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US 6,445,880 B1Granted
Water heating system with automatic temperature control
AssigneeAerco International, Inc.
InventorsPhilip S. Hollander, Gerald A. Fioriti
Life of this patent
Estimating the term…
Abstract
A water heating system having an electric heater and an automatic temperature control system having high dynamic response for supplying water on demand at a substantially constant, controlled temperature is provided. The device includes a heat exchanger, and inlet diverting pipe, an outlet diverting pipe, a mixed flow pipe and a temperature control system. A tuning valve on each of the inlet flow diverting pipe and the outlet flow diverting pipe controls the ratio of heated and unheated flow entering the mixed flow pipe. The temperature control system controls the temperature of the water by establishing an empirical, monotonic relationship between the current applied to the heater and the temperature of the mixed flow.
Claims17
A heating system for supplying a liquid at a predetermined setpoint temperature, comprising:
- a heat exchanger tank having an inlet for receiving an inlet flow of liquid into the tank, an outlet for allowing an outlet flow of liquid to leave the tank;
- a heater positioned in the heat exchanger tank and configured to heat the liquid passing through the heat exchanger tank from the inlet to the outlet;
- an inlet flow diverting pipe carrying a portion of the inlet flow diverted from flowing into the heat exchanger tank;
- an outlet flow diverting pipe carrying a portion of the outlet flow diverted from the outlet;
- a mixed flow pipe configured to carry a mixed flow of liquid partially received from the inlet flow diverting pipe and partially received from the outlet flow diverting pipe;
- a first tuning valve on the inlet flow diverting pipe to control flow in the inlet diverting pipe and a second tuning valve on the outlet flow diverting pipe to control flow in the outlet diverting pipe, wherein the tuning of the first tuning valve and the second tuning valve provides a fixed ratio of inlet flow and outlet flow into the mixed flow pipe;
- a temperature sensor configured to determine the temperature of the mixed flow in the mixed flow pipe;
- and
- a temperature control system configured to modulate the current to the heater in response to the temperature of the mixed flow in the mixed flow pipe based on a monotonic, empirical relationship between the temperature of the mixed flow in the mixed flow pipe and the current applied to the heater determined by the setpoint temperature and the tuning of the first tuning valve and the second tuning valve.
6 more elements
A heating system for supplying a liquid at a predetermined setpoint temperature, comprising:
- a heat exchanger tank having an inlet for receiving an inlet flow of liquid into the tank, an outlet for allowing an outlet flow of liquid to leave the tank;
- a heater positioned in the heat exchanger tank and configured to heat the liquid passing through the heat exchanger tank from the inlet to the outlet;
- an inlet flow diverting pipe carrying a portion of the inlet flow diverted from flowing into the heat exchanger tank;
- a first tuning valve on the inlet flow diverting pipe to control flow in the inlet diverting pipe;
- an outlet flow diverting pipe carrying a portion of the outlet flow diverted from the outlet;
- a second tuning valve on the outlet flow diverting pipe to control flow in the outlet diverting pipe;
- a mixed flow pipe configured to carry a mixed flow of liquid partially received from the inlet flow diverting pipe and partially received from the outlet flow diverting pipe;
- a temperature sensor configured to determine the temperature of the mixed flow in the mixed flow pipe;
- and
- a temperature control system configured to modulate the current to the heater in response to the temperature of the mixed flow in the mixed flow pipe based on a monotonic, empirical relationship between the temperature of the mixed flow in the mixed flow pipe and the current applied to the heater, the monotonic, empirical relationship having a first data point defined by the condition wherein the first and second tuning valves are tuned such that the temperature of the mixed flow in the mixed flow pipe is a predetermined temperature above the temperature of the inlet flow when the heater is at a substantially maximum current and a second data point defined by the condition wherein the first and second tuning valves are tuned such that the temperature of the mixed flow is a predetermined temperature below the setpoint temperature when the heater is at a substantially minimum current.
7 more elements
A heating system for supplying a liquid at a predetermined setpoint temperature, comprising:
- a heat exchanger tank having an inlet for receiving an inlet flow of liquid into the tank, an outlet for allowing an outlet flow of liquid to leave the tank;
- a heater positioned in the heat exchanger tank and configured to heat the liquid passing through the heat exchanger tank from the inlet to the outlet;
- an inlet flow diverting pipe carrying a portion of the inlet flow diverted from flowing into the heat exchanger tank;
- an outlet flow diverting pipe carrying a portion of the outlet flow diverted from the outlet;
- a mixed flow pipe configured to carry a mixed flow of liquid partially received from the inlet flow diverting pipe and partially received from the outlet flow diverting pipe;
- a temperature sensor configured to determine the temperature of the mixed flow in the mixed flow pipe;
- a first tuning valve on the inlet flow diverting pipe to control flow in the inlet flow diverting pipe and a second tuning valve on the outlet flow diverting pipe to control flow in the outlet diverting pipe, wherein the first tuning valve and the second tuning valve are tuned such that the temperature of the mixed flow in the mixed flow pipe is a predetermined temperature above the temperature of the inlet flow when the heater is at a substantially maximum current and the temperature of the mixed flow is a predetermined temperature below the setpoint temperature when the heater is at a substantially minimum current;
- and
- a temperature control system configured to modulate the current to the heater in response to the temperature of the mixed flow in the mixed flow pipe based on a monotonic, empirical relationship between the temperature of the mixed flow in the mixed flow pipe and the current applied to the heater as determined by the setpoint temperature and the tuning of the first tuning valve and the second tuning valve.
6 more elements
Dependencies are inferred from the claim text.