HDTenEightyP/NetNews huggingface dataset:
From: stead@skadi.CSS.GOV (Richard Stead)
Newsgroups: sci.energy
Subject: Re: Flywheels and Space Stations
Keywords: posted in sci.electronics also
Date: 3 Jan 93 20:52:31 GMT

In article <1338@blue.cis.pitt.edu>, karol+@pitt.edu (Filip M. Gieszczykiewicz (fmgst+@pitt.edu)) writes:
> 	I'm sure most folks have seen the designs for 23rd century space
> 	stations - you know, the "wheel" ones. Yup, how practical would
> 	it be to use the spinnin motion of some parts of the station as a
> 	storage medium? From my point of view, the gyroscopic effect of
> 	a giga-flywheel would be benificial because it would stabilize the
> 	station and oppose all the forces like shuttles docking, folks

This is a case of you can't have your cake and eat it too.  Basically,
the space station either spins for stabilization or you remove the spin
to power the station.  If you extract power from the rotation, the
station must slow its spin.  Also, it will take energy to spin the
station up in the first place.  That energy is undoubtedly easier
stored in whatever form it was originally transported to the station
as.  May as well store it that way and use it directly, saving any
of the conversion losses.

> 	So, say we have a space station that NASA wants to build. During
> 	the time that it is exposed to sunligh (or magnetic field or
> 	whatever) motors are spinning up the flywheel which can then
> 	supply power to the station either when main power fails or
> 	simply as the MAIN power source.

For temporary storage, I could see this working.  Basically, you would
need a no-net-torque situation; for example, a two-disk station where
available power is used to increase the relative rotation between the
two balanced disks, then power is drawn out when required through
generators built into the coupling between the two disks.  Such a
coupling for operation in space would be very difficuly to design.
Also, it would mean that the craft has a time-varying artificial
gravity that might be difficult to cope with.  Finally, any imbalances
in the two disks could tear the station apart at the coupling (for example -
people walking around inside, or shuttles docking).

> 	I'm sure this beats having a breeder/fusion/fuelcell in the

What's wrong with fuel cells?  Or fusion power (other than the fact we
haven't got it yet).  As far as fission is concerned, it, too, is
not a problem - space background radiation greatly exceeds anything
one of those little space reactors produces; and stick it out on
a simple boom, and even a meltdown (however unlikely) will cause no
problem.  Space reactors have been used for decades without any
problems except for one Russian one that fell on Canada.


--
Richard Stead
Center for Seismic Studies
Arlington, VA
stead@seismo.css.gov
Newsgroups: sci.energy
From: Essential Information <ei@igc.apc.org>
Newsgroups: sci.energy
Date: 31 Dec 92 12:42 PST
Subject: Re: Energy Ideas - Thermal Env.
Nf-ID: #R:cdp:1466300127:cdp:1466300130:000:2266
Nf-From: cdp.UUCP!ei    Dec 31 12:42:00 1992



THE HEAT ISLAND EFFECT

Light-colored surfaces mitigate what is known as the "heat
island" effect.  According to a September 1990 article in
Scientific American, downtown temperatures in Los Angeles are
over five degrees fahrenheit warmer than they were in 1940, and
they are increasing at a rate of nearly one degree every 10
years.  

This is attributable to the increased use of asphalt across the
city.  Asphalt is dark and absorbs heat very effectively.  The
use of asphalt also displaces trees which cool the air by
evapotranspiration.  The net cost in Los Angeles from the effect
is estimated to be $100,000 annually in additional cooling costs. 
Lightening asphalt and roof surfaces and replanting trees  in
urban areas can reduce the amount of heat which a city will
absorb.

Light-colored surfaces also improve the energy efficiency of
individual buildings.  According to the Solar Energy Corporation
of New Jersey, a white roof will stay 30 degrees cooler on a
sunny day than a dark roof.  The cooler roof temperature results
in a smaller cooling load in the upper floors of a building. 
However, white surfaces radiate as effectively as a dark surface
and will radiate heat into a building.  Low-emissivity surfaces,
such as radiant barriers (see page six), are more effective at
reflecting the heat from sunlight.

CASE STUDY:

Light-Colored Roofing in Mesa, Arizona
The City of Mesa replaced or re-coated the roofs of four
buildings with light-colored insulation board and spray styrofoam
as part of an energy retrofit for each building.  Prior to the
retrofit, each of the buildings had a dark green or black roof
and no insulation.  The heating and cooling load attributed to
the roof is expected to be reduced by 20 to 30 percent.   The
estimated payback for the project is quite long, about 20 years. 
However, this project was completed as part of a major retrofit,
including energy efficient lighting and heating, ventilating and
air conditioning (HVAC) improvements, which had much shorter
paybacks.  By performing all energy improvements at the same
time, the city of Mesa included a project which was not highly
cost-effective but still energy-efficient.  (Contact: Larry Kell,
City of Mesa, Box 1466, Mesa, AZ  85211-1466, (602) 644-3287).
From: dpeders1@cc.swarthmore.edu (Daniel Pedersen)
Newsgroups: sci.energy
Subject: Re: Mileage vs. Safety concerns in autos
Date: 1 Jan 93 04:25:38 GMT
Reply-To: dpeders1@cc.swarthmore.edu (Daniel Pedersen)
Organization: Swarthmore College

hinz@picard.med.ge.com (David Hinz Mfg 4-6987 ~BHOSVWZ#097) writes:
> John F Nielsen (jnielsen@magnus.acs.ohio-state.edu) wrote:
> 
> : A light car impacting a wall would produce the same damage to
> : occupants as a heavy car impacting a wall.
> 
> Lots of variables here.  Say you are riding on a 1-ton steel bar, and impact
> the wall.  The forces on your body would be considerable.  Say you are on a 
> 1-ton, gradually crumpling (whatever), you'll come out lots better.  

But if all other variables are kept constant, such as crumpability, the
heavier car will experience a smaller acceleration/deceleration than the
lighter car, and less damage will be caused to the occupants.  the heavier
the car, the greater the chance that it will break through the
wall/telephone pole.  If the car breaks through the wall, the deceleration
is less.  But I agree that weight is not the only determining factor.

> : 
> : I guess my point is the following:
> : It is incorrect to say that CAFE standards will encourage the building
> : of flimsy cars. Since, if everyone drove these resulting 
> : small cars, size is no longer an issue. Flimsy does not equal small
> : it equals poorly engineered.
> 
> I disagree, for the most part here.  In an ideal world, where all manufacturers
> would care enough, they would strive to find better ways to improve survivability.

About the CAFE standards and decreased safety in autos:  How can we improve
the car mileage without sacrificing safety?  in other words, what can be
done to promote development of better engines rather than just making the
cars lighter?

> 
> : Size only matters to saftey when you have all types of cars on the
> : road. In that case you would want the biggest best engineered car you
> : can find.
> 
> I would say that size doesn't even matter then.  I'd rather have the best   
> engineered car I can (find & afford), rather than the biggest.

Just a point to think about:  The safety of the car is important in one
vehicle accidents as well (which according to some statistics presented by
a GM engineer are the most common).  If you crash into a tree, it doesn't
really matter how massive/light the other cars on the road are.  What
interests me is how well will my car protect my family and myself if we hit
anything.  I'd rather have a >50 MPG Volvo, but hey...



-->Daniel Pedersen  -  Keren's Daddy		(215)543-8961
	dpeders1@cc.swarthmore.edu	pedersen@engin.swarthmore.edu
======================================================================
Highway sign on I-10, AZ: "Federal Prison - Do Not Pick Up Hitch-Hikers"
	50 yards later: "Campground	Next Right"
"Why do you kill people?"   -   "I am a terminator."  [Terminator 2]
From: oberland@vax.sonoma.edu
Newsgroups: sci.energy
Subject: Re: Electric Vehicle
Date: 22 Dec 92 09:08:53 GMT
Organization: Sonoma State University

Well, I guess you all showed me...

Looks like EV's can't compare to IC's.
BUT... they ARE catching up, and I would gladly pay double the operating cost
for clean air andthe simplicity.

AS I SAID: I am willing to pay more for an EV.  
While Ev's may never reach the levels that IC's can in sheer cost to opertate,
let me state once again that cost is NOT the end-all that you all seem to make
it out to be.  OF COURSE a new technology is not going to even compete with a
technology that is roughly 100 years old in terms of price.

*I* WILL pay more, and while it may not be the most economical option available
to me, it IS my choice.  - How many choices do YOU make that are not based
purely on what is the cheapest option?  Be truthful...

Given that ONLY battery cost holds them back, they should be a viable
alternative in 10 years or so.

Batteries such as Hydrogen fuel cells offer better options if they can be
developed fully.  Some make Ni-cads look like trash.  Onlycost is obsticle.
This will pass, but not soon.

As for the comments about poor performance, look at the specs for the electric
Honda CX that that one guy has(forget his name) gets VERY respectable
performance.

My reading this group HAS helped me a bit, but also has made me see that there
are better options than an EV.

BEST SEEN TO DATE:Steam engine.  Closed cycle, flash design.
This looks like it might be the god-send that all us city-dwellers need.
It should cost only a little more than an IC to mass-produce, is currently 
buildable, and offers MUCH better mileage at a fraction of the emissions.

As for the flywheel thread, I am still amazed that some people still cannot see
that the forces are WAYYYY too large for anything less than, say, a mountain to
contain.  Not only that, any heat that did occur, even from a manageable
design(if such a thing could ever be built-and I'm not betting on it) would
most likely melt the front end of the car(and possibly the occupants)

Nice idea, but one that will not work, much less be economical in our
lifetimes.

Well, this has been fun, but I NOW get to go on vacation for two weeks(and the
machines here are down for 2 weeks as well).  Machine dies on the 24th, so any
mail sent before then will get through.

As for NEWS/postings, I will still be around :)

Any mail should be sent to me on the 5th or later, and there are two things I
am interested in:
1:Steam designs(cost and mileage/emissions)
2:How much electricity that Japanese EV uses per mile

Happy Hollidays,
Joe
From: mwilson@ncratl.AtlantaGA.NCR.COM (Mark Wilson)
Newsgroups: sci.energy
Subject: Re: Electric Vehicle
Date: 22 Dec 92 14:44:16 GMT
Organization: NCR Engineering and Manufacturing Atlanta -- Atlanta, GA

In <1992Dec22.010853.1@vax.sonoma.edu> oberland@vax.sonoma.edu writes:

|BUT... they ARE catching up, and I would gladly pay double the operating cost
|for clean air andthe simplicity.

Electrics are only clean if you happen to have a clean source of electricity.
Unfortunately no such sources exist.
-- 
Mob rule doesn't become any prettier, just because the mob start to call itself
a government.
It ain't charity if you are using someone else's money.
Mark.Wilson@AtlantaGA.NCR.com
From: mwilson@ncratl.AtlantaGA.NCR.COM (Mark Wilson)
Newsgroups: sci.energy
Subject: Re: hot water
Date: 23 Dec 92 20:10:41 GMT
Organization: NCR Engineering and Manufacturing Atlanta -- Atlanta, GA

In <5016.1017.uupcb@spacebbs.com> howard.smith@spacebbs.com (Howard Smith) writes:

|M> First, my home heating system is essentially a oil-fired hot water
|M> heater (except the hot water heats my house not a shower) and it is
|M> rated as 87% efficient.  Higher efficiency is available.  I see no
|M> reason why an oil fired hot water heater should be only 20-30%
|M> efficient.

|The problem with oil and gas water heaters is the flue. It has to have
|low thermal resistance to the water and also low resistance to the flow
|of the fumes and air up from the bottom of the flue. Much heat goes up
|the flue.

|Real inefficiency occurs when the heater reaches temperature and shuts
|off, leaving the heat from the pilot light and the water, back through
|the low thermal resistance, to pass up the flue by convection. The
|less hot water you use, the less efficient the system. Some sort of
|electric pilot light and automatic, insulated damper in the flue are
|needed to stop this loss.

|If the damper fails, you're in trouble.

|Electric heaters don't have these problems.

|The most efficient system for a large household is an active, roof-top
|mounted, solar heater with a large electric heater in loop for storage
|and standbye heating. All well insulated, of course.

|M> Second, while the electric heater is 100% efficient at converting
|M> the electricity you pay for into heat, the power plant is only about
|M> 40% efficient at generating the electricity and getting it to you.

|M> This is reflected in the higher price of electricity compared to oil.

|Yes, but you also have pay the man to bring the oil to your house.

I saw an interesting gas water heater a few months ago.  This unit had the
burner outside the water heater.  A small electric pump moved water through
the burner when the flame is on.  It also had a one way valve so that the
water could not flow backwards when the burner was off.

This totally eliminated the need for the central flue.  Claimed to be a lot
more efficient, but it cost more.

-- 
Mob rule doesn't become any prettier, just because the mob start to call itself
a government.
It ain't charity if you are using someone else's money.
Mark.Wilson@AtlantaGA.NCR.com
From: Essential Information <ei@igc.apc.org>
Newsgroups: sci.energy
Date: 31 Dec 92 12:38 PST
Subject: Energy Ideas -- Solar Power
Nf-ID: #N:cdp:1466300121:000:1233
Nf-From: cdp.UUCP!ei    Dec 31 12:38:00 1992



ENERGY IDEAS -- SOLAR TECHNOLOGY -- Vol. 1, No. 2, August 1992

This issue of "Energy Ideas" reports on solar technology and
commercially-available, cost-effective applications.  

Although solar thermal power has been used for well over a century,
and photovoltaic cells have been in existence for over thirty
years, solar power has not gained widespread acceptance in the
United States' economy.  While a few efforts have been made at
large-scale power generation with solar power, most notably the
solar thermal plants built in California by Luz International,
today's market niches for solar power are decentralized, small-
scale applications.  Photovoltaic systems are inexpensive and
reliable sources of power for outdoor lights, water pumps,
communications equipment and a host of other outdoor applications. 
Solar thermal systems can provide heat to swimming pools and
commercial buildings for a lower cost than natural gas.  This issue
describes these pollution-free technologies and provides dozens of
case studies.

Each article can be called up by typing the <index #>.<article #>

TABLE OF CONTENTS:

1.  Introduction
2.  Photovoltaics
3.  Financing Solar Power
4.  Solar Thermal Energy
5.  Resources for Solar Power
From: ho@sumex-aim.Stanford.EDU (Hiang-Kwee Ho)
Newsgroups: sci.energy
Subject: Re: Domestic Hot Water Heaters - oil vs. electric
Date: 31 Dec 1992 19:45:40 GMT
Organization: KSL, Stanford University, CA 94305, USA
Distribution: world
NNTP-Posting-Host: hpp.stanford.edu

In article <BzoMuq.F7z@world.std.com>, moroney@world.std.com (Michael Moroney) writes:
> dbliss@fox.nstn.ns.ca (Doug Bliss) writes:
> 
> >I have heard that oil-fired domestic hot water heaters are very 
> >ineffecient (20-30% efficiency) compared to electric hot water heaters.  
> >Does anyone have any information on efficiencies and heat losses expected 
> >from these types of hot water heaters?
> 
> First, my home heating system is essentially a oil-fired hot water heater
> (except the hot water heats my house not a shower) and it is rated as 87%
> efficient.  Higher efficiency is available.  I see no reason why an oil
> fired hot water heater should be only 20-30% efficient.
> 
> Second, while the electric heater is 100% efficient at converting the
> electricity you pay for into heat, the power plant is only about 40%
> efficient at generating the electricity and getting it to you.
> 
> This is reflected in the higher price of electricity compared to oil.
> 
> (consider gas, if possible, too)
> 
> -Mike

Michael's figures are certainly closer to reality than Doug's, but that's only
part of the story, since the figures are based on "first law" efficiency.
First law efficiency does not distinguish between the different "quality"
of energy (e.g. difference between work and heat, and between heat at 
different temperature levels). So, from first law analysis (based on the
heating value of the fuel as the input), the efficiency turns out to be
approximately 80% and 40% respectively for oil and electricity.

However, in theory (and in practice in some cases), a much more efficient way 
of heating is to use a heat pump. Since a heat pump produces typically
3-7 times the amount of heat for a given input of work (or electricity), its
performance beats the performance of any oil or electric water heater by
a wide margin. (The actual "efficiency" or coefficient of performance of the 
heat pump depends on the initial temperature of the cold water, the desired
hot water temperature etc.)

Of course the problem is that it is more expensive initially, and will 
probably cost more to install and maintain. Whether the lower operating
costs will overcome these other higher costs requires more detailed economic
analysis.

Hiang-Kwee Ho
Newsgroups: sci.energy
From: carl@SOL1.GPS.CALTECH.EDU (Carl J Lydick)
Newsgroups: sci.energy
Subject: Re: Motor/Generator ???
Date: 28 Dec 1992 22:24:23 GMT
Organization: HST Wide Field/Planetary Camera
Distribution: world
Reply-To: carl@SOL1.GPS.CALTECH.EDU
NNTP-Posting-Host: sol1.gps.caltech.edu

In article <1992Dec23.092927.1@pa881a.inland.com>, schiewer@pa881a.inland.com (Don Schiewer) writes:
>Can anyone say a few words about motor/generators.
>
>Are generators more efficient that motor/generators?
>
>Would a good motor like those used in R/C cars and planes 
>be a good generator?

You don't seem to understand what a motor/generator is.  It consists of one
motor and one generator, both on the same shaft.  The motor drives the shaft,
and the shaft drives the generator.  The combination can be used for several
reasons:
	1)  To provide electrical isolation;
	2)  To convert electrical power with one set of characteristics to
	    electrical power with another set of characteristics;
	3)  To smooth out power from a source that's prone to spikes and
	    dropouts (this is, of course, a special case of 2)
	4)  To provide some warning of an imminent power failure (the power
	    fail sensor can be on the input side of the motor/generator, and
	    with a large enough flywheel in the system, the motor/generator can
	    continue to supply power for some time after power to the motor
	    fails).
In light of that definition, you might reconsider your questions.
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.
Newsgroups: sci.energy,sci.chemistry
From: mikep@polaris.unm.edu (Mike Prine CIRT)
Subject: Battery chemistry info wanted
Date: Sat, 02 Jan 93 20:08:02 GMT
Organization: University of New Mexico, Albuquerque

	After looking through several books on batteries I failed to find some
of the information I wanted. Hopefully someone on the net can fill in the gaps.
	I am comparing Lead-Acid, Nickel-Iron and Nickel-Cadmium. While the 
books had adequate information for standard usage, typical voltages, 
charging-rates, cost and discharge characteristics, they were lacking in much 
specific information about what happens to batteries that are abused 
particularly on the discharge side. As Lead-Acid cells are in more common use 
I was able to obtain enough info about them but got conflicting statements on 
the Nickel types even in the same book.
	In particular I am want to know what chemical reactions take place
during cell polarity reversals and how detrimental they are to cell capacity
and life expectancy. Such reversals can occur in systems with poor voltage
regulation where one or more cells reach exhaustion before the rest of the
battery and are driven to a reverse polarity by the remaining cells forcing
current through the now discharged cell in an attempt to power the load.
	If you have any information on this I would appreciate it, particularly
book references. If the information is restricted to a particular construction
type like the pocket plate or sintered, Please indicate that in your reply.
A reply by email (instead or in addition to a post) would be appreciated. I
read sci.energy but not sci.chemistry on a regular basis. Thanks in advance
for any info you can supply.
-- 
Michael Lee Prine	 IRC (Information Resource Center) consultant
Internet: mikep@hydra.unm.edu, Bitnet: MIKEP@UNMB, Phone: 1-505-277-8135
I get most of my electricity, at home, from the sun. It's a hobby, 
who cares if it's cost effective yet.
Newsgroups: sci.energy
From: weimer@spud.NoSubdomain.NoDomain (Gary Weimer 726-3370)
Subject: Re: A gripe, and Re: Flywheel batteries...
Reply-To: weimer@pixel.kodak.com
Organization: Eastman Kodak Co.; Rochester, NY
Date: Thu, 31 Dec 92 15:30:07 GMT

In article <1992Dec31.031634.13720@ke4zv.uucp>, gary@ke4zv.uucp (Gary Coffman) writes:
|> 
|> Most of the mass of a 65 ton tank
|> is armor designed to defeat a 10 kg penetrator travelling at 5,000
|> m/s. Since the flywheels we are talking about would have a rim velocity
|> of 5,000 m/s or greater, and would mass more than 10 kg, it should become
|> obvious that containment would need to exceed 65 tons of armor to stop
|> it should it fail.

This argument doesn't make much sense. That 65 tons of armor is designed
to stop a penetrator striking any point on a very large tank. A
penetrator focuses it's energy on a small area; a flywheel would have to
break before hitting the containment, spreading the energy. A penetrator
hits the tank head-on; parts of a failing flywheel will be grazing the
containment vessel at an angle. How much would a "tank" with the inside
dimensions of a standard battery weigh? It seems this would be our
worse-case containment vessel...

-- 

Gary Weimer (weimer@pixel.kodak.com)