Automatic firing rate control for a heat exchanger
AssigneeRheem Manufacturing Company
InventorsRaymond Ibrahim Hallit, Jorge Gamboa, Stephen Thomas Thurlkill
Life of this patent
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Abstract
A heat exchanger includes a burner configured to burn a combustible gas to produce heat, a heat exchanger configured to receive the heat from the burner, a flow sensor configured to measure a flow rate of a coolant passing through the heat exchanger; and a controller comprising processing circuitry. The processing circuitry receives flow data from the flow sensor and controls a firing rate of the burner based on a predetermined relationship between a differential temperature of coolant flowing through the heat exchanger and the coolant's flow rate.
Claims30
A heat exchanger system, comprising:
- a burner configured to burn a combustible gas to produce heat;
- a heat exchanger configured to receive the heat from the burner and transfer the heat to a coolant flowing through the heat exchanger;
- a flow sensor disposed with respect to the heat exchanger to measure flow rate of the coolant through the heat exchanger;
- and
- a controller comprising processing circuitry, wherein the processing circuitry is configured to
- receive data from the flow sensor indicative of the flow rate, and
- after an initial ignition of the burner, control a firing rate of the burner based on a predetermined relationship between a temperature difference of the coolant across predetermined positions in the coolant's flow path through the heat exchanger (DT) and the flow rate, in which DT varies with the flow rate and the firing rate of the burner is controlled to maintain the DT at or below a maximum DT, the maximum DT being lower than a predetermined threshold DT likely to cause damage to the heat exchanger.
A method of controlling operation of a heat exchanger system having a burner configured to burn a combustible gas to produce heat, a heat exchanger configured to receive the heat from the burner and transfer the heat to a coolant flowing through the heat exchanger, and a flow sensor disposed with respect to the heat exchanger to measure flow rate of the coolant through the heat exchanger, said method comprising the steps of:
- receiving data from the flow sensor indicative of the flow rate, and
- after an initial ignition of the burner, controlling a firing rate of the burner based on a predetermined relationship between a temperature difference of the coolant across predetermined positions in the coolant's flow path through the heat exchanger (DT) and the flow rate, in which DT varies with the flow rate and the firing rate of the burner is controlled to maintain the DT at or below a maximum DT, the maximum DT being lower than a predetermined threshold DT likely to cause damage to the heat exchanger.
Dependencies are inferred from the claim text.