Heat in the home

[Ben@Forest]

We have a wood pellet plant a few miles away.
It has huge piles of wood stored in the open. Some of the wood is large trunks but most is narrow branches.
We cycle past regularly and always comment about the large amount of smoke, or possibly steam, pouring out from a very tall chimney.
Energy to cut the trees, to process it into pellets , bag it (plastic) and distribute it. I compare this to wood bought from a local farmer. Energy to fell and log the tree and energy for the tractor to deliver it. I'd say our wood burner is far greener than a pellet stove.

The very large trunks or much smaller branchwood is because neither will go for sawlogs. It's disappointing how often l have to tell owners their magnificent (but plantation conifer) trees are oversize and actually not really in demand for the market.

I'd agree your local energy supply for a wood burning stove is greener than primary pellet manufacture (as said some of it is from co-product). But your (and my) woodburning stoves kick out particulates that are harmful. The Welsh Assembly has (or at least had when built) a wood pellet boiler. The pellets are easily deliverable and are burnt in boilers that meet smoke control legislation. And I know a major food processing company that runs a plant on wood pellets - you can't do either of those things with firewood delivered by the local farmer.

[pwa]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

The machinery that makes pellets requires the sawdust used to be completely dry. I know that because I used to regularly talk to a bloke who ran one of the early pelleting operations. It took him ages to get it producing reliably dense pellets without the machinery clogging. They went bust after a couple of years, probably helped by the expected market increase not coming as swiftly as they had budgeted for. They couldn't service their debts in the end. Sad really.

[Ben@Forest]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

The machinery that makes pellets requires the sawdust used to be completely dry. I know that because I used to regularly talk to a bloke who ran one of the early pelleting operations. It took him ages to get it producing reliably dense pellets without the machinery clogging. They went bust after a couple of years, probably helped by the expected market increase not coming as swiftly as they had budgeted for. They couldn't service their debts in the end. Sad really.

The market fluctuates a lot relative to gas and oil prices. I imagine wood pellet and woodchip boiler companies have been taking a lot of enquiries over the last few months!

[francovendee]

My wood burning stove does certainly emit a large amount of particulates and I wouldn't have or recommend one for use in a town.
I'm not sure a wood pellet stove would be a good idea either. I've seen figures on emissions of 15 times that of oil and 1800 times more than from gas.
If electricity is from a green source then in pollution terms it's an obvious choice. Being able to afford to run it is a different matter.
The problem is greater for someone like me living in an old stone house. Very costly/difficult to insulate to modern standards.

[gbnz]

living in an old stone house. Very costly/difficult to insulate to modern standards.

+ 1. Heating is too expensive in an old stone house, so a withdrawal to the kitchen and/or bed is required in winter months! Makes bicycle maintenance very difficult, as floor area in the kitchen is slightly under 4 square metres. Due to the pannier rack can't really fit the tourer in unless the front wheels removed, a real nuisance

[mjr]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

[francovendee]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

Providing you have power to run the pump.

[Jdsk]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

Providing you have power to run the pump.

Is there a self-powered solution... that's obviously possible if there's some energy storage. But if there's a temperature difference it might be possible without... I feel the First Law looming...

Jonathan

[francovendee]

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

Providing you have power to run the pump.

Is there a self-powered solution... that's obviously possible if there's some energy storage. But if there's a temperature difference it might be possible without... I feel the First Law looming...

Jonathan

Look into perpetual motion while you're at it.

[[XAP]Bob]

Self powered - define.

Nothing that produces useful work is self powered.

[Jdsk]

Self powered - define.

Nothing that produces useful work is self powered.

Enough power from somewhere to run the heat pump and essential ancillaries without mains electricity. As in the context of the preceding posts.

Jonathan

[mjr]

A wood pellet boiler has a major convenience advantage in its favour. Tip in a bag of pellets and that's refuelling seen to for a day. No constant topping up during the day.

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

Providing you have power to run the pump.

Sure, but that's not the fuel. That would be like saying the person loading wood into the stove is fuel.

[Pebble]

Pebble^^
Your experiment is working.
Keep going!
The curve will become less steep but it will continue to lose weight for a while.

The indoor piece of oak has lost 254 grams in 8 days.
So 4 pieces would have lost a litre, 8 pieces 2 litres, and so on.
A saucepanful thrown on the carpet, or perhaps better described as trickled over the hot wood-burner.

I see the outside piece latterly gained a bit of weight - wind driven rain?

The outside curve is slow too.
No wonder folk say you need to stack it a year or more.
The curve would be much steeper in dry hot summer conditions of course.

I think you are right about hard dense oak being around 35% moisture by weight.
(it is under normal outside drying conditions impossible to get all of it out.)

An Update

(readings have not been taken daily hence the uniform line)

The one inside has not dried out as much as I would have guessed and the outside one has done better than predicted.
I can't imagine either will loose a third of their weight - may be this was already dead before the storm brought it down.

I need to restart with another couple of pieces!

[francovendee]

Heat pumps are even better. Put it outside or plug it into the ground and that's refuelling seen to for a very long time.

Providing you have power to run the pump.

Sure, but that's not the fuel. That would be like saying the person loading wood into the stove is fuel.

Yes, but maybe someone else could load the wood.
Where else would you get the electricity unless you have a battery source, unlikely in the vast majority of homes.

[[XAP]Bob]

Dynamo?