Fuel consumption of a 175kw Batch Boiler

[difflock]

From my own measured experience:

0.5m3 (and prob a slightly generous 0.5m3) of 1.0m long split Lodgepole Pine at an accurately measured 12-15% moisture content was averaging 165kg. (measured with 300kg capacity crane scales)

When tightly strapped in a bundle.

So say 300kg/m3 allowing for a looser filled m3 volume

or 3m3 per tonne. . . near-nuff.

[arboriculturist]

I thought you had a boiler

 

Yes, but own fabrication, not a 175KW factory built.

[arboriculturist]

We have a 200kw log boiler and we are using 3m3 of 20 per cent or less larch wood every 24hrs which registers 3000 kW on the meter.

 

Is yours running a complete 40ft container?

 

My experience is it takes 15m3 of 20% MC Larch to dry a 40ft container of green mixed hardwood down to 20% MC. Would you agree?

[Duffryn]

Has anyone on the Forum got a 175kw wood fired Batch Boiler heating a 40ft shipping container to dry firewood?

 

Can you advise on the fuel consumption / 24hrs burning 'dry' wood as fuel in the boiler?

 

Thanks

 

As others have said this will depend on the efficiency of the boiler and the moisture content of the fuel. If is a home build boiler I doubt you will be claiming RHI on it, thus you will only have to worry about the clean air act.

 

In my experience it is much easier to increase the efficiency of the boiler if you do not have to meet the emissions requirements of RHI.

 

RHI compliance in any batch fed boiler can only be achieved by burning very small loads of fuel which then governs the position of the secondary air. Remove this restriction and the secondary air can be placed in the correct place for a decent fuel load which will dramatically improve the boilers efficiency. Just goes to show what a farce the RHI situation is !

[arboriculturist]

As others have said this will depend on the efficiency of the boiler and the moisture content of the fuel. If is a home build boiler I doubt you will be claiming RHI on it, thus you will only have to worry about the clean air act.

 

In my experience it is much easier to increase the efficiency of the boiler if you do not have to meet the emissions requirements of RHI.

 

RHI compliance in any batch fed boiler can only be achieved by burning very small loads of fuel which then governs the position of the secondary air. Remove this restriction and the secondary air can be placed in the correct place for a decent fuel load which will dramatically improve the boilers efficiency. Just goes to show what a farce the RHI situation is !

 

Even though my super insulated hot air self fabricated unit is very efficient burning sub 20% timber, I am still interested in RHI using Solar Thermal, Insulation optimisation and flue recovery system.

 

At present these type of installations are few and far between in the UK and available data is practically zero. It appears that it is down to the individual to research, design and build their own installation.

 

Of course available sunlight is the issue, but solutions do exist.

[Duffryn]

Even though my super insulated hot air self fabricated unit is very efficient burning sub 20% timber, I am still interested in RHI using Solar Thermal, Insulation optimisation and flue recovery system.

 

At present these type of installations are few and far between in the UK and available data is practically zero. It appears that it is down to the individual to research, design and build their own installation.

 

Of course available sunlight is the issue, but solutions do exist.

 

I presume that both are using hot water. Would it not be possible to have a hybrid system solar in the spring /summer and biomass in the winter. The switching and metering between eligible and non eligible heat for RHI would be fairly straight forward . You would get the best of both worlds then ?

[arboriculturist]

I presume that both are using hot water. Would it not be possible to have a hybrid system solar in the spring /summer and biomass in the winter. The switching and metering between eligible and non eligible heat for RHI would be fairly straight forward . You would get the best of both worlds then ?

 

No the woodfired unit is forced 'hot air', controlled, which I plan to harvest container vent heat in the near future. We are on a different temperature gradient than most kilns.

 

Uncanny that I had been considering hybrid as a way forward but I have been finding it tedious getting answers as to wether I could have biomass and Solar T. as 2 seperate NEW certified power sources supplying energy to a common commercial wood drying installation.

 

Perhaps I should have sought your advice?

[Duffryn]

No the woodfired unit is forced 'hot air', controlled, which I plan to harvest container vent heat in the near future. We are on a different temperature gradient than most kilns.

 

Uncanny that I had been considering hybrid as a way forward but I have been finding it tedious getting answers as to wether I could have biomass and Solar T. as 2 seperate NEW certified power sources supplying energy to a common commercial wood drying installation.

 

Perhaps I should have sought your advice?

 

You would be best to consult Ofgem on this for a definitive answer but my understanding is that so long as there was a bypass that ensured that one heat source could not affect the energy readings on the other heat source and so long as they were separately metered then a common dryer should not be an issue. I think you will struggle to pass the emissions test on a home built batch boiler though, you might be better off building an efficient boiler, forgetting the RHI and claiming RHI on the solar element. You could also look at Farm 2000.

[arboriculturist]

You would be best to consult Ofgem on this for a definitive answer but my understanding is that so long as there was a bypass that ensured that one heat source could not affect the energy readings on the other heat source and so long as they were separately metered then a common dryer should not be an issue. I think you will struggle to pass the emissions test on a home built batch boiler though, you might be better off building an efficient boiler, forgetting the RHI and claiming RHI on the solar element. You could also look at Farm 2000.

 

Agreed, my heat exchanger is producing just 'hot air' so metering not practical.

 

All things considered, I think ultimately I will be able to dispose of some assets and go with a 40ft passive container with heat recovery and come up with a Heizomat solution with Rob Nash.

Those 198 Heizomats are extremely frugal on fuel, looking at equivalent of 2m3 firewood / 24hrs.

 

The idea of stoking a 200kw batch boiler several times a day for 20 years does not appeal anymore!

 

With chip you can run 24/7 maximum output and with a good lead time on drying own roundwood/contract chipping there is an extremely robust business model with good margins, as you have indicated previously.

 

Economies of scale stack up extremely well.

 

Appreciate your input.

[arboriculturist]

We have a 200kw log boiler and we are using 3m3 of 20 per cent or less larch wood every 24hrs which registers 3000 kW on the meter.

 

What make of boiler do you have, is there a reason why you chose the make you did and do you feed it with 0.5 m lengths of split Larch?

Thanks