Some blog followers might be interested in a recent post “Could the U.S. Significantly Reduce Its Yearly Emission of CO2 By Covering Its Rooftops With Photovoltaic Solar Panels? #2” [Hake (2012b)]. The abstract reads:
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ABSTRACT: In a previous post “Concentration of Energy by Photovoltaic Solar Panels” [Hake (2012a) I posed the following “Fermi Problem”:
“What fraction ‘f’ of the yearly total U.S. fossil-fueled electrical energy (and thus fraction of yearly tons of CO2 emission from U.S. fossil-fueled electrical energy production) could be eliminated if all rooftops in the U.S. were covered by photovoltaic solar panels?”
In this post I estimate f = 1.1 - considerably larger than the estimate f = 0.08 of MathEdCC’s Guy Brandenburg. Perhaps others would like to consider this problem.
In Hake (2012a) I warned (paraphrasing): “Before recommending that all U.S. rooftops be covered with Photovoltaic Solar Panels one should consider the EMERGY associated with such a plan. Odum wrote: “EMERGY measures both the work of nature and that of humans in generating products and services. . . . The photovoltaic power grid at Austin, Tex., evaluated by King & Schmandt (1991), is taking more EMERGY out of society than it is generating.”
So is the motto of Solar Forward http://solarforward.com/: “SAVING THE PLANET, ONE SOLAR SYSTEM AT A TIME” a deception? I THINK NOT because the evaluation of King & Schmandt (1991), failed to consider the devastating decrease in EMERGY due to global warming if the world’s dependence on fossil fuels is not reduced.
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To access the complete 18 kB post please click on http://bit.ly/zT7dKj.
Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References
which Recognize the Invention of the Internet (PEDARRII)
rrhake@earthlink.net
http://www.physics.indiana.edu/~hake
http://www.physics.indiana.edu/~sdi
http://HakesEdStuff.blogspot.com
http://iub.academia.edu/RichardHake
REFERENCES [URL’s shortened by http://bit.ly/ and accessed on 10 Feb 2012.]
Hake, R.R. 2012a. “Concentration of Energy by Photovoltaic Solar Panels” online on the OPEN! AERA-L archives at http://bit.ly/wdkAoL. Post of 6 Feb 2012 09:59:03-0800 to AERA-L and Net-Gold. The abstract and link to the complete post were transmitted to several discussion lists and are also on my blog “Hake'sEdStuff” at http://bit.ly/Aimt1K with a provision for comments.
Hake, R.R. 2012b. “Could the U.S. Significantly Reduce Its Yearly Emission of CO2 By Covering Its Rooftops With Photovoltaic Panels? #2” online on the OPEN! AERA-L archives at http://bit.ly/zX0oHw. Post of 10 Feb 2012 13:43:02-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to several discussion lists.
Showing posts with label Entropy. Show all posts
Showing posts with label Entropy. Show all posts
Friday, February 10, 2012
Monday, February 6, 2012
Concentration of Energy by Photovoltaic Solar Panels
Some blog followers might be interested in a recent discussion-list post
“Concentration of Energy by Photovoltaic Solar Panels” [Hake (2012)]. The abstract reads:
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ABSTRACT: Physoc’s Bud Nye wrote (paraphrasing): “Systems ecologist Howard T. Odum’s energy-focused books http://amzn.to/xkp9cP suggest to me that the probable ‘purpose of life’ involves CONCENTRATING ENERGY by moving it from the lowest quality, most disbursed carriers, such as sunlight, into the most dense, highest quality, highest transferity carriers possible, such as electricity and information, thus minimizing the entropy of systems over time. . . . . . . . but those of us in the West and the U.S. have worked extremely hard to DISPERSE energy and increase entropy. This does not bode well for our long-term future. . . . . ."
An apparent way to concentrate energy is by installing PhotoVoltaic Solar Panels (PVSP) on rooftops. Consider the following “Fermi Problem”: WHAT FRACTION OF THE YEARLY TOTAL U.S. FOSSIL-FUELED ELECTRICAL ENERGY (AND THUS FRACTION OF YEARLY TONS OF CO2 EMISSION FROM U.S. FOSSIL-FUELED ELECTRICAL ENERGY PRODUCTION) COULD BE ELIMINATED IF ALL ROOFTOPS IN THE U.S. WERE COVERED BY PHOTOVOLTAIC SOLAR PANELS?
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To access the complete 12 kB post please click on http://bit.ly/wdkAoL.
Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References
which Recognize the Invention of the Internet (PEDARRII)
rrhake@earthlink.net
http://www.physics.indiana.edu/~hake
http://www.physics.indiana.edu/~sdi
http://HakesEdStuff.blogspot.com
http://iub.academia.edu/RichardHake
“Saving the planet, one solar system at a time.”
Motto of “Solar Forward” http://solarforward.com/
REFERENCES [URL shortened by http://bit.ly/ and accessed on 06 Feb 2012.]
Hake, R.R. 2012. “Concentration of Energy by Photovoltaic Solar Panels” online on the OPEN! AERA-L archives at http://bit.ly/wdkAoL. Post of 6 Feb 2012 09:59:03-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to several discussion lists.
“Concentration of Energy by Photovoltaic Solar Panels” [Hake (2012)]. The abstract reads:
************************************************
ABSTRACT: Physoc’s Bud Nye wrote (paraphrasing): “Systems ecologist Howard T. Odum’s energy-focused books http://amzn.to/xkp9cP suggest to me that the probable ‘purpose of life’ involves CONCENTRATING ENERGY by moving it from the lowest quality, most disbursed carriers, such as sunlight, into the most dense, highest quality, highest transferity carriers possible, such as electricity and information, thus minimizing the entropy of systems over time. . . . . . . . but those of us in the West and the U.S. have worked extremely hard to DISPERSE energy and increase entropy. This does not bode well for our long-term future. . . . . ."
An apparent way to concentrate energy is by installing PhotoVoltaic Solar Panels (PVSP) on rooftops. Consider the following “Fermi Problem”: WHAT FRACTION OF THE YEARLY TOTAL U.S. FOSSIL-FUELED ELECTRICAL ENERGY (AND THUS FRACTION OF YEARLY TONS OF CO2 EMISSION FROM U.S. FOSSIL-FUELED ELECTRICAL ENERGY PRODUCTION) COULD BE ELIMINATED IF ALL ROOFTOPS IN THE U.S. WERE COVERED BY PHOTOVOLTAIC SOLAR PANELS?
************************************************
To access the complete 12 kB post please click on http://bit.ly/wdkAoL.
Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References
which Recognize the Invention of the Internet (PEDARRII)
rrhake@earthlink.net
http://www.physics.indiana.edu/~hake
http://www.physics.indiana.edu/~sdi
http://HakesEdStuff.blogspot.com
http://iub.academia.edu/RichardHake
“Saving the planet, one solar system at a time.”
Motto of “Solar Forward” http://solarforward.com/
REFERENCES [URL shortened by http://bit.ly/ and accessed on 06 Feb 2012.]
Hake, R.R. 2012. “Concentration of Energy by Photovoltaic Solar Panels” online on the OPEN! AERA-L archives at http://bit.ly/wdkAoL. Post of 6 Feb 2012 09:59:03-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to several discussion lists.
Saturday, January 7, 2012
Re: Entropy again
Some blog followers might be interested in a recent discussion-list post “Re: Entropy again”[Hake (2012)]. The abstract reads:
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ABSTRACT: Antti Savinainen in his Phys-L post “Entropy again” wrote that:
(a) he was about to teach entropy at the high school level but realized that the syllabus statement “entropy is a system property that expresses the degree of disorder in the system” was not a satisfactory characterization of entropy; and
(b) “it would be interesting to hear ideas on how to define or characterize entropy at an introductory level.”
Antti pointed to 4 references on entropy by Denker, Lambert, and Leff that he regarded as “useful, or at least interesting.” I add 6 more references to Antti’s list and then quote portions of Denker’s response to Antti, in which Denker advocates the “probabilistic approach” to entropy and severely criticizes the “spreading metaphor” of Lambert and Leff.
Henri Poncare wrote: “When we say force is the cause of motion we talk metaphysics, and this definition, if we were content with it, would be absolutely sterile. FOR A DEFINITION TO BE OF ANY USE, IT MUST TEACH US TO MEASURE FORCE; moreover, that suffices; it is not at all necessary that it teach us what force is in itself, nor whether it is the cause or the effect of motion.”
Likewise, in discussions of entropy it would seem worthwhile to specify HOW ENTROPY CAN BE MEASURED. Leff (2012) does so in the context of the “spreading metaphor.” I wonder if Denker could explain how his favored “probabilistic approach” specifies how to physically MEASURE entropy in real substances?
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To access the complete 16 kB post please click on http://bit.ly/zVixYk.
Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References which Recognize the
Invention of the Internet (PEDARRII)
rrhake@earthlink.net
http://www.physics.indiana.edu/~hake
http://www.physics.indiana.edu/~sdi
http://HakesEdStuff.blogspot.com
http://iub.academia.edu/RichardHake
“Conflict is the gadfly of thought. It stirs us to observation and memory. It instigates to invention. It shocks us out of sheep-like passivity, and sets us at noting and contriving. Not that it always effects this result; but that conflict is a sine qua non of reflection and ingenuity.”
John Dewey “Morals Are Human,” Dewey: Middle Works, Vol.14, p. 207
REFERENCES [All URL’s shortened by http://bit.ly/ and accessed on 07 Jan 2012.]
Hake, R.R. 2012. “Re: Entropy again,” online on the OPEN! AERA-L archives at http://bit.ly/zVixYk. Post of 7 Jan 2012 14:51:15-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to several discussion lists..
Leff, H. 2012. “Removing the Mystery of Entropy and Thermodynamics - Part I,” Phys. Teach. 50(1): 28-31; online to subscribers at http://bit.ly/wLy3En. Parts II-V will be published in Phys. Teach 50 (2012).
************************************************
ABSTRACT: Antti Savinainen in his Phys-L post “Entropy again” wrote that:
(a) he was about to teach entropy at the high school level but realized that the syllabus statement “entropy is a system property that expresses the degree of disorder in the system” was not a satisfactory characterization of entropy; and
(b) “it would be interesting to hear ideas on how to define or characterize entropy at an introductory level.”
Antti pointed to 4 references on entropy by Denker, Lambert, and Leff that he regarded as “useful, or at least interesting.” I add 6 more references to Antti’s list and then quote portions of Denker’s response to Antti, in which Denker advocates the “probabilistic approach” to entropy and severely criticizes the “spreading metaphor” of Lambert and Leff.
Henri Poncare wrote: “When we say force is the cause of motion we talk metaphysics, and this definition, if we were content with it, would be absolutely sterile. FOR A DEFINITION TO BE OF ANY USE, IT MUST TEACH US TO MEASURE FORCE; moreover, that suffices; it is not at all necessary that it teach us what force is in itself, nor whether it is the cause or the effect of motion.”
Likewise, in discussions of entropy it would seem worthwhile to specify HOW ENTROPY CAN BE MEASURED. Leff (2012) does so in the context of the “spreading metaphor.” I wonder if Denker could explain how his favored “probabilistic approach” specifies how to physically MEASURE entropy in real substances?
************************************************
To access the complete 16 kB post please click on http://bit.ly/zVixYk.
Richard Hake, Emeritus Professor of Physics, Indiana University
Honorary Member, Curmudgeon Lodge of Deventer, The Netherlands
President, PEdants for Definitive Academic References which Recognize the
Invention of the Internet (PEDARRII)
rrhake@earthlink.net
http://www.physics.indiana.edu/~hake
http://www.physics.indiana.edu/~sdi
http://HakesEdStuff.blogspot.com
http://iub.academia.edu/RichardHake
“Conflict is the gadfly of thought. It stirs us to observation and memory. It instigates to invention. It shocks us out of sheep-like passivity, and sets us at noting and contriving. Not that it always effects this result; but that conflict is a sine qua non of reflection and ingenuity.”
John Dewey “Morals Are Human,” Dewey: Middle Works, Vol.14, p. 207
REFERENCES [All URL’s shortened by http://bit.ly/ and accessed on 07 Jan 2012.]
Hake, R.R. 2012. “Re: Entropy again,” online on the OPEN! AERA-L archives at http://bit.ly/zVixYk. Post of 7 Jan 2012 14:51:15-0800 to AERA-L and Net-Gold. The abstract and link to the complete post are being transmitted to several discussion lists..
Leff, H. 2012. “Removing the Mystery of Entropy and Thermodynamics - Part I,” Phys. Teach. 50(1): 28-31; online to subscribers at http://bit.ly/wLy3En. Parts II-V will be published in Phys. Teach 50 (2012).
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