Distance back boiler to Thermal store

[Ketelbinkie]

We are renovating an old Mill and want to install a Thermal store which can produce hot water and underfloor heating. Our power sources are to be electricity, which is produced on site with a micro hydro system, and a woodburning stove with a back boiler. Eventually we want to be able to put in solar panels also.
Our difficulty is that our proposed position of the woodburner is quite far away from the thermal store. Can anyone here tell me whether 10 meters is too long a pipe run for a thermal syphon to take the hot water to the Thermal store.

 

[Deleted member 2053]

In theory if your pipe is large enough in diameter and you rise all the way to he store then it will convect. But as this is going to have to be done in copper why not use 15mm pipe and a pump? It will be a lot cheaper than using 28mm pipe or upwards.

The best thermal stores I have used are from Nuheat in Honiton who will also design and supply the parts for your underfloor heating. They will almost certainly be able to provide all the technical support you need for your heat source.

 

[Ketelbinkie]

Thanks for your reply Grahamep. As you probably realise I'm not a plumber. This is a home build, husband as builder and I'm researching the possibilities for heating etc. Plumber will install the system but on first discussion not too familiar with heat banks (thermal stores) and thought piperun too long from stove.

Since posting the question I have read the technical specs for a possible wood burner where it said the maximum distance from the cylinder is 20ft.
Re heat bank, we have looked at DPS systems ( heatweb) do you have any experience with them?

I take the point of using a pump to circulate the water from the back boiler but we are in a remote area and have the risk of power cuts in winter due to snow. A pump means we have to put out the fire in the stove. So would prefer it to circulate by convection.
I realise the heat exchanger from the store also needs a pump but apparantly it's possible to get a battery backup to allow hot water to be drawn off,

 

[Deleted member 2053]

No experience with DPS but I will research them. Would be worth checking that distance to find out what the constraints are. These things are not always as set in concrete as they first appear.

Make sure you buy a thermal store that has the extra heat exchanger for solar!
Grahame

 

[miket]

Hi
I have experience of Nu heat having installed a number of their underfloor systems they are quite a good outfit. (not good if you need to return anything) All their tanks are on the small size and are pressurised, no good if you are not qualified to install pressurised system, and they need an annual inspection. If you are installing a tank for a none gas or oil system I would go for the largest vented tank you can afford and accommodate. Try www.halorsolar.com
As for your stove you need to run 2 separate loops one to the heat store pumped and including pipe stats and control gear, this can be as long as you want. And a convection, vented heat dump loop to a radiator ( usually in the bathroom) this acts as a safety to stop the stove over heating and so that the stove does not have to be put out if the power goes off.
I will warn you there is lot of UK outfits who do not know much about these systems and will sell you anything. I have bought a heat stores and sent them back before I got the right one.
Best of luck

 

[Mike Kirwin]

Did u finish the project?*

I've a similar project on the go, no plumbing experience and welcome anyone sharing their experience in this type of set-up.
I'm trying to integrate micro hydro, wood burning stove with back boiler (to feed 4 small'ish radiators upstairs and hot water on a gravity fed system (incase of power failure)), underfloor heating downstairs, solar panel for elecky during a sustained dry spell, but have only just discovered accumulators. My hydro should have an electic dump for when the battery bank is charged and there's an excess of power. If this went to contribute to the same hot water supply - would I be overkilling things with an accumulator?*