Skirting Heat Exchanger - btu calculator needed

[Syne Wave]

I have some heat exchanger skirting tubes within my central heating system and wish to work out what btu's I can expect from them.
The pipes are 22mm copper with a standard wall thickness and have 'fins' of aluminium around them at approx 8-10mm apart and the 'fins' measure approx 60mm x 90mm.
So what I need to know is what btu output can I expect per foot or meter.
I have heard conflicting data of 1,000 btu per 2 feet and also 1,000 btu per meter.

 

[kevplumb]

try google or failing that try mears exept with the latter you need a bit of sense

 

[Syne Wave]

try google or failing that try mears exept with the latter you need a bit of sense

I must have spent hours googling, try all kinds of combinations of words to find this information. So as a last hope I posted the question.... I think I am in a time loop. I think I am in a time loop. I think I am in a time loop.

All I want is the amount of btu per foot (or similar)

 

[Nige F]

you`re in a 70`s loop that`s when it used to be fitted If I knew the output I`d tell you

 

[doitall]

Impossible to tell without knowing all the technical stuff like flow temperatures, one pipe or two etc.

As a very rough guide 0.75watts per meter.

If you want to be on the safe side 0.5 watts

 

[kevplumb]

this might help

 

[Syne Wave]

To: DOITALL: Thanks for the info and I have just been off and looked at some of the conversion sites to get back to btu's and feel that a figure of .75 watts per metre gives 2.56 btu's per metre, which is awfully low.
Also, I can see that there are loads of other factors to mix into the equasion like flow and ambient temp. BUT at the same time, my other, newer radiators, fresh from the shop all give an expected btu rating. eg: I have a single Myson Superline 600mm x 600mm with a rear heat sync, which according to Myson gives 2684btu. (per/hr?) Comparing this to my skirting heaters makes them little more than useless.

To: KEVPLUMB: That site was interesting and I may send them an email to see if they would be kind enough to give me the technical details I seek.

The Exchanger I am using, is
a 22mm copper pipe with a standard wall thickness
with 'fins' of aluminium around them at approx 8-10mm apart
each 'fins' measure approx 60mm x 90mm as is like are thick foil (ie when they get bent they are easy to straighten).
Underneath is the 'cold' return pipe which does not have any fins on.

It runs along a under a window with a heat exchanger length of 14' 6" (4m). Which has a board over the top, which also forms the window sill and a smaller board in front which allows the air in through a small gap at the bottom with a corresponding gap at the top.

Flow Rate? - Put it this way I have a Oil fired Myson Velaire 50/70 and I have just fitted a new WILO Smart Pump which is set on the middle (second setting) unfortunatly the manual doesn't divulge the flow rate.

There is also a little confusion with converting from watts, as there is also a need to know if they are in seconds, hours, fortnights etc......? So here I am assuming hours ...

 

[Agile]

I think that DIA must have been on the cider or something!

The typical output is about 500w per metre length.

I have always liked the idea of this type of radiator but it never seriously caught on and has been rarely used since the 1970s.

I dont understand why anyone wants to do heat calcs in BTUs which are a very old fashioned unit.

Everything is in kilowatts now!

Tony

 

[Syne Wave]

Agile: Thanks, that's beginning to make more sense now.

BTU's: Well, all my rads were bought with a btu estimate of output, so I kind of stuck with them. I have been googling since to get the conversion for btu's to watts, thats when I came up against a time factor - which I assumed to be by the hour.
And I have just converted 500 watts to btu's which is 1706, which seems more realistic.

As for using old stuff, well, I admit to being one for recycling as well as I couldn't afford to replace the old skirting heaters. They worked, ergo I use.

This place was built about 1966 and I have lived here since 1980. So naturally there are old items still around. It originally had a coal fired boiler, which was a real event in the village when it caught fire (before I came). It used powdery coal and apparently the hopper feed got clogged.

I am working on a floor plan which shows all the direction flows for central heating, with all the T junctions etc, so I can now include all the watts outputs. I already did individual schematics for each room, including vent and drain points as there are a number of them. This might be useful when I come to sell this place if the government insist on us providing a house 'log book', which I am in favour of.

My next project is to see how effecient it all is, as it runs on oil, just so that I can compare (costs) to see if I were to run on electricity/gas if it would be cheaper/more efficient.

SO I would like to thank everyone who took the trouble to respond, despite the Cider.