- #1
Robertphysics
- 16
- 4
I know for them for some time and I understand how induction heating works in general , where you have a coil through which a high frequency AC current is fed that creates a magnetic field which changes fast according to the frequency and this excites electrons in the metal introduced and heats it up.
I’ve done some googling and found that some companies offer induction water heaters. If I understand correctly water itself wouldn’t heat up as fast or as good as iron does when inserted in the heater coil but hence water is passed through an iron pipe located in the heater that’s where it heats up.
Now here’s what I wonder , the most common method for electrical water heating is resistive coils. But in those all the electricity is converted to heat so it sounds efficient in terms of conversion but it consumes a lot of energy, is it physically true that heating up say the same amount of water through induction heating would be much more efficient ?
If I understand this then in the induction heating process the only losses are the copper coil circuit losses in the heater itself which are resistive losses and probably some capacitive losses since high frequency AC is employed correct?
But then I don’t understand where would the water or metal or whatever is inserted in the heater coil get its energy ? Because the induction heater is not a transformer with a shorted secondary but an inductor and the heating occurs due to the large eddy losses and other in a solid iron block or pipe which sits there instead of a laminated core as would in normal inductors like those for PFC in SMPS supplies right ?
So this is what I don’t understand , apart from the ordinary circuit copper resistance losses and reactive losses in the induction heater , what is the main source of power loss/transfer from the electrical supply to the heated iron in the middle of the coil , since it’s not a transformer with a shorted or high load secondary but an inductor and as far as I know inductors store applied AC as magnetic field which minus some losses should consume next to no power at all.
Or is it that the induction heater is simple on purpose made an extremely bad and extremely lossy inductor whose main purpose is to cause as much eddy currents as possible instead of eliminating them and by this cause the iron to heat rapidly?
But then I have another question , why do eddy currents cause the inductor to consume power instead of simply storing it as magnetic field and then delivering it back , is it because eddy currents cause the original magnetic field that made them to lose it’s power and so the current making that field is now consumed?
I’ve done some googling and found that some companies offer induction water heaters. If I understand correctly water itself wouldn’t heat up as fast or as good as iron does when inserted in the heater coil but hence water is passed through an iron pipe located in the heater that’s where it heats up.
Now here’s what I wonder , the most common method for electrical water heating is resistive coils. But in those all the electricity is converted to heat so it sounds efficient in terms of conversion but it consumes a lot of energy, is it physically true that heating up say the same amount of water through induction heating would be much more efficient ?
If I understand this then in the induction heating process the only losses are the copper coil circuit losses in the heater itself which are resistive losses and probably some capacitive losses since high frequency AC is employed correct?
But then I don’t understand where would the water or metal or whatever is inserted in the heater coil get its energy ? Because the induction heater is not a transformer with a shorted secondary but an inductor and the heating occurs due to the large eddy losses and other in a solid iron block or pipe which sits there instead of a laminated core as would in normal inductors like those for PFC in SMPS supplies right ?
So this is what I don’t understand , apart from the ordinary circuit copper resistance losses and reactive losses in the induction heater , what is the main source of power loss/transfer from the electrical supply to the heated iron in the middle of the coil , since it’s not a transformer with a shorted or high load secondary but an inductor and as far as I know inductors store applied AC as magnetic field which minus some losses should consume next to no power at all.
Or is it that the induction heater is simple on purpose made an extremely bad and extremely lossy inductor whose main purpose is to cause as much eddy currents as possible instead of eliminating them and by this cause the iron to heat rapidly?
But then I have another question , why do eddy currents cause the inductor to consume power instead of simply storing it as magnetic field and then delivering it back , is it because eddy currents cause the original magnetic field that made them to lose it’s power and so the current making that field is now consumed?