Using Indirect Cylinder To Heat Radiators

[Beegee69]

Hello, I’m wondering if I could use an indirect cylinder to heat the water for a small central heating system. My plan is to use the the heat from inside of the cylinder to heat the coil and then use a pump connected to a thermostat to circulate the water to around 6 radiators. I ask because where we live we don’t have a gas boiler and our garden is far too small for oil and access is difficult for lpg to be installed. Could this work? An expansion vessel will be fitted obviously.

 

[SimonG]

How you heating the cylinder?

 

[Pickwickpick]

For starters I can't see your electric immersion heater providing enough heat to heat your water and 6 rads. Also this isn't something you could set up yourself, its an unvented system, so would require a plumber with G3 unvented qualification and they wouldn't touch this with a barge pole I'm afraid as it would be using appliances for purposes not approved by the manufacturer which in turn would be contravening building regs. That's my take on it at least, others might have a different opinion.

 

[SimonG]

Amptec electric boiler, won't be cheap to run but more efficient than what you are thinking about.

 

[Pickwickpick]

How you heating the cylinder?

I presume they mean they'd use the electric immersion heaters on the indirect cylinder to heat it and rather than the coil being hooked up to a boiler in order to heat the cylinder, they hook the coil up to the rads and use the immersion heaters effectively to heat the coil and the rads.

Although I might have got the wrong end of the stick, but that's how I read it...

 

[SimonG]

I presume they mean they'd use the electric immersion heaters on the indirect cylinder to heat it and rather than the coil being hooked up to a boiler in order to heat the cylinder, they hook the coil up to the rads and use the immersion heaters effectively to heat the coil and the rads.

Although I might have got the wrong end of the stick, but that's how I read it...

That's what I was thinking but want confirmation.

Always room for an oil tank. Bundled steel tanks made to order.

 

[ShaunCorbs]

Direct Thermal store but won't be cheap to run

 

[Aire]

If you don't have gas and can't get oil or lpg have you considered an air source heat pump?

 

[Beegee69]

For starters I can't see your electric immersion heater providing enough heat to heat your water and 6 rads. Also this isn't something you could set up yourself, its an unvented system, so would require a plumber with G3 unvented qualification and they wouldn't touch this with a barge pole I'm afraid as it would be using appliances for purposes not approved by the manufacturer which in turn would be contravening building regs. That's my take on it at least, others might have a different opinion.

I’m aware of that, it will take longer to heat with an element.

 

[Beegee69]

Amptec electric boiler, won't be cheap to run but more efficient than what you are thinking about.

Wouldn’t an electric boiler work out about the same in terms of energy use?

 

[Beegee69]

Direct Thermal store but won't be cheap to run

Yes, although how would it be powered? I don’t have solar panels or a boiler?

 

[ShaunCorbs]

Yes, although how would it be powered? I don’t have solar panels or a boiler?

normally two or three elec immersions

 

[SimonG]

Wouldn’t an electric boiler work out about the same in terms of energy use?

Nope.

And in answer to your original question. Yes it would work, very badly. You would dissipate heat faster than you could input it. So in effect would be circulating cold water around your radiators with a 3kw immersion buzzing away for nothing.

If the jobs worth doing then it's worth doing properly, and that is definitely not the way to do it.

 

[Beegee69]

normally two or three elec immersions

So a thermal store is the way to go? I don’t see any where you can have 3 immersion heaters the max amount is 2 and wouldn’t running 2 or 3 at the same time be a safety issue?

 

[SimonG]

If you're going thermal store then look at adding a multi fuel stove to help feed it in the winter.

Imho tho I would go direct unvented hot water (subject to flow and pressures) and an amptec heating system.

 

[ShaunCorbs]

So a thermal store is the way to go? I don’t see any where you can have 3 immersion heaters the max amount is 2 and wouldn’t running 2 or 3 at the same time be a safety issue?

Torrent Stainless OV | Gledhill etc

or you can get gledhill to do a custom one with 3 immersions in

 

[Beegee69]

Torrent Stainless OV | Gledhill etc

or you can get gledhill to do a custom one with 3 immersions in

What’s the advantage of a thermal store if only using the electric elements, I mean would it not be better to use an vented indirect cylinder with the 2 immersions? The only advantage I see is mains pressure hot water running through the coil and not the central heating water.Which brings me to the asking if it is indeed safe to run 2 elements together and not on an economy setup?

 

[ShaunCorbs]

true but you wouldnt have heating with the unvented cylinder

 

[Beegee69]

true but you wouldnt have heating with the unvented cylinder

Sorry not sure I understand, what I meant was use an standard economy vented indirect cylinder and use the coil for the flow and return for the radiators and use the coil inside as a heat exchanger to heat them using the heat from the cylinder.

 

[ShaunCorbs]

Sorry not sure I understand, what I meant was use an standard economy vented indirect cylinder and use the coil for the flow and return for the radiators and use the coil inside as a heat exchanger to heat them using the heat from the cylinder.

Won't be able to cope you want a thermal store if your planning that

 

[Beegee69]

Won't be able to cope you want a thermal store if your planning that

Is that because of the hot water draw off to the taps?

 

[SimonG]

You could just ignore all the good advice you are getting and just crack on.

 

[Beegee69]

You could just ignore all the good advice you are getting and just crack on.

I’m not ignoring any advice. I’m asking a question.

 

[Riley]

Which has been answered about 4 times now. You will not get the heat transfer you require. A thermal store will do this

 

[gpbeck]

6 radiators will give off 6KW of heat, maybe more.
Your immersion element might be 3KW, so not enough energy provided at the source.

 

[dan_the_plumber]

Direct thermal store fed from a solid fuel burner or air source heat pump would be my suggestion.
If it’s heated electrically: 6 rads, day 1kw each, 2 kw to heat cylinder plus 20% that’s about a 10kw requirement. With a 3kw immersion? Ok 2 immersion’s? 3 immersion’s?
It starts to get a bit silly doesn’t it