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re: why not? was: re: fuel cells for home use
20 nov 2000
news wrote:
>> >> >> > these fuel cell units use natural and lpg gas. for
>> >> >> > hot water and central heating is best to go direct and
>> >> >> > use gas furnaces/boilers. that will be more efficient...
>> you did say "more efficient," right?
>> >> >it is best to use gas direct, using high-efficient appliances,
>> >> >instead of another energy conversion...
>> >> ah, faith vs physics again...
>> a recurring theme.
>ah yes!
and proud of it too...
>if you needed the electricity from a fuel cell then it's efficiency rises
>as the heat produced may be extracted for something else that is useful.
up to the point where the heat needs to be wasted. (who would want to own
a fuel cell if they didn't need the electricity?)
>i can only think of using it heavily for a/c, and can you utilise all
>that heat from it in summer?
maybe, but low-temp absorption ac seems bulky and expensive, and we can't
cook with hot water, so we might say the only practical uses for this kind
of heat in a home are winter space heating and ongoing hot water.
>"efficiency" takes on a different meaning when paying utility bills,
>which doesn't necessarily fall in line with the efficiencies of physics.
time to muddy the waters again? :-)
>> ...i wonder if the heat/electricity power fraction can be adjusted,
>> as with a turbine or hybrid pv/thermal solar panel...
we can also try to match the heat/electricity demand to a fuel cell by
selecting different kinds of appliances, eg a gas or electric stove
for cooking, as you say.
seasonal load banking is another way to match needs. make lots of
electricity and space heat in the winter, and make the meter run
backwards, storing energy in the grid, then use lots of electricity
from the grid for ac in summertime, with a lower heat energy need
(maybe none, if the ac also heats water.)
>there are many factors and many numbers which may say (probably will)
>there is a cheaper option overall than going fuel cell when all is
>taken into account.
stirring up serious muck from the bottom here...
>looking at purchase costs and fuel cell lifespan alone, these don't appear
>something the average household would go for on cost grounds.
suppose a typical uk house uses 30k kwh/year of energy, 1/4 electrical and
3/4 space and water heating, and purchased electricity costs 10 cents/kwh
and gas heat costs 3 cents/kwh, and a load-matched fuel cell costs $10k
and lasts 15 years with $100/year maintenance...
time to change the subject again? :-)
nick
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