CA2251390A1 - Thermostat control system for a furnace - Google Patents
Thermostat control system for a furnace Download PDFInfo
- Publication number
- CA2251390A1 CA2251390A1 CA002251390A CA2251390A CA2251390A1 CA 2251390 A1 CA2251390 A1 CA 2251390A1 CA 002251390 A CA002251390 A CA 002251390A CA 2251390 A CA2251390 A CA 2251390A CA 2251390 A1 CA2251390 A1 CA 2251390A1
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- Prior art keywords
- thermostat
- heating element
- temperature
- maximum
- signal
- 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.)
- Abandoned
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- 238000010438 heat treatment Methods 0.000 claims abstract description 70
- 230000000007 visual effect Effects 0.000 claims abstract description 13
- 230000003213 activating effect Effects 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 11
- 239000012790 adhesive layer Substances 0.000 claims description 5
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- 241000282849 Ruminantia Species 0.000 claims description 3
- 238000009434 installation Methods 0.000 abstract description 2
- 230000008901 benefit Effects 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 239000000523 sample Substances 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 230000009849 deactivation Effects 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 238000003306 harvesting Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000007420 reactivation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/20—Arrangement or mounting of control or safety devices
- F24H9/2064—Arrangement or mounting of control or safety devices for air heaters
- F24H9/2085—Arrangement or mounting of control or safety devices for air heaters using fluid fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/022—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/10—Control of fluid heaters characterised by the purpose of the control
- F24H15/156—Reducing the quantity of energy consumed; Increasing efficiency
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/208—Temperature of the air after heating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/254—Room temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/281—Input from user
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/305—Control of valves
- F24H15/31—Control of valves of valves having only one inlet port and one outlet port, e.g. flow rate regulating valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/345—Control of fans, e.g. on-off control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/355—Control of heat-generating means in heaters
- F24H15/36—Control of heat-generating means in heaters of burners
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/395—Information to users, e.g. alarms
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
A furnace system has the efficiency improved the addition of a second thermostat which measures the temperature in the heating chamber of the gas furnace and controls the heating element so that it is deactivated when it reaches its normal maximum operating temperature and is reactivated at a predetermined temperature drop of the order of 10°F. The second thermostat is set in installation by providing a manually operable adjustment for the set maximum temperature which is adjusted when the furnace reaches its normal maximum operating temperature to cause the thermostat to deactivate the heating element and to activate a visual indicator light when the thermostat is tripped. The minimum temperature is adjusted automatically with the maximum temperature so as to maintain the fixed temperature drop.
Description
THERMOSTAT CONTROL SYSTEM FOR A FURNACE
FIELD OF THE INVENTION
The present invention relates to a thermostat control system for a furnace.
BACKGROUND
The improvement of fuel efficiency of furnaces and particularly gas fired furnaces is an important goal for reduction in emissions and of fuel usage.
One established technique for improving efficiency is that of providing a duty cycle by which the furnace is cycled on and off so that ruminant heat in the heating system is extracted during each cycle before the heating element is reactivated to introduce more heat. Recent furnaces have techniques for automatically providing fuel efficiency of this type. However previous furnaces and furnaces of less complexity do not utilize a duty cycle.
Even in systems which utilize a duty cycle, this is normally controlled by a timing system. However the timing system does not provide the best advantage since it is necessarily a compromise for different operating conditions.
SUMMARY
It is one object of the invention, therefore, to provide an improved method for controlling heating of an area.
According to the present invention, therefore, there is provided a method of heating an area comprising:
providing a furnace having:
an air intake;
a fan;
a heating element;
and a heated air outlet chamber;
FIELD OF THE INVENTION
The present invention relates to a thermostat control system for a furnace.
BACKGROUND
The improvement of fuel efficiency of furnaces and particularly gas fired furnaces is an important goal for reduction in emissions and of fuel usage.
One established technique for improving efficiency is that of providing a duty cycle by which the furnace is cycled on and off so that ruminant heat in the heating system is extracted during each cycle before the heating element is reactivated to introduce more heat. Recent furnaces have techniques for automatically providing fuel efficiency of this type. However previous furnaces and furnaces of less complexity do not utilize a duty cycle.
Even in systems which utilize a duty cycle, this is normally controlled by a timing system. However the timing system does not provide the best advantage since it is necessarily a compromise for different operating conditions.
SUMMARY
It is one object of the invention, therefore, to provide an improved method for controlling heating of an area.
According to the present invention, therefore, there is provided a method of heating an area comprising:
providing a furnace having:
an air intake;
a fan;
a heating element;
and a heated air outlet chamber;
providing a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
providing a second thermostat having a sensor in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
setting the set maximum of the second thermostat at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
setting the set minimum of the second thermostat at a temperature less than the maximum and greater than the set maximum of the first thermostat;
causing the second thermostat to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the second thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the second thermostat;
and causing the fan to be operated at least during the time when the first thermostat has provided a signal for activating the heating element such that ruminant heat in the heating element and the heated air outlet chamber is extracted by the fan during the time when the heating element is deactivated by the second thermostat.
Preferably the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
Preferably the second thermostat includes a manually adjustable setting for adjusting the set maximum.
Preferably the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the second thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the second thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
Preferably the set minimum of the second thermostat is a predetermined temperature difference below the maximum.
Preferably the predetermined difference is of the order of 10°F.
Preferably the second thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
According to a second aspect of the invention there is provided a supplementary thermostat for use in a furnace, the furnace comprising:
an air intake;
a fan;
a heating element;
a heated air outlet chamber;
and a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
providing a second thermostat having a sensor in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
setting the set maximum of the second thermostat at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
setting the set minimum of the second thermostat at a temperature less than the maximum and greater than the set maximum of the first thermostat;
causing the second thermostat to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the second thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the second thermostat;
and causing the fan to be operated at least during the time when the first thermostat has provided a signal for activating the heating element such that ruminant heat in the heating element and the heated air outlet chamber is extracted by the fan during the time when the heating element is deactivated by the second thermostat.
Preferably the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
Preferably the second thermostat includes a manually adjustable setting for adjusting the set maximum.
Preferably the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the second thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the second thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
Preferably the set minimum of the second thermostat is a predetermined temperature difference below the maximum.
Preferably the predetermined difference is of the order of 10°F.
Preferably the second thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
According to a second aspect of the invention there is provided a supplementary thermostat for use in a furnace, the furnace comprising:
an air intake;
a fan;
a heating element;
a heated air outlet chamber;
and a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
the supplementary thermostat comprising a sensor arranged to be located in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
the set maximum of the supplementary thermostat being arranged to be set at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
the set minimum of the supplementary thermostat being arranged to be set at a temperature less than the maximum and greater than the set maximum of the first thermostat;
the supplementary thermostat being arranged to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the supplementary thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the supplementary thermostat.
Preferably the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
Preferably the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum.
Preferably the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the supplementary thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
Preferably the set minimum of the supplementary thermostat is a predetermined temperature difference below the maximum.
Preferably the predetermined difference is of the order of 10°F.
Preferably the supplementary thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
Figure 1 is a schematic illustration of a system according to the present invention.
Figure 2 is an isometric view of the second thermostat of the system of Figure 1.
Figure 3 is a circuit schematic of the second thermostat of Figures 1 and 2.
DETAILED DESCRIPTION
A conventional heating system is shown generally in Figure 1 including an area 10 to be heated by a furnace 11. The furnace includes an air intake 12 having a filter 13 and a fan 14 for driving air into a heating chamber 15. An air outlet 16 directs air heated from the chamber 15 into the area 10 for heating the area. A
gas burner 17 is located in the chamber 15 for heating the air in the chamber and the gas burner has a supply duct 18 having a valve 19 for controlling the supply of gas to the burner 17 from a supply line 20.
the set maximum of the supplementary thermostat being arranged to be set at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
the set minimum of the supplementary thermostat being arranged to be set at a temperature less than the maximum and greater than the set maximum of the first thermostat;
the supplementary thermostat being arranged to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the supplementary thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the supplementary thermostat.
Preferably the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
Preferably the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum.
Preferably the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the supplementary thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
Preferably the set minimum of the supplementary thermostat is a predetermined temperature difference below the maximum.
Preferably the predetermined difference is of the order of 10°F.
Preferably the supplementary thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate an exemplary embodiment of the present invention:
Figure 1 is a schematic illustration of a system according to the present invention.
Figure 2 is an isometric view of the second thermostat of the system of Figure 1.
Figure 3 is a circuit schematic of the second thermostat of Figures 1 and 2.
DETAILED DESCRIPTION
A conventional heating system is shown generally in Figure 1 including an area 10 to be heated by a furnace 11. The furnace includes an air intake 12 having a filter 13 and a fan 14 for driving air into a heating chamber 15. An air outlet 16 directs air heated from the chamber 15 into the area 10 for heating the area. A
gas burner 17 is located in the chamber 15 for heating the air in the chamber and the gas burner has a supply duct 18 having a valve 19 for controlling the supply of gas to the burner 17 from a supply line 20.
A conventional thermostat 21 in the area 10 includes a control line 22 for providing a signal for controlling the valve 19. The thermostat 21 has a manually adjustable control 23 by which the user can set a maximum and minimum set temperature. At the maximum temperature, a signal is emitted on the wire 22 for deactivating the valve 19 and heating element. At the minimum temperature, a signal is provided for activating the heating element.
The present system provides an additional second thermostat 30 for providing control of the temperature in the system and for the heating element accordingly.
The second thermostat 30 comprises a generally rectangular housing 31 having a front face on which is provided a power switch 32, a power on indicator light 33, a gas on indicator light 34 and a manually adjustable set screw 35 for adjusting the maximum set temperature of the thermostat. From the housing is provided a first wire connector 36 having a thermostat probe 37. A power line receives power from a transformer 39 of the furnace. A control wire 40 connects to the wire 22 from the first thermostat 21.
In installation, the following steps are carried out:
1. The first thermostat is turned to a low setting so that the heating element is deactivated.
2. The housing 31 is attached to the outside of the furnace using an adhesive layer 41 on the rear surface of the rectangular housing.
3. The power supply line 38 is connected to the relevant terminals of the furnace transformer.
4. The wires 22 from the first thermostat to the furnace are identified and one of the wires is cut so as to connect the second thermostat in series with the first thermostat so that it can override the first thermostat.
The present system provides an additional second thermostat 30 for providing control of the temperature in the system and for the heating element accordingly.
The second thermostat 30 comprises a generally rectangular housing 31 having a front face on which is provided a power switch 32, a power on indicator light 33, a gas on indicator light 34 and a manually adjustable set screw 35 for adjusting the maximum set temperature of the thermostat. From the housing is provided a first wire connector 36 having a thermostat probe 37. A power line receives power from a transformer 39 of the furnace. A control wire 40 connects to the wire 22 from the first thermostat 21.
In installation, the following steps are carried out:
1. The first thermostat is turned to a low setting so that the heating element is deactivated.
2. The housing 31 is attached to the outside of the furnace using an adhesive layer 41 on the rear surface of the rectangular housing.
3. The power supply line 38 is connected to the relevant terminals of the furnace transformer.
4. The wires 22 from the first thermostat to the furnace are identified and one of the wires is cut so as to connect the second thermostat in series with the first thermostat so that it can override the first thermostat.
5. The thermostat line 36 is inserted into the chamber 15 so that the probe hangs well into the furnace hotter output area allowing monitoring of the hot air output temperature.
6. The first thermostat is moved to the maximum the temperature to run the furnace for a time period of approximately seven minutes sufficient to ensure that the heat exchanger 17 reaches its normal maximum operating temperature.
7. The manually operable set screw 35 is adjusted gradually until the gas on indicator 34 is illuminated indicating that the thermostat is just tripped at the normal maximum operating temperature of the furnace thus positioning the set maximum of the second thermostat at the normal operating maximum temperature of the furnace.
6. The first thermostat is moved to the maximum the temperature to run the furnace for a time period of approximately seven minutes sufficient to ensure that the heat exchanger 17 reaches its normal maximum operating temperature.
7. The manually operable set screw 35 is adjusted gradually until the gas on indicator 34 is illuminated indicating that the thermostat is just tripped at the normal maximum operating temperature of the furnace thus positioning the set maximum of the second thermostat at the normal operating maximum temperature of the furnace.
8. The first thermostat is reset to the normal desired setting so as to operate normally to maintain the area at the required temperature.
The circuit shown in figure 3 contains conventional components as shown to provide a power transformer circuit 50 and a comparator and operating circuit 51. The power supply circuit 50 includes a rectifier arrangement generating a power voltage V1 and operating the diode 33. The comparator circuit 51 compares the output from the resistance of the probe 37 with the required output from the adjustable resistor 35 to actuate a power switch at the output 40.
The set minimum of the second thermostat is a predetermined temperature difference from the adjustable set maximum which is preferably of the order of 10°F so that it is necessarily above the ambient temperature or above the maximum set temperature of the first thermostat.
In operation, therefore, the second thermostat controls the furnace so that when it reaches its maximum normal operating temperature, the heating _$_ element is deactivated for a time period sufficient that the temperature in the heated air chamber drops to the set minimum of the second thermostat whereupon the heating element is reactivated. This deactivation and reactivation occurs over the set temperature difference and occurs always at the maximum normal operating temperature. Regardless therefore of the operating which depend upon various factors including the temperature drop between the intake and the air outlet and the flow rate, the control of the heating element is activated to provide the best efficiency of operation.
The present invention has the following advantages:
1. It increases heating efficiency.
2. It reduces gas consumption by up to 20%.
3. It extends the life of the heat exchanger thus reducing the high cost of maintenance.
4. It reduces the consumption of fossil fuel thus providing environmental advantages.
5. It reduces the production of emissions thus providing environmental advantages.
The device improved efficiency by harvesting the retained heat from the heat exchanger and using it as a supplementary heat source. Without this device this retained heat dissipates up the flu thus increasing emissions and reducing fuel efficiency.
While one embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.
The circuit shown in figure 3 contains conventional components as shown to provide a power transformer circuit 50 and a comparator and operating circuit 51. The power supply circuit 50 includes a rectifier arrangement generating a power voltage V1 and operating the diode 33. The comparator circuit 51 compares the output from the resistance of the probe 37 with the required output from the adjustable resistor 35 to actuate a power switch at the output 40.
The set minimum of the second thermostat is a predetermined temperature difference from the adjustable set maximum which is preferably of the order of 10°F so that it is necessarily above the ambient temperature or above the maximum set temperature of the first thermostat.
In operation, therefore, the second thermostat controls the furnace so that when it reaches its maximum normal operating temperature, the heating _$_ element is deactivated for a time period sufficient that the temperature in the heated air chamber drops to the set minimum of the second thermostat whereupon the heating element is reactivated. This deactivation and reactivation occurs over the set temperature difference and occurs always at the maximum normal operating temperature. Regardless therefore of the operating which depend upon various factors including the temperature drop between the intake and the air outlet and the flow rate, the control of the heating element is activated to provide the best efficiency of operation.
The present invention has the following advantages:
1. It increases heating efficiency.
2. It reduces gas consumption by up to 20%.
3. It extends the life of the heat exchanger thus reducing the high cost of maintenance.
4. It reduces the consumption of fossil fuel thus providing environmental advantages.
5. It reduces the production of emissions thus providing environmental advantages.
The device improved efficiency by harvesting the retained heat from the heat exchanger and using it as a supplementary heat source. Without this device this retained heat dissipates up the flu thus increasing emissions and reducing fuel efficiency.
While one embodiment of the present invention has been described in the foregoing, it is to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.
Claims (14)
1. A method of heating an area comprising:
providing a furnace having:
an air intake;
a fan;
a heating element;
and a heated air outlet chamber;
providing a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
providing a second thermostat having a sensor in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
setting the set maximum of the second thermostat at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
setting the set minimum of the second thermostat at a temperature less than the maximum and greater than the set maximum of the first thermostat;
causing the second thermostat to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the second thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the second thermostat;
and causing the fan to be operated at least during the time when the first thermostat has provided a signal for activating the heating element such that ruminant heat in the heating element and the heated air outlet chamber is extracted by the fan during the time when the heating element is deactivated by the second thermostat.
providing a furnace having:
an air intake;
a fan;
a heating element;
and a heated air outlet chamber;
providing a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
providing a second thermostat having a sensor in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
setting the set maximum of the second thermostat at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
setting the set minimum of the second thermostat at a temperature less than the maximum and greater than the set maximum of the first thermostat;
causing the second thermostat to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the second thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the second thermostat;
and causing the fan to be operated at least during the time when the first thermostat has provided a signal for activating the heating element such that ruminant heat in the heating element and the heated air outlet chamber is extracted by the fan during the time when the heating element is deactivated by the second thermostat.
2. The method according to Claim 1 wherein the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
3. The method according to Claim 2 wherein the second thermostat includes a manually adjustable setting for adjusting the set maximum.
4. The method according to Claim 1 wherein the second thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the second thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the second thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
5. The method according to Claim 1 wherein the set minimum of the second thermostat is a predetermined temperature difference below the maximum.
6. The method according to Claim 5 wherein the predetermined difference is of the order of 10°F.
7. The method according to Claim 1 wherein the second thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
8. A supplementary thermostat for use in a furnace, the furnace comprising:
an air intake;
a fan;
a heating element;
a heated air outlet chamber;
and a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
the supplementary thermostat comprising a sensor arranged to be located in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
the set maximum of the supplementary thermostat being arranged to be set at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
the set minimum of the supplementary thermostat being arranged to be set at a temperature less than the maximum and greater than the set maximum of the first thermostat;
the supplementary thermostat being arranged to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the supplementary thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the supplementary thermostat.
an air intake;
a fan;
a heating element;
a heated air outlet chamber;
and a first thermostat having a sensor in the area to be heated arranged to provide a signal for activating the heating element when the temperature in the area drops below a set minimum and to provide a signal for deactivating the heating element when the temperature in the area rises above a set maximum;
the supplementary thermostat comprising a sensor arranged to be located in the heated air outlet chamber and arranged to provide a signal to deactivate the heating element when the temperature in the chamber reaches a set maximum and to provide a signal to reactivate the heating element when the temperature in the chamber reaches a set minimum;
the set maximum of the supplementary thermostat being arranged to be set at a temperature substantially equal to the normal maximum operating temperature in the chamber when the heating element is operating;
the set minimum of the supplementary thermostat being arranged to be set at a temperature less than the maximum and greater than the set maximum of the first thermostat;
the supplementary thermostat being arranged to override the first thermostat such that, when the first thermostat has provided a signal for activating the heating element, the supplementary thermostat acts to cycle the heating element off and on between the set maximum and set minimum of the supplementary thermostat.
9. The thermostat according to Claim 8 wherein the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element.
10. The thermostat according to Claim 9 wherein the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum.
11. The thermostat according to Claim 8 wherein the supplementary thermostat includes a visual indicator for indicating the output of a signal for deactivating the heating element, wherein the supplementary thermostat includes a manually adjustable setting for adjusting the set maximum, and wherein the set maximum of the supplementary thermostat is set manually by operating the heating element for a time period sufficient to reach the normal maximum operating temperature and by manually adjusting the setting such that the signal is emitted and the visual indicator operated.
12. The thermostat according to Claim 8 wherein the set minimum of the supplementary thermostat is a predetermined temperature difference below the maximum.
13. The thermostat according to Claim 12 wherein the predetermined difference is of the order of 10°F.
14. The thermostat according to Claim 8 wherein the supplementary thermostat includes a housing having an adhesive layer on a rear surface for attachment to an exterior wall of the furnace, a first wire for connection to a power supply of the furnace, a second wire for connection to a wire of the first thermostat and a third wire having the thermostat sensor thereon for insertion into the chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002251390A CA2251390A1 (en) | 1998-10-26 | 1998-10-26 | Thermostat control system for a furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002251390A CA2251390A1 (en) | 1998-10-26 | 1998-10-26 | Thermostat control system for a furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2251390A1 true CA2251390A1 (en) | 2000-04-26 |
Family
ID=29425513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002251390A Abandoned CA2251390A1 (en) | 1998-10-26 | 1998-10-26 | Thermostat control system for a furnace |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2251390A1 (en) |
-
1998
- 1998-10-26 CA CA002251390A patent/CA2251390A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |