heats the heating water using the heat burned by the burner, exhaust gas temperature sensor which is installed in the exhaust port and detects the temperature of the exhaust gas discharged after heat exchange by the heat exchanger, and supplies the air necessary for the gas to burn In the control device of the proportional control gas boiler having a blower, the burner and the exhaust gas temperature sensor and a controller for controlling the overall operation of the boiler including the blower, wherein the controller is detected by the exhaust gas temperature sensor When the temperature is determined to fall below the reference temperature set to the temperature at which the condensation can occur in the heat exchanger is configured to drive the blower at the maximum rotation speed, by reducing the heat exchange time of the exhaust gas to a certain range Proportional control, characterized in that to prevent condensation Exhaust gas temperature-holding device of the boiler. The apparatus of claim 1, wherein the heat exchanger is designed with an efficiency of 85%.

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