wood pellet boilers

[jase17uk]

Hello all,

I am considering installing a wood pellet boiler to work alongside with a solar water heating (3 panels & thermal store) to feed ground floor UFH (4 zones) and 5 CHs upstairs and mains pressure DHW.

I am considering either MCZ Compact 24 or Extraflame LP20 (due to space restrictions). Which is better and why? Perhaps you know of a better boiler in terms of price & efficiency?

Thanks in advance

 

[Jamesie]

Have you looked at baxi? I was chatting to a baxi rep last month, about renewables etc, and he absolutely raved about a pellet burner baxi have, fully automatic and very efficient. he was saying it can also be made as a feature, as i think the combustion chamber is visable.

 

[Biggles..]

Windhager

 

[Agile]

I do hope you have lots of space to store your wood pellets!

If everyone used them they would become expensive as I expect they are made from waste wood offcuts at the moment.

Someone was killed recently by carbon monoxide gas from stored wood pellets so never expose yourself to breathing air where they are stored!

Tony

 

[jase17uk]

Thanks for replies

I do have space to store about 2 tons of pellets... I'll have a look at baxi pellet boiler as mentioned in here.

I'll still need some1 who knows about pellet boilers who can advise which is best and why.

 

[Biggles..]

Best by a country mile is Hoval based 20miled from you at Newark, they won't instal, indtatherm do most for them.

The Baxi unit is as far as I know a rebadged unit, very expensive and the output isn't much cop.
If you want my advice, Baxi make ok gas boilers, avoid anything renewables by them at the minute. Their CHP/solar ain't good, their biomas isn't either.

Seriously consider wind hager, brilliant company and solid units.

 

[big-all]

2 tonnes wont last long
you need to find out your average energy consumption to heat the house
you need to take the boiler efficiency and assume very near the bottom value
then take heat output from the pellets and again assume near the bottom value untill you know better
i assume you dont have the far cheaper mains gas option

 

[Biggles..]

Do you get RHi for mains gas?

 

[Norcon]

Wouldn't take the gift of a combi styled pellet boiler. The ordinary ones can give enough trouble.
But there is a lot of makers out there. ETA, Froiling, Gerkros, HDG, Okofan, Benekov, Grant Spira, Per eko WBI, Janfire, Biotech, Viessman, Prosat, Galmet Eko, Atmos. To name but a few.

In the 20- 40kw range you can pay from £1,600 for the per eko too over £12k for the froiling.
Then storage costs after that.
Good luck.

Here in NornIron the grant for biomass is £2500 with yearly Renewable Heat Premium Payment scheme (RHPP) payments to follow after that for donkeys years.

 

[jase17uk]

Combining the pellet boiler with solar thermal should reduce the boiler start ups also far cheaper than oil also they are like a gas combi meaning I can get mains pressure DHW. Using UFH meaning lower return temperature. My house is being renovated and will be super insulated so wont need high output from the boiler.

I'll probably get someone around to calculate the kW I'll need from the boiler.

 

[Agile]

You can calculate the whole house heat loss yourself.

But its going to be fairly irrelevant ( except for pellet consumption/costs ) if you are having a combi rated at 24 kW or more.

Have you checked the costs of delivered pellets ( in the volume that you can store! ) in your area?

A typical three bed semi has a heatloss of about 10-12 kW.

Solar panels only heat stored hot water and do not contribute to heating the house.

Tony

 

[Norcon]

Combining the pellet boiler with solar thermal should reduce the boiler start ups also far cheaper than oil also they are like a gas combi meaning I can get mains pressure DHW. Using UFH meaning lower return temperature. My house is being renovated and will be super insulated so wont need high output from the boiler.

I'll probably get someone around to calculate the kW I'll need from the boiler.

Biomass sizing is totally different from the usual fuels like gas and oil. The majority of plumbers and boiler technicians won't be aware of this!

DHW recovery for a 210 liter cylinder for example based on 1 hour re-heat will need 14920w allocated and this is added to heat loss and ventilation loss.

So if your heat/vent loss is 10kw you add 14920w = 24920w plus another 30% for manufacturer efficiency, boiler in cold garage and radiator/ufh heat up losses. 10% each!
24920 + 30%= 32kw.

Thus for a 10kw heatloss and 210/L cylinder you would need a boiler rated at 32kw.

This is in line with HHIC/CIBSE/ BRE recommendations.

And from a letter sitting on my desk...

The design and sizing of biomass heating systems is important and needs to be carried out to a greater accuracy than with other forms of heating systems e.g. natural gas.
David Forward - Senior Consultant

Also there is a CEN standard for wood pellets which is CEN/TS14961:2005 and not all pellets are manufactured to meet this standard.
So the above sizing method will keep you well protected against a bad batch which is not uncommon.

 

[victorfirst]

Hi we have just built 2400 square foot house with 14 zones of underfloor 5 rads and 210 s/s cylinder. It is heated with 24 KW Grant Spira wood pellet boiler.Running costs are approx 22 pounds a week or 10 10KG bags. We buy 2 tonnes for 440 pounds on two pallets and it does not take up to much room.With goverment grant of 2500 pounds and possibility of more to come i cant recommend enough so long as you have space

 

[victorfirst]

Sorry 14 loops of underfloor not 14 zones as mentioned above