Posted by Winston_Smith on March 19, 2009, 11:33 pm
>On Thu, 19 Mar 2009 19:34:05 -0700, Winston_Smith wrote:
>>>Actually, survival without electricity is not only doable, one may
>>>find it very refreshing and relaxing.
>>
>>Agreed. Still a radio to find out how close the spikey hair mutants
>>are getting is a good thing.
>Perhaps. I look back on the days when we used the outhouse, pumped
>our water by hand, heated on a wood stove in the back yard and took a
>bath in the "washtub" on the back porch. I look back on them as the
>good old days when things were so much simpler. I didn't have a
>telephone until I moved out of the house and still don't have much use
>for them today.
>Back in those days, you usually heard when riff-raff were around at
>church on Sunday when someone was talking about shooting the chicken
>thief with a couple of rounds of rock salt.
>If all you are looking at is powering a receiver, it could be done
>with a marine battery and a small solar charger capable of supplying
>over .5 amp charge or slightly over. Nothing too elaborate there. I
>would be very cautious about transmitting since the spikey hairs may
>have the ability to locate the transmitter.
Agreed. I'm a ham and have transmitters, but post SHTF it's listen
only.
I guess we were a bit better of than you. We were often one of the
first to get things but I still remember an awful lot of firsts. I
still can't help thinking of my mp3 player as just a very sexy record
player.
We always had AM radio in the range of my memory. I remember our
first telephone. The copper shortage lasted well after the end of WW2
and they were rationed with a long waiting list. And we got it before
most folks because of my sisters job. Three digit phone number, no
dial, flash the operator and tell her what you wanted to be connected
to. Local immediately, long distance, she set up the circuit and
called you back.
I remember trekking up to a neighbor's in the afternoons to watch a
cowboy shoot 'em up on that huge 12 or 13 inch screen. She liked
kids, hers were grown and gone, and usually had a herd of us. And
some years later I remember getting our first set. Really big 15 or
17 inch thing. All of three stations. I'm the world's biggest
Hopalong Cassidy fan.
We had my grandfathers crank up acoustic only record player but our
first electric one was one of my birthday presents. All that existed
were 78 rpm records. Still have them. When I retire I'll digitize
them and make a gift to the web. Lot of newsgroups active in that
sort of thing.
Bath water was heated on the stove and poured into the tub. Cold
water plumbing and drains but no hot water heater. We had a regular
flush toilet but the outhouse was still there and in use since it was
handy if you were outside.
Coal furnace in the cellar, hand stoked. No circulation system. The
thing just got hot and there were grates in the floor between the
cellar and the living room and between the living room and the
bedrooms so heat rose up. The grates were maybe 3 feet by 3 feet.
The neighborhood grape vine worked well. Darn it. When ever we did
something a bit naughty, my parents knew about it before I got home
and we didn't have a phone then. If you got in trouble at school you
took your punishment without complaint because if the teacher talked
to your parents you were really in trouble.
As a result I still live a pretty simple life and don't have that much
technology except the computer. None of it is essential to me.
Posted by Tim Jackson on March 20, 2009, 4:22 am
Winston_Smith wrote:
>
>> If one approach has twice the efficiency of another then for he same amount
>> of net power you only need half the capacity in the various parts.
>
> Two to one is a rather radical improvement in the real world. It is
> mostly achieve in advertising copy. I think it was Don that estimated
> a generic alternator was 50% efficient. You can spend a whole lot of
> money on improvements and not approach 100% - which is double.
>
Most people would consider "double the efficiency" to mean "half the
losses" not "double the output" so 75% efficient is double the
efficiency of 50% efficient.
So in John's example you would need 2/3 of the capacity, not half.
Actually doubling the numerical efficiency figure is obviously
meaningless: if I have a converter that is 90% efficient, if I say I
double its efficiency I don't mean I get one that is 180% efficient and
gives me 80% more power out than I put in!
Tim Jackson
Posted by John Gilmer on March 21, 2009, 10:47 pm
> Most people would consider "double the efficiency" to mean "half the
> losses" not "double the output" so 75% efficient is double the efficiency
> of 50% efficient.
Maybe.
Most folks think doubling the efficiency means just that!
If you have a complicated path of energy flow from a windmill fan to a
generator to a pump then back to a turbine and then to a "demand" generator,
you would be quite lucky to get double digit "efficiency" just relative to
the "shaft hp" of your wind mill.
"Rube Goldberb" engineering pays off at the 100 megawatt level but not at
the sub kw level.
> So in John's example you would need 2/3 of the capacity, not half.
> Actually doubling the numerical efficiency figure is obviously
> meaningless: if I have a converter that is 90% efficient, if I say I
> double its efficiency I don't mean I get one that is 180% efficient and
> gives me 80% more power out than I put in!
That's quite true.
In a "survival" situation, once you reach 50% efficiency (initial shaft
power to useful electrical work on demand) it's definitely time to work on
something else and leave "gud enuf" alone.
Posted by You on March 22, 2009, 1:00 pm
> "Rube Goldberb" engineering pays off at the 100 megawatt level but not at
> the sub kw level.
"Rube Goldberg" Engineering just isn't DONE at the 100 Megawatt Level...
At that "Level"of Investment only the most qualified of Professional
Engineers are used, to design and construct Systems. Way to much money
at risk if, Old Rube didn't get it "Right" starting with the Original
Concept"....
Posted by Bob F on March 25, 2009, 7:08 pm
David Williams wrote:
> -> Most people would consider "double the efficiency" to mean "half
> the
> -> losses" not "double the output" so 75% efficient is double the
> -> efficiency of 50% efficient.
> I don't think so! Most people define efficiency as (quantity out)
> divided by (quantity in). If I put 100 joules of heat into a heat
> engine and it produces 20 joules of useful work, then it is 20 percent
> efficient.
> -> Actually doubling the numerical efficiency figure is obviously
> -> meaningless: if I have a converter that is 90% efficient, if I say
> I
> -> double its efficiency I don't mean I get one that is 180%
> efficient and
> -> gives me 80% more power out than I put in!
> Right. You can't double the efficiency of something that is already
> more than 50 percent efficient.
How about with a heat pump?
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>>>Actually, survival without electricity is not only doable, one may
>>>find it very refreshing and relaxing.
>>
>>Agreed. Still a radio to find out how close the spikey hair mutants
>>are getting is a good thing.
>Perhaps. I look back on the days when we used the outhouse, pumped
>our water by hand, heated on a wood stove in the back yard and took a
>bath in the "washtub" on the back porch. I look back on them as the
>good old days when things were so much simpler. I didn't have a
>telephone until I moved out of the house and still don't have much use
>for them today.
>Back in those days, you usually heard when riff-raff were around at
>church on Sunday when someone was talking about shooting the chicken
>thief with a couple of rounds of rock salt.
>If all you are looking at is powering a receiver, it could be done
>with a marine battery and a small solar charger capable of supplying
>over .5 amp charge or slightly over. Nothing too elaborate there. I
>would be very cautious about transmitting since the spikey hairs may
>have the ability to locate the transmitter.