domestic fuel system planning/ sourcing

[roys]

I consider my system to quite simple.

I stay in a small cottage with a log burner with back boiler.

Above the woodburner in the loft is a 210L twin coil cylinder, one coil fed from the back boiler the other coil from two solar thermal panels.

I have a pipe switch on on back boiler return pipe, when the temp reaches 55 deg C I think the pump switches on and pumps it around 5 radiators. Initially the pump is only on for 3 or 4 minutes as a cold slug of water turns the pipe switch off, but as the system gets hotter and hotter the rads are on for longer.

The solar coil in the cylinder means I don't need to light the fire on a sunny warm day just to have a shower, it also acts as a pre heat on the not so sunny days.

[Dean O]

thanks guys - not wanting to quote and reply to all comments but all good stuff.

 

its an old stone built farm house with thick walls and not a huge space to add insulation to loft spaces - though I'm sure they could be improved.

 

I had looked into wet under floor heating as I like the idea of this but from what I've read - to make it efficient I would have to take the old floors up to insulate then re concrete/screed to avoid loosing heat into the ground, and I don't fancy getting into that.

 

the oil boiler is currently in the hallway with a million pipes emanating to all the rads, but adjacent to this is a utility room where a water store and log burner could go - which if I can utilise a 'linked in' type system might make sense.

 

due to the house layout it would be difficult to incorporate a back boiler type log stove into the centre of the house that could easily tie into the central heating loops.

 

we fancy an aga type jobby, but an electric oven will make more sense and keep the heating system separate.

 

there's a log burner in the living room, but, again, would be difficult to tie it into the heating system if we swapped it for a back boiler type.

 

I've got a friend that can spec systems based on assessing the requirements of the house - his back ground was through the 'green deal' and rhi assessments, but I feel we need the practical elements to be worked through too and I'm not sure that that is his strong point.

[difflock]

Dean,

I hope I am correct in saying that I recall reading a discussion on the greenbuildingforum, in respect of the validity of insulating beneath underfloor heating, this came up in an "Interseasonal Heat Store" thread.

Anyway the gist was that any heat "lost" downwards, wasnt really, it simply warmed the ground up, then reached a state of equilibrum.

A "mega" storage heater in effect.

AS LONG AS round the walls was insulated, and there was not a stream of groundwater flowing under the house stripping the heat away.

Which since the early stone built houses were ALWAYS built on a dry place, is highly unlikely.

BUT, for the first few winters, one will think the house is unheatable, until the ground warms up

food for thought?

marcus

Edited August 5, 2016 by difflock

[cornish wood burner]

Another option for you to consider is to put the heat store outside and just run the pipes to it. Underground pipe work, a boiler next to the store then no space taken up in the house. Solid walls are a pain to get through but anything is possible.

[AardvarkTreeServices]

due to the house layout it would be difficult to incorporate a back boiler type log stove into the centre of the house that could easily tie into the central heating loops.

i.

 

The back boiler will need a gravity loop into a hot water tank/thermal store to dissapate heat. You can pump from the bolier into central heating but you always need the gravity loop to dump heat if theres a power cut.

[Commando]

Have a look on Navitron website, lots of advice there. We installed a 300L heat bank/store fed from an oil fired Marshall stove (steer clear of Rayburn!) and Dunsley Yorkshire wood-burning boiler stove. The heat bank also has 2 x immersion heaters and is plumbed ready for solar.

We have had the system for 5yrs and TBH it's efficient and flexible. My advice on going down the 'wood only' route would be to ensure you realise how much wood you will need and the sweat needed to get it!

With reference to the floor, our farmhouse had a traditional stone uninsulated floor, we struggled to get the place warm and the floor was painfully cold. IMHO underfloor insulation and heating is the way to go.

 

 

Sent from my iPad using Arbtalk

[kevinjohnsonmbe]

An alternative to AGA / Rayburn, is the Heritage Range, designed, manufactured, supplied & fit by http://www.heatingsouthwest.co.uk/cookers-liskeard-cornwall.php.

 

Well worth a look / talk to Jim before committing to the better known brands above.

 

👍🏻

[cornish wood burner]

Dean,

I hope I am correct in saying that I recall reading a discussion on the greenbuildingforum, in respect of the validity of insulating beneath underfloor heating, this came up in an "Interseasonal Heat Store" thread.

Anyway the gist was that any heat "lost" downwards, wasnt really, it simply warmed the ground up, then reached a state of equilibrum.

A "mega" storage heater in effect.

AS LONG AS round the walls was insulated, and there was not a stream of groundwater flowing under the house stripping the heat away.

Which since the early stone built houses were ALWAYS built on a dry place, is highly unlikely.

BUT, for the first few winters, one will think the house is unheatable, until the ground warms up

food for thought?

marcus

We use the same principle for heating our glasshouses. We insulate around the edges but just lay sheets of old polythene in the centre. I work on

100W/ sq metre for underfloor heating with 20 mm pipes 200 mm apart. 60 deg

flow through 20mm polypropylene pipes give us all the heat we need.

[Dean O]

Thanks guys

 

yes Id prefer to not be 'wood only'.

looking at things I'm now swaying away from the solar thermal and industrial type log burner/boiler and back towards a aga type setup.

 

however from what I can see - if it can also cook then it wouldn't be possible on the rhi?

 

rhi doesn't seem to be much cop for payments and the cost of install appears higher than I had imagined. This would mean payback may never happen.

 

I like the idea that underfloor might be a possibility though.

 

I've contacted a couple of companies, and Ill see where I get.

 

Thanks for the advice all, lots to think about

Dean

[openspaceman]

We use the same principle for heating our glasshouses. We insulate around the edges but just lay sheets of old polythene in the centre. I work on

100W/ sq metre for underfloor heating with 20 mm pipes 200 mm apart. 60 deg

flow through 20mm polypropylene pipes give us all the heat we need.

 

 

I've also read this but assumed the edge insulation needed to be sunk down a few feet??

 

Also not a good idea if the floor needs venting as it's over granite.

 

Of course you have a very big surface area to perimeter ratio compared with a house so heat losses to the sides are small in relation to the heated area.

 

I do remember digging in a large barn near here which was open at the sides and being amazed at how dry the soil was so our sandy soil would be good to create a large thermal store.

 

Of course you currently heat the house with the flooring as is so there's still a gain from the comfort of having the heat at foot level and I would expect the additional losses to be negligible if the slab is only heated to 25C.