Re: [FRIAM] A leetle thermodynamics!
living nomadically in their age-old way with yak-felt Ger's (Yurts) gave over and learned to live in concrete apartments with central heat and food from the markets. Several generations (50 years) passed and all of the old ways were forgotten. The Soviet Union collapsed and not only did the well-meaning Soviet Bureacrats leave, but they took their natural gas and oil with them, leaving a people with inherently unlivable concrete caves to live in and no residual skills for living in "the old ways". It is bad enough when we outrun our own headlights but when we encourage people who have steady-state ways of living to join us in our breakneck rush into the future, we are not always doing them favors. I'm not saying it never works out, I suspect it often does, I'm not really trying to be a wet blanket nor a Luddite, but I am chiding us on "local optimizations" like assuming that trading in the burning of wood or charcoal gathered or made nearby for something very low tech by our standards (but high tech by theirs) like cardboard boxes, aluminum foil and acrylic or glass covers is not always the win we assume it is. And I also don't think most of us think about how these new technology "prizes" are going to be integrated into everyday life and culture. If/when/as such things *do* get integrated, they surely have the chance of improving lives, decreasing long term degradation of resources, etc. Wikipedia gives "the 1973 fuel crisis" as the date of emergence of the term Appropriate Technology and proceeds to define it mostly in terms of lowering the capital investment and maintenance aspects of technology (in natural reaction to the huge amounts of unsustainable tech we exported during our various waves of colonization). I heard about it in the late 70's from some friends working in South America trying to introduce the "Coffee Can Twig Stove" as an alternative to other forms of cooking/heating. They used the term to focus on both technological and cultural "appropriateness" and were struggling to understand the various peoples they were interacting with enough to know whether these "twig stoves" made from a simple tin can (nominally a coffee can, but usually a large can of other rations) could ever catch on. Sometimes they did, sometimes they didn't, and often for reasons they could never have guessed. It is interesting (to me) that many of these "low tech" solutions are centered around high-tech materials we consider to be waste (cardboard boxes and steel food cans)... perhaps there is a hint in there somewhere. It is also interesting that we seem to be most concerned about the "energy use" in the third world everytime our own energy sources get threatened (1973 crisis, current crisis). I think I'll go see if my dinner is done, my truck has been idling for most of an hour... surely the stew is done by now! - Steve -Original Message- From: friam-boun...@redfish.com [mailto:friam-boun...@redfish.com] On Behalf Of Owen Densmore Sent: Saturday, April 11, 2009 4:04 PM To: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] A leetle thermodynamics! As usual, Wikipedia has some info: http://en.wikipedia.org/wiki/Solar_cooker#Using_a_solar_cooker Looks like Peter is right about the time it takes. Pretty slow process, but that may not be as big an issue for the users compared to gathering fuel etc. -- Owen On Apr 10, 2009, at 8:40 PM, Victoria Hughes wrote: Hey, that is a pretty cool bunch of information. Egyptian Ice, eh - a new delicacy, only for heirophants. How did they know to do that? Arabs? Sounds Tom Robbins-y. Love it. Tory On Apr 10, 2009, at 3:25 PM, Peter Lissaman wrote: Solar cookers can break your heart, but not the laws of thermodynamics. Consider this elementary fact, my dear Dr. Watson. The insolation on earth near the equator is about 800 W/m2, it is less at the end of the day, and much less after sunset. For an aperture of 0.1 m2, you getting about 80 W black body, ignoring losses. Concentrators have nuttin to do with it! This amounts to about 270 BTU/hr from which you could boil a bit less than 2 pints of water in an hour, assuming no losses. BTW, you can, with care and ceremony, make ice in the Egyptian deserts every cloudless night, by exploiting radiation to the stars from shallow water trays, and careful control of nucleation, convection and vaporization. In fact, the temple priests used to do it on the flat roofs of the temples to impress the unwashed on the bounty of whatever God they were scamming that week. Much hoopla, involving sanctified water brought up from the basement (where it had got pretty cool, mixed with yesterday's ice), throwing holy dust on the surface (to provide nucleation particles) and wafting the surfa
Re: [FRIAM] A leetle thermodynamics!
Microwave ovens, gas stoves, coal stoves, fireplaces, and solar cookers; all have a price-time tradeoff. The solar cooker is slow and cheap. Most people would rather have an option and the freedom not choose it, than no option at all. For a $50,000 prize, I wish I invented it. -- Rob -Original Message- From: friam-boun...@redfish.com [mailto:friam-boun...@redfish.com] On Behalf Of Owen Densmore Sent: Saturday, April 11, 2009 4:04 PM To: The Friday Morning Applied Complexity Coffee Group Subject: Re: [FRIAM] A leetle thermodynamics! As usual, Wikipedia has some info: http://en.wikipedia.org/wiki/Solar_cooker#Using_a_solar_cooker Looks like Peter is right about the time it takes. Pretty slow process, but that may not be as big an issue for the users compared to gathering fuel etc. -- Owen On Apr 10, 2009, at 8:40 PM, Victoria Hughes wrote: > Hey, that is a pretty cool bunch of information. > Egyptian Ice, eh - a new delicacy, only for heirophants. > How did they know to do that? Arabs? > Sounds Tom Robbins-y. Love it. > Tory > > On Apr 10, 2009, at 3:25 PM, Peter Lissaman wrote: > >> Solar cookers can break your heart, but not the laws of >> thermodynamics. Consider this elementary fact, my dear Dr. Watson. >> The insolation on earth near the equator is about 800 W/m2, it is >> less at the end of the day, and much less after sunset. For an >> aperture of 0.1 m2, you getting about 80 W black body, ignoring >> losses. Concentrators have nuttin to do with it! This amounts to >> about 270 BTU/hr from which you could boil a bit less than 2 pints >> of water in an hour, assuming no losses. >> BTW, you can, with care and ceremony, make ice in the Egyptian >> deserts every cloudless night, by exploiting radiation to the stars >> from shallow water trays, and careful control of nucleation, >> convection and vaporization. In fact, the temple priests used to do >> it on the flat roofs of the temples to impress the unwashed on the >> bounty of whatever God they were scamming that week. Much hoopla, >> involving sanctified water brought up from the basement (where it >> had got pretty cool, mixed with yesterday's ice), throwing holy >> dust on the surface (to provide nucleation particles) and wafting >> the surface at just the right time and rate with magic ostrich >> featherwands to actually control heat transfer due to convection >> and vapors. It's just thermodynamics, Nefertiti! And if sometimes >> the ice didn't form, it was because someone's mother-in-law was a >> witch! It's amazing what them religious guys know!! >> I usedta teach elementary courses in thermo in CA and the >> conversion constants are from memory and only roughly correct. >> FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
Re: [FRIAM] A leetle thermodynamics!
As usual, Wikipedia has some info: http://en.wikipedia.org/wiki/Solar_cooker#Using_a_solar_cooker Looks like Peter is right about the time it takes. Pretty slow process, but that may not be as big an issue for the users compared to gathering fuel etc. -- Owen On Apr 10, 2009, at 8:40 PM, Victoria Hughes wrote: Hey, that is a pretty cool bunch of information. Egyptian Ice, eh - a new delicacy, only for heirophants. How did they know to do that? Arabs? Sounds Tom Robbins-y. Love it. Tory On Apr 10, 2009, at 3:25 PM, Peter Lissaman wrote: Solar cookers can break your heart, but not the laws of thermodynamics. Consider this elementary fact, my dear Dr. Watson. The insolation on earth near the equator is about 800 W/m2, it is less at the end of the day, and much less after sunset. For an aperture of 0.1 m2, you getting about 80 W black body, ignoring losses. Concentrators have nuttin to do with it! This amounts to about 270 BTU/hr from which you could boil a bit less than 2 pints of water in an hour, assuming no losses. BTW, you can, with care and ceremony, make ice in the Egyptian deserts every cloudless night, by exploiting radiation to the stars from shallow water trays, and careful control of nucleation, convection and vaporization. In fact, the temple priests used to do it on the flat roofs of the temples to impress the unwashed on the bounty of whatever God they were scamming that week. Much hoopla, involving sanctified water brought up from the basement (where it had got pretty cool, mixed with yesterday's ice), throwing holy dust on the surface (to provide nucleation particles) and wafting the surface at just the right time and rate with magic ostrich featherwands to actually control heat transfer due to convection and vapors. It's just thermodynamics, Nefertiti! And if sometimes the ice didn't form, it was because someone's mother-in-law was a witch! It's amazing what them religious guys know!! I usedta teach elementary courses in thermo in CA and the conversion constants are from memory and only roughly correct. FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
Re: [FRIAM] A leetle thermodynamics!
Hey, that is a pretty cool bunch of information. Egyptian Ice, eh - a new delicacy, only for heirophants. How did they know to do that? Arabs? Sounds Tom Robbins-y. Love it. Tory On Apr 10, 2009, at 3:25 PM, Peter Lissaman wrote: Solar cookers can break your heart, but not the laws of thermodynamics. Consider this elementary fact, my dear Dr. Watson. The insolation on earth near the equator is about 800 W/m2, it is less at the end of the day, and much less after sunset. For an aperture of 0.1 m2, you getting about 80 W black body, ignoring losses. Concentrators have nuttin to do with it! This amounts to about 270 BTU/hr from which you could boil a bit less than 2 pints of water in an hour, assuming no losses. BTW, you can, with care and ceremony, make ice in the Egyptian deserts every cloudless night, by exploiting radiation to the stars from shallow water trays, and careful control of nucleation, convection and vaporization. In fact, the temple priests used to do it on the flat roofs of the temples to impress the unwashed on the bounty of whatever God they were scamming that week. Much hoopla, involving sanctified water brought up from the basement (where it had got pretty cool, mixed with yesterday's ice), throwing holy dust on the surface (to provide nucleation particles) and wafting the surface at just the right time and rate with magic ostrich featherwands to actually control heat transfer due to convection and vapors. It's just thermodynamics, Nefertiti! And if sometimes the ice didn't form, it was because someone's mother-in-law was a witch! It's amazing what them religious guys know!! I usedta teach elementary courses in thermo in CA and the conversion constants are from memory and only roughly correct. FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
[FRIAM] A leetle thermodynamics!
Solar cookers can break your heart, but not the laws of thermodynamics. Consider this elementary fact, my dear Dr. Watson. The insolation on earth near the equator is about 800 W/m2, it is less at the end of the day, and much less after sunset. For an aperture of 0.1 m2, you getting about 80 W black body, ignoring losses. Concentrators have nuttin to do with it! This amounts to about 270 BTU/hr from which you could boil a bit less than 2 pints of water in an hour, assuming no losses. BTW, you can, with care and ceremony, make ice in the Egyptian deserts every cloudless night, by exploiting radiation to the stars from shallow water trays, and careful control of nucleation, convection and vaporization. In fact, the temple priests used to do it on the flat roofs of the temples to impress the unwashed on the bounty of whatever God they were scamming that week. Much hoopla, involving sanctified water brought up from the basement (where it had got pretty cool, mixed with yesterday's ice), throwing holy dust on the surface (to provide nucleation particles) and wafting the surface at just the right time and rate with magic ostrich featherwands to actually control heat transfer due to convection and vapors. It's just thermodynamics, Nefertiti! And if sometimes the ice didn't form, it was because someone's mother-in-law was a witch! It's amazing what them religious guys know!! I usedta teach elementary courses in thermo in CA and the conversion constants are from memory and only roughly correct. FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
[FRIAM] A leetle thermodynamics!
Solar cookers can break your heart, but not the laws of thermodynamics. Consider this elementary fact, my dear Dr. Watson. The insolation on earth near the equator is about 800 W/m2, it is less at the end of the day, and much less after sunset. For an aperture of 0.1 m2, you getting about 80 W black body, ignoring losses. Concentrators have nuttin to do with it! This amounts to about 270 BTU/hr from which you could boil a bit less than 2 pints of water in an hour, assuming no losses. BTW, you can, with care and ceremony, make ice in the Egyptian deserts every cloudless night, by exploiting radiation to the stars from shallow water trays, and careful control of nucleation, convection and vaporization. In fact, the temple priests used to do it on the flat roofs of the temples to impress the unwashed on the bounty of whatever God they were scamming that week. Much hoopla, involving sanctified water brought up from the basement (where it had got pretty cool, mixed with yesterday's ice), throwing holy dust on the surface (to provide nucleation particles) and wafting the surface at just the right time and rate with magic ostrich featherwands to actually control heat transfer due to convection and vapors. It's just thermodynamics, Nefertiti! And if sometimes the ice didn't form, it was because someone's mother-in-law was a witch! It's amazing what them religious guys know!! I usedta teach elementary courses in thermo in CA and the conversion constants are from memory and only roughly correct. FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
