Heat Pumps

[MikeG.]

Well put, Wobblycogs. Saved me a good 5 minutes of typing

Mike

 

[big soft moose]

Heat pumps are electrical, and are therefore carbon dioxide emitting users of fossil fuel.

Mike

only if you run them on national grid electrickery - i remember reading somewhere about a guy who powered his heat pump from a 3kw PV array on the roof - that would qualify as renewables based.

Well, not quite the whole story! Photovotaics in this country take about 12 years to generate the same amount of electricity as went into their production in the first place, so the PV array running the heat pump would for 12 years be essentially running on fossil fuel. Of course, the fundamental flaw with this proposal is that in the winter when you want the heat, the sun isn't shining very much. I suspect that the chap you refer to lives somewhere like Canada or parts of Europe, where winter sun is much more common than here.

Mike

nah - central london - will anderson , diary of an eco builder isbn 10 1-903998-79-4 , hes also using a solar hot water heatig array to provide uplift on his heat pump.

 

[MikeG.]

nah - central london - will anderson , diary of an eco builder isbn 10 1-903998-79-4 , hes also using a solar hot water heatig array to provide uplift on his heat pump.

So what he is doing is heating his hot water with a heat pump, and augmenting it with solar panels? Fair enough I suppose, but a long way from the carbon-neutral he could have obtained by using a wood pellet boiler.

Mike

 

[Jake]

Wood pellets can't be totally carbon neutral, surely?

 

[wobblycogs]

Depends on the manufacturing process. In terms of the wood they are made with they are carbon neutral as the carbon that made the tree came from the air. All the processing of the wood and the shiping will probably have been powered by electricity (coal mainly) and oil so that bit isn't carbon neutral unless they are off-setting in some way or powering the processes from renewable sources (very unlikely). It's better than burning north sea gas but not as good as freezing your privates off

 

[big soft moose]

nah - central london - will anderson , diary of an eco builder isbn 10 1-903998-79-4 , hes also using a solar hot water heatig array to provide uplift on his heat pump.

So what he is doing is heating his hot water with a heat pump, and augmenting it with solar panels? Fair enough I suppose, but a long way from the carbon-neutral he could have obtained by using a wood pellet boiler.

Mike

no you got the wrong end of the stick there, hes using a solar array to heat his hot water when hot , and when cooler it is redirected to the heat pump proving an uplift in the incoming temperature thus allowing the heat pump to be more efficient.

btw if we wanted to be picky the process of making the wood pellets for a wood pellet boiler and the transport of the pellets to site isnt carbon neutral either

 

[MikeG.]

Granted the pellets aren't neutral. I'll dig out some figures if anyone is interested, but if not perfect they are very good.

OK, got the picture re his heating set up.......amounts to much the same thing actually.

Mike

 

[SimonB]

Mike, thanks for the info on biomass systems, not something I was aware of. Did some googling and found some useful information, in particular I found a relatively local equipment supplier and this trade article which provides CO2 emission comparisons. Whether the reduction compared to fossil fuel offsets the production/delivery cost would be interesting to know.

http://www.uk.remeha.com/index.php?id=339&tx_ttnews[tt_news]=23&tx_ttnews[backPid]=338&cHash=1653bcc804

 

[johnf]

John,

replacement for your old boiler, whereas the heat-pump would require a vast amount of digging.

Heat pumps are a bit of a fad, and are really a glorified form of electric heating. When the inefficiencies of generation and transmission of electricity are taken into consideration the net efficiency is actually very poor. This may not interest you, understandably.

Mike

Mike i was hopeing to lay the heat pump piping under water (no diging)

How do these wood pellet burners feed they can't be as easy as a oil burner that feeds its'self for years on end.
I am just looking at my options at this stage possibly I will just replace the oil fired boiler the easy way out.

 

[RogerS]

Lots of info here

http://www.nef.org.uk/logpile/pellets/storage.htm

 

[johnf]

Lots of info here

http://www.nef.org.uk/logpile/pellets/storage.htm

Thanks for the link somehow I get the feeling the pellet thing is a non runner one reason it is not feasible to to have a pellet store adjacent to the room the boiler is in also I like to go to the sun in the winter and leave the boiler running there can't be enough pellets in the boiler to last 2-3 weeks

thanks anyway

 

[MikeG.]

Yeah there can! Pellets are stored in a hopper/ bunker which can be as big as you like. They are fed automatically into the boiler on demand, via an auger (Archimedes screw). This bunker can also be located wherever is convenient, and the pellets fed through a 4" pipe. They flow like a fluid.

Mike

 

[Doug B]

I like to go to the sun in the winter and leave the boiler running there can't be enough pellets in the boiler to last 2-3 weeks

Can`t see a problem with the Pellets, but the stoves do need weekly maintenance.


Also as they use electric, they are as prone as any other system to power failure.

 

[MikeG.]

No they don't Doug....at least, not all of them. There are plenty of self-cleaning ones, that shuffle the ash off somewhere.

 

[Doug B]

No they don't Doug....at least, not all of them. There are plenty of self-cleaning ones, that shuffle the ash off somewhere.

I wasn`t just referring to the ash, Mike.

The burner pot, auger & hopper need checking, i wouldn`t like to leave one burning unattended for a week, let alone 2 to 3.

This site gives a guide to maintenance, for anyone interested in a stove.
http://www.daviddarling.info/encycloped ... nance.html