Energy-conserving thermostat and method
First Claim
1. A fuel-conserving thermostat for controlling operation of a heating system that consumes fuel during a fuel-on interval and heats a defined space, thereby increasing a space temperature of said space;
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
said heating system comprising;
heating means for providing heat during said fuel-on interval;
delivery means for delivering heat to said space during a delivery interval, whereby a heat flux occurs from said heating means to said space during said delivery interval;
a heat exchanger;
signal-receiving means, coupling said thermostat and said heating means, for;
initiating one of said fuel-on intervals, which begins when said signal-receiving means receives a fuel-"1" signal from said thermostat;
terminating said fuel-on interval and initiating a fuel-off interval in which said furnace does not consume fuel, said fuel-off interval beginning when said signal-receiving means receives a fuel-"0" signal from said thermostat;
initiating one of said delivery intervals, which begins when said signal-receiving means receives a delivery-"1" signal from said thermostat; and
terminating said delivery interval and initiating a nondelivery interval in which said furnace does not deliver heat to said space, said nondelivery interval beginning when said signal-receiving means receives a delivery-"0" signal from said thermostat;
said thermostat including;
a clock providing clock signals;
a temperature sensor having means for providing a space-temperature signal representative of said space temperature;
means for providing a set-point-temperature signal representative of a set-point temperature; and
means for providing said fuel-"0," fuel-"1," delivery-"0," and delivery-"1" signals;
and said thermostat further comprising;
means for providing a maximum-on signal representative of a maximum fuel-on interval, where said maximum-on signal is provided by signal generating means for providing a signal representative of how long said heat exchanger can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear; and
burn-control means for causing a fuel-on interval to have a duration of no longer than said maximum fuel-on interval.
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Accused Products
Abstract
A thermostat is described for controlling a furnace for a hot air, hot water, or steam heating system which delivers heat to a heated space via a delivery system. The thermostat causes the system to conserve energy by limiting the "burn" or on-time cycle to a system-specific interval during which the heat exchanger of the furnace operates in its linear region. At the end of this interval (designated a "MAX-- ON" interval), the burn cycle is terminated, but delivery of heat to the heated space continues for a secondary-delivery interval during which the furnace'"'"'s blower (or other delivery means) continues operation. The secondary-delivery interval ends when the residual heat has been extracted from the furnace and delivery system. The system then remains off until the next burn cycle begins. The duration of the off-time interval is such that heat input to the heated space and heat outflow to the ambient from the heated space are kept in equilibrium. Methods and apparatus are described for making a site-specific measurement of MAX-- ON and secondary-delivery intervals, at a furnace plenum or in a hot-air delivery duct.
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Citations
85 Claims
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1. A fuel-conserving thermostat for controlling operation of a heating system that consumes fuel during a fuel-on interval and heats a defined space, thereby increasing a space temperature of said space;
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
said heating system comprising;heating means for providing heat during said fuel-on interval; delivery means for delivering heat to said space during a delivery interval, whereby a heat flux occurs from said heating means to said space during said delivery interval; a heat exchanger; signal-receiving means, coupling said thermostat and said heating means, for; initiating one of said fuel-on intervals, which begins when said signal-receiving means receives a fuel-"1" signal from said thermostat; terminating said fuel-on interval and initiating a fuel-off interval in which said furnace does not consume fuel, said fuel-off interval beginning when said signal-receiving means receives a fuel-"0" signal from said thermostat; initiating one of said delivery intervals, which begins when said signal-receiving means receives a delivery-"1" signal from said thermostat; and terminating said delivery interval and initiating a nondelivery interval in which said furnace does not deliver heat to said space, said nondelivery interval beginning when said signal-receiving means receives a delivery-"0" signal from said thermostat; said thermostat including; a clock providing clock signals; a temperature sensor having means for providing a space-temperature signal representative of said space temperature; means for providing a set-point-temperature signal representative of a set-point temperature; and means for providing said fuel-"0," fuel-"1," delivery-"0," and delivery-"1" signals; and said thermostat further comprising; means for providing a maximum-on signal representative of a maximum fuel-on interval, where said maximum-on signal is provided by signal generating means for providing a signal representative of how long said heat exchanger can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear; and burn-control means for causing a fuel-on interval to have a duration of no longer than said maximum fuel-on interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
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38. A fuel-conserving thermostat for controlling operation of a heating system that consumes fuel during a fuel-on interval and heats a defined space, thereby increasing a space temperature of said space;
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
said heating system comprising;heating means for providing heat during said fuel-on interval; delivery means for delivering said heat to said space during a delivery interval, whereby a heat flux occurs from said heating means to said space during said delivery interval; a heat exchanger; signal-receiving means, coupling said thermostat and said heating means, for; initiating one of said fuel-on intervals, which begins when said signal-receiving means receives a fuel-"1" signal from said thermostat; terminating said fuel-on interval and initiating a fuel-off interval in which said furnace does not consume fuel, said fuel-off interval beginning said signal-receiving means receives a fuel-"0" when signal-receiving means receives a fuel-"0" signal from said thermostat; initiating one of said delivery intervals, which begins when said signal-receiving means receives a delivery-"1" signal from said thermostat; and terminating said delivery interval and initiating a nondelivery interval in which said furnace does not deliver heat to said space, said nondelivery interval beginning when said signal-receiving means receives a delivery-"0" signal from said thermostat; said thermostat including; a clock providing clock signals; a temperature sensor having means for providing a space-temperature signal representative of said space temperature; means for providing a set-point-temperature signal representative of a set-point temperature; and means for providing said fuel-"0," fuel-"1," delivery-"0," and delivery-"1" signals; and said thermostat further comprising; means for providing a maximum-on signal representative of a maximum fuel-on interval, said maximum-on signal being provided by signal-generating means for providing a signal representative of how long said heat exchanger can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear, said signal-generating means comprising a probe means for measuring changes over time of a temperature representative of the temperature of the heat exchanger of the specific heating system installed at the location of the defined space; first burn-control means for causing a fuel-on interval having a duration of no longer than said maximum fuel-on interval; delivery-control means for causing heat to be delivered to said space during a delivery interval comprising said fuel-on interval and continuing after it ends until said heat exchanger falls to a temperature level such that said heat exchanger can operate in a linear mode during a next-following fuel-on interval; and second burn-control means for causing a nondelivery interval to follow said delivery interval for a duration at least as long as said heat exchanger takes to fall to said temperature level. - View Dependent Claims (39, 40, 41)
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
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42. An apparatus for providing a signal representative of a maximum fuel-on interval for a furnace, said interval being how long a heat exchanger for said furnace can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear, said apparatus comprising:
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a temperature probe for providing probe signals representative of temperature of said heat exchanger; means for; receiving said probe signals; registering said probe signals at time intervals; and providing signals representative of temperature increments occuring over said time intervals; means for registering and storing a reference temperature increment signal representative of a reference start-up temperature increment over a start-up time interval occurring near the beginning of a delivery interval; and means for; comparing signals representative of temperature increments over successive said time intervals following said start-up time interval, said successive intervals occurring during a continuous fuel-on and delivery interval; determining a stop-time point when one of said temperature increments has a normalized value equal to or less than a normalized value of said reference start-up temperature increment multiplied by a predetermined constant c, where 0<
c<
1; andproviding a probe-means output signal which is representative of the total time elapsing between the beginning of said delivery interval and said stop-time point.
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43. An apparatus for providing a signal representative of a secondary-delivery interval, said interval being how long it takes after a fuel-off interval of a furnace begins before a heat exchanger of said furnace falls to a temperature level such that said heat exchanger can operate in a linear mode during a fuel-on interval following said fuel-off interval, said apparatus comprising:
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a temperature probe for providing probe signals representative of temperature of said heat exchanger; means for receiving and storing a reference probe signal which is a probe signal registered at a start-up time occurring when said fuel-off interval begins; means for receiving further probe signals which are probe signals registered at successive times following said start-up time, during a continuous delivery interval occurring thereafter; means for providing a first difference signal representative of a difference between said reference probe signal and a current one of said further probe signals; means for providing a second difference signal representative of a difference between said reference probe signal, on the one hand, and either said set-point-temperature signal or said space-temperature signal, on the other hand; means for providing a ratio signal representative of a ratio between said first and second difference signals; means for determining a stop-time point when said ratio signal becomes equal to or more than a predetermined constant c, where 0<
c<
1; andmeans for providing a probe-means output signal which is representative of the total time elapsing between the end of said fuel-on interval and said stop-time point.
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44. A method for conserving energy utilization in a heating system for heating a defined space and thereby increasing a space temperature of said space;
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
said heating systemconsuming fuel, during a fuel-on interval, to provide heat; delivering said heat, during a delivery interval, to said space; having a heat exchanger; having signal-receiving means coupled to a thermostat, for; initiating one of said fuel-on intervals, which begins when said means receives a fuel-"1" signal from said thermostat; terminating said fuel-on interval and initiating a fuel-off interval in which said heating system does not consume fuel, said fuel-off interval beginning when said signal-receiving means receives a fuel-"0" signal from said thermostat; initiating one of said delivery intervals, which begins when said signal-receiving means receives a delivery-"1" signal; and terminating said delivery interval and initiating a nondelivery interval, during which said heating system does not deliver heat to said space, said nondelivery interval beginning when said signal-receiving means receives a delivery-"0" signal said method comprising; (1) providing said thermostat with a signal maximum-on representative of a maximum fuel-on interval, where said maximum fuel-on interval is how long said heat exchanger can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear; (2) sending from said thermostat to said signal-receiving means fuel-"1" signals of duration no longer than said maximum fuel-on interval; (3) when one of said fuel-"1" signals reaches a duration of said maximum fuel-on interval, sending a fuel-"0" signal from said thermostat to said signal-receiving means; and (4) sending from said thermostat to said signal-receiving means delivery-"1" signals while said thermostat sends said fuel-"1" signals. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76)
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
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77. A method for conserving energy utilization in a heating system for heating a defined space and thereby increasing a space temperature of said space;
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
said heating systemconsuming fuel, during a fuel-on interval, to provide heat; delivering said heat, during a delivery interval, to said space; having a heat exchanger; and having signal-receiving means coupled to a thermostat, for; initiating one of said fuel-on intervals, which begins when said means receives a fuel-"1" signal from said thermostat; terminating said fuel-on interval and initiating a fuel-off interval in which said heating system does not consume fuel, said fuel off-interval beginning when said signal-receiving means receives a fuel-"0" signal from said thermostat; initiating one of said delivery internals, which begins when said signal-receiving means receives a delivery-"1" signal; and terminating said delivery interval and initiating a mondelivery interval, during which said heating system does not deliver heat to said space, said nondelivery interval beginning when said signal-receiving means receives a delivery-"0" signal said method comprising; (1) measuring a maximum fuel-on interval, said interval being how long said heat exchanger can operate during a fuel-on interval in a linear mode before its mode of operation becomes nonlinear; (2) providing a maximum-on signal representative of the duration of said maximum fuel-on interval; (3) providing said maximum-on signal to said thermostat; (4) measuring a secondary-delivery interval, said interval being how long said heat exchanger takes to cool from its temperature at the end of a maximum fuel-on interval to a temperature level such that said heat exchanger can operate in a linear mode during a next-following fuel-on interval; (5) providing a secondary-delivery signal representative of the duration of said secondary-delivery interval; (6) providing said secondary-delivery signal to said thermostat; (7) sending from said thermostat to said signal-receiving means a fuel-"1" signal of duration no longer than said maximum fuel-on interval; (8) when one of said fuel-"1" signals reaches a duration of said maximum fuel-on interval, sending a fuel-"0" signal from said thermostat to said signal-receiving means; (9) sending from said thermostat to said signal-receiving means a delivery-"1" signal while said thermostat sends one of said fuel-"1" signals and continuing said delivery-"1" signal thereafter until said secondary-delivery interval ends; (10) preventing any fuel-"1" signal from being sent from said thermostat to said signal-receiving means before said secondary-delivery interval ends, thereby providing a fuel-off interval that continues at least until said secondary-delivery interval ends; and (11) sending from said thermostat to said signal-receiving means a delivery-"0" signal when said secondary-delivery interval ends, thereby terminating a delivery interval and initiating a nondelivery interval. - View Dependent Claims (78, 79, 80)
- said space being thermally conductive to an ambient, whereby a heat flux occurs from said space to said ambient;
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81. A method for decreasing utility peak load comprising installing individual thermostats to control heating systems of a set of separate buildings, said thermostats limiting fuel-on intervals of said heating systems to less than a 100-percent duty cycle, where said fuel-on intervals are how long said heating system'"'"'s heat exchanger can operate in a linear mode during a fuel-on interval before operating in a nonlinear mode.
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82. A method for decreasing or limiting peak-load usage of fuel, said method comprising installing in buildings thermostats to control heating systems of said buildings, said thermostats comprising:
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means for limiting a fuel-on interval of a heating system, during which said heating system consumes fuel, to no longer than a predetermined maximum fuel-on interval, where said maximum on-time interval is how long said heating system'"'"'s heat exchanger can operate in a linear mode during a fuel-on interval before operating in a nonlinear mode; and means for initiating a fuel-off interval of said heating system, during which said heating system does not consume fuel, said interval continuing for at least a predetermined secondary-delivery interval.
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83. A method for decreasing or limiting peak-load usage of fuel, said method comprising installing in buildings thermostats to control heating systems of said buildings, said thermostats comprising:
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means for limiting a fuel-on interval of a heating system, during which said heating system consumes fuel, to no longer than a predetermined maximum fuel-on interval; and means for initiating a fuel-off interval of said heating system, during which said heating system does not consume fuel, said interval continuing for at least a predetermined secondary-delivery interval, where said secondary-delivery interval is how long said heating system'"'"'s heat exchanger takes to return, after a fuel-on interval ends, to a temperature level such that said heat exchanger operates in a linear mode in a next-succeeding fuel-on interval.
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84. A method for decreasing or limiting peak-load usage of fuel, said method comprising installing thermostats in buildings to control heating systems of said buildings, where said thermostats:
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(a) limit fuel-on intervals of said heating systems, during which said heating systems consume fuel, to no longer than predetermined maximum fuel-on intervals, where said maximum on-time interval is how long said heating system'"'"'s heat exchanger can operate in a linear mode during a fuel-on interval before operating in a nonlinear mode; and (b) initiate fuel-off intervals of said heating systems, during which said heating systems do not consume fuel, said intervals continuing for at least a secondary-delivery interval.
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85. A method for decreasing or limiting peak-load usage of fuel, said method comprising installing thermostats in buildings to control heating systems of said buildings, where said thermostats:
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(a) limit fuel-on intervals of said heating systems, during which said heating systems consume fuel, to no longer than predetermined maximum fuel-on intervals; and (b) initiate fuel-off intervals of said heating systems, during which said heating systems do not consume fuel, said intervals continuing for at least a secondary-delivery interval, where said secondary-delivery interval is how long said heating system'"'"'s heat exchanger takes to return, after a fuel-on interval ends, to a temperature level such that said heat exchanger operates in a linear mode in a next-succeeding fuel-on interval.
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Specification