http://sleekfreak.ath.cx:81/3wdev/VITAHTML/SUBLEV/EN1/EVAPCOOL.HTM
for those who didn't know to delete the space in the url below! :)

Cheers,

Mark

> -----Original Message-----
> From: richard allain [mailto:allain@...]
> Sent: 06 March 2005 21:10
> To: RefrigeratorAlternatives@yahoogroups.com
> Subject: [RefrigeratorAlternatives] Evaporative food coolers
>
>
>
>     Sounds like a good thought in warm dry climates.
> VITA Document VIII F-2,013594
> sleekfreak.ath.cx:81/3wdev/ VITAHTML/SUBLEV/EN1/EVAPCOOL.HTM

--- Phillip Cook <norightshere@...> wrote:
>
> Does anyone now how much heat a propane refrigerator
> has to have in degrees F.  Is it possible to
> generate this much through super heated type soler
> water heating vacuum tubes?
<SNIP!>
Excuse my ignorance "solar water heating vacuum
tubes"? Can you describe these, please?

Thanks!


Duncan P.K. Gardner
+++
Email me for information on AMSOIL, the #1 in synthetics!
----
"Speaking the Truth in times of universal deceit is a revolutionary
act."  ~George Orwell
----
"Silence can be equated with fraud where there is a legal or moral duty to
speak, or where an inquiry left unanswered would be intentionally misleading. .
. We cannot condone this shocking behavior by the IRS.
Our revenue system is based on the good faith of the taxpayer and the
taxpayers should be able to expect the same from the government in its
enforcement and collection activities."
U.S. v. Tweel, 550 F.2d 297, 299. See also U.S. v. Prudden, 424 F.2d
1021, 1032; Carmine v. Bowen, 64 A. 932.
---
"Fear not the path of truth for the lack of people walking on it"
-Robert F. Kennedy




__________________________________
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Yahoo! Netrospective: 100 Moments of the Web
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Sounds like a good thought in warm dry climates.
VITA Document VIII F-2,013594
sleekfreak.ath.cx:81/3wdev/ VITAHTML/SUBLEV/EN1/EVAPCOOL.HTM -

[Non-text portions of this message have been removed]

Hi All,

I recall hearing that desert dwellers use water skins hanging on their
camels, or on the bullbars of their 4x4s, to keep their water cool. The
principle is that the skins are not watertight and slowly pass water to the
outside. Once outside the skin the water evaporates from the surface of the
skin keeping the remaining water cool.

It would seem to me that the principles of this are:
1) Water permeable container.
2) Container outside surface that does not absorb radiative heat - e.g. a
lighter colour skin.
3) Wind is more effective in keeping the skin cool by causing evaporation
when compared to sunlight causing evaporation.

So perhaps a modern equivalent would be a material that has a silvered
external surface and that is water permeable. The 'bag' would be shaded, but
exposed to wind. The 'bag' would be insulated against conduction of heat
into the bag - e.g. it would not be supported in a way that the supports
would aid the transmission of heat, by conduction, into the bag.

Anyone able to move these thoughts along? This is all I know.

Cheers,

Mark

Does anyone now how much heat a propane refrigerator has to have in degrees F. 
Is it possible to generate this much through super heated type soler water
heating vacuum tubes? would it be possible to use an oil type heat exchange
fluid to carry heat from tubes to the heat tube on a refrigerator, and to store
excess heat in an insulated storage tank for night/rainy day cooling?  Just some
initial thoughts to stir up some disscussion on this new board.  Thanks to those
of you who thought to do this site, it is an excellent idea.


---------------------------------
Celebrate Yahoo!'s 10th Birthday!
  Yahoo! Netrospective: 100 Moments of the Web

[Non-text portions of this message have been removed]

http://www.epinions.com/content_2636488836

-Laren Corie-
Integral Solar Building Design Since 1975

                    - LittleHouses-
    Everything To Do With Little Houses
http://groups.yahoo.com/group/LittleHouses

   The Energy Self-Sufficiency Newsletter
      Now available for free download at:
               www.rebelwolf.com

                      - WoodGas -
      Generate Electricity from firewood.
      Build a WoodGas stove in an hour
http://groups.yahoo.com/group/WoodGas

>
> Hi Glen;
>
>  That is a Peltier device, like used in small DC coolers,
> where you reverse the plug and it becomes a warmer.
> You can also heat one side, cool the other, and it will
> produce electric current. The 40° remark, and batteries
> were a dead give away.  They are fun toys, > -= Laren =-

Thanks Laren,

That's why i'm here...because everyday i learn something new...

Glen

Hi Daniel,

Since I live in the hot and humid part of Texas, I recently asked the
same question of George Helmholz at Small Power Systems. They've
developed a solar heated absorption refrigerator and my question for
George was whether the technology could be scaled up for air
conditioning purposes. Here is his answer.

"Larry,
    Thanks for your interest and I will put you on our mailing list.
Currently we don't believe the refrigerator we have developed is a
commercially viable product due to safety questions with ammonia and the
difficulty of installation.  So unless some new ideas pan out our intent
is to put information on how to build the refrigerator on the web.  It
isn't that difficult.

    Our technology doesn't work well for air-conditioning.  It is
possible to use solar for air-conditioning at this time using a number
of different methods.  You can either use photovoltaics and traditional
air-conditioning or some sort of high temperature collector, presumably
evacuated tube, with an absorption chiller.  Cheapest though is proper
design though that may be difficult in your climate. "

Peace,
ldb

Larry D. Barr
Editor/Publisher, Energy Self Sufficiency Newsletter
http://www.rebelwolf.com/essn.html
Owner, Rebel Wolf Energy Systems
http://www.rebelwolf.com/
Moderator, 12VDC Power group
http://groups.yahoo.com/group/12VDC_Power



Daniel Soria wrote:

> Hello there and congratulation to your group,I think
> it is one of the important subject to talk about since
> I'm living in the tropics and it is hot and humid
> here.
>
> What I want to know is refrigeration and air
> conditioning does this two go hand in hand since both
> of them uses compression and cooling system?
>
> What is the alternative for this two,is there an
> available appliances in the market?
>
>
>
>
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>

"Mac McQuaid" <mac@...> wrote;

> Does anyone have any "hands on" experience with a thermal mass
> refrigerator? I have read about them in the Earth Ship books by
> Michael Reynolds and have been planning on building one for
> quite a while. So ... if anyone has suggestions and advise I would
> appreciate hearing the same.
>
> We live in an "off grid" home here in western Montana.
> We need to reduce the demand for electric power as
> much as possible. We have six 90 watt solar panels
> and a large battery bank. We also run a 6hp Listeroid
> generator on WVO and produce 120/240 single phase
> power for home and shop plus 12 volt DC when needed to
> assist in battery charging.

Hello Mac;

   You might want to read my first post. It is about a cold
climate Passive Annual Refrigeration system, that stores
winter coolth for summer use. Instead of just simple mass
it uses the latent heat of fusion from water and brine solutions
for both refrigerator and freezer. It also discusses using
earth sheltering to increase the cold mass.  There will be
several posts about it. That is just the first.  There is an
ongoing, fairly detailed discussion, on another group, that
will be transfered, to continue here.

-Laren Corie-
Integral Solar Building Design Since 1975

                    - LittleHouses-
    Everything To Do With Little Houses
http://groups.yahoo.com/group/LittleHouses

   The Energy Self-Sufficiency Newsletter
      Now available for free download at:
               www.rebelwolf.com

                      - WoodGas -
      Generate Electricity from firewood.
      Build a WoodGas stove in an hour
http://groups.yahoo.com/group/WoodGas

"richard allain" <allain@...>

> www.earthtoys.com/ emagazine.php?issue_number=03.06.01&article=little

That links further to the following page, about the
SunDanzer chest type refrigerator or freezer. The
refrigerator's energy consuption is only 168 Wh
per day, which at $0.085/kWh, comes out to
slightly over $5 per YEAR of electricity.
The freezer uses $13-14 per year.

http://vegastrailer.com/sundanzer/Specifications.html

-= Laren =-

Hello all ..

I am really pleased to see this group exists ... I look forward to
learning a bunch about alternative methods of keeping things cold.

Does anyone have any "hands on" experience with a thermal mass
refrigerator? I have read about them in the Earth Ship books by
Michael Reynolds and have been planning on building one for quite a
while. So ... if anyone has suggestions and advise I would appreciate
hearing the same.

A little background on us. We live in an "off grid" home here in
western Montana. We need to reduce the demand for electric power as
much as possible. We have six 90 watt solar panels and a large battery
bank. We also run a 6hp Listeroid generator on WVO and produce 120/240
single phase power for home and shop plus 12 volt DC when needed to
assist in battery charging.

I look forward to your thoughts ...

Mac McQuaid
www.wchi.net

Hello there and congratulation to your group,I think
it is one of the important subject to talk about since
I'm living in the tropics and it is hot and humid
here.

What I want to know is refrigeration and air
conditioning does this two go hand in hand since both
of them uses compression and cooling system?

What is the alternative for this two,is there an
available appliances in the market?




__________________________________
Celebrate Yahoo!'s 10th Birthday!
Yahoo! Netrospective: 100 Moments of the Web
http://birthday.yahoo.com/netrospective/

I was looking to see if I could find a link to a sun powered refrigerator.
Awhile back a man was designing an absorbsion refrigerator using sun instead of
propane or kerosene.
     I stumble upon this link and I think that it is worth a read. I'm not
associated with this company in any way but you may have to cut the addy past
the com part. The rest gives you the issue number of their emagazine
Richard Allain
www.earthtoys.com/ emagazine.php?issue_number=03.06.01&article=little

[Non-text portions of this message have been removed]

"richard allain" <allain@...>

> Why not put hese links in the files section?

Hi Richard;

  With so good links, about so many different ways to
cool, it will probably be better to set up a data base
(Database section) where we can have separate
categories for each type of system. If anyone would
like to start setting that up, it would be appreciated.
I still have a lot of other group work to do.We have
gone from nothing to 150 members in just one day.
It has been a very busy time.

-= Laren =-

Why not put hese links in the files section?
   ----- Original Message -----
   From: LarenCorie
   To: RefrigeratorAlternatives@yahoogroups.com
   Sent: Saturday, March 05, 2005 1:43 PM
   Subject: [RefrigeratorAlternatives] Re: Root Cellar


   wsm311@...

     > I live in an underground house. For many years we had no electricity. >
Our root cellar is GREAT! ;-)

     > http://peaceandcarrots.homestead.com/RootCellar.html

     Hi Wendy;

        Glad to see you here, in our new group.
     Thank you for posting the link to your site,
     and to that long list of other links. Do you
     keep a thermometer in your cellar?  I
     suspect that your two holes are around
     stabile ground temperature, which is
     probably near 45°F.  Does the cellar
     swing much from winter to summer?
     Do you open the vents, to freeze the
     whole thing in winter?
     Thanks,
     Laren


[Non-text portions of this message have been removed]

"roadhse2" <roadhse2@...>  Wrote;

> We recieved a 'shoppers' catalog in the mail that had this personal
> cooler in it...i was just curious if anyone knows how this works and
> if it could be applied to fridges in some way for food storage...
>
> http://www.solutionscatalog.com/jump.jsp?
> itemID=4879&itemType=PRODUCT&sSearch=YES

Hi Glen;

  That is a Peltier device, like used in small DC coolers,
where you reverse the plug and it becomes a warmer.
You can also heat one side, cool the other, and it will
produce electric current. The 40° remark, and batteries
were a dead give away.  They are fun toys, and a lot
of people have been trying to make them viable for
electrical production, using woodstoves as their heat
source (they tend to be destroyed by too high temp)
but their efficiency is very low, as is their output, but
not their price. Space probes use them, with nuclear
heat sources, and they seem to be good for very
remote frozen locations, where ambient serves as
the cold side, and a propane flame provides the
heat.  I have two of the coolers, but even with
super insulation, they only work to about 40°F,
below ambient, so efficiency is effected by the
reduced deltaT. Peltier modules can be linked
in series to achieve great deltaTs, but that
requires even more energy.

-= Laren =-

We recieved a 'shoppers' catalog in the mail that had this personal
cooler in it...i was just curious if anyone knows how this works and
if it could be applied to fridges in some way for food storage...

http://www.solutionscatalog.com/jump.jsp?
itemID=4879&itemType=PRODUCT&sSearch=YES

Glen

wsm311@...

   > I live in an underground house. For many years we had no electricity. > Our
root cellar is GREAT! ;-)

   > http://peaceandcarrots.homestead.com/RootCellar.html

   Hi Wendy;

      Glad to see you here, in our new group.
   Thank you for posting the link to your site,
   and to that long list of other links. Do you
   keep a thermometer in your cellar?  I
   suspect that your two holes are around
   stabile ground temperature, which is
   probably near 45°F.  Does the cellar
   swing much from winter to summer?
   Do you open the vents, to freeze the
   whole thing in winter?
   Thanks,
   Laren

[Non-text portions of this message have been removed]

"William Carr" Jkirk3279@...  wrote;

> I read about this ice making technique last year.
>
> There's a way to get it to work without a desert, or so the
> story goes.   I haven't tried it yet.
>
> You need a reflector.   Get a large rectangle of cardboard, three by
> five feet is good.
>
> Now, get a cast iron pot.

You should not need a cast iron pot, however a non-metal
finish is needed for good emissivity, and the conductivity
of the metal is an advantage. In olden times, they had neither
the metal pot/pan, nor the reflectors. They just hid the
operation behind a north facing wall, where it never got
sunlight in the winter.

> At night, you point the reflector cone toward the sky,
> set the pot of water on a trivet in the center of the cone,
> and walk away. The heat in the water will radiate from
> the cast iron, bounce from the reflector cone, and head
> out into space.

Yes,  the objective of the reflector, since the heat is
coming from the water tray not the sky, is to shield
the water from a "view" of anything warm. The fairly
tall cone also shields the water from any breezes, and
allows the cold to pool inside. It acts like a bowl of
cold air.

> The interesting thing is that the heat will keep escaping
> until a skim of ice forms on the water.

It was common for them to quickly freeze a thin pool,
then cover that with fresh water, and build up layers.
This avoided the surface ice insulating the water
beneath it, resulting in greater net ice production.

> Using the turkey bag might be a good idea here too,
> as it might keep warm air from warming the cast iron.

The deep cone (not all that good for Solar cooking)
should keep the air still. There should be no openings
in the bottom for the cool air to fall out through. The
bag would probably just keep the warmth of the
water from rising, and also interfere with evaporation,
which is another key factor in the cooling and freezing.

> Finally, this won't work well under a tree as any
> infrared from the tree will end up warming the
> water rather than cooling it.

Yes, the view factor is very important. The water
should not be able to "see" anything but clear
night sky.  However, if all else is ideal, it should
still work well, as it did hundreds of years
ago in the Middle East.

-= Laren =-

Hi -

My name is Bob Cromer and I am a retired Mechanical Engineer.  I am
currently on several of the alternate energy groups.  I live in the
foothills of the Adirondack Mountains.  Our winters go down to the minus
20 degree F. levels at night and we have nighttime temps below 40 degree
F. for at least five months of the year.  There are still some examples
of 1890-1920 circulla Ice Houses in the mountains along side of lakes.
Typically, when they were harvesting ice, the Ice House still had 25-30%
of ice leftover from the previous season!!!  They used sawdust as their
insulation and would spread about a foot's worth around the huddled ice
pile.

If you think of solar heating in reverse, you come up with a fairly
simple cold storage system.  Any finned pipe heat exchanger (like a
baseboard hot water heater) cold easily cool down a water antifreeze mix
when the air temperature was below 40 degrees F. (40 degrees F. is
pretty much inside refrigerator temperature).  An insulated waterproof
"box" containing sand and PEX tubing loops (Vinyl Landscaping tubing
might also work, kids vinyl snow tubes are pretty rugged), would store
the cold. An additional plastic tubing loop would take the cold to the
refrigerator.  A small continuously operating electric motor and pump
(think small aquarium sized pump) bringing in the cold from the outside
"cold" storage box.  The refrigerator could have some holes drilled
through it and copper tubing could be looped inside under the racks.  So
as long as the cold pile had sufficient cold storage, the refrigerator
would not run at all.  The freezer is a different problem.

Here in the cold north, I could make an additional very cold box.  This
box would only accept cold when the temperature was down below Zero
degrees F.  A similar system would take the very cold to the freezer.
If you lived where it never got below zero, then this method would not
work.  You could allow the Refrigerator/Freezer to use the cold pile
water as its starting point verses room temperature to perform cooling.
With this scenario, the refrigerators heat releasing tubes would be
thermally surrounded with the cold pile temperature.  This would be very
similar in performance to a ground water induced heat pump.  Heat pumps
with 55 degree F ground water system have a COP (Coefficient of
Performance) of a bout 3.5.  This means that they pump 3.5 times the
energy across that they consume.  So if you started with an Energy Star
Refrigerator (or better) and provided it with 40 degrees F or colder on
the fin side, it would not run very much at all.

To construct the cold boxes,  I would look at what they did in the
Passive Annual Heat Storage system.  There they had insulation all
around dry sand with air tubes running through the "box".  In this case,
we would use plastic tubing.  Keeping the "box" dry is the most
important factor.  Running water thought the box would remove all of our
stored heat.  Since sawdust is cheap up here, I would use it.  I can buy
a ton of it for around ten bucks!!!  I would put it in plastic heavy
duty garbage bags, the 55 gallon size.  If I took a small piece of
landscaping cloth/screen, and placed it on the top of a sawdust filled
bag, I could evacuate the air out of the bag using a shop vac.  I could
then rent a bottle of welding Argon (under 50 bucks, more like $25).  I
would then repopulate the sawdust bag with Argon.  Sawdust is roughly
R3.5 per inch in air.  I think the six inch thick 55 gallon sawdust bag
Argon filled would be close to R40!!!  Since termites can not live with
oxygen, they would not be a problem.  On the bottom of the box, I would
use Styrofoam due to all of the weight of the sand.  On the sides and
top of the cold box, I would use the sawdust bags.  The overall size of
the cold box would vary on latitude.  The further north, the smaller the
box needed.  For me, my "gut" says 6 foot by 8 foot by 8 foot for the
cold and half that for the very cold.  For latitudes around Washington
DC, the size would have to be much larger.  I would cover the box with
several layers of 6 mil plastic.  I would also incorporate french drains
around the box to take away the rain water.  Grass could be planted over
the box(es) after they were constructed.

Sorry for being so wordy,

Bob Cromer
03/05/05...

I read about this ice making technique last year.

There's a way to get it to work without a desert, or so the story goes.
    I haven't tried it yet.

You need a reflector.   Get a large rectangle of cardboard, three by
five feet is good.

Now, get a cast iron pot.    Put the pot on the cardboard at the (long)
bottom edge, half way along.

You need to trace around the pot to make a half-circle in the bottom
edge, then cut it out.

Now you have a rectangle with a half circle cut out on the bottom edge.


Cover the cardboard with shiny aluminum foil.     Use Aluminum Foil
tape to lock it down.

Here's the trick.   You need to take the edges of the rectangle and
warp it around that half-circle cutout until the half-circle closes to
a smaller circle, then overlap the edges of that bottom side and use
aluminum tape to seal it.

You now have a form of cone.


In daylight, this reflector cone can be used to boil water from
sunlight.   Put the cast iron pot in an oven turkey roasting bag, put
it on a trivet in the center of the cone and point the cone at the sun.

(The bag keeps the breeze from cooling the cast iron).

At night, you point the reflector cone toward the sky, set the pot of
water on a trivet in the center of the cone, and walk away.

The heat in the water will radiate from the cast iron, bounce from the
reflector cone, and head out into space.

The interesting thing is that the heat will keep escaping until a skim
of ice forms on the water.

Using the turkey bag might be a good idea here too, as it might keep
warm air from warming the cast iron.


Finally, this won't work well under a tree as any infrared from the
tree will end up warming the water rather than cooling it.









The Constitution is not an instrument for the government to restrain
the people, it is an instrument for the people to restrain the
government - lest it come to dominate our lives and interests.
--Patrick Henry

A couple good links to research thermoacoustic refrigeration.
http://www.compukiss.com/populartopics/entertainmenthtm/article1155.htm

http://ehp.niehs.nih.gov/docs/1994/102-9/innovations.html
                                                                                        
Terry




[Non-text portions of this message have been removed]

http://members.aon.at/solarfrost/main.html
http://www.whispergen.com/whispgn.html
http://www.ggw.org/~cac/IcyBall/crosley_icyball.html
http://techref.massmind.org/techref/other/spac.htm
http://www.backwoodshome.com/articles/hackleman56.html
http://www.fridge.lionheart.net/descript.htm
http://www.acs.comcen.com.au/refrigeration.html
http://www.eg-solar.de/english/solar_cooling.htm
http://www.limsi.fr/Individu/mpons/solaradsor.htm
http://www.sundanzer.com/
http://www.solarfrost.com/frameprincipal.htm
http://www.rexresearch.com/interefr/patents.htm


links deposit: htp://groups.yahoo.com/group/andorprojex

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the RefrigeratorAlternatives
group.

   File        : /solarice.pdf
   Uploaded by : pinghansen <ping@...>
   Description : Using the sun for cooling

You can access this file at the URL:
http://groups.yahoo.com/group/RefrigeratorAlternatives/files/solarice.pdf

To learn more about file sharing for your group, please visit:
http://help.yahoo.com/help/us/groups/files

Regards,

pinghansen <ping@...>

Hi All,

Just happened to be going through some stuff in storage yesterday and
ran across a catalog I'd forgotten about. These Thermofoil heaters may
be an answer to RE electric heat for absorption cycle refers.

http://www.minco.com/products/heaters.aspx?id=42

If anbody gets the chance to experiment before I do, please pass on the
results.

ldb

--
Larry D. Barr
Editor/Publisher, Energy Self Sufficiency Newsletter
http://www.rebelwolf.com/essn.html
Owner, Rebel Wolf Energy Systems
http://www.rebelwolf.com/
Moderator, 12VDC Power group
http://groups.yahoo.com/group/12VDC_Power

http://tinyurl.com/4ch9y

-Laren Corie-
Integral Solar Building Design Since 1975

                    - LittleHouses-
    Everything To Do With Little Houses
http://groups.yahoo.com/group/LittleHouses

   The Energy Self-Sufficiency Newsletter
      Now available for free download at:
               www.rebelwolf.com

                      - WoodGas -
      Generate Electricity from firewood.
      Build a WoodGas stove in an hour
http://groups.yahoo.com/group/WoodGas

Quote:

" RadCool or radiant cooling is one method of providing passive
  freezing and refrigeration for the home. It is based upon simple
  principals of physics, heat loss by radiation. Numbers for this
  amount of heat loss are available in books on radiant heat loss
  from glazed surfaces in books on building. Here, heat loss is
  desired instead of a problem. During the middle ages, ice was
produced this way in egypt by guilds who packed water in
  ditches insulated with straw from the ground. The clear desert
  night allowed rapid loss of heat to the sky, resulting in freezing
  of the water in the ditches. During the day, the ditches were
  covered with stone and straw insulation to keep the water and
  ice cold until it could be chilled further at night. The desert
  provides a perfect environment for this type of refrigeration.
Temperatures drop instantly with the sun, and continue to drop
  through the night. In a wet humid environment, the water in the
  air reflects heat back towards the ground and prevents the
  extreme heat loss which occurs in the desert. "
That is from:

http://astro.umsystem.edu/atm/ARCHIVES/SEP98/msg01110.html


-Laren Corie-
Integral Solar Building Design Since 1975

                    - LittleHouses-
    Everything To Do With Little Houses
http://groups.yahoo.com/group/LittleHouses

   The Energy Self-Sufficiency Newsletter
      Now available for free download at:
               www.rebelwolf.com

                      - WoodGas -
      Generate Electricity from firewood.
      Build a WoodGas stove in an hour
http://groups.yahoo.com/group/WoodGas

Last this year, I did a series of posts to a different
Yahoogroup, about building a seasonal ice storage refrigerator/
/freezer. They are reprinted below. Basically, there are various
approaches, for different needs. The thing they have in common, is
that they operate passively to freeze, water and brine, inside the
unit, in the winter, so that it will stay cold all year, or at least
through the warm months. It can be used for long term cold
storage, but the frozen containers can also be taken out to keep
both a refrigerator, and a freezer cold in the kitchen. Using ice,
frozen in the winter, then insulated, to be removed, and used for
summer refrigeration, has a long tradition in northerm climes.

There have been conversation since, exploring a variety of
option. They will be post later. There is quite a bit to think
about in this post, as it is. The following is long. It was
written as the ideas developed, and questions were asked.

-Laren Corie-
______________________________________

   Storing coolth from the winter, to use in the summer is more
attractive in cold climates. Water stores equal to a 143°F temp-
-erature change as it freezes. It is ironic that you bring up long
term storage at this time. Just this morning, I found myself
compelled to look at a rough design for a freezer/refrigerator,
that would work in a northern climate, passively, on only the
coolth of winter. I spent less than a half hour thinking about it,
and punching in numbers, but what I came up with looks promising.

What I see is a box 8' high, and 4'x4', surrounded by a foot of
cellulose or high R fiberglass, or 7" of isocyanurate, or 8" of
extruded polystyrene. (R45) Three sides would be either under-
-ground or fully bermed. It could be buried next to the house,
with an opening into the basement. The top would need to be
vented passively. I have not looked into how much venting would
be needed, but over a long winter, it would not need to be much.

The upper 5' of the box would contain five 1' high wire shelves.
Each shelf would hold 100 2-liter PET soda bottles filled with
water. To set the phasechange temperature for freezer use,
sodium chloride, or propylene glycol could be used. A freezer
section could set between the colder temperature bottles and
the plain water filled ones. These bottles seem to be able to
hold up well under freezing. It may be advantageous to keep
the coolth storage up the back wall of the box, instead of at
the top. This storage will give over 300,000 BTUs at the temp
-erature of fusion. If it only had to overcome my ground
temperature, of about 45°F, it would take 9 months to melt
the ice. It will have to overcome more, but the ground
temperature will also be lowered by the frozen box.

The effective food storage underneath the five shelves of frozen
bottles, would be 3' high, and 4'x4' (48ft³). A roll-out drawer
would be the most energy saving configuration. There would
need to be a lot of details worked out, but the basic principle
will work. However, there are other options for refrigeration.
I have an absorption unit, waiting in my garage to start playing
around with. I want to see if I can set it up to work on charcoal,
which I can easily make.

"M" wrote;

>Storing ice can be a low tech solution,
> though it can be a lot of work.

Hi M;

No work at all. The system I proposed was totally passive
It does not require any human action, or have any moving parts.

> (There isn't much of a temperature difference between
> ice and what you want to keep cool.)

That would depend on what it is you want to keep how cool, and
then what kind of ice it is. It is very easy to modify the freezing
temperature of water, downward. The key is to not set it so cold
that the DeltaT is increased to a point where it gains heat so fast
that it uses its coolth to quickly. Or, that there is not enough time,
when the weather is cold enough, to freeze it during the winter.
However, you can have a smaller freezer section surrounded by
a refrigerator section, just like in many fridge/freezer combin-
-ations. There can be considerable difference from year to year
too. Sizing the system is challenging, just as sizing any totally
inflexible passive system is. However, with small containers for
the ice, there is a degree of flexibility.

You could, of course, drastically oversize the system, but cost
effectiveness is always a primary consideration. So, I like the
idea of building it with 4'x8' sheets, and a freezer/refrigerator
area of 48ft³ In my design there is also plenty of room to
increase the thermal storage, by using other containers besides
2-liter bottles. I used them in that quick model, because they
are cheap, durable, able to withstand the pressures of repeated
freezing, easily replaced, easily handled, and they have great
surface area for fast heat transfer to/from the air, plus it is
only about 2¼" to their core from the surface, so they can
freeze completely, fast. However, in the model I presented
there is only 45% as much water as could fill the volume of the
thermal storage area. There is a lot of room to fill part of the
area with rectangular containers, alternating with rows of the
bottles. It should be possible to increase the thermal capacity
by 70+% without inhibiting the heat exchange from the food
storage area. It looks good to me.

> BTU= energy to raise 1 lb water 1 degree
> one gallon of water = 8.3 lbs of ice

Yes

"B" wrote;

> Check out this link for an ice box fridge. Not quite the
> same as Larens plan, but it has been working for twenty
> years. http://fourmileisland.com/IceBox.htm

Hey! Thanks for the great link, B.

It said:

"It has no freezer, so we can't store frozen food, but to
paraphrase the inventor Scott Nielsen, one of the great
sacrifices we make is that we have to eat all the ice
cream as soon as we get it home from the store. "

I am pretty sure that my design will keep ice cream frozen all
year. However, there are options, if it didn't.

1) dry ice, inside of a box that is surrounded by cold air, will
keep for a very long time.
2) Ice cream is used in many ways, like cold drinks, that don't
require it to remain frozen. The low fat, and no sugar added
varieties make a reasonable substitute for milk in cooking etc,
and is great to mix with granola, or bran flakes. ;O)

Their design and mine are not really that different. They use one
single piece of ice, where I use 5-600 separate containers, but
the amount of storage mass is basically the same. They use a
refrigerant to move heat from the mass to the cold outdoor air,
while in the nature of my history of working with air panels and
sunspaces, I orient to my usual passive air transfer. They insulate
with 16" of extruded polystyrene, which may seem to be a lot more
than my design, but I buried my on three side like an earth sheltered
house. So, the insulation in mine is possibly even greater. The two
designs are fundamentally very similar.

With the individual water containers, it is possible to have a
freezer box, with a little propylene glycol, or salt, to lower the
freezing/melting transition temperature.

-Laren-

"N" wrote;

> Wonder how cold it would have to get for me to get a big
> ole block of water to freeze up enough to make it worthwhile.
> We spent a LOT of time below freezing this winter...!

Hi N;

Time is a major factor, and since it is very hard to control,
heat exchanger surface area and reduced R value can be used
to make up for it. Fresh snow has an R-value of 1.5-2/in, so
ice might have an R of about .5/in. If you are using a 4'x4'x3'
container, with a fluid running through the middle, the exchanger
is somewhere around 10" from the average water, and will be
insulated to about R10 or higher by the time you are trying to
freeze the last of the water. I prefer my approach, which has
over 500ft² of heat exchanger surface area, with an average
heat exchanger insulation, at full freeze, of only about R1.5.
The further south you are, the more critical it will be to have
a bigger heat exchange area, in order to take advantage of
the much shorter cooling opportunities.

-Laren Corie-

"M" <mperry@e...> wrote

> Laren: You are saying that it's the changing from solid
> to liquid that stores the energy, correct?

Yes, an equivalent amount of energy to a 143°F change.

> Is that fusion, or would it be a phase change?

"Latent Heat of Fusion," or "phase change" or "change of state."
It is not "nuclear" fusion. ;O)

"B wrote;

> I did some more research. To achieve a 20 degree Fahrenheit
> freezing point would require a 10% salt solution or a 20%
> propylene glycol. Your plan has about 250 gallons or 2100 lbs.
> of water. That works out to about 210 lbs. of salt or 50 gallons
> of propylene glycol. The salt should run about $20. The glycol
> is about $20 per gallon or $1000 for the fridge.

Hello B;

The refrigerator cooling would be plain water, with no anti-freeze.
The anti-freeze would only be a small amount for the freezer section.

I have not investigated the details of using salt. Are you referring
to sodium chloride, calcium chloride, or a different salt? The
temperature of the thermal storage mass would need to be slightly
colder than the desired freezer temperature. There could be two
freezers. one at 5°F for long term storage, and an every day
freezer at about 20°F.

I am fairly sure that the propylene glycol can be procured
for $5-7/gal. The auto anti-freeze variety will do fine.
I suspect that a small whole drum would even be cheaper.

> Could the two litter bottles be stacked in the rear of the
> fridge?

Yes, I have considered that, but there are a few factors that
effect the configuration. Fast passive convection, is one, but
that needs to be weighed against a simple small fan/thermostat
system. The passive venting would need to be big, in order to
take advantage of brief cold times in the middle of the night.
That is not all that critical for the refrigerator heat storage
in a cold climate, but for the freezer in a moderate climate, it
is very critical. Placing the bottles up the back wall would not
only make access to the food storage area easier, it would also
slow the heat exchange from food storage to thermal mass, and
from the mass to the ambient environment.

The freezer, with its mass, are a separate system, which must
function on its own, though it may set within the thermal envelope
of the refrigerator system. It is important to optimize the mass,
the insulation, the heat exchange areas, and other factors for each
system individually, for the specific climate, with enough inherent
flexibility for yearly variations. It is my feeling that, as I have
found with passive Solar heating for cold cloudy climates, there
is probably a better solution within the definition of "hybrid"
It may be advantageous to use a small fan to cool the bottles
when the ambient temperature drops very low in January.
That would make the system viable for much milder climates.

Another solution may be, to collect ambient coolth passively,
then distribute it to the cooling site actively, with a very small
fan. This is what I have found to give the best results and control
for heating. It may be the solution for refrigeration as well..
...or it may not. I simply have not taken this problem to that
stage of design yet. It is noteworthy to mention that standard
refrigerators, still use both active an passive convection.

> The bottom front could be the freezer section.
> The top front would be for refrigeration.

That configuration would be excellent for keeping the system
cold, but it presents problems for 'getting' the system cold.
That is not meant, at all, as a condemnation of the configuration,
just a quick assessment of the first problem that I notice,
which would need to be addressed. At this point I am keeping
my mind open to any configuration.

> Baffles could be set up and adjusted to control air flow.

That could work well if needed, to be manually set, but I
have found that automatic baffles and dampers can be a real
hassle, especially where they can frost up. It may be advan-
-tageous to use small fans for control. A fan would make the
use of simple very low-cost dampers possible. I am no purest.
100% passive is nice, but so is 99%, or 98%, and even 75%.

Could a six to eight foot tall fridge have enough
stratification of air temperature for this to work?

Most definitely. Look at old refrigerators. They just used
a small, open, heat exchange cube, as the freezer. My little
"dorm type" refrigerator still does. Even though it is at the
top, it still keeps foods 20-30°F colder than in the fridge,
which is cooled by the freezer. Stratification can retain
sizable differentials if the air is still. I have seen bathtubs
under windows, where you could close your eyes and lower
your hand, and feel the point where the cold air was pooled
in the tub, similar to how you would feel if it were filled
with cold water (not as extreme).

Someone mentioned alcohol. It doesn't freeze until some-
-thing like -112°F so it should make a great antifreeze. It
used to be use in cars, but it was flamable, and it would
evaporate away at relatively low temperatures. It would
probably be ideal for the freezer, and could even be home
made and distilled. Most windshield washer antifreeze is
(I believe) methanol. Any substance that disolves in water,
will lower its freezing temperature.

-Laren-

The seasonal ice box has a lot of potential, but needs huge
amounts ($) of insulation, if it is not buried in the ground, so
it will usually be a ways from the kitchen, and a small kitchen
refrigerator will still be needed. Another plan, which might
work better, is to have the large buried seasonal ice box,
totally filled with two-liter bottles, in sections of both ice
water and alcohol, or brine. Then, as needed, the bottles
could be fetched from the "ice cellar" the same way that
food is gotten from the fruit, or the root cellars.

In northern states, the 4'x4'x8' box, filled completely with
two-liter PET soda bottle of water, and of brine, should still
handle all the refrigeration for the full year. A super insul-
-ated top opening icebox refrigerator in the kitchen, should
be able to go all year on the frozen bottles from the "ice cellar."

A system to vent the refrigerator, and the freezer
with ambient air could also be used for the winter cooling.

If your area gets any freezing weather, then it is possible to do
seasonal ice storage. The problem is, how practical is it to have
enough heat exchanged to freeze enough water during a very limited
time, and then how much insulation is needed to keep that much ice,
frozen, for that long? There are often more effective projects.
This is primarily a northern system.

-Laren Corie-
Integral Solar Building Design Since 1975

http://groups.yahoo.com/group/WoodGas
"Generate electricity from wood"