Post by thread:[OT]Solar Ice Maker

jtroxas wrote: > Is it posible to use Acetone in place of pure Ammonia which is toxic as > refrigerant in one of those Solar Icemaker(file attched).. Or is the boiling > point of > acetone just too high... both has almost equal heat of vaporization.. > > Ammonia Adsorption Solar Icemaker > http://www.aidg.net/index.php?option=com_remository&Itemid=34&func=download&filecatid=2 > > > > The difference is more to do with the ability of ammonia to compress easily rather than its heat of vaporation. Acetone doesn't compress easily (if at all). Also, ammonia is preferred as a refrigerant (while being toxic) because it won't damage the ozone layer like freon does. I am not sure that the method shown in the article is very efficient. I have seen a "closed loop" refrigerator similar to this in rural Nicaragua. Here's what I remember about that one: the owner placed it outside in the sun until the ammonia was fully compressed (heat from the sun caused the ammonia to be forced into liquid form into a pool by a one-way valve). When it was then put into the "icebox" and a valve released, it made ice all night long as the ammonia evaporated. Except for the fuss of dealing with the "cooling equipment", it worked as good as any modern refrigerator. I remember it as being made of glass and tubes, but it might have been stainless steel here and there. I have a client who is incredibly interested in solar products. He is presently experimenting with "swamp" (water evaporative) coolers. He has reduced the temperature of my office from 110F to 75F by use of a proprietary means of forcing the evaporation of water by breaking the water into a fine mist. This "swamp cooler" and the Nicaraguan refrigerator work in a similar way. --Bob Axtell

Quoting Bob Axtell <spam_OUTengineerTakeThisOuTcotse.net>: > I have a client who is incredibly interested in solar products. He is > presently experimenting with "swamp" (water evaporative) coolers. He has > reduced the temperature of my office from 110F to 75F by use of a > proprietary means of forcing the evaporation of water by breaking the > water into a fine mist. > > This "swamp cooler" and the Nicaraguan refrigerator work in a similar way. > > --Bob Axtell The "swamp coolers" are usable in places with very low RH such as Arizona, but not too useful elsewhere. A friend in Phoenix has a cooling system outside on his deck. Very high pressure water (800-1000 PSI or something like that) is forced through nozzles so it can be atomized into very fine particles, which very quickly evaporate. It lowers the temperature on the deck by 20'F almost instantly, with very little energy consumption. I've also seem them used in Tucson for house A/C. The Nicaraguan fridge is interesting. It obviously stores a fair amount of energy in the phase change. Best regards, Spehro Pefhany

>-----Original Message----- >From: .....piclist-bouncesKILLspam@spam@mit.edu [piclist-bouncesKILLspammit.edu] >On Behalf Of Bob Axtell >Sent: 03 August 2007 16:18 >To: Microcontroller discussion list - Public. >Subject: Re: [OT]Solar Ice Maker > > >I have a client who is incredibly interested in solar products. He is >presently experimenting with "swamp" (water evaporative) >coolers. He has >reduced the temperature of my office from 110F to 75F by use of a >proprietary means of forcing the evaporation of water by breaking the >water into a fine mist. > >This "swamp cooler" and the Nicaraguan refrigerator work in a >similar way. "Overclockers" have been using home brewed water based evaporators (known as "bongs"!) to cool their tortured CPUs for quite a long time. The danger with air conditioning using water are the nasties such as legionaires. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. =======================================================================

---- Bob Axtell <.....engineerKILLspam.....cotse.net> wrote: > I have seen a "closed loop" refrigerator similar to this in rural > Nicaragua. Here's what I remember about that one: the owner placed it > outside in the sun until the ammonia was fully compressed (heat from > the sun caused the ammonia to be forced into liquid form into a pool by > a one-way valve). When it was then put into the "icebox" and a valve > released, it made ice all night long as the ammonia evaporated. NH3/H2O intermittent absorption cycle works well. Such refrigerators, powered by kerosene, were commercially available before WW2. One can imagine a solar powered version... www.ggw.org/~cac/IcyBall/HomeBuilt/HallPlans/IB_Directions.html

{Quote hidden}> > I have seen a "closed loop" refrigerator similar to this in > rural Nicaragua. Here's what I remember about that one: the > owner placed it outside in the sun until the ammonia was > fully compressed (heat from the sun caused the ammonia to be > forced into liquid form into a pool by a one-way valve). When > it was then put into the "icebox" and a valve released, it > made ice all night long as the ammonia evaporated. Except for > the fuss of dealing with the "cooling equipment", it worked > as good as any modern refrigerator. I remember it as being > made of glass and tubes, but it might have been stainless > steel here and there. > > I have a client who is incredibly interested in solar > products. He is presently experimenting with "swamp" (water > evaporative) coolers. He has reduced the temperature of my > office from 110F to 75F by use of a proprietary means of > forcing the evaporation of water by breaking the water into a > fine mist. > > This "swamp cooler" and the Nicaraguan refrigerator work in a > similar way. Have you seen our heard of Zeolite adsorption (not misspelled) cooling? http://techref.massmind.org/techref/other/zeolitefridg.htm Check the links at the bottom of the page. --- James Newton, massmind.org Knowledge Archiver EraseMEjamesspam_OUTTakeThisOuTmassmind.org 1-619-652-0593 fax:1-208-279-8767 http://www.massmind.org Saving what YOU know.

{Quote hidden}> > On Aug 3, 2007, at 10:53 AM, James Newtons Massmind wrote: > >> >> I have seen a "closed loop" refrigerator similar to this in >> rural Nicaragua. Here's what I remember about that one: the >> owner placed it outside in the sun until the ammonia was >> fully compressed (heat from the sun caused the ammonia to be >> forced into liquid form into a pool by a one-way valve). When >> it was then put into the "icebox" and a valve released, it >> made ice all night long as the ammonia evaporated. Except for >> the fuss of dealing with the "cooling equipment", it worked >> as good as any modern refrigerator. I remember it as being >> made of glass and tubes, but it might have been stainless >> steel here and there. >> >> I have a client who is incredibly interested in solar >> products. He is presently experimenting with "swamp" (water >> evaporative) coolers. He has reduced the temperature of my >> office from 110F to 75F by use of a proprietary means of >> forcing the evaporation of water by breaking the water into a >> fine mist. >> >> This "swamp cooler" and the Nicaraguan refrigerator work in a >> similar way. The ammonia approach does not add humidity to the air while the swamp cooler increases humidity and works poorly when humidity is already high. http://en.wikipedia.org/wiki/Evaporative_cooler <---- see second paragraph Cedric {Quote hidden}> > Have you seen our heard of Zeolite adsorption (not misspelled) > cooling? > > http://techref.massmind.org/techref/other/zeolitefridg.htm > > Check the links at the bottom of the page. > > --- > James Newton, massmind.org Knowledge Archiver > jamesspam_OUTmassmind.org 1-619-652-0593 fax:1-208-279-8767 > http://www.massmind.org Saving what YOU know. > > --

James Newtons Massmind wrote: {Quote hidden}>> I have seen a "closed loop" refrigerator similar to this in >> rural Nicaragua. Here's what I remember about that one: the >> owner placed it outside in the sun until the ammonia was >> fully compressed (heat from the sun caused the ammonia to be >> forced into liquid form into a pool by a one-way valve). When >> it was then put into the "icebox" and a valve released, it >> made ice all night long as the ammonia evaporated. Except for >> the fuss of dealing with the "cooling equipment", it worked >> as good as any modern refrigerator. I remember it as being >> made of glass and tubes, but it might have been stainless >> steel here and there. >> >> I have a client who is incredibly interested in solar >> products. He is presently experimenting with "swamp" (water >> evaporative) coolers. He has reduced the temperature of my >> office from 110F to 75F by use of a proprietary means of >> forcing the evaporation of water by breaking the water into a >> fine mist. >> >> This "swamp cooler" and the Nicaraguan refrigerator work in a >> similar way. >> > > > Have you seen our heard of Zeolite adsorption (not misspelled) cooling? > > http://techref.massmind.org/techref/other/zeolitefridg.htm > > Check the links at the bottom of the page. > > --- > James Newton, massmind.org Knowledge Archiver > @spam@jamesKILLspammassmind.org 1-619-652-0593 fax:1-208-279-8767 > http://www.massmind.org Saving what YOU know. > > A great link, James. Thanks.

What is Zeolite??... Is Zeolite those white crystals people put in their underarms to cure underarm body odor... Also since the working fluid is water which freezes from top to bottom.... wont the frozen ice on the top prevent further vaporization... so that only some percent of the water is vaporized.. preventing further cooling.. "James Newtons Massmind" <KILLspamjamesnewtonKILLspammassmind.org> wrote in message news:02ce01c7d5ee$d6f3e7b0$1100a8c0@SONYGRT270PB... {Quote hidden}>> >> I have seen a "closed loop" refrigerator similar to this in >> rural Nicaragua. Here's what I remember about that one: the >> owner placed it outside in the sun until the ammonia was >> fully compressed (heat from the sun caused the ammonia to be >> forced into liquid form into a pool by a one-way valve). When >> it was then put into the "icebox" and a valve released, it >> made ice all night long as the ammonia evaporated. Except for >> the fuss of dealing with the "cooling equipment", it worked >> as good as any modern refrigerator. I remember it as being >> made of glass and tubes, but it might have been stainless >> steel here and there. >> >> I have a client who is incredibly interested in solar >> products. He is presently experimenting with "swamp" (water >> evaporative) coolers. He has reduced the temperature of my >> office from 110F to 75F by use of a proprietary means of >> forcing the evaporation of water by breaking the water into a >> fine mist. >> >> This "swamp cooler" and the Nicaraguan refrigerator work in a >> similar way. > > > Have you seen our heard of Zeolite adsorption (not misspelled) cooling? > > http://techref.massmind.org/techref/other/zeolitefridg.htm > > Check the links at the bottom of the page. > > --- > James Newton, massmind.org Knowledge Archiver > RemoveMEjamesTakeThisOuTmassmind.org 1-619-652-0593 fax:1-208-279-8767 > http://www.massmind.org Saving what YOU know. > > --

> > Have you seen our heard of Zeolite adsorption (not > misspelled) cooling? > > > > techref.massmind.org/techref/other/zeolitefridg.htm > > > > What is Zeolite??... http://en.wikipedia.org/wiki/Zeolite Zeolites (Greek, zein, "to boil"; lithos, "a stone") are minerals that have a micro-porous structure > Is Zeolite those white crystals people put in their underarms > to cure underarm body odor... Not where I come from, but I suppose it would work... > Also since the working fluid is water which freezes from top > to bottom.... > wont the frozen ice on the top prevent further > vaporization... so that only some percent of the water is > vaporized.. preventing further cooling.. The ice will melt as the container absorbs heat from the freezer box, restarting the evaporation as needed. It may be that a level, shallow container would work better than a narrow, tall one. --- James Newton, massmind.org Knowledge Archiver spamBeGonejamesspamBeGonemassmind.org 1-619-652-0593 fax:1-208-279-8767 http://www.massmind.org Saving what YOU know.

> Also since the working fluid is water which freezes from top to bottom.... > wont the frozen ice on the top prevent further vaporization... so that only > some percent of the water is vaporized.. preventing further cooling.. No, the ice will absorb heat, (~970 btu/lb), melt, and boil off, or sublime if the pressure is low enough. It's the pressure I'm dubious about - I'm recovering from a move right now and can't lay hands on the data, but am guessing you need a pressure of <.01 psi or so for the system to behave as described. Not exactly a hard vacuum, of course, but could be a challenge for a hand-pumped PVC pipe rig... I'd like to try it.

I fudged the numbers - Solid to liquid phase absorbs 144 btu/lb. Liquid to vapor phase absorbs 970 btu/lb. Cycling 2 lbs of water a day in a well insulated box would make a pretty good cooler. Interesting stuff! Jack ---- TakeThisOuTgofloEraseMEspam_OUTcox.net wrote: > No, the ice will absorb heat, (~970 btu/lb), melt, and boil off, or sublime > if the pressure is low enough. It's the pressure I'm dubious about - I'm > recovering from a move right now and can't lay hands on the data, but > am guessing you need a pressure of <.01 psi or so for the system to > behave as described. Not exactly a hard vacuum, of course, but could > be a challenge for a hand-pumped PVC pipe rig... I'd like to try it.

On 8/3/07, RemoveMEgofloTakeThisOuTcox.net <gofloEraseME.....cox.net> wrote: > > > Also since the working fluid is water which freezes from top to bottom.... > > wont the frozen ice on the top prevent further vaporization... so that only > > some percent of the water is vaporized.. preventing further cooling.. > > No, the ice will absorb heat, (~970 btu/lb), melt, and boil off, or sublime > if the pressure is low enough. It's the pressure I'm dubious about - I'm > recovering from a move right now and can't lay hands on the data, but > am guessing you need a pressure of <.01 psi or so for the system to > behave as described. Not exactly a hard vacuum, of course, but could > be a challenge for a hand-pumped PVC pipe rig... I'd like to try it. I came to the same conclusion. Search for Crosley IcyBall in the archives: ========================================================= On 10/7/06, James Newtons Massmind <EraseMEjamesnewtonmassmind.org> wrote: > > > techref.massmind.org/techref/other/zeolitefridg.htm > > > > That one is very interesting. A couple of questions: > > > > - what is the purpose of the heat exchanger? Could the water > > freeze in there and cause maintenance problems? > > To cool the refrige box. If the water freezes, it will only stop operation > long enough for the ice to melt. I thought that the water evaporating in the box did the cooling? > > - how much vacuum is required? I'm thinking an electric > > vacuum pump made for hot rods might be useful. They > > generally turn on at < 15 psi and pump until 25 psi is reached. > > The purpose of the vacuum is to make the water boil at a lower temperature. > So the amount of vacuum needed is enough to make the water boil at the > temperature you want the refrige to maintain. Looking at this link: http://www.chemistrycoach.com/vapor_pressure_of_water.htm if you wanted to get down to -10*C, you would need a pressure of 2.1mmHg. Even at 0*C, you need 4.6mmHg (0.08895psi), which is a very low pressure. Am I looking at the right chart? BTW this site does nice conversions: http://www.convert-me.com/en/convert/pressure

Which kind/form of Zeolite is used here??.. "James Newtons Massmind" <RemoveMEjamesnewtonEraseMEEraseMEmassmind.org> wrote in message news:038b01c7d619$279f3460$1100a8c0@SONYGRT270PB... {Quote hidden}>> > Have you seen our heard of Zeolite adsorption (not >> misspelled) cooling? >> > >> > techref.massmind.org/techref/other/zeolitefridg.htm >> > >> >> What is Zeolite??... > > http://en.wikipedia.org/wiki/Zeolite Zeolites (Greek, zein, "to boil"; > lithos, "a stone") are minerals that have a micro-porous structure > >> Is Zeolite those white crystals people put in their underarms >> to cure underarm body odor... > > Not where I come from, but I suppose it would work... > >> Also since the working fluid is water which freezes from top >> to bottom.... >> wont the frozen ice on the top prevent further >> vaporization... so that only some percent of the water is >> vaporized.. preventing further cooling.. > > The ice will melt as the container absorbs heat from the freezer box, > restarting the evaporation as needed. It may be that a level, shallow > container would work better than a narrow, tall one. > > --- > James Newton, massmind.org Knowledge Archiver > RemoveMEjamesspam_OUTKILLspammassmind.org 1-619-652-0593 fax:1-208-279-8767 > http://www.massmind.org Saving what YOU know. > > --