Digital modulation for a gas-fired heater
AssigneeGas Research Institute
InventorsSteven Casey, John Bowman
Life of this patent
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Abstract
A method is disclosed for operating a gas-fired heater to maintain temperature within a zone. The gas-fired heater is modulated between a higher firing rate and a lower firing rate within a pseudo steady-state mode until a current firing rate exceeds a predetermined maximum time period ttrans. The gas-fired heater is then modulated between an updated higher firing rate and an updated lower firing rate within a transient mode until an updated current firing rate exceeds a predetermined maximum time period tdiag. Finally, the higher firing rate and the lower firing rate are redefined in a diagnostic mode until the gas-fired heater returns to the pseudo steady-state mode.
Claims13
A method of operating a gas-fired heater to maintain temperature within a zone, the method comprising:
- modulating the gas-fired heater between a higher firing rate and a lower firing rate within a pseudo steady-state mode until a current firing rate exceeds a predetermined maximum time period ttrans;
- modulating the gas-fired heater between an updated higher firing rate and an updated lower firing rate within a transient mode until an updated current firing rate exceeds a predetermined maximum time period tdiag;
- and
- redefining the higher firing rate and the lower firing rate in a diagnostic mode until the gas-fired heater returns to the pseudo steady-state mode.
A method of operating a gas-fired heater with a modulator to maintain temperature within a zone, the method comprising:
- operating the modulator at a higher firing rate when the zone is not sufficiently heated;
- operating the modulator at a lower firing rate when the zone is sufficiently heated;
- toggling between the higher firing rate and the lower firing rate in a pseudo steady-state mode;
- sensing an updated heat requirement from a thermostat;
- adjusting the higher firing rate and the lower firing rate based upon the updated heat requirement in a transient mode;
- and
- toggling between an adjusted higher firing rate and an adjusted lower firing rate.
A method of operation of a gas-fired heater comprising:
- operating the gas-fired heater within a load zone between a high firing rate and low firing rate in a pseudo steady-state mode of operation;
- sensing a change in a demand signal within a prescribed time period ttrans;
- entering a transient mode if no change is sensed within ttrans;
- sensing a change in a demand signal within a second prescribed time period, tdiag;
- entering a diagnostic mode if no change is sensed within tdiag;
- driving a firing rate of the gas-fired heater over a plurality of increments to determine a new load zone;
- estimating a new high firing rate and a new low firing rate based upon the new load zone;
- and
- returning to the pseudo steady-state mode of operation.
Dependencies are inferred from the claim text.