Method and apparatus for forced air heater measurement and control

A system for outputting heated air at a controlled temperature and flow rate, comprising:

• an inlet and an outlet;
• an electric air blower for urging a flow of air;
• an electric air heater including an electric resistance element upstream of the outlet;
• a conduit for conducting air from said electric blower to the electric heater;
• a mass flow sensor connected upstream of an input of the electric air blower in a direction opposite the flow of air for generating a mass flow measurement signal MassFlow;
• a temperature sensor connected to an inlet of the electric air heater for generating an input temperature signal TempIN representing an input temperature;
• a heater power control circuit for controlling electric power to said electric air heater in response to a first control signal;
• means for controlling mass flow through said electric air heater in response to a second control signal;
• and a controller receiving the mass flow measurement signal MassFlow and the input temperature signal TempIN and having a user input for inputting a temperature command signal TempCMD and a volume command signal VolumeCMD used by the controller for outputting air at a controlled temperature, said controller computing
• TempCMD=TempIN+ΔT,
• TempCMD=TempIN+((K×PowerIn/MassFlow)), and
• PowerIn=(TempCMD−TempIN)×MassFlow/K,
• and generating said first and second control signals, wherein the temperature sensor is arranged at the inlet of said electric air heater for generating said input temperature signal TempIN.