45 AMP MCB'S

[EFLImpudence]

I know there may be all sorts of clever modern methods , but -

the standard storage heater only has a thermostat for the whole (depending on input setting - low to high; not specific temperature).
It does not cycle the elements on and of until a maximum temperature of the whole has been met, and then
if the output has been left open, which it will have been, (more) heat will escape until the elements are switched on again to regain the maximum.

This may be useful for keeping up the temperature during the night.





Could anyone with E7, John ?, calculate (roughly) how many hours a night the power must have been on from their bills?

 

[JohnW2]

It does not cycle the elements on and of until a maximum temperature of the whole has been met, and then if the output has been left open, which it will have been, (more) heat will escape until the elements are switched on again to regain the maximum. ... This may be useful for keeping up the temperature during the night.

Yes, I suppose that's true - although if one wanted night-time heating, one would probably do better to have separate (additional) conventional heaters using the off-peak.

Could anyone with E7, John ?, calculate (roughly) how many hours a night the power must have been on from their bills?

I can't, because I don't have storage heaters - but I'll see what a little research can turn up - watch this space!

Kind Regards, John

 

[ericmark]

With storage heaters it would depend how and where the energy is stored, those using water are extremely well insulated so if not used the energy is still there a week latter the off peak only tops it up, but considering what they were for the individually room brick type were very poorly insulated and if they charged up in first 3 hours likely even if off would require a top up before the seven hours have lapsed. Those with a central brick store and electric fans to distribute as and when required also work quite well. However as to down rating MCB's the time given at which no down rating is required is 30 minutes and what ever system is used it is unlikely to be able to recharge from cold in 30 minutes so the MCB's would require de-rating. However most boards I have seem for off peak have 16A MCB's not 45A MCB's although I never looked at the power requirement in Lixwm in Flintshire where the council houses had the central heat store and thermostatically and time controlled fans.

 

[JohnW2]

Could anyone with E7, John ?, calculate (roughly) how many hours a night the power must have been on from their bills?

As I said I would do, I've done a little research, by looking at the specs of half a dozen or so different makes of storage. All of them quote 'power' in exactly the same way - they give the electrical input power (generally ranging from ~0.8kW to ~3.4kW for different models in a range) and then a figure for "maximum charge acceptance" or "accumulated energy" or somesuch, that figure always being 7 times the input power.

Odd though this seems to me, it appears to imply that one can leave them 'on' (with no switch-offs due to thermostatic control) for 7 hours and (ignoring heat losses) they will store all that energy. If this is true, not only am I surprised but it negates some of my previous arguments!

Kind Regards, John

 

[stillp]

Odd though this seems to me, it appears to imply that one can leave them 'on' (with no switch-offs due to thermostatic control) for 7 hours and (ignoring heat losses) they will store all that energy. If this is true, not only am I surprised but it negates some of my previous arguments!

If you were to be asked to design something that would take advantage of a 7 hour period of cheap energy, it might make sense to design it to use all of that 7 hours.

 

[Iggifer]

All of them quote 'power' in exactly the same way - they give the electrical input power (generally ranging from ~0.8kW to ~3.4kW for different models in a range) and then a figure for "maximum charge acceptance" or "accumulated energy" or somesuch, that figure always being 7 times the input power.

Odd though this seems to me, it appears to imply that one can leave them 'on' (with no switch-offs due to thermostatic control) for 7 hours and (ignoring heat losses) they will store all that energy. If this is true, not only am I surprised but it negates some of my previous arguments!

I suspect they would find themselves in hot water if they said they ran for 3 hours, (as they likely do in the majority of installations) but one poor sod with sash windows and no insulation found they ran for 7 hours and kicked up a stink about it.

I feel the x7 is like takeaway hot drinks that say 'Caution! Contents may be hot' on them. Covering their behinds

 

[JohnW2]

If you were to be asked to design something that would take advantage of a 7 hour period of cheap energy, it might make sense to design it to use all of that 7 hours.

All that really matters is that all of the electricity required to heat the bricks to the required temperature is consumed within the cheap-energy period. If, say, a 1kW heater takes 7 hours to do that, then a 3.5kW one could presumably achieve the same in no more than (in practice, a bit less than) 2 hours. Unless one regards the night-time heat 'losses' as an advantage (providing some night-time heating), then it would presumably be more efficient to use the 3.5kW one, powered for just the last two hours of the cheap-rate period.

Kind Regards, John

 

[EFLImpudence]

I think the difference in size is the only reason for the different wattages.

That is, in general, the elements are around 1100W; the 3.4kW being three elements and more bricks.

 

[JohnW2]

I think the difference in size is the only reason for the different wattages. That is, in general, the elements are around 1100W; the 3.4kW being three elements and more bricks.

That may well be true, in which case it might also be true that they do all take ~7 hours to get to the 'working temperatures'. If that is the case then, as I have said, for anything other than the highest power one, that is not necessarily the most efficient approach (unless one 'wants the lost heat' for night-time heating).

Kind Regards, John

 

[stillp]

True, but a lower wattage would cost less to make.

 

[Taylortwocities]

True, but a lower wattage would cost less to make.

And the stored heat will degrade quicker, so it will mostly gone by the time you get home from work.

 

[ban-all-sheds]

So in the main the shower size is selected to match the cable and MCB, rather than the cable and MCB selected to match the shower.

© AAF Design Consultancy.

 

[stillp]

True, but a lower wattage would cost less to make.

And the stored heat will degrade quicker, so it will mostly gone by the time you get home from work.

I doubt if the thermal store knows the wattage of the heater used to increase its temperature.

 

[JohnW2]

And the stored heat will degrade quicker, so it will mostly gone by the time you get home from work.

I doubt if the thermal store knows the wattage of the heater used to increase its temperature.

Is not TTC's point the same as the one I have been making - that if a low wattage element is used, so that it takes the whole 7 hours for the bricks reach working temperature, the thermal losses (throughout all 7 hours of that night period) will be greater than if a much higher wattage element were used that could heat the bricks to operating temperature in just the last hour or two of the cheap-rate period?

Kind Regards, John

 

[ban-all-sheds]

Another way of looking at thermal losses comes from renaming them "night time heating".