Wood pellets, grain or rape cake?

Do-more · 16-08-2006 06:54AM #1

I am considering a multi-fuel wood pellet boiler to replace my oil boiler.

I am wondering if anyone has done the maths on which fuel is most economic?

Does anyone know the calorific values of wood, grain and rape cake so that an accurate comparison of which gives the best output/€ can be made?

Cheers

Do-more

Pocari Sweat · 17-08-2006 12:15AM

In Joules I thinks it is wood that is up there.

ircoha · 18-08-2006 05:33PM

I googled and got a lod, including this
http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html

The problem for these fuels is what moisture content are u basing it on.

[Will u be able to keep the stuff "bone dry" in bulk?]
In addition are there any stats on the efficiency of a multi fueled boiler as opposed to a single fuel one, such as pellets.

boomshackala · 18-08-2006 08:41PM

The primary problem with burning crops that grow on a short rotation e.g. grain, corn, elephant grass is that they contain alot of minerals.

The way efficient wood boilers work is they burn almost the entire product, ie turn the carbon to CO2. This process happens at high temperatures (900 degrees and above). Fuel with minerals melt at these temperatures, forming clinker. This means they make bad fuels. It also damages your expensive boiler.

Certain boilers use methods of reducing burning temperature without affecting the combustion process, such as flue gas recirculation. These are high end boilers and not generally available on a domestic level.

If you want to reduce fuel cost, buy a boiler than will burn logs, less than 50% of the cost of pellets. You can buy boilers that need loading as little as twice per week. You can also use the wood chip option, about 2/3 price of pellets

Fuel, Cost (cents/KWH)
Pellets, 3.3
Wood chip, 2.5
Wood logs, 1.5

Wood pellets, grain or rape cake?

Comments