GB1562536A - Apparatus for determining the efficiency of a heating appliance - Google Patents
Apparatus for determining the efficiency of a heating appliance Download PDFInfo
- Publication number
- GB1562536A GB1562536A GB50550/77A GB5055077A GB1562536A GB 1562536 A GB1562536 A GB 1562536A GB 50550/77 A GB50550/77 A GB 50550/77A GB 5055077 A GB5055077 A GB 5055077A GB 1562536 A GB1562536 A GB 1562536A
- Authority
- GB
- United Kingdom
- Prior art keywords
- heating appliance
- flue gases
- air
- computing device
- carbon dioxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D1/00—Measuring arrangements giving results other than momentary value of variable, of general application
- G01D1/16—Measuring arrangements giving results other than momentary value of variable, of general application giving a value which is a function of two or more values, e.g. product or ratio
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
- F23N5/006—Systems for controlling combustion using detectors sensitive to combustion gas properties the detector being sensitive to oxygen
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2223/00—Signal processing; Details thereof
- F23N2223/08—Microprocessor; Microcomputer
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/26—Details
Description
(54) APPARATUS FOR DETERMINING THE EFFICIENCY OF
A HEATING APPLIANCE
(71) We, N.V. NEDERLANDSE GASUNIE, a Netherlands Limited Liability
Company, of P.O. Box 19, Groningen, The
Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to apparatus for determining the efficiency of a heating appliance, which apparatus comprises measuring instruments for generating electrical signals responsive to the temperature, and to the oxygen content or the carbon dioxide content, of flue gases leaving the heating appliance.
The efficiency of heating appliances for example central heating installations, geysers and boilers may be measured according to the equation
heat applied-heat of flue gases '1= heat supplied
The heat supplied is the amount of calories theoretically produced by complete combustion of the fuel used. The degree of efficiency Is affected by the design and operating conditions, particularly the fuel/air ratio.The percentage of heat loss (heat supplied-heat of flue gases), is approximately represented by Siegert's equation T-t w = f , in which
[CO2]
w = percentage heat loss at complete
combustion;
f = the so-called Siegert coefficient,
which is dependent on the fuel; T = the temperature of the flue gases
"C; t = the temperature of the combus
tion air supplied, OC; [CO2] = the carbon dioxide content of the
flue gases, % by vol.
Sieger's coefficient, f, is not quite constant for any given fuel, but is to some degree dependent on the carbon dioxide content of the flue gases, [CO2].
If not the carbon dioxide content but the oxygen content of the exit gases is measured, the percentage loss is approximately represented by a similar equation T-t
w = f' --------- , in which [O2]atm - [O2] a = a coefficient (different from f) dependent on the fuel; [ 2] = the oxygen content of the flue gases,
% by vol.; [O2]atm '= the oxygen content at atmo
spheric pressure of the combus
tion air supplied, % by vol.
In most instances the oxygen content of the combustion air is 21%.
It is found in practice that the heating appliance is not adjusted for optimum efficiency. One reason is that the separate measuring of the carbon dioxide or oxygen content and the temperature of the flue gases, and the calculation from these measurements of the efficiency by means of Siegert's equation, is too complicated and time-consuming for the average operator. Thus there is a requirement for apparatus which can indicate simply and rapidly the degree of operating efficiency and also for indicating the cause of the operating efficiency not being at a maximum.
It is the object of the invention to provide apparatus which will fulfil the above requirement.
The invention provides apparatus for determining the efficiency during operating of a heating appliance, which apparatus comprises measuring instruments for generating electrical signals responsive to the temperature, and to the oxygen content or the carbon dioxide content of the flue gases leaving the heating appliance, characterized in that the said measuring instruments are connected to a computing device capable of digital presentation of the operating efficiency (Q) after it has computed the said quantity Q from the measuring data received in the form of the said electric signals, in accordance with the equation::
{[%l$' t]c1 r or #= B-###### + C # #r@ in which [ 2] = the measured oxygen content of
the flue gases, % by vol.; [Oiatm = the oxygen content at atmo
spheric pressure of the combus
tion air supplied, % by vol.;
[CO2] = the measured carbon dioxide con
tent of the flue gases, % by vol.;
A, B, C, D = constants that are pre-set into
the said computing device
and whose values depend on
the fuel used in the said
heating appliance;
AT = the difference between the tem
perature T of the flue gases and
a reference temperature.
Usually the temperature of the combustion air supplied is taken as the reference temperature, and [O]-atm iS put equal to 21%.
For any given fuel the quantity D is determined by:
lower calorific value
D = -------- X 100% upper calorific value
The apparatus according to the invention is particularly suitable for determining the efficiency of heating appliances using natural gas as fuel, e.g. containing 81.3% CH4, 14.4%
N2 and 0.9% CO2. The values of A, B and
C for Groningen natural gas and for arbitrarily chosen types of domestic heating oil, fuel oil and coke are set forth in the accompanying
Table.
w A B C Groningen natural gas 0.78 0.34 0.C076 Domestic heating oil 0.67 0.48 0.0075 Fuel oil 0.67 0.51 0.0062 Coke 0.84 0.69 0.OQ43 For other types of gas, oil or coke different
values may apply. The constants A, B, C and
D usually have the following values:
A: between 0.6 and 0.9
B: between 0.3 and 0.8
C: between 0.004 and 0.009
D: between 75 and 95.
Apparatus according to the invention for use in efficiency measurements on heating appliances firing different types of fuel is preferably provided with means for setting the constants A or B, C and D to the values for the particular fuel used.
For natural or synthetic gas as fuel, the constants A or B, C and D are preferably adjusted or adjustable to values not differing from the following values by more than 10%:
A = 0.78
B = 0.34
C = 0.0076
D = 90.
So as to provide an indication of the cause of a possible failure of a heating appliance to reach the optimum efficiency, apparatus according to the invention is preferably provided with means by which also the measured temperature T, can be presented in digital form and/or means by which also the air excess (n), the air factor (as hereinafter defined), the measured oxygen content, [ 2] and/or the measured carbon dioxide content, [CO2], can be presented in digital form.It is preferred that the apparatus is of such design that the computing device can present the 'air excess' (n) in digital form as a per centage, after having computed this quantity from the measuring datum in the form of the abovementioned electric signals in accordance with the equation: [O2] n = - X 100% [O2] or: stm [CO2] - [CO2]
n = < X 100%, [CO2] in which:
n = the air excess, /O; [CO2] = the maximum possible value max of the carbon dioxide content of the ue flue gases, % by vol, for the fuel used in the heating appliance, i.e. the value holding at stoichiometric quantity of the air supplied and for complete combustion; and [O2], [O2] [CO2] have the same mean atom, ings as explained before.
It is also possible to have the apparatus present the air factor (L), as a ratio in digital form. The term 'air factor' is hereby defined as a quantity L satisfying the following equation: Q
L = ss in which
Qe X Q = the quantity of air supplied; Q < -i") = the minimum quantity of combus- tion air required for stoichiometroic combustion.
Also the 'air factor' can be calculated from the measured oxygen or carbon dioxide content; however, preference is given to the use of the 'air excess' as defined above.
If the apparatus according to the invention is of such design that the computing device can determine the air excess n from [CO2], as indicated above, the apparatus is preferably provided with means for setting the quantity [CO2] to a value in accordance max with the fuel fired by the heating appliance.
For Groningen natural gas [CO2] 11.8%.
The invention is hereinafter particularly described and illustrated in the accompanying drawing, which is a schematic representation of one embodiment of a device according to the invention.
The features in the drawing have the following references:
1. A heating appliance firing natural gas;
2. A flue for the removal of flue gases
from the heating appliance 1;
3. An exhaust pyrometer by means of
which hot flue gases can be drawn
from the flue 2 at about the place
where this joins the heating appliance
1;
4. The suction tube of the exhaust pyro
meter 3;
5. A thermocouple by means of which
the temperature of the hot flue gases
drawn off by the exhaust pyrometer
can be measured;
6. A fan by means of which flue gases
can be drawn off through the suction
tube;
7. A cooler for cooling the gas drawn off;
8. A fan by means of which cooling air
can be drawn through the cooler 7;
9. A gas line (pipe or flexible tube) con
necting to the fan 6, for further con
ducting the cooled combustion gas to:
10.An analyzer which receives cooled
combustion gases through the line 9
and can generate an electric signal
commensurate with the carbon dioxide
content of the combustion gases;
11. A measuring circuit connected to the
thermocouple 5 and capable of generat
ing an electric signal commensurate
with the measured temperature, T, of
the hot combustion gases;
12. An electronic computing device which
receives the output signals of the
analyzer 10 and the temperature
measuring circuit 11, and is capable
of computing therefrom the efficiency '1 and the air excess n, as hereinbefore
referred to;
13. A selector switch by means of which
the applicable values of the required
constants can be simultaneously set in
the computing device 12 for a given
type of fuel.This switch is shown as a
rotary switch, but may be of a different
type e.g. a switch with selector buttons;
14. A digital display unit connected to
the computing device 12, presenting in
digital form the air excess (n), the
temperature of the combustion gases
(T,), and the efficiency 11; 15. A casing, accommodating parts 10 to
14.
WHAT WE CLAIM IS:
1. Apparatus for determining the efficiency during operation of a heating appliance, which apparatus comprises measuring instruments for generating electrical signals responsive to the temperature and to the oxygen content or carbon dioxide content of the tiue gases leaving the heating appliance, characterized in that the said measuring instruments are connected to a computing device capable of digital presentation of the operating efficiency (rl) after having computed the said quantity Q from the data received in the form of the said electric signals, in accordance with the equation:
# = D - # ###########C# #r or
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (12)
1. A heating appliance firing natural gas;
2. A flue for the removal of flue gases
from the heating appliance 1;
3. An exhaust pyrometer by means of
which hot flue gases can be drawn
from the flue 2 at about the place
where this joins the heating appliance
1;
4. The suction tube of the exhaust pyro
meter 3;
5. A thermocouple by means of which
the temperature of the hot flue gases
drawn off by the exhaust pyrometer
can be measured;
6. A fan by means of which flue gases
can be drawn off through the suction
tube;
7. A cooler for cooling the gas drawn off;
8. A fan by means of which cooling air
can be drawn through the cooler 7;
9. A gas line (pipe or flexible tube) con
necting to the fan 6, for further con
ducting the cooled combustion gas to:
10.An analyzer which receives cooled
combustion gases through the line 9
and can generate an electric signal
commensurate with the carbon dioxide
content of the combustion gases;
11. A measuring circuit connected to the
thermocouple 5 and capable of generat
ing an electric signal commensurate
with the measured temperature, T, of
the hot combustion gases;
12. Apparatus according to Claim 1, substantially as hereinbefore described with particular reference to the drawing.
12. An electronic computing device which
receives the output signals of the
analyzer 10 and the temperature
measuring circuit 11, and is capable
of computing therefrom the efficiency '1 and the air excess n, as hereinbefore
referred to;
13. A selector switch by means of which
the applicable values of the required
constants can be simultaneously set in
the computing device 12 for a given
type of fuel.This switch is shown as a
rotary switch, but may be of a different
type e.g. a switch with selector buttons;
14. A digital display unit connected to
the computing device 12, presenting in
digital form the air excess (n), the
temperature of the combustion gases
(T,), and the efficiency 11;
15. A casing, accommodating parts 10 to
14.
WHAT WE CLAIM IS:
1. Apparatus for determining the efficiency during operation of a heating appliance, which apparatus comprises measuring instruments for generating electrical signals responsive to the temperature and to the oxygen content or carbon dioxide content of the tiue gases leaving the heating appliance, characterized in that the said measuring instruments are connected to a computing device capable of digital presentation of the operating efficiency (rl) after having computed the said quantity Q from the data received in the form of the said electric signals, in accordance with the equation::
# = D - # ###########C# #r or
0 D [ ss C ] AT
in which
[02] = the measured oxygen content of
the flue gases, % by vol.; [ 2] atm = the oxygen content of the com
bustion air supplied, % by vol.;
[CO2] = the measured carbon dioxide con
tent of the flue gases, % by vol.;
A, B, C, D = constants that are pre-set into
the said computing device
and whose values depend on
the fuel used in the said
heating appliance;
AT = rhe difference between the tem
perature T of the flue gases and
a reference temperature.
2. Apparatus according to Claim 1, provided with setting means for setting the quantities A or B, C and D in the said computing device for values for fuel to be used in the said heating appliance.
3. Apparatus according to Claim 1 or
Claim 2, wherein the quantities A or B and
C and D are adjusted or adjustable between the values:
A: between 0.6 and 0.9;
B: between 0.3 and 0.8;
C: between 0.004 and 0.009;
D: between 75 and 95.
4. Apparatus according to Claim 3, wherein the said quantities A or B, C and D are adjusted or adjustable to values not differing from the following values by more than 10%:
A = 0.78;
B = 0.34;
C = 0.0076;
D = 90.
5. Apparatus according to any of Claims 1 to 4, wherein the measured flue gas temperature, T, is presentable in digital form.
6. Apparatus according to any of Claims
1 to 5, wherein the air excess, the air factor (as hereinbefore defined), the measured oxygen content, [02), or the measured carbon dioxide content, [CO2], is presentable in digital form.
7. Apparatus according to Claim 6, wherein the computing device can present a quantity n in digital form after having computed the
said quantity n from the measuring data re
ceived in the form of the said electric signals,
in accordance with the equation: [O2] n = - X 100% [ 2] or lltm [CO2] - [CO2] n = > 3t X 100%
[CO2]
in which:
n = the air excess, %; [CO2] = the maximum possible value
max of the carbon dioxide content of the flue gases, % by vol., for a particular fuel used in the heating appliance; and [O2], [ 2] [CO2] have the meanings
atTn, set forth in Claim 1.
8. Apparatus according to Claim 7, provided with means for measuring the carbon dioxide content [CO2] of the flue gases, and with means for setting the quantity [CO2]
max to a value in accordance with the fuel to be used by the said heating appliance.
9. Apparatus according to any of Claims 1 to 8, wherein a selector switch is provided by means of which the values of the required constants A, B, C, D and [CO2] can be
max simultaneously set in the computing device for a given type of fuel.
10. Apparatus according to any one of
Claims 1 to 9, provided with an exhaust pyrometer for determining the temperature T of the flue gases.
11. Apparatus according to Claim 10, wherein the said exhaust pyrometer also serves for aspirating sample gas for the determination of [O2] or [CO2].
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7613622A NL7613622A (en) | 1976-12-08 | 1976-12-08 | DEVICE FOR DETERMINING THE EFFICIENCY OF A STOVE. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1562536A true GB1562536A (en) | 1980-03-12 |
Family
ID=19827350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB50550/77A Expired GB1562536A (en) | 1976-12-08 | 1977-12-05 | Apparatus for determining the efficiency of a heating appliance |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE2753485A1 (en) |
| FR (1) | FR2373779A1 (en) |
| GB (1) | GB1562536A (en) |
| NL (1) | NL7613622A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423487A (en) * | 1979-11-23 | 1983-12-27 | Neotronics Limited | Apparatus for measuring the efficiency of combustion appliances |
| US4565788A (en) * | 1983-02-23 | 1986-01-21 | Milovidov Boris A | Method of determining heat losses due to incomplete fuel combustion |
| US4685072A (en) * | 1981-12-10 | 1987-08-04 | The Babcock & Wilcox Company | Steam generator on-line efficiency monitor |
| US4815965A (en) * | 1983-05-12 | 1989-03-28 | Applied Automation, Inc. | Monitoring and control of a furnace |
| US7720635B2 (en) | 2004-02-20 | 2010-05-18 | Martin Donath | Determination of the connected heating load of a building |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2470371B1 (en) * | 1979-11-23 | 1985-09-13 | Neotronics Ltd | APPARATUS FOR MEASURING THE EFFICIENCY OF A COMBUSTION INSTALLATION |
| DE3039994A1 (en) * | 1980-10-23 | 1982-05-06 | Karl Dungs Gmbh & Co, 7067 Urbach | METHOD FOR SETTING COMPONENT CONTROLLERS FOR BURNERS IN HEAT GENERATING SYSTEMS |
| CH670149A5 (en) * | 1985-10-28 | 1989-05-12 | Landis & Gyr Ag | |
| AT397715B (en) * | 1989-10-31 | 1994-06-27 | Prueller Josef | Furnace, in particular for solid-fuel heating boilers |
-
1976
- 1976-12-08 NL NL7613622A patent/NL7613622A/en not_active Application Discontinuation
-
1977
- 1977-12-01 DE DE19772753485 patent/DE2753485A1/en not_active Ceased
- 1977-12-05 GB GB50550/77A patent/GB1562536A/en not_active Expired
- 1977-12-08 FR FR7736993A patent/FR2373779A1/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423487A (en) * | 1979-11-23 | 1983-12-27 | Neotronics Limited | Apparatus for measuring the efficiency of combustion appliances |
| US4685072A (en) * | 1981-12-10 | 1987-08-04 | The Babcock & Wilcox Company | Steam generator on-line efficiency monitor |
| US4565788A (en) * | 1983-02-23 | 1986-01-21 | Milovidov Boris A | Method of determining heat losses due to incomplete fuel combustion |
| US4815965A (en) * | 1983-05-12 | 1989-03-28 | Applied Automation, Inc. | Monitoring and control of a furnace |
| US7720635B2 (en) | 2004-02-20 | 2010-05-18 | Martin Donath | Determination of the connected heating load of a building |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2373779A1 (en) | 1978-07-07 |
| DE2753485A1 (en) | 1978-06-15 |
| NL7613622A (en) | 1978-06-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |