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re: why not? was: re: fuel cells for home use
19 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?
>> >> have you considered using the hot water output of the ge fuel cell? :-)
>> >yes and i have read their web site. it is best to use gas direct, using
>> >high-efficient appliances, instead of another energy conversion...
>> ah, faith vs physics again...
a recurring theme.
>> an average american house uses about 10k kwh/year of electricity, say
>> 25 kwh/day. say the water and space heating needs of a house match a fuel
>> cell's 33% gas-to-electric and 75% cogen efficiencies.
btw, i wonder if the heat/electricity power fraction can be adjusted,
as with a turbine or hybrid pv/thermal solar panel...
>>we might either
>> a) make 25 kwh/day of electricity with our fuel cell using 75 kwh of gas,
>> and use the 0.75x75kwh-25kwh = 31.25 kwh of "waste heat" in the house, or
>> b) buy 25 kwh/day of electricity from a 50%-efficient natural gas utility
>> that burns 50 kwh of gas, and burn another 31.25 kwh of gas in the house
>> for hot water and space heat, at say 100% efficiency (being generous),
>> using a total of 81.25 kwh/day of gas.
>> the fuel cell is more efficient, and may be cheaper as well.
>too early to say. then there is payback as these expensive monsters only
>last 15 years. then there is the annual service cost and other breakdowns -
>i'm sure not cheap.
so, if these efficiency numbers contradict your faith,
you muddy the waters to avoid losing the argument :-)
nick
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