Alternative Energy Sources?

[MikeG.]

Groundsource heat pumps are in the same category, I'm afraid. In principal, you are cooling something down to heat something else up, doing it electrically, and the temperature of the thing you are cooling is an irrelevance (as long as it is above freezing).

You will hear manufacturers' claims of 4:1 efficiency (heat out:energy in).........but taking account of a (generous) efficiency estimate for electricity generation and transmission of about 25%, that means that your heat is gained as efficently overall as if you had burned the coal or gas directly in your own boiler. If all our electricity was generated sustainably and without carbon emissions, then this form of heating would be fair enough. Until then, wait for claimed afficiencies of 5:1 before ground-source heatpumps become really worthwhile.

IMO, you understand!!

Mike

 

[John McM]

Mike, I totally accept your cynicism. I'm sceptical myself. As it happens our neighbour is having a gshp installed as part of his extension/renovation. It will be good to see how he gets on. As for the new generation of ASHP, I'd like to see genuine references from satisfied customers.
Cheers

 

[Jake]

Hmm.

I knew that ground source isn't all it is creacked up to be when the electric costs are taken into account. The differential temp must make ground source 'less inefficient' than air, though.

I still don't see how there can be net energy gain from taking heat from something at temp X and transferring it to something else at temp X. More thinking needed but my brain's hurting - back to the woodwork I think.

 

[MikeG.]

John,

I would just re-iterate my ealier point about air-source heat pumps......they are the bog-standard air-conditioner, just with the cycle reversed. Indeed, you could achieve the same results completely crudely simply by turning an air-conditioner around so that all the cold air goes outside the house and the "exhaust" from the unit goes into the house. It is that simple, and that crude.....and is a very poor idea in energy-use terms.

I'd be interested to hear whatever you hear.......

Mike

 

[Rich]

Get yourself a good old fashioned open fire with a combination of coal and logs,it's nice to look at, you can do an indoor barbecue under the grate and the flue warms the upstairs rooms and the air changes in the room are more beneficial to ones health as opposed to central heating. :wink:

Rich.

 

[MikeG.]

Get yourself a good old fashioned open fire with a combination of coal and logs,it's nice to look at, you can do an indoor barbecue under the grate and the flue warms the upstairs rooms and the air changes in the room are more beneficial to ones health as opposed to central heating. :wink:
Rich.

..........an extrememly efficient way of cooling your house in winter! Net heat losses up chimneys are many many times the output of any open fire. Indeed, between 80% and 90% of the heat from your fire goes straight up the chimney anyway. ie £10 worth of firewood buys you £1.00 worth of heat.........bargain!!!!

All the time that you don't have warm air going up the chimney, you have cold air plummetting down it! What is the point of insulating, and then leaving a huge hole open to the outside?

You would be far warmer blocking the chimney up.

Given the instinct to have a fire, the most efficient way is to have a wood-burning stove........a heavyweight cast iron jobby with controlled combustion rates. A flue liner and register plate will ensure that the cold air that would otherwise create draughts around your house is trapped within the wood-burner (providing you shut the door!!), and although this will still lead to a temperature reduction, it is nowhere near as bad as having your lounge open to the sky.

Mike

 

[Scott]

'scuse my ignorance - what's a register plate?

Cheers

 

[MikeG.]

Its a piece of steel that closes off the chimney just above the opening into the room..........but it has a hole for the flue to pass through, and can sometimes have moveable vents.

 

[Digit]

The problem is where to stop Mike. My house is that well insulated that we have reached the ridiculous situation of having to sleep with the bedroom window slightly open if we want the door shut!

Roy.

 

[tnimble]

..........an extrememly efficient way of cooling your house in winter! Net heat losses up chimneys are many many times the output of any open fire. Indeed, between 80% and 90% of the heat from your fire goes straight up the chimney anyway. ie £10 worth of firewood buys you £1.00 worth of heat.........bargain!!!!

One of the most misconceptions about open fire places. This holds up true only (and then the perceptual losses are still debatable) with very crude medieval like open fire places consisting only of a large hole to the outside with a pile of wood under it.

Both gas and wood fuelled open fire places can be as efficient near that of wood burning stoves, only modern controlled masonry heaters are more efficient due to the vast amount of heat stored.

Modern open fire places have at least a double channel chimney, one for the supply of oxygen, one for the exhaust. They often have a turbo charger so that the exhaust gasses are fed trough the fire a second time from underneath, have a catalyser and heat exchanger in the exhaust. It can be combined with central heating through a hot water heat exchanger, or combined with heat reclaming central ventilation to heat the rest of the house.

 

[MikeG.]

Modern open fire places have at least a double channel chimney, one for the supply of oxygen, one for the exhaust. They often have a turbo charger so that the exhaust gasses are fed trough the fire a second time from underneath, have a catalyser and heat exchanger in the exhaust. It can be combined with central heating through a hot water heat exchanger, or combined with heat reclaming central ventilation to heat the rest of the house.

I notice that you live in the Netherlands.......

 

[Jenx]

:wink: I been a heating engineer for more years than I care to remember. - there is so much bull talked nowadays its untrue.
Fuels' calorific value ain't never gonna alter.. regardless of what is is, oil gas. solid fuel ( coal ), wood, coke, charcoal, paper, old Y fronts blah blah,...
Each has its 'potential energy' and no more.

You want to save money - Insulate, get the best 'controls' system you can devise / afford.

Its all about slowing down the rate of heat-exchange between area of your building that are at different temperatures. The bigger the difference, the faster the rate of heat exchange. -- INSULATE. !!!!!!!!!!!!

The bit about 'dry air' from dehumidifiers making the boiler work more efficiently etc etc.... the difference, in a domestic property especially, wont buy you 20 Fags in a year.

Forget all that hype and what we up here would politely refer to as 'keech',
Insulate & Controls..

And another thing - can't swallow the combustion of wood being 'carbon neutral' ( ridiculous phrase that it is.. )... due to the 'tree absorbing so much Co2 whilst it was growing' or however its 'sold' to us as being 'environmentally friendly' or whatever ... come on ! :shock:
How daft are we supposed to have become to swallow this ?

heavans above... MAX INSULATION / MAX LEVEL of CONTROL and leave the hype where it belongs.
End of.

 

[wizer]

can you expand on the controls bit?

 

[MikeG.]

Almost completely right, Jenx........almost! So, typically, rather than discuss what we agree on.......

Trees are made of carbon. They do absorb carbon as they grow, and they give it off when they rot or burn. Coal and oil (2 different forms of carbon) formed from dead trees and other plant life, depending on what conditions the dead matter found itself in.

Plants absorb carbon dioxide from the atmosphere during growth, and release it as they decay. As they give up the same amount of carbon dioxide whether they are burnt or just rot, it would seem sensible to get some useful energy from burning the wood....rather than just allowing it to rot.

Because the amount of carbon released into the atmosphere on burning is roughly the same as is absorbed in total during the trees life, wood as a fuel is said to be virtually carbon neutral. Of course, if a chainsaw is used to cut the tree down in Brazil, then a truck and a ship used to get it to the UK before you end up burning it on your fire, it would not be carbon neutral......that wasted energy is known as embodied energy.

On all other things in your post I am in complete agreement.............if only people would take notice rather than suggesting that all of this stuff is a conspiracy!

Mike

 

[tnimble]

Modern open fire places have at least a double channel chimney, one for the supply of oxygen, one for the exhaust. They often have a turbo charger so that the exhaust gasses are fed trough the fire a second time from underneath, have a catalyser and heat exchanger in the exhaust. It can be combined with central heating through a hot water heat exchanger, or combined with heat reclaming central ventilation to heat the rest of the house.

I notice that you live in the Netherlands.......

I'm not entirely sure how that relates. IMO the insulation, heat sources and ventilation used, the knowledge of what exist, and how to use in daily life of both common man and expert are near moronic at times. Most descent ideas, product innovations and usage, common sense when to apply what and how to maintain and use it comes from Germany, Belgium, Austria, Sweden, UK, etcetera.

 

[MikeG.]

Sorry Christian,

that wasn't meant to be a dig.......it was simply to suggest that the specification of open fire you describe is virtually unheard of in the UK.

My job is designing buildings. My passion is low-energy stuff.......and so if anyone is likely to have specified something like this in the UK it would be me. As a researcher in the field for over twenty years I am well aware that northern Europe leads the way in these fields......I regularly specify energy-related products that are only available from Germany, Sweden etc.

I reiterate my basic point......a properly designed and constructed low-energy house has no need of a chimney or an open fire. Indeed, it has no need for central heating. Put a chimney into such a house and you will necessarily increase the amount of energy required to keep it warm.....however good the chimney is.

Mike

 

[ByronBlack]

wow, this thread has taken a wild detour from 'alternative energy sources'.

 

[Jenx]

can you expand on the controls bit?

To the 'nth degree', ( sadly :wink: )

Basically - the more controls you have in place, the more effectively you can control your system.
Individual roomstats, programmeable roomstats, zoning, an efficiently combusting heat-source, cylinder-stats, 7 Day timers, correctly balancing the system, BMS, etc etc etc... if goes on and on .

The more you can spend on it - the better a control system you can devise, and the more 'economy' can be gained from it.

Its very difficult to quantify what levels of payback in fiscal terms are going to be gained.. heating 'areas' up is not an exact science... simply because there are too many variables with a person's or family's ever changing lifestyles .... a small 'change' in the way people live can bring about more air-changes per hour in a given living space, and vastly alter the way that 'heat' is called for around the house.

Beyond any doubt though, as others have rightly said too... Insulate & Control. - You can never have 'too much' insulation in essence.
You CAN have too much by way of control.. because its 'possible' although not particularly easy, to have different elements 'fighting' each other somewhat.... but you gotta work hard at making a 'pigs ear' out of it, but I've seen it done :wink:

If you dont want your boiler to cost you money - switch it off.
That is the only way to make it stop costing money to run.
What you can do, is give it the best chance to run efficiently, for it to support a well-designed and well CONTROLLED system, in an efficiently well insulated building.
Then, it stands a reasonable chance of keeping you warm, keeping up with your household's hot water needs, in as economically a fashion as it can.

 

[Jenx]

Plants absorb carbon dioxide from the atmosphere during growth, and release it as they decay. As they give up the same amount of carbon dioxide whether they are burnt or just rot, it would seem sensible to get some useful energy from burning the wood....rather than just allowing it to rot.

And if they neither rot or are burnt ? ...

heard a very interesting guy ( a Prof, no less ! ) quoting from "factual evidence" on the Radio a few months back...
Apparently - 95 % of the worlds "greenhouse gases" are put into the atmosphere by Volcanic activity, and (as was interesting re your post ) rotting vegitation.

Now, if the old Human hand contributes on a worldwide scale, the remaining 5%, and we in the UK contibute say, what at a reasonable guess 0.1% of that 5%, and we are targetted to reduce that 0.1% by whatever the figure is, 18% ( thats 18% of what is 0.1% of 5% of the Greenhouse gas problem ... that not 1/5th remember, its 0.1 per cent of a hundred percent of the 5% !! ... following this ? , its not that easy to get the old head round ! !! ) - then even if we achieve the target, it doesn't take a rocket scientist to deduce its not exactly going to amount to really anything worth making the initial effort in the first place for !
I think I smell a rat here !
And FWIW, I dont reckon it makes any difference from a Lefty or a Righty or a Middle of the Roady Political standpoint, regardless of who's 'implementing' it, - they all will have their hand in our pocket, and tell us its justified in the name of 'environmental awareness and effort'.

But then again, I'm turning into my dad.. a grumpy cynical old grouch !
Gone is the 'exhuberance of youth' to be replaced with the cantancarous contempt that accompanies the onset of middle age ! ha ha
( Well, almost :wink: )

As ever, with tongue firmly lodged in cheek...
AJ,
in the cold and expensive north.
( bring in some more of that English subsidy cash ! ....
touchpaper lit.. retire to safe distance ...... )

 

[tnimble]

Indeed, the whole point on using alternative sources has all to do with independence, better use of the natural resources, and more comfort and satisfaction, not saving the planet from CC.

Sorry Christian,
that wasn't meant to be a dig.......it was simply to suggest that the specification of open fire you describe is virtually unheard of in the UK.

My job is designing buildings. My passion is low-energy stuff.......and so if anyone is likely to have specified something like this in the UK it would be me. As a researcher in the field for over twenty years I am well aware that northern Europe leads the way in these fields......I regularly specify energy-related products that are only available from Germany, Sweden etc.

I reiterate my basic point......a properly designed and constructed low-energy house has no need of a chimney or an open fire. Indeed, it has no need for central heating. Put a chimney into such a house and you will necessarily increase the amount of energy required to keep it warm.....however good the chimney is.

Mike

Indeed a good designed an well insulated house has virtually no need for heating. There are quite some houses build by now in a few countries that are fully self sufficient. Good insulation, storing heat during the summer etc. However the costs are large and not for every one. In the case of an open fire a simple fairly modification to the chimney to be able to close it off when not in use and adding a double inner tube to supply oxigine solved most of the associated problems with cooling down the house instead of heating it properly.