It calculates the thermal and electric energy needed to heat a fluid with a continuous flow rate. It gives also the necessary values for design the electrical supply circuit.
Kind of fluid
Fluid specific heat
Temperature of the inlet fluid
Temperature of the output fluid required
Fluid flow rate
Mono-phase line or dc current
Tri-phase line, star configuration
Tri-phase line, delta configuration
|Equivalent thermal power||kcal|
|Required current in steady-state||A|
|Supply voltage on each resistor||V|
|Electrical resistance in steady-state (each resistor)||ohm|
The output fluid will have a flow rate slightly higher than at the inlet, here the coefficient of expansion is not considered.
Results valid until the temperature doesn't reach the 90% of the boiling temperature of the choosed fluid at the working pressure of the circuit, over these values, some ignored factors like latent heat of evaporation, coefficient of expansion etc.. become important.
Electric heaters have a positive coefficient of electric resistance, the cold start needs higher current, so the thermal energy given at the beginning is higher and stabilize after a certain time depending by the mass to be heat (contained fluid + container + resistance).
The container mass of the heater is ignored, at the steady-state, if insulated, is pratically insignificant.