There's no such unit as Kw/hr. The unit is kWh or kJ. 1kWh = 3.6MJ.
tonyrockyhorror,
May 26, 11:44pm
None of which have any impact on the energy efficiency.
tonyrockyhorror,
May 26, 11:45pm
Some are correct, some pure fantasy.
40wav,
May 26, 11:56pm
Yes, PCBs. But that is only in the old ones (heaters anyway). If it's newer that 10 or so years it will not have PCBs. Easiest way to check the oil is put a drop of it in water, if it's ok it will float, if it contains PCBs it will sink.
foxdonut,
May 27, 12:56am
I think the questions he is asking are along the lines of:
During the course of its life, will the oil change in any way!
If it does change, will it still work the same as it was new!
I don't think there is any confusion about efficiency of electricity to heat, I think it is more like "If the state of the oil changes, will it still create heat at the same rate!"
Yes, there is no way to "absorb" energy and it remains "100% efficient" as in, 100% of the electricity sent to the element gets transferred to the oil, its the time at which this happens that is the question. The real question is along the lines of "If it takes the heater 1 hour to warm the room to 25 degree's today, in ten years time and assuming the properties of the room haven't changed at all, will it still take 1 hour, or, will the oil have changed in such a way that it now takes 1.5 hours because the oil heats up slower due to its state after 10 years of being heated and allowed to cool!"
If that were the case then the heater would no longer be as "efficient" because it used to take it an hour to do the job, but now it takes it an hour and a half.
tonyrockyhorror,
May 27, 11:08pm
No, the efficiency doesn't change. Only the effectiveness.
foxdonut,
May 27, 11:16pm
So, the column heaters "efficiency" then.
v8_mopar,
May 28, 12:05am
So the heater costs no more to use but the room is colder longer! is that what you are saying with this comment
tonyrockyhorror,
May 28, 12:10am
No. The energy efficiency is always the same but effectiveness can vary. LIke with a night store heater. all the heat stored is released, but some of the heat is released when it's not yet needed, leaving less for when it is needed. Thus it's less effective, but just as efficient.
foxdonut,
May 28, 12:12am
Just go read a dictionary okay!
We stopped talking about energy efficiency a long time ago.
tonyrockyhorror,
May 28, 12:17am
Yes. The room temperature may not reach the same level as the speed of heat transfer (kW), due to the slightly higher specific heat capacity of the oil, means that the energy put into it results in a lower temperature in the oil in the first place. Thus it may be less effective at heating the air as the rate of heat transfer to the air is governed by the temperature difference.
However, this is largely moot as, in the case of an oil column heater, the temperature of the oil is regulated by the thermostat. It may take longer to reach operating temperature, meaning it's not as effective as soon, but once switched off it will be effective for longer as the rate of temperature decrease in the oil will be reduce due to the same higher specific heat. It's just a case of lag in heat transfer, really. No less effective or efficient.
tonyrockyhorror,
May 28, 12:18am
Then there's nothing whatsoever to discuss.
msigg,
May 28, 12:53am
I would say yes over a long time, I know oil in transformers does break down eventually. Nothing lasts forever.
sr2,
May 28, 12:54am
Where on earth did the idea that heat cycling oil changes it's specific heat come from!
v8_mopar,
May 28, 3:11am
Anyway I swear my 14 year old 15 bar column heater worked better when I got it but maybe the worlds just cooling
jmma,
May 28, 3:39am
Maybe the thermostat is buggered (o:
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