Combining Gas Ch, Wood stove & Solar

[Northbridge]

sorry, lightfoot, you are correct, I must stop speed reading!!!!!

Yes, we are all trying to solve the same problem.  And yes, there might be a power cut, and we all have to cater for the worst case scenario.  The answer escapes just about everyone i know.  It's the lack of control thing.  No interlock, no shut off...... I may just go nutty.  Sorry, more nutty.

[Richard Owen]

Have set up a three coil system for heating water. 

In the winter by firing a 4KW woodburner 4-5 times a week, we heat the house by the burner itself, it feeds three radiators and the heat also goes through the third coil on the cylinder. 

Result
Full tank of 172 ltrs in 45 mins (Winter) - Full tank each day (summer) curtosy of the sun and Gas powered HW and CH only when we want it.  Our gas bill for the worst 1/4 was only £115

PS - Those that remember my bike generator - it works !!! Along with a 55w panel i can make my own power via 12v battery bank and have a switch over in the house for leach lighting circuit.  This gives approx 3-4 nights per week.

Cheers

Pie Eyes

Any chance of some pictures in a 'show us yours' thread?

[dhaslam]

The wood burner must be putting out a lot more than 4Kw if it can heat a 172litre cylinder in 45 minutes.  My woodburner, now retired,  could heat a slightly smaller cylinder in about 20 minutes but its output was closer to 30kw and it weighs 750kgs

[Andrew_Rigamonti]

Pie eyes,

can the gas boiler also heat the rads or is it only connected to the DHW? Simpler but it does mean you have to light a fire most days.

Andrew

[Pie Eyes]

 

Sorry My mistake the woodburner is 6KW.  I will put some photos on in the next few days.
The benefit of our house is that the out pipe has a short incline run 4ft before going veritcle to the HW tank. It takes about 10-15 mins to warm up but from that point it is heating as quickly as the central heating boiler.  I have purchased some clip on magnetic temp gauges at three points of the system so as not to overheat. (ETI ltd) The control unit for the solar panel is really helpful because you also get the top and bottom temp from the control unit as well.
The pipe rises slightly higher than the "in" point of the tank to create a fall effect at the junction, where it feeds the three additional radiators. Landing, bedroom and bathroom.  The latter is the one that needs the fire on full to heat to work effectively.  We are going to tweak the system by changing the feed for the rads from a t piece to a y piece. Also have about 10" of 22mm before reducing to a smaller pipe.  The rads are dedicated to the wood burner and we have found that we only ever use the CH in the winter on particuarly cold mornings if the fire has gone completely out.

 Most weekends we have to limit the output if the fire is on all day and we are now going to have the shower converted over to HW pumped directly from the tank as we have excess supply.  The knack is to feed short runs of the verticle pipe and ensure you do not overstretch the ability of the burner to pump the system by it's heat.  A bit of trial and error and some understanding of fluid dynamics.  I have been very happily surprised at the efficiency of the system.
Apart from anything else the heat from a real fire is so much better than our CH.  and the house, and in pasrticular the chimney seems to retain the heat for a couple of days.