Re: Good Grief

[Tim Lamb]

> Ah! I had not considered you as a Hetas adviser.

> >I'm not, the commercial stuff I did didn't need part J. Unfortunately the >firm I was doing that for went bust when the Austrian boiler manufactures >decided to market to GB directly, order book suddenly vanished. The staff >and directors seem all to have been paid off, it was only creditors that >were caught, that included my last months bill ;-(.

Let us hope their pension investments are in something Icelandic.

>> Angela is badgering me >> to install a wood burner to back up the central heating. I have got as >> far as discovering that anything over 4.9kW requires an air supply and >> that you can mix gravity water with pumped CH water with a neutraliser >> but my cheque book hasn't twitched yet:-) > >It's only a 6" air brick! Actually 5kW is fine for a back up.

Yes. Actually there is a suspended floor so I am considering installing a duct terminating next to the hearth. Logistically, any log burner will only operate while there is somebody to light and feed so early morning heat will always be gas.

Lining the existing chimney looks straight forward as does adapting the register plate. Where I am struggling is whether to go for room heat only , graft a 2-3kW gravity back boiler into the existing gas system or go for something with a wrap around boiler producing 10kW or so but, presumably, needing much more complication by way of controls.

In fact for >mild days you'll have noticed that a cheap reversible air conditioner is >cheaper than gas or oil because the delta T it pumps through is low and the >COP is high.

I have ground/water source heat pump in mind for a different project. Air-con is something I have never considered for a domestic use.

>The neutraliser is just a ridiculously small, expensive thermal store, I'll >bet you can do it cheaper with a hot water cyclinder and some zone valves.

2-300ukp from Dunsley. I assume there is a limit to how much heat you can transfer using gravity and a fixed bore/head system. I must ask them. They don't seem to answer e-mail:-(

cross posted to uk.d-i-y

regards

[Dave Liquorice]

Not cheap, the trick that the neutraliser performs is to have all the inlets/outlets at the same static pressure. Not sure if all inlet and all outlets have to be the same pressure or if just all the members of a set have to be the same with the other set at a different pressure,

This could be tricky to arrange on a cylinder, adding extra primary connections isn't that easy on a cylinder as access inside is a tad restricted. Getting something fabricated might be an option.

There probably is but I'd be using 28mm tube for the gravity loop and that is well capable of shifting a few kW from a wood burner.

[meow2222]

If its just for use if the main system fails, an electric immersion element is an easy low cost option. 3kW is adequate for a hw cylinder.

NT

[andrew]

In which case the dhw cylinder will probably be hot before the woodstove is lit.

Its all to do with capital expense, I serviced a log gasifier which heats a large house, the owner was a timber framing contractor and his wife stoked the device, it was filled each afternoon and then set itself going at 6:00 the next day, it could be reloaded during the cycle and I think it was

25kW(t), now that's about 7kg of dry wood an hour at 70% efficiency, double for fresh oak. I wouldn't want to traipse through the house with that much. It cost >GBP20k installed with a heatstore. I doubt I often put more than 4kg/day through my little Jotul (30 years old but relined with bits cut from broken manhole covers). I haven't plumbed in either of my wood burners.

An air conditioner is a heat pump when run in reverse, its just air sourced. Actually they run the same way, just swap the hot end for the cold end of the circulating fluid I think.

AJH

[Tim Lamb]

In message , [e-mail] writes

Yes. Long reach installed.

We already have an open log burning fire in the lounge but from a house heating POV, with open plan rooms, this is probably neutral: radiant heat to one room but lots of gas heated air sucked up the chimney.

Retirement/more time in the house plus labour cost only fuel leads to an ambition to offset at least some of the central heating cost.

We started a related thread some time back with some interesting input from TNP etc. The Demon news feed has been sickly so I am only just following up. I have been collecting glossy brochures meanwhile:-)

There appear to be three options (4 if you count the do nothing one)....

1) Install a simple room heater. The available fire opening is in the middle room of three. Using the on line heating requirement calculator and allowing a bit for open stairwell, around 10kW is needed. I guess this would make the middle room uninhabitable! 2) Install a 6kW heater with a modest back boiler giving 3kW to the room and 3 to offset the gas. Costly to install without saving much gas. 3) Install a heater with a wrap around boiler giving 3kW to the room and 7 to offset the gas. Provided the neutraliser can handle this amount of gravity heat the only extra is more logs.

regards