Open To Ideas - Heating System Rethink

[dhaslam]

Looks like an estate cottage that was  built with an  elegant exterior.  However the  extention at the back  seems like  an afterthought and not so well planned,  northwest facing and with no view to the back  plus the fireplace on the outside wall where it wouldn't help  heat the core of the house. 

     

     

[desperate]

Yo tarrel, nice place you have there, looks nice and peacefull, we stayed at a house in Elgin a couple of years back, really enjoyed exploring the area, and single malts

Anyway the heating system, how about a WBS with boiler in the lounge feeding a thermal store in one of the bedrooms, this could be connected direct and would run fine on a gravity system, thus safe in the event of power cuts etc, you could also fit a bleed radiator for one or more of the upstairs bedrooms if you wish. Within the thermal store would be 2 coil heat exchangers, one for the input of the solar panels, one an output for the heating system which remains pressurised as existing, so in effect you have 2 heat sources for your heating. The advantage of this is that when you are not able to burn the WBS for whatever reason the oil combi does not have to heat the store before you get heat to the house or the hot water. In fact the Oiler never heats the store.

The hot water could either be provided by a third coil in the store which preheats the water on its way to the oiler, or you could bite the bullet and convert the oiler to a system boiler, install a new hot water cylinder and feed that from both the solar and/or the store/oiler. This would end up being very similar to our system here at cactusville, but with one big advantage, your thermal store would be within the heated envelope of the house, so during the heating season any losses from it would usefully heat the bedroom. The thermal store could also act as a heatdump in the summer for the solar, with the slight chance that you could recover some of the previously dumped heat.

Personally I wouldn't bother with both a batch boiler and a wood stove in a property of your size, after more than 2 years we find the stove and the solar supply over 80% of our heating and hotwater, and the gasser just sits there sulking, but very handy when you have a stinking cold to be able to press the button and warm the place up.

Whaddya reckon, this is just my take on what may work for you, some will disagree some wont, others will be along with more ideas, but for now................

Cheers

Desp

[charlieb]

My tuppence worth, not a heating engineer or anything fangled, but have done lots of work. 

Big woodstove with backboiler will do all heating and hot water in the winter, and make the space warm. My first choice would be that, in whichever room suited and with a relatively big thermal store/tank, and a smaller stove as well in the other downstairs room which could do Autumn/spring heat.  Then plenty of solar thermal feeding into the store for 70% of summer hot water.   Keep the oil combi for summer hotwater otherwise, and when it dies probably just use the immersion.   An always on range cooker could replace the smaller stove, and contribute good autumn/spring hot water. Just bear in mind the cost of a new

2nd choice would be an outdoor batch boiler, which would make the wood management a bit simpler, but less pleasant (stoking a woodstove is very satisfying if you approach it that way). That way solar thermal would be less vital, but you wouldn't get any of the psychological benefits of the stoves (although you'd probably want one stand alone as power-cut backup come to think of it). And you'd need a big old expensive heat store to avoid having to fire the boiler every couple of days in the summer.

I wouldn't go near heat pumps if I was you.  And I would spend time and money on a good quality, and big, heat store.

[tarrel]

Some interesting ideas folks; thanks so much.

@ Desp;
Like the idea of keeping the boiler separate.  If I understand you correctly, would the heating coil just be inserted into the existing heating circuit?

If I went down the WBS (as opposed to batch boiler) route, would anyone have a rough idea of what size store I would need?  We have an airing cupboard in the main bedroom which I guess used to house the DHW tank before the combi was installed.  I wonder if a tall, thin store would go in there if the capacity didn't have to be that large.

@ Charlieb; I think you make a good point about the "psychology".  I've thought about batch boilers.  If we were both working full time and needed to just load it up and rush out the door, then I guess a batch boiler would be really useful, but in fact we do have the opportunity to keep the thing fed most of the time.

Can wood burning stoves be kept in overnight so they can be easily restarted next morning?  (Sorry - I've never had one; only an open fire).

[desperate]

Like the idea of keeping the boiler separate.  If I understand you correctly, would the heating coil just be inserted into the existing heating circuit?

Yes, it becomes like a second boiler for the heating system, a changeover stat on the store selects that coil if the store is hotter than Xdeg C or the oiler if below X.

, would anyone have a rough idea of what size store I would need?

Our store is 200 litres, it runs the heating for an hour in the morning while we are showering etc, usually the gasser doesn't come on during that hour. The WBS heats it all up again in the evening.

Can wood burning stoves be kept in overnight so they can be easily restarted next morning?  (Sorry - I've never had one; only an open fire).

Yes ours regularly has a good layer of just glowing charcoal in the morning, and the chimbley breast/living room is pleasantly warm.

Desp

[tarrel]

Sounds like a plan is coming together.  Here's the fireplace in the lounge.  Does anyone know; could a stove be installed in front of this, or would it need to be removed?

[dhaslam]

It is possible  to  fit an insert stove or one in front of the  existing fireplace.    I still think the better option would be  to put it at the other side of the room, backing onto the kitchen wall,  with short  pipe runs to a store above and from there to  kitchen and bathroom.   It would change the character of the  house a bit.  

This is my setup,  I can store a several weeks  supply of wood inside and the storage space is  heated.  Not quite competed yet but the  air extracted from the store on the far left  will be directed into the  heat recovery system and warm air directed to there from behind the stove.     The gasifying stove (Walltherm) ideally needs wood at about 15% moisture.

[billi]

I would  not force   a decision   too early.... , i would move in  and live there for a year with the oil burner  .....(or at least one winter)

to find out your needs and fuel demand

Its an old house ,  single glassed ,and the  extension  to the back  (living room)  seems to be built with blocks  and thin  walls ( single glassed as well ?)   cavity insulation ?

Surely  solar thermal for  DHW makes sense ,  straight away , and a wood burner (with back boiler) in the living room as well ,  but perhaps  you invest  too early in a system that will not cope with your expectations .....

As you are having  a  business  involved  in "biomass" (Christmas biomass  )  and have lots of "waste"  perhaps it makes sense to  shredder /palletize and have a central automated heating idea  ......... 

Billi

[tarrel]

Thanks for your further thoughts folks.

The living room is built similarly to the rest of the house.  Walls are stone and around 0.5m thick.  The room is single glazed though, and the windows are quite large.  I am investigating possibility of double-glazed units in the existing sash windows, along with draught-proofing (although this doesn't seem to much of a problem).

We have owned the property for three years.  We let it as a holiday-let in the summer, as well as using it ourselves.  Over the winter we have a team of lugworm-diggers staying there (I kid you not!).  They look after the place really well, and ensure that the house is heated and ventilated during the winter months while paying us rent.  BUT..they really get through the oil!  They have waders and all sorts of outdoor clothing that they need to get dry.  I suspect they run the system 24/7.  They're using about 600 litres a month.  So, we do have an idea of the potential fuel demand during the winter.

Picking up on some of the responses here, I think I'm going to look at insulation as a priority, then likely go the "wood burning stove in the living room" route.

[charlieb]

I'd second what Bili says. Get a stove somewhere in the sitting room and/or kitchen asap and start burning wood (bear in mind it'll need dried for a year or so), which will give you one nice warm room and massively reduce the time you need heating on for. Gives you a chance to focus on insulation,e tc, and deciding what you really want to do with wood (ie batch logs, WBS logs, chip, sell).  A stove really is incomparable to an open fire - you will love it as soon as you get one.   As Desp says, you could install one in front of that open fire (you may have to extend the hearth, or put a paving stone hearth over the woodfloor) with a rear-exit flue going into the chimney through a vertical register plate.  That would involve no building and could get you up and running in the time it takes to order the stove or buy a second hand one on ebay.  (It IS worth spending money on a decent stove).   Or you could faff around getting an insert - both will make the room lovely to spend time in.