Space Heating Calculations - replacing electric storage heaters with central heating

[Rayment84]

Hi there,

I am needing to design a heating system to heat a flat that was converted from the upper half of a barn around 40years ago (downstairs is still used as a woodshed etc with no heating.) The wall construction is varied and unknown as the farm and building is centuries old, so calculating the adequate heating requirements would be extremely difficult...so, I am trying to design the system to match the output of the electric storage heaters that are currently in the property as they were adequate for heating the premises previously.

The issue I have is that the storage heaters dont have any info on them regarding output, and when searching the specifications, they only give their storage rating and no output:

https://www.specifinder.com/brochures/7739_pdf28.pdf

3rd page down (TSR Sensor Plus & Slimline - Electric storage heaters - TSR12A/MW + TSR24A/MW)

If anyone can give some advice or help on this it would be hugely appreciated.

Many thanks

Dave

 

[Ermintrude]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

24A at 240v 5.7kw. If running all night to charge up say 8 hours that's and input of 45.6kwh so assuming that keeps it warm for whole day that's 16h output. So 45.6 / 16 = 2.85kw - big bum rad!

 

[Rayment84]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

Thanks for your reply Ermintrude.

Sorry but not sure where 5.7kW came from...is that just an example?

And on the basis it is an example, using the figures for the current storage rating for each rad, then the following would apply?:

- TSR18 = 2.5kW x 8hrs to charge = 20kWh...16 hour storage, so 20 / 16 = 1.25kW output
- TSR24 = 3.4kW x 8hrs to charge = 27.2kWh...16 hour storage, so 27.2 / 16 = 1.7kW output

Is this correct?

Thanks

 

[Sparkgap]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

Rough rule of thumb for each room would be 50W/cu.m or 5BTUs/cu.ft. Should be about right for a 40yr old building! I never rely on storage rad ratings anyway.

 

[AWheating]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

Best thing to do is get your heating engineer to design it and blame him/ her if its incorrect. You really need an idea of the u values of the walls to do it correctly. I would also advise to insulate floor and ceiling well to make required outputs a lot lower.

Post a picture of the wall material and the area your from and we maybe able to give you an idea of the u value so you can do the calculations.

 

[zzzjim]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

If available previous bills MAY be a clue so long as most of electricity bill is storage
( not so usefull if Hot water -immersion + mini Laundrette )

May get a -Cold winter figure !

Unless quantity of electricity used is grey area ...

 

[AWheating]

Re: Space Heating Calculations - replacing electric storage heaters with central heat

General stone u values

12" thick - 2.78
18" thick - 2.23
24" thick - 1.68

plaster and any gaps between plaster and stone will make a slight difference.