Virtual sensing system

A method of predicting temperature of at least one location in a fluid flow system having a heater disposed in a heating system for heating fluid, the method comprising:

• obtaining a mass flow rate of fluid flow of the fluid flow system;
• obtaining at least one of a fluid outlet temperature and a fluid inlet temperature of the heater;
• obtaining power provided to the heater;
• and
• calculating temperature at the at least one location based on a model of the fluid flow system and the obtained mass flow rate and fluid outlet and inlet temperatures.

A method of predicting outlet temperature after each of a plurality of resistive heating elements in a heater system disposed in a fluid flow system comprising:

• obtaining a mass flow rate of fluid flow;
• obtaining a fluid inlet temperature to at least one of the plurality of resistive heating elements;
• obtaining power provided to at least one of the plurality of resistive heating elements and characteristics of the fluid flow system that relate power input to at least one of the plurality of resistive heating elements to power transferred to the fluid flow;
• and
• calculating the outlet temperature based on a model of the fluid flow system.