Biomass/Solar eco experts, advice sought. Stoner +?

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Biomass/Solar eco experts, advice sought. Stoner +?

175 posts & 16 voices | Started 8 months ago by 29erKeith | Latest reply from paul4stones

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29erKeith - Member

bit of a long ramble here just trying to get some ideas....

Just had an offer accepted on a new house (old brick Built slate roofed cottage in the New forest) needs loads of work doing to it inc. an extension which should make it'll up to about 120-130sqm.

I really don't want to use gas/electric for heating/water.

I know insulate first that'll be done but then I'm thinking Biomass with Solar (evacuated tubes) a thermal store with a half to two third of downstairs with underfloor heating and the rest with conventional radiators. I've done loads of looking around solar seems pretty straight forward and not to pricey or difficult DIYing it and using the place recommended off of here on one of Stoner's threads. I'm ok at plumbing and have mates in trades that can help on the more complicated bits.

due to funds I may initially reuse the gas boiler with solar and thermal store until I can afford the new biomass (depending on extension costs) Is that feasible?

Biomass boilers seems to vary massively!!! in price, any recommendations?
Baxi have some 15KW ones which seem pretty cheap, also Fuel? I really can't make my mind up, I'm leaning on pellet/chip with auto feed so there's less faf. I can get unseasoned chip free/cheap from a friend (but how long before it can be used?) I would like the option of logs too. Anybody with such a system have any comments on how much effort is involved in keeping it all going, through a winter especially. My boiler room will probably be in a separate out building only a meter or so from the house due to National park planning and trying to maximise living space.
Any ideas on a ballpark costs assuming 90+% is DIY. My very very! rough estimates are:
Solar £1k for 2 sets of the large Evac' tubes pump etc
thermal store £1k
Biomass about £5k
then £2k for headers, underfloor, pumps, controllers, manifold pipes etc

Am I right in thinking the savings on DIY will outway payback by using approved installers to get feed in/micro generation payments?

how have you found prices of fuel and sourcing it?

Any thoughts comments resources and advices gratefully received.

Thanks if you stuck with that
Keith

Posted 8 months ago #
CaptainFlashheart - Member

You should seek the opinion of a medical professional.

Posted 8 months ago #
Stoner - Member

oooh lots to talk about. Do feel free to email me off forum to if you have any other questions.

Im no expert, but have learnt a good deal through my experiences.

First of all: sizing.

Large biomass boilers dont cost a whole lot more than smaller ones and you will get best performance ragging your boiler flat out for as few an ignition cycles as possible and using your buffer (thermal store) to achieve this. To this end sizing isnt as important as say for a combi gas boiler that produces heat on call.

Id recommend learning about u-values, heatloss and vent loss calcs and having a stab at what kind of energy your new house is going to need after youve done as much insulating as possible.

from that you can work out what kind of thermal store size would work best during winter.

The great thing about the thermal store as you mention is that you can swap the call for heat source from gas to biomass at a later date (hell, if it isnt in the way, you could even leave the gas boiler in situ as a back up )

Pellet fired is probably the way to go for simplicity. There';s lots of suppliers out there now, and buying 10Kg bags or blown loads is easy. My neighbour has a 4 ton bag into which deliveries are blown. I have a store in which I can store about 2-3 tons of 10Kg bags. I manhandle these bags in 600Kg at a time to my boiler room. But Im young and fit. To make life easier I could convert my store into a 2t ply tank and buy a vacuum transport system to move the pellets 150Kg at a time into my "week" hopper next to the boiler at a flick of a switch.

If you can factor in pellet storage right next to the boiler, then you can just use the supply auger, for a simpler system (vaccuum transport is pricey)

Chip is not the same as pellet. Its wetter and less efficient but your fuel source is more versatile if you have access to waste wood and a chipper, but I reckon longer term, youll find pellets a more reliable, if more expensive energy source.

...

hmmmm this is going to be a very long post. SO much to cover. You should really come and visit and I can show you mine, and my neighbours set up (his is very whizzy, techno complex and expensive, but theres lots to be learnt from his system design) mine's more basic and low tech (I can service and fix my boiler - no need to pay engineer fees!)

ball park figures:
5k for boiler, 1.5k for thermal store and solar coil
1-2k for solar thermal
1-2k for UFH

EDIT: BTW, your plans are almost identical (but about 50% for sizing) to mine: biomass of pellets with logs, + solar thermal + UFH + radiators upstairs. WIll psot pics to illustrate in case you havent seen them before

Posted 8 months ago #
Stoner - Member

UFH manifold. UFH downstairs controlled by single thermostatic controller in middle of ground floor. Each of 6 zones is balanced to provide even 18 deg heat across whole of 1,500 sq ft ground floor (all open plan). Water comes from middle (50-60deg ish) of thermal store and blended with UFh return down to 40ish.

UFH Laying out prior to screed (i laid it out and installed the UFH, and paid for others to screed)

~~Nuclear reactor~~Boiler being delivered

720l Thermal store

Low volume aluminium radiators upstairs. Controlled by a single thermostatic timer located in upstairs corridor. Draws hot water (mixed with return water back to 50ish) direct from boiler (not thermal store), each rad has its own TRV

Biotriplex by Jaspi. LHS for logs in furnace, RHS pellets (red box on front is burner). "Week" tank will take about 180Kg. This time of year will last for 40-50 days +, mid winter -10degs, lasts about 5 days. Can also see expansion vessel for system. 1.5Bar max (which is very low). But theres about 1000litres of water in the system. You can see the radiator flow and return coming out the top of the boiler.

Thermal store.

Posted 8 months ago #
Stoner - Member

Wood store, pellets kept on pallet. ABout 25-30ft from the week tank. Takes about 40 minutes to transfer 60 bags into boiler room.

moved this lot in the other day, will last until well into november

Posted 8 months ago #
29erKeith - Member

I had sort of used your set up as a bit of a template tbh backed up by a fair bit of reading on the net too. I've followed and bookmarked your previous threads already for reference

I'm only at really initial stages at the moment we don't even move in until next month but will want to get planning rolling asap as the national park makes things a bit complicated.

I'll certainly email you when I'm further down the line and thanks for the offer of a visit too, really kind, it'll be really helpful before I get head on into it (sometime next year probably).
Where about in the country are you?

Posted 8 months ago #
Stoner - Member

Im in malvern. Bring a bike* and a notebook.
welcome to stay over if it's a long trip and grab a ride etc.

*Although I have a spare 29er if you fancy coming by train!

Posted 8 months ago #
Stoner - Member

BTW, the other thing to consider is what geoffj on here is lookg at, which is a log burner with a boiler on the back and linking that to the thermal store via a load charger.

Posted 8 months ago #
29erKeith - Member

oh btw I was thinking of using the pitched roof space for pellet storage with a hole and shoot to reload the week ish sized hopper
That way it'll be easy reloading and not too much hassle to get it blown in there

Posted 8 months ago #
29erKeith - Member

All sounds great I'll be in touch
cheers

Posted 8 months ago #
Stoner - Member

like the sound of that.
Blown loads can be delivered over at least 30 metres IIRC.

There are some issues with combustable fuel storage in a house though, but Id need to read up on it, not sure if it applies to pellets.

Dont forget 2-4tons of pellets is quite a load on ceiling joists - youd need to reinforce.

Posted 8 months ago #
29erKeith - Member

Don't suppose your doing the Bear Bones 200 next month are you?

Posted 8 months ago #
Stoner - Member

Bear Bones 200

Posted 8 months ago #
29erKeith - Member

guess not then

200k Bivy thingy, mid wales, by guys that did the welsh ride thing

Posted 8 months ago #
Stoner - Member

Ah. no.

BTW - Part J (Fuel storage) doesnt apply to solid fuels.

Posted 8 months ago #
geoffj - Member

I'd say stoner has it covered.
After a bit of looking around, I'm getting my solar kit from Navitron - http://www.navitron.org.uk/category.php?catID=71 they have a forum too.

I got my cylinder from Newark Copper Cylinders, so I could customise the type and location of the coils (http://www.newarkcoppercylinder.co.uk/)

My thermal store will have feeds from a multifuel boiler stove, oil fired central heating boiler (already in) and the solar evacuated tubes. Unfortunately, we can't do underfloor heating, so everything is sized for higher temps using (new but) traditional rads.

I'm hoping that the load charger (http://www.stovesonline.co.uk/wood_burning_stoves/Load-units-and-laddomats.html) is going to help to maintain stratification and stop the stove running as a radiator in the summer with the heat from the evacuated tubes.

Its currently all sitting in the garage waiting for my polish installer friend to get started.

I think the RHI payments on the solar thermal part are probably going to work out at 300-350 per year for me. The RHI payments for biomass are 7.9p per kwh - there is a calculator you can try here http://www.biomassenergycentre.org.uk/pls/portal/url/ITEM/9DFC29E3FE404C21E04014AC08044E0E

There may be an issue with keeping the gas boiler if you want to register and claim RHI.

Posted 8 months ago #
ransos - Member

If you insulate well enough, you don't need a biomass boiler, or any kind of central heating system for that matter. You should also consider mechanical heat recovery and ventilation.

Best place to ask these sorts of questions is here: http://www.greenbuildingforum.co.uk/newforum/

Posted 8 months ago #
Stoner - Member

If you insulate well enough you don't need ... any kind of central heating system

not really an option in an existing building. If you were constructing a passivhaus from scratch then possibly. But not a 150yr old, draughty slate cottage in the new forest.

Posted 8 months ago #
ransos - Member

"not really an option in an existing building. If you were constructing a passivhaus from scratch then possibly. But not a 150yr old, draughty slate cottage in the new forest."

The OP suggest that lots of work needs doing - the thought occurs that if (for example) all the windows are to be replaced, floors taken up etc, living without central heating is a possibility. But you're right that it wouldn't be easy.

In any case, given that the house already has a gas boiler, and is to be insulated, I can't see how biomass is going to be cost effective.

Posted 8 months ago #
Stoner - Member

I agree to a point. for at least the next 10-15 yrs i expect mains gas to be the most economical fuel if you can get it. but adding a thermal store, with solar and log boiler isnt a bad idea. its nice to have some energy independance as well.

Posted 8 months ago #
Rickos - Member

Ground source heat/cooling pump? Warms in the winter and cools the house in summer. Is that not worth a look? I know sod all about it, just thought it may be a simple one to put in to reduce the load/size of your boiler. Suppose it depends on how much land you have and whether digging up your garden is an option.

Posted 8 months ago #
29erKeith - Member

thanks Geoff some useful resources there I'll have a look into them properly later

Ransos I will do what I can with the house with regards insulation but it's an old place not a new build + it's in a national park so I'm a bit restricted with what I can do certainly externally I'm not sure I can get away with no direct heat sources. I will have a look though

cheers

Posted 8 months ago #
Stoner - Member

Im not a fan of GSHP because theyre still pegged to electricity in terms of energy cost which is only going to go one way. But ASHP with a wet CH system would be a good replacement for night storage heaters for example.

Posted 8 months ago #
29erKeith - Member

Gardens is an ok size 12m x 22m but that's probably not big enough is it?

cost is still a major factor + I'm not sure how effectively we'd be able to seal and insulate the house up to that level

as I said I will probably initially do the solar and thermal store and get everything ready but re-use the gas boiler that's there for the moment and just swap the Biomass in when funds allow
Yes cost is a factor but the environment is too I accept pellets may cost a bit more at the moment but as Stoner says that should change Gas is only going one way

Posted 8 months ago #
geoffj - Member

its nice to have some energy independance as well.

This is my main motivation. Last December, there was a 3 week delay for oil deliveries and when they finally were able to supply, the lorry couldn't get to our neighbours because of the snow.

Being on oil, looking at alternative / supplementary technologies is a no brainer for us. I'm just surprised at how many folk in our village are mindlessly replacing oil fired combi boilers, without investigating alternatives.

Posted 8 months ago #
Stoner - Member

if you use the average kWh consumption figure and british gas tarif structures, the weighted average cost of gas fuel is about 4.9p/kWh. At 90% efficiency for an A rated combi, that's a real heat generation cost of about 5.5p/kWh

My pellets cost about £259/tonne, with an energy density of about 4.9kWh per Kg, 5.2p/kWh
At 89% efficiency in my pellet boiler, thats 5.8p/kWh.

With heating oil prices at around £300/500 litres and oil energy density of 10kWh/litre, oil boilers are a little more efficient at around 92%, so cost comes out at 6.5p/kWh

Those calcs rather surprise me. When I first did these figures 18 months ago, gas was loads cheaper, and oil was the second cheapest - something like 3.5p gas, 4.4p Oil and 5.5p wood.

Posted 8 months ago #
29erKeith - Member

Boiler mainly and initial set-up costs are much higher than a std Gas/oil system and many think very short term, I think that would put a lot of people off + effort of keeping it running
Gas is certainly fit and forget, and oil's not far off, biomass is more effort

I don't think a lot of people in the general public know much about biomass either. I didn't until I saw Stoner's threads on here and went looking for more info

Stoner with your boiler being dual fuel how does that bit work?
what I'd ideally like is it to use logs if they're there, then pellets if not. Is it that clever?

Posted 8 months ago #
Stoner - Member

mines quite simple. Before the tank temperature has fallen to the ignition trigger point (say 55dges or 65 degs) I build a fire in the furnace.

Once a starter fire is going nicely, then you load the furnace with neatly stacked logs - can take about two large armfuls. Let it get going properly and then shut it down. It will burn all morning and can raise about 500l of water by about 20degrees. The pellet boiler wont fire until the temp gets down to the trigger point.

You dont light the fire if the tank is showing 85degs though. Theres a supression system that kicks in at 90degrees.

Might have a pic or vid somewhere...hang on....

Posted 8 months ago #
Stoner - Member

here we are, this shows the starter fire on the grid at the bottom of the furnace. I now load the logs in a neat stack on top of the fire.

The fire burns from the bottom up, so it can look after it self. You can control the air flow through the wood stack or through the bottom, it then goes through the throat at the bottom of the furnace (where the ash pan is) and then up into the boiler heat transfer chambers.

www.youtube.com/watch?v=wSTxJWtWf88

Posted 8 months ago #
ransos - Member

29er: I appreciate you're restricted because of your location, but consider internal insulation: I had it installed in one of my bedrooms and the difference amazed me. Underfloor insulation is well worthwhile, too.

A well insulated house with MHRV, and a wood burner with back boiler? It could connect to the thermal store...given that you have mains gas, I honestly think that a pellet boiler is overkill.

As a general point, we have commissioned the installation several biomass boilers at work (schools etc) and whilst they reduce carbon emissions, the economics don't really stack up. You'd also need to be pretty sure that the RHI subsidy is going to continue for many years.

Posted 8 months ago #
29erKeith - Member

I'll try and do as much internal insulation as I can but I really don't want to have to loose any space from the rooms, the 2 bedrooms in the part of the house which will be remaining are only 3.5m x 3m so not big it's not a massive house so I want to make the most of the space available.

I will look at the numbers in greater detail, Biomass is just a thought, back boiler like Geoffj's is also an option too

Insulation, Thermal store and solar are 100% on the list though

cheers all

Posted 8 months ago #
Stoner - Member

and of course UFH without floor insulation is just nuts

BTW - you may want to keep in touch with Marin_Maketh_The_Man on here as I believe he's venturing into the world of smoke and fire too.

Posted 8 months ago #
29erKeith - Member

The UFH section will be a new sub-base with insulation which I'll do and as you did get the pro's in to screed it, it'll probably have engineered Oak floor/tiles in the kitchen

So the log section is a manual load and start up, not to much hassle at all then

I'll have a search for Marin_Maketh_The_Man threads too

Posted 8 months ago #
Stoner - Member

So the log section is a manual load and start up, not to much hassle at all then

No. Its quite therapeutic in the morning, after coffee, to go make a fire for the day's hot water. It's the equivalent of the "free" summer solar energy.

I'll have a search for Marin_Maketh_The_Man threads too

Dont think he's done a thread yet, just contacted me off forum. But he's in much the same position as you, and since you'll both be doing research 18 months after I did, you may find you each have more contemporary info to share than I can. He has a pm email.

EDIT
Oak floor/tiles in the kitchen

NEVER wood floor in a kitchen
And stone is by far the best thermally performing floor material for UFH

Posted 8 months ago #
Mounty_73 - Member

Some very good Swedish products;

http://www.allweatherheating.co.uk/

Posted 8 months ago #

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