JPH09280552A - Combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve energy saving while eliminating problems on a drain and the amount of production of NOx. SOLUTION: Air supply amount set means 2A sets the amount of supply of combustion air to a burner 12 such that an air excess rate is increased as a fuel supply amount is increased in response to the fuel supply amount. The combustion air supply amount is set such that heat efficiency indicative of a rate of the amount of heat produced by combustion of a fuel supplied to the burner 12 to a heat amount provided to a heat medium in a heat exchanger 13 is set such that a value of the fuel supply amount when it is a minimum within an adjustment range thereof is larger than a value wheren it is a maximum within an adjustment range therof, and when the fuel supply amount falls between the maximum and the minimum in the adjustment region the combustion air supply amount is set such that it is the minimum value within the adjustment range or more and it is the minimunm value within the adjustment range or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner for heating a heat exchanger for heating a heating medium, a fuel supply amount adjusting means for adjusting a fuel supply amount to the burner, and a combustion air supply to the burner. An air supply amount adjusting means for adjusting the amount, and an air supply amount setting means for setting the combustion air supply amount according to the fuel supply amount so that the excess air ratio increases as the fuel supply amount increases. The present invention relates to a combustion apparatus provided with a control unit that controls the operation of the air supply amount adjusting unit so that the combustion air supply amount is set by the air supply amount setting unit.

[0002]

2. Description of the Related Art Conventionally, an air supply amount setting means has been configured to set a combustion air supply amount as described below. That is, as shown in FIG. 5, regardless of the fuel supply amount F, the excess air ratio α increases in accordance with the fuel supply amount F as the fuel supply amount F increases so that the thermal efficiency R is maintained constant. Thus, the combustion air supply amount is set according to the fuel supply amount F so that the excess air ratio α thus set is obtained.

The thermal efficiency is indicated by the ratio of the amount of heat given to the heat medium in the heat exchanger to the amount of heat generated by burning the fuel supplied to the burner. That is, F is the amount of fuel supply, C is the amount of heat generated when a unit amount of fuel is burned, and T is the temperature at which the heat medium flows into the heat exchanger.
i, the outflow temperature of the heat medium from the heat exchanger is To, the flow rate of the heat medium is Qi, and the heat capacity of the heat medium is D, the thermal efficiency R is
It is calculated from the following formula. R = {(To-Ti) × Qi × D} ÷ (F × C) ……………… (1)

In other words, increasing the thermal efficiency means decreasing the excess air ratio. Therefore, the higher the thermal efficiency, the higher the temperature of the combustion gas in the burner, and the higher the outflow temperature of the heat medium from the heat exchanger, which is advantageous in terms of energy saving. (Hereinafter, NOx) and condensed water that corrodes the heat exchanger (hereinafter, drain) are increased in amount, which is a problem.

Therefore, conventionally, as shown in FIG. 5, when the fuel supply amount F is the maximum within the adjustment range (hereinafter sometimes referred to as the maximum fuel supply amount F _max ), the amount of drainage and NOx generation is as but equal to or less than the allowable value that does not cause a problem, set the thermal efficiency R (e.g., about 80% or less, thus setting the thermal efficiency R may be referred to as maximum input Tokinetsu efficiency value R _a), the fuel supply Quantity F
Regardless of this, the combustion air supply amount is adjusted so that the thermal efficiency R is maintained at the maximum input thermal efficiency value _Ra , so that the drainage and NOx generation amount do not become a problem.

[0006]

However, the conventional combustion apparatus has no problem in terms of the amount of drainage and NOx generated, but there is still room for improvement in terms of energy saving.

The present invention has been made in view of the above circumstances, and an object thereof is to improve energy saving while not causing a problem in terms of the amount of drainage and NOx generation.

[0008]

[Means for Solving the Problems] If the thermal efficiency is the same,
As the fuel supply amount decreases, the amount of drain and NOx generated decreases. Therefore, when the fuel supply amount is smaller than the maximum value, the thermal efficiency can be set to a value larger than the maximum input thermal efficiency value while the drainage and NOx generation amounts are suppressed to the allowable values or less.

The present invention is based on the above point of view, and in the characteristic configuration according to claim 1, drainage and NOx are provided.
With the amount of generation kept below the allowable value, the thermal efficiency is the value when the fuel supply amount is the minimum within the adjustment range, and the value when the fuel supply amount is the maximum within the adjustment range, that is, the maximum input. When the fuel supply amount is between the maximum and the minimum within the adjustment range, the fuel supply amount is equal to or higher than the maximum input thermal efficiency value and the fuel supply amount is the minimum within the adjustment range. To be less than or equal to the value when
The amount of combustion air supplied is set. Based on the above viewpoint, when the fuel supply amount is the minimum within the adjustment range, the thermal efficiency can be set to the maximum, so that the thermal efficiency is set to the maximum when the fuel supply amount is the minimum within the adjustment range. When the value is set to the maximum and the fuel supply amount is between the maximum and the minimum within the adjustment range, it is effective in terms of energy saving if it is set below the value when the fuel supply is the minimum within the adjustment range. Becomes Therefore, it has become possible to improve energy saving while not causing a problem in terms of drainage and NOx generation amount.

By the way, although the thermal efficiency can be increased as the fuel supply amount decreases, the excess air ratio decreases as the thermal efficiency increases, and if the excess air ratio becomes too small, stable burnability of the burner is impaired. A problem occurs. Therefore, even if the thermal efficiency is increased, it is necessary to ensure the stable burnability of the burner.

Therefore, according to the characteristic construction of claim 2,
As shown in FIG. 2, the fuel supply amount F is the maximum within the adjustment range.
When small (hereinafter, minimum fuel supply amount F_minSometimes called
A), the excess air ratio that enables stable combustion of the burner
the minimum value of α_minAnd the minimum excess air ratio α_minTo
The corresponding thermal efficiency R is the maximum thermal efficiency value R_maxSet as
You. Further, within the regulation range of the fuel supply amount F, thermal efficiency
R is the maximum thermal efficiency value R _maxDrainage and N
Fuel supply that can keep the amount of Ox generated below the allowable value
Obtain the maximum value of the quantity F and set the maximum value to the set value F_Sage
To set. Then, the thermal efficiency R and the fuel supply amount F are
Set value F_SIn the above cases, the amount of drain and NOx generated is allowed
When the fuel supply amount F is large,
And the fuel supply amount F is the maximum fuel supply amount F_maxNoto
Is the thermal efficiency value R at the time of maximum input_aAnd
The fuel supply amount F is the set value F_SIf less than,
Maximum thermal efficiency R_maxSet to keep. Soshi
Fuel supply so that the thermal efficiency R set in that way is achieved.
Set the excess air ratio α according to the supply amount F and set it as such
Set the combustion air supply rate so that the excess air ratio α
You do it.

By the way, when the thermal efficiency R is set in a state where the stable burnability of the burner is ensured, for example, as shown in FIG. 3, the thermal efficiency R is set so that the fuel supply amount F is the minimum fuel supply amount F.
The value when _min is set to the maximum thermal efficiency value R _max , the value when the fuel supply amount F is the maximum fuel supply amount F _max is set to the maximum input thermal efficiency value R _a , and the fuel supply amount F is minimum. When the fuel supply amount F _{min is} between the maximum fuel supply amount F _max , the thermal efficiency R is set to be smaller as the fuel supply amount F becomes larger, or as shown in FIG. , When the fuel supply amount F is smaller than the set value Fs, the maximum thermal efficiency value R _max is maintained, and when the fuel supply amount F is equal to or larger than the set value Fs, the maximum input thermal efficiency value R _It is assumed that the setting will be maintained at a.

However, as compared with the case where the thermal efficiency is set as shown in FIGS. 3 and 4, when the burner is set as shown in FIG. 2 as in the characteristic configuration of claim 2, stable burnability of the burner is obtained. The thermal efficiency can be set as high as possible while ensuring the above. Therefore, according to the characterizing structure of claim 2, it becomes possible to improve energy saving as much as possible while not causing a problem in terms of the amount of drainage and NOx generation.

According to the third aspect of the invention, the heat medium heated by the heat exchanger is supplied to the heating device as a heat source. Since the heating device is operated for a long time, applying the present invention to a combustion device for supplying a heating medium to the heating device is preferable in terms of energy saving.

According to the fourth aspect of the invention, the heat medium heated by the heat exchanger is supplied to the floor heating device as a heat source. Among the heating devices, the floor heating device is operated for a long period of time and in a low input state in which the fuel supply amount is small. Therefore,
When the present invention is applied to a combustion device for supplying a heat medium to a floor heating device among heating devices, it is optimal in terms of energy saving.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a heat source device for a floor heating system will be described below with reference to the drawings. As shown in FIG. 1, a heat source unit H for a floor heating device as an example of a combustion device according to the present invention is a hot water generator 1
And a control unit 2 for controlling the operation of the hot water generator 1, and an operation unit 3 for instructing the control unit 2 to perform a control operation. The heating medium generated by the hot water generator 1 is supplied to the heating device. It is configured to circulate and supply to the floor heating device M as described above to heat the room.

The hot water generator 1 includes a combustion chamber 11 and a combustion chamber 1
1, a gas burner 12 provided inside 1, a heat exchanger 13 that is heated by the gas burner 12 to heat water as a heat medium, a fan 14 that supplies combustion air to the gas burner 12, and a heat exchanger. A heating return water channel 15 for supplying a heating heat medium to the heating element 13, a heating return water channel 16 for sending out the heating medium heated in the heat exchanger 13, and a fuel supply channel 17 for supplying a fuel gas to the gas burner 12. It is configured with.

In the heating return water passage 15, a water supply amount sensor 18 for detecting the flow rate Qi of the heat medium flowing through the heat exchanger 13, and an incoming water temperature sensor 19 for detecting the inflow temperature Ti of the heat medium into the heat exchanger 13. In addition, the heating outflow water channel 16 is provided with a hot water outlet temperature sensor 20 that detects the outflow temperature To of the heat medium from the heat exchanger 13. The fuel supply passage 17 is connected to a gas supply pipe for general households, and the fuel supply passage 17 includes an electromagnetic gas amount adjusting valve 21 for adjusting the fuel supply amount F to the gas burner 12 and a gas supply to the gas burner 12. An electromagnetic on-off valve 22 for intermittently supplying the fuel gas is provided. An igniter 2 for igniting the gas burner 12 is provided near the gas burner 12.
3 and a frame rod 24 for detecting the ignition. In addition, the heating return water channel 15 has a heating outward water channel 1
A pump 25 for delivering hot water from 6 is provided.

That is, the gas amount adjusting valve 21 corresponds to the fuel supply amount adjusting means, and the fan 14 corresponds to the air supply amount adjusting means.

The operation unit 3 includes an operation switch 26 for instructing the operation and stop of the heat source unit H, a temperature setting switch 27 for setting the target hot water supply temperature Ts, a display unit 28 for displaying the set target hot water supply temperature Ts, and lighting. An operation display lamp 29 and the like for displaying a state in which the heat source unit H is operated is provided.

The control unit 2 is provided with a microcomputer, and the detection information of each of the operation unit 3, the water supply amount sensor 18, the incoming water temperature sensor 19, the hot water temperature sensor 20 and the frame rod 24 is preset and stored. The fan 14, the gas amount adjusting valve 21, the opening / closing valve 22, and the igniter 2 are based on the control program based on various kinds of stored information.
3 and the pump 25 are configured to control their respective operations.

The floor heating device M is constructed by embedding a hot water flow path 5 through which a heating medium flows in a mat-like body 4 laid on the floor in a meandering manner over substantially the entire mat-like body 4. I am doing it. The inlet part of the hot water flow passage 5 is connected to the heating outward water passage 16 of the hot water generator 1, and the outlet part of the hot water flow passage 5 is connected to the heating return water passage 15 of the hot water generator 1. Then, in the hot water generator 1, the heat medium heated to the target hot water supply temperature Ts set by the temperature setting switch 26 is supplied to the hot water flow passage 5 through the heating outward water passage 16 and the hot water flow passage 5 is supplied.
Is made to flow, and then the return heat medium is supplied again to the hot water generator 1 through the heating return water channel 15.

Next, the control operation of the control unit 2 will be described. When the operation is commanded by the operation switch 26,
Operate the pump 25. When the flow rate Qi detected by the water supply amount sensor 18 exceeds the set water amount, the ignition control of the gas burner 12 and the fuel supply amount F to the gas burner 12 so that the outflow temperature To becomes the target hot water supply temperature Ts.
The rotation speed of the fan 14 and the fuel supply amount F
On the other hand, hot water supply control is executed to control the rotation speed of the fan 14 so as to reach a preset target rotation speed. When the operation switch 26 issues a stop command,
Extinguishing control is performed to stop the combustion of the gas burner 2 while stopping the pump 25.

In the ignition control, the on-off valve 22 and the gas amount adjusting valve 21 are opened to supply the fuel gas to the gas burner 2 and the igniter 18 ignites. When ignition is confirmed by the frame rod 24, the ignition control is stopped, and then hot water supply control is executed.

The hot water supply control will be described below. In advance,
As shown in FIG. 2, the thermal efficiency R and the excess air ratio α are set according to the fuel supply amount F. In addition, in FIG. 2, α _min indicates that the fuel supply amount F is the minimum fuel supply amount F.
_At the time of _min , it is the minimum value of the excess air ratio α that enables stable combustion of the gas burner 12, and the maximum thermal efficiency value R
_max is the thermal efficiency R corresponding to the minimum excess air ratio α _min
It is. F _S is within the adjustment range of the fuel supply amount F,
When the thermal efficiency R is set to the maximum thermal efficiency value R _max , it is the maximum value of the fuel supply amount F that can suppress the amount of drainage and NOx generation to the allowable value or less, and corresponds to the set value. Then, when the fuel supply amount F is equal to or more than the set value F _S , the thermal efficiency R becomes smaller as the fuel supply amount F becomes larger and the fuel amount becomes smaller as the fuel supply amount F becomes larger than the allowable value. when the supply amount F is smaller than the set value F _S, it is set to maintain the maximum heat efficiency value R _{ma x. Ra} is the value of the thermal efficiency R when the fuel supply amount F is the maximum fuel supply amount _Fmax , and corresponds to the maximum input thermal efficiency value. Further, the fuel supply amount F is set so that the thermal efficiency R set in this way is obtained.
The excess air ratio α is set accordingly.

Then, the rotational speed of the fan 14 is set in advance in accordance with the fuel supply amount F so that the relationship between the fuel supply amount F and the excess air ratio α as shown in FIG. It is stored in the control unit 2.

For example, when the maximum fuel supply amount F _max is a heat source unit H having a capacity of 12000 kcal / hour in terms of heat quantity, the set value F _S is 8000 kcal / hour, and the maximum input thermal efficiency value is _Ra to 80%,
The maximum thermal efficiency value R _max is set to 85%, respectively. In that case, the excess air ratio α when the fuel supply amount F is the maximum fuel supply amount F _max is 1.8, and the excess air ratio α when the fuel supply amount F is the set value F _S is 1.6. .

The control unit 2 controls the target hot water supply temperature Ts set by the temperature setting switch 27, the flow rate Qi detected by the water supply amount sensor 18, the inflow temperature Ti detected by the incoming water temperature sensor 19, and the hot water discharge. Based on the outflow temperature To detected by the temperature sensor 20, the outflow temperature To is set to the target hot water supply temperature Ts.
The fuel supply amount F required to satisfy Further, the gas amount adjusting valve 21 is controlled so that the calculated fuel supply amount F is obtained, and the target rotation speed corresponding to the calculated fuel supply amount F is determined from the stored target rotation speed information. And set it so that the set target speed is reached.
The fan 14 is controlled.

In the fire extinguishing control, the on-off valve 22 and the gas amount adjusting valve 21 are closed to cut off the fuel gas supply to the gas burner 2 to extinguish the gas burner 2.

Therefore, the control unit 2 is used to set the combustion air supply amount according to the fuel supply amount F such that the larger the fuel supply amount F, the larger the excess air ratio α. Amount setting means 2A and its air supply amount setting means 2A
The control means 2B for controlling the operation of the fan 14 is configured so that the combustion air supply amount set in step 1 is obtained.

Another Embodiment Next, another embodiment will be described.
You. Set value F_S, Thermal efficiency value R at maximum input_a,maximum
Thermal efficiency value R_max, Fuel supply amount F is maximum fuel supply amount F_max
At this time, the excess air ratio α and the fuel supply amount F are set values F _SNoto
The respective excess air ratios α of the mushrooms are appropriate according to the specifications of the heat source unit H.
It can be set appropriately.

The relationship between the fuel supply amount F and the thermal efficiency R is
The relationship is not limited to that shown in FIG. For example, figure
As shown in Fig. 3, the thermal efficiency is R
Supply F_{mi n}Is the maximum thermal efficiency value R_maxSet to
However, the fuel supply amount F is the maximum fuel supply amount F _maxThe value when
Thermal efficiency value R at maximum input_aSet to, fuel supply amount F
Is the minimum fuel supply F_minAnd maximum fuel supply F_maxBetween
In case of, it will decrease as the fuel supply amount F increases
It may be set to Also, as shown in FIG. 4, fuel supply
When the quantity F is smaller than the set value Fs, the maximum thermal efficiency value R_maxTo
In order to maintain, the fuel supply amount F is equal to or more than the set value Fs.
When, the maximum input thermal efficiency value R_aI'll keep
It may be set to

In the embodiment of the invention described above, the rotational speed of the fan 14 is set in advance in accordance with the fuel supply amount F so that the relationship between the fuel supply amount F and the excess air ratio α as shown in FIG. Then, it is stored in the control unit 2 as the target rotation speed, the fuel supply amount F required to bring the outlet heated water temperature To to the target hot water supply temperature Ts is calculated, and the target rotation speed corresponding to the calculated fuel supply amount F is calculated. Determine and set from the stored target speed information so that the set target speed is reached.
As an example, by controlling the fan 14, the thermal efficiency R is controlled according to the fuel supply amount F as shown in FIG.

Instead of this, the actual value of the thermal efficiency R is obtained, and the fan 14 is controlled so that the obtained thermal efficiency R becomes as shown in FIG. 2 according to the fuel supply amount F. Good. In this case, the control unit 2 may be configured to execute the following control operation, for example. That is, based on the target hot water supply temperature Ts set by the temperature setting switch 27, the flow rate Qi detected by the water supply amount sensor 18, and the inflow temperature Ti detected by the water temperature sensor 19, the fuel supply amount F And the calculated fuel supply amount F
The gas amount adjusting valve 21 is controlled so that And
The calculated fuel supply amount F, the flow rate Qi detected by the water supply amount sensor 18, the inflow temperature T detected by the incoming water temperature sensor 19.
i, and the outflow temperature T detected by the hot water temperature sensor 20
Based on o, the thermal efficiency R is calculated by the above equation (1), and the calculated thermal efficiency R is the fuel supply amount F as shown in FIG.
The fan 14 is controlled so as to have a value according to

In the embodiment of the invention described above, the case where the gas burner 12 that burns gas fuel is applied as the burner has been exemplified, but in addition to this, the burner is a liquid that burns liquid fuel such as heavy oil or petroleum. A fuel burner can be applied.

In the embodiment of the invention described above, water is applied as the heat medium, but the heat medium is not limited to water, and any heat exchangeable and fluid substance may be used.
Other chemicals dedicated to the heat medium can be applied.

In the embodiment of the invention described above, the case where the present invention is applied to the heat source device for the floor heating device is illustrated, but in addition to this, the present invention is also applied to the heat source device for various heating devices and hot water supply. It can be applied to devices and the like.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram of a heat source unit for a floor heating system.

FIG. 2 is a diagram showing a relationship between a fuel supply amount, thermal efficiency, and excess air ratio.

FIG. 3 is a diagram showing a relationship between a fuel supply amount and thermal efficiency and excess air ratio in another embodiment.

FIG. 4 is a diagram showing a relationship between a fuel supply amount and thermal efficiency and excess air ratio in another embodiment.

FIG. 5 is a diagram showing a relationship between a fuel supply amount and thermal efficiency and an excess air ratio in a conventional combustion device.

[Explanation of symbols]

 12 burner 13 heat exchanger 14 air supply amount adjusting means 21 fuel supply amount adjusting means 2A air supply amount setting means 2B control means M heating device

Claims (4)

[Claims] 1. A burner (12) for heating a heat exchanger (13) for heating a heat medium, a fuel supply amount adjusting means (21) for adjusting a fuel supply amount to the burner (12), and the burner. An air supply amount adjusting means (14) for adjusting the combustion air supply amount to (12), and the combustion air supply amount is increased according to the fuel supply amount, as the fuel supply amount increases, the excess air ratio increases. The air supply amount setting means (2A) to be set so that the air supply amount adjusting means (1) is set so that the combustion air supply amount is set by the air supply amount setting means (2A).
4) A combustion device provided with a control means (2B) for controlling the operation of the burner (1).
In the heat generation amount generated by the combustion of the fuel supplied to 2), the thermal efficiency indicating the ratio of the heat transfer amount given to the heat medium in the heat exchanger (13) is set within the control range of the fuel supply amount. The fuel supply so that the value at the minimum is greater than the value at the maximum when the fuel supply amount is within the adjustment range, and when the fuel supply amount is between the maximum and the minimum within the adjustment range. Combustion configured to set the combustion air supply so that the amount is equal to or greater than the maximum value within the adjustment range and is equal to or less than the minimum value within the adjustment range. apparatus. 2. The air supply amount setting means (2A) reduces the thermal efficiency as the fuel supply amount increases, when the fuel supply amount is equal to or greater than a set value corresponding to an intermediate portion within the adjustment range. And when the fuel supply amount is smaller than the set value, the combustion air supply amount is set so as to maintain the thermal efficiency at the value when the fuel supply amount is the set value. The combustion apparatus according to claim 1, which is provided. 3. The combustion device according to claim 1, wherein the heat medium heated by the heat exchanger (13) is configured to be supplied as a heat source to the heating device (M). 4. The combustion device according to claim 3, wherein the heating device (M) is a floor heating device.