bio mass boiler

[atkinsthenook]

hi I have a fairly large biomass boiler fitted outside my property, make unknown? its to heat two houses, its piped direct to an open vented system in the main house and to a small thermal store in the cottage. I think it needs to be changed to one main thermal store and coiled to keep everything separate. also a proper solution to controlling heat im no plumber and need some expert advice. im in the Carlisle area does anyone know of someone fairy local to me who is clued in as I have had some bad advice up to now. regards mike

 

[Worcester]

I'll put the word out to a few people I trust. Without visiting it is difficult to give advice, however, it would be most normal to into a large buffer tank / thermal store first #1 reason, biomass boilers can take up to 10 mins to reach optimum efficiency so you don't want them switching on and off, so,e are capable of modulation to reduce output, however if you can avoid them cycling more than 3 - 4 times a day that is best.

Q: How long ago was it installed.
Q: Really do need to know the make AND model
Q: What output is it?
Q: What fuel?
Q: How many tonnes of fuel are you burning a year?
Q: Build/Construction (age and type) and Sqm of the two properties.

 

[atkinsthenook]

I'll put the word out to a few people I trust. Without visiting it is difficult to give advice, however, it would be most normal to into a large buffer tank / thermal store first #1 reason, biomass boilers can take up to 10 mins to reach optimum efficiency so you don't want them switching on and off, so,e are capable of modulation to reduce output, however if you can avoid them cycling more than 3 - 4 times a day that is best.

Q: How long ago was it installed.
Q: Really do need to know the make AND model
Q: What output is it?
Q: What fuel?
Q: How many tonnes of fuel are you burning a year?
Q: Build/Construction (age and type) and Sqm of the two properties.

thanks for reply. installed last yr but hardly used due to problems, it is a fabricated industrial thing(I will add picture) output I think is 45kw and burns logs, property 1 is about 200sqm brick/stone/slate and old,prop 2 is 50sqm stone/slate 5yrs old. some trustworthy advice would be appreciated. regards mike

 

[Ermintrude]

Agree on buffer then two seperate indirect systems running in parallel on s plan with individual DHW storage . Main house probably need a leak rad or two tho.

 

[Worcester]

As it's serving two properties, was it installed under the commercial RHI scheme, and registered on the MCS database?

Photos would help.

Being log, definitely needs a leak rad / heat dump and at 45kW, probably two. (some people put them in the basement / cellar if it exists). Manual fed logs, two sites, without a large buffer tank (2500ltr) this is going to be a nightmare to balance / get right. Adding in DHW cylinders has the advantage of adding another 500litres or so of HW storage.

The problem is that without a massive buffer tank is that your demand will never match up with your supply. - Log boilers aren't like pellet ones, they can't produce heat on demand.

Re-reading your initial post "small thermal store" is probably one of the core parts of the problem.

Sounds like the inbetween bits between boiler and emmiters (rads) needs redesigning from scratch based on what you've got. You're looking at a couple of days work just to design it all properly.

 

[Ermintrude]

Couple of days ? me mate down pub does them on beer mat. Probably did this monstrosity after a few pints.

 

[Worcester]

Have a look at the attached. As a (very) simple rule of thumb we'd start by working on 50ltrs/kW (so 2500 ltrs should be about right)

2500 ltrs would store in the region of 30x2500x0.00116= 87kWh of heat. (30 is temperature drop from say 80° to 50°)

If you have a heat loss across the two buildings of 15kW then you're going to get just under 6 hours of heat out of the tank (in the middle of winter). It should reheat in 3 hours from your boiler. Most times it would last a couple of days.

How long does one full load take to burn?
A MAJOR factor on performance is not using properly seasoned logs - they cause massive amounts of problems.
Hence the Austrians and Scandanavians have massive log fuel stores.

Under (and over) sized thermal stores are the scourge of biomass systems!

If you have a smaller store, then you're going to be constantly refilling an oversized boiler and throwing heat away as it generates it.

View attachment Principal_drawing_for_standard_AKVA_accumulator.pdf

 

[Nostrum]

You'll need a large accumulator in the region of 2000 litres for a 45kw batch fired log gasification boiler. If it's designed for 1 load a day ( anyone's guess by the sounds of it) then there should be little need for heat leaks. If they have tried to install it like a traditional system and your loading it up to run your heating in an evening then your wasting your time.

 

[Worcester]

Found it - this is what he needs File:Fernwärmespricher Theiss.JPG - Wikipedia, the free encyclopedia

 

[Ermintrude]

Found it - this is what he needs File:Fernwärmespricher Theiss.JPG - Wikipedia, the free encyclopedia

Thought u knew your stuff? Well undersized. Two or three in series with nice sappy conifer or even some sycamore. Extremely high density fuel!

 

[Jimbob]

This doesn't sound great

No accumulator? I'm also quite involved with this kind of work, we would usually use a large accumulator/buffer/thermal store, 2000-3000 litres. Then to break system we would use plate heat exchangers at the entry point on each build to separate system.

Some pictures might be helpful then we can see exactly what's been installed.

Surely can't even be MCS compliant?

 

[atkinsthenook]

for some reason it wont let me put in pics I will try and get my wizkid teenager to do it . I didn't find out about commercial rhi scheme till after boiler was put in,so iam going to apply as soon as problems are ironed out. I burn dry logs only as im in the forestry game, the boiler takes approx 2 hrs do burn one load. I might struggle to fit in that size of buffer(last attached link:smile5 but 2500/3000lts will fit. the main house will suck up large amount of the demand as long as I could control boiler better, heat leaks shouldn't be a problem as they can be put anywhere cant they? should the cold mains be attached to primary circuit as a failsafe? would tank require coils to separate rad systems, I was thinking 2 one for each property, or would heat exchangers be a better way to go. thanks for all the advice mike

 

[atkinsthenook]

 

[Worcester]

@atkinsthenook post the pictures on flickr / picasweb / photobucket and share the link here, you have to have a dozen or so posts before you can post up a piccy I believe.

 

[missplumb]

i think the best way to doit as jimbob says is to install a buffer tank and have seperate district heating lines to each building, terminating at a plate exchanger where entry into the buildings.