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re: saving electricity
16 jul 2005
lou wrote:
>did you ever do the high school experiment of boiling water at room
>temperature? you put a shallow container of water on a vacuum pump,
>cover it with a bell jar, and turn on the pump...
i've done that with a flask and aspirator attached to a sink faucet.
>in a theoretical sense, it would be possible to build a dryer that operated
>along the same lines - put the wet laundry into the drum, seal it up air
>tight, and turn on a vacuum pump while tumbling.
and watch the dryer implode? :-)
>> >>maybe american dryers should operate like european washers, taking
>> >>longer to do their job at a lower temperature, eg 80 f, with a motor
>> >>that rests most of the time and only exhausts air and turns the drum
>> >>for a few seconds every few minutes, when the rh inside the dryer
>> >>rises to 60%...
it could be easy to modify a us electric dryer to make it work this way.
add grainger's 2a179 $88.15 programmable cycle timer and its $4.37 5x852
octal socket and put a humidistat in the exhaust to shorten the on-time
during each cycle. how much electrical energy could we save?
>so how about a cite? how much electricity do a european style washer
>consume to evaporate a given amount of water compared to a us style dryer?
i'm sure some european horizontal-axis washers use less electrical energy
than us washers because of the way they operate, with less water and longer
cycle times and less motoring. i think european dryers also use less energy.
i seem to recall longer cycle times (5 hours?) on some web pages, and they
may work at lower temps with less motoring. i don't recall any mention of
the water content of the clothing, but i do recall some mention of kwh.
we might just hang wet clothes in a closet with a dehumidifier or a few
incandescent light bulbs and a 60% humidistat, with more wrinkles and less
human handling. the closet might have a poly film latent heat exchanger
on the back to condense water in wintertime for the light-bulb version.
>> >there's more than one way to build a dryer, and different strategies will
>> >differ in their effectiveness. i find it most convenient when the drying
>> >cycle takes about the same time as the wash cycle - i can get the laundry
>> >done in the minimum amount of time.
>>
>> maybe american washers should operate like european washers. if i only do
>> laundry once a week and i don't watch the machine during the entire cycle,
>> i don't care much whether the cycle takes 20 minutes or 4 hours. how much
>> energy can we save with longer cycles?
>
>i don't watch it either. to a certain extent, i don't care how long it
>takes, but if i have 10 loads to wash, taking 40 hours to do it is less
>convenient than getting it all done in an evening.
that could happen with just a few visiting football teams.
>a quibble. having a drying cycle take longer won't save any energy - it
>takes a fixed amount of energy to evaporate a fixed amount of water. it may
>be possible to save electricity (or natural gas, or whatever) by changing
>the cycle time. in this context, "energy" and "electricity" are not
>synonymous.
drying clothes requires heat energy, but that needn't add to heating or
air conditioning bills, if we condense water vapor indoors in the winter
and evaporate water indoors in the summer.
nick
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