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S, brian whatcott pi?e:

It really would help if you were not so convinced the other guy is wrong.
This is called the "physics undergrad effect."

I do wrong decissions's too.

OF COURSE you isolate the water /pump arrangement from the main? cooler circuit.
Forget a hand pump. This is simple and effective - all it takes is time.

I'm not shure I understand you right. I have 1l evaporator already filled with watter. It's near full. Then I have sorber (the zeolite container) with aprox 5l voids. and I have one hose connecting them. So the hose and evaporator has total 1dl air needed to evacuate. But the sorber has the greatest volume and any water vapour here just decrease cooling capability.

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On 6/10/2011 1:37 AM, Slavko Kocjancic wrote:

S, brian whatcott pi?e:

On 6/9/2011 12:45 PM, Slavko Kocjancic wrote:

?

An attractive primitive pump down method presents itself: given
a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence.

Hmm.. I don't understand that. Can you explain more precisely? (Probably the reason is only my bad english, and fact that I'm electronic man and my knowledge is slick in vaccum)


Slavko.

Fill a tank with steam.
Close the tank off and chill it to ambient - open a valve to the system to pump down.
Repeat ten or more times, with a good size tank.

Brian W

Ahh I understand. But afraid that this will saturate zeolite quick. I will try to make hand pump like described in patent here.

It really would help if you were not so convinced the other guy is wrong.
This is called the "physics undergrad effect."

OF COURSE you isolate the water /pump arrangement from the main? cooler circuit.
Forget a hand pump. This is simple and effective - all it takes is time.

Brian W

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S, brian whatcott pi?e:

On 6/9/2011 12:45 PM, Slavko Kocjancic wrote:

?

An attractive primitive pump down method presents itself: given
a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence.

Hmm.. I don't understand that. Can you explain more precisely? (Probably the reason is only my bad english, and fact that I'm electronic man and my knowledge is slick in vaccum)


Slavko.

Fill a tank with steam.
Close the tank off and chill it to ambient - open a valve to the system to pump down.
Repeat ten or more times, with a good size tank.

Brian W

Ahh I understand. But afraid that this will saturate zeolite quick. I will try to make hand pump like described in patent here.

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On 6/9/2011 12:45 PM, Slavko Kocjancic wrote:

?

An attractive primitive pump down method presents itself: given
a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence.

Hmm.. I don't understand that. Can you explain more precisely? (Probably the reason is only my bad english, and fact that I'm electronic man and my knowledge is slick in vaccum)


Slavko.

Fill a tank with steam.
Close the tank off and chill it to ambient - open a valve to the system to pump down.
Repeat ten or more times, with a good size tank.

Brian W

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S, brian whatcott pi?e:

Finally, the penny drops!

In the last forty years the structure of even the simplest zeolite (A) has been investigated and
its uses as? adsorption and catalytic surfaces has been investigated.

Here is a straightforward paper on the topic


Recently people have been interested in zeolites as heat exchangers.
This is a demo model of the kind I expect that triggered this thread.

Not exactly this research post but is the same stuff.

Zeolite (etymology "boiling rock", for its exothermal behavior in adsorbing up to 30% by weight of water) is an interesting material.
Zeolites are ideally heated to 250degC to desorb the attached water again.
But lower temps can release a fair proportion of the water.

Now having got those facts out of the way, its time to mention something else interesting:?? If a dry zeolite is pumped down in the presence of water vapor,
the zeolite will self-pump down further.

I see that behaviour as when I stop pumping the pressure goes down even without pump. Not far but it's goes down.

An attractive primitive pump down method presents itself: given
a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence.

Hmm.. I don't understand that. Can you explain more precisely? (Probably the reason is only my bad english, and fact that I'm electronic man and my knowledge is slick in vaccum)


Slavko.

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Finally, the penny drops!

In the last forty years the structure of even the simplest zeolite (A) has been investigated and
its uses as? adsorption and catalytic surfaces has been investigated.

Here is a straightforward paper on the topic


Recently people have been interested in zeolites as heat exchangers.
This is a demo model of the kind I expect that triggered this thread.

Zeolite (etymology "boiling rock", for its exothermal behavior in adsorbing up to 30% by weight of water) is an interesting material.
Zeolites are ideally heated to 250degC to desorb the attached water again.
But lower temps can release a fair proportion of the water.

Now having got those facts out of the way, its time to mention something else interesting:?? If a dry zeolite is pumped down in the presence of water vapor,
the zeolite will self-pump down further.

An attractive primitive pump down method presents itself: given
a side water reservoir and an air reservoir connected with taps, the classical method of steaming out the air reservoir and chilling it down with waste water, then connecting to the chiller system, several times will pull the chiller pressure down enough for the zeolite to work its magic, given three gas taps are plumbed in to give the desired evacuation sequence.

A suitable scavenged container might be provided by a used propane cylinder or two, which can take the vacuum easily.

Brian Whatcott
Altus Oklahoma

S, Thomas Bryhn pie:

Slavko,
I don't question the test you did. However, if this is going to be more
than a toy you'll need to add food/drinks into the system. You may be ably
to cool a small amount of air very rapidly, but it's really the food that
you want to refrigerate, isn't it? I'm afraid that will take some energy
...

Now, if the food was already frozen, you could settle for a vacuum around
a container with the food. That should provide very good isolation from
the warmer surroundings.

Best regards,
Thomas Bryhn

It's intended to keep stuf cold not to cool it down..

Slavko,
I don't question the test you did. However, if this is going to be more
than a toy you'll need to add food/drinks into the system. You may be ably
to cool a small amount of air very rapidly, but it's really the food that
you want to refrigerate, isn't it? I'm afraid that will take some energy
...

Now, if the food was already frozen, you could settle for a vacuum around
a container with the food. That should provide very good isolation from
the warmer surroundings.

Best regards,
Thomas Bryhn

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S, brian whatcott pi?e:

I think you need to do a little more testing and a little more calculating.
5 minutes? at 200 watts input?? (optimistic) is not going to get you a usable
cool box. If? you could pump down to a few millibars in 5 min, so your water boils, then
the pressure goes up again - so you have to keep pumping.

Sounds like you did as physics class quite a few years ago: is that the way it was?

:-)

Brian W

Well I did physic class few decades ago... :D

..but you do not read my post. Let's explain again:
I have two boxes. One is near full of water and the second is filled full of zeolite. Both are connected with hose. Under atmospheric pressure nothing happens. So let's start with all temperatures at 24C. When I start to pump and reach 30mBar the water will start to boil. Reaching this point should be very quick (minute or two). With that pressure the water will boil and presure will balance. Here the zeolite come in action. It's work like sponge for water vapour. And they wil adsorb the water wapour. No ned to pump any more if I want 24 degres C. But as I wan't to go lower I sustain pumping. So the water will agresively boil as presure is so low. So I can't get 5mBar but just few mBar under current water vapour pressure. But the side efect of pumping that is that I pump the water vapour AND remaining air. And I want to evacuate the AIR as water vapour will always balance with temperature. So after reaching 30mBar @24 degres I ned to pump litle longer but the gauge wil stay at 30mBar. (wel it wil go lower as water is colled by evaporation).

I did that test with (borowed) vacum pump and it's work as is writen here.
The pump reach 30mBar after 20 second and I leave it running for full minute reaching 20mBar.
I switch pump off. And check after 10 minutes. The gauges reads 12mBar @ 10 degres C.
Then I start pump again for one minute. The pump reach 6 mBar and I stop it.
10 minutes later the gauge reads 2 mBar and temperature is -6 degres. The water is frozzen.
3 hours latter the result is same. After 6 hour the presure start to rise and temperature too. All that without insulation!.

and about of energy..
We need 2260 kJoule to evaporate 1 kg of water. And 4 kg of zeolite can eat 1kg of water wapour easy.
If I have 40cm X 40cm X 40cm colling box the surface of box is 1m2. I want 8 degres C in cold box and hottest out temperature is 30 degres. So difference is 22 degres C. With insulation R=1.5 I need (22 * 1 / 1.5)=14.6 J. With 2260000 Joules available that give me 154794 seconds working time. (2579 minutes or 43 hour)

ahh yes I need to explain why I don't evacuate that system at home with borrowed pump. I have 2 reasons.
1. Don't want to heat my cabin. The zeolite container get hot!!!. So I put it out of lodge and need to assemble it on place
2. After saturating zeolite that need to be heated and thus dried. It's easyer just to remove canister from system and heat it in the stove or whatever hot source and let wapour to go out. In other case I need the condenser in line but that gave problems. (ice build up and others)

So Again.. I NEED THE SIMPLE VACUUM PUMP.. I study options I have and this is best one to have. And cost me under $50 + pump...

Slavko.

I'll second Ed's warning about ammonia.

How about a low vacuum boiling acetone fridge? You can recover (well most off it anyway) the boiled off acetone by condensation, if you go with a simple open loop system. Vacuum boiling acetone will get you well down into the -0C range with ease and so long as you recover as much as you can shouldn't be too expensive to run if you use a top loading fridge/freezer (these will use as little as 0.1kwhr when run at 4C) box as your fridge.

A venturi vacuum pump running on either compressed air/steam or water should do it. I'd go with water as this will condense out your acetone at the same time.....

Thomas.

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On 6/8/2011 2:07 PM, ed ward wrote:

Friends ammonia dissolves copper,brass and silver solder fast everything that comes in contact has to stainless steel or iron and welded, ammonia is a good solvent for silver and copper and brass.edsworkshp

Did I mention Einstein got so upset when he read of deaths due to a domestic ammonia based cooler, he set out to design another style to NOT use ammonia?

Brian W

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On 6/8/2011 12:28 PM, Slavko Kocjancic wrote:

/snip/

Cooling a liter of water by one degree costs you a?kilo-calorie?(one food calorie),

assuming your cooling method is 100% efficient. The vacuum fridge you describe

will be lucky to be 10% efficient. So to cool 5 liters from 30 degrees to 7 degrees,

you need 5 * 10 * (30 - 7) = 1,150 calories of food if you want to do this by hand

using a hand pump.

Haha. I'm not crazy. I need to evacuate system down to pressure and then leave it here. The zeolite in container will adsorb the water wapour and make operation continous. The problem come when zeolite saturate. Then I need to regenerate it. It can be done with sun, woodstove, or anithing capable to heat to 200 centigrade. After that I need to reassemble all thing and evacuate again. As I calculated I need to regenerate aprox twice a week. (When come to lodge and before I leave it - if I wan't to be in cold state)

Looking up the calories for various activities, we find that 1,150 calories is?

3 hours of walking briskly, or running 13 kilometers in 1 hour and four minutes.

Trying to expend 1,150 calories squeezing a hand pump with one hand will

take the better part of a day. I have one of those hand pumps, and I can pump

it for perhaps 10 minutes before my hand is too fatigued to continue. So you

will need a lot of friends to help you. But they will eat a lot, so you need a bigger

fridge, and then...

Misleading. I (hope) need to pump under 5 minutes. The zeolite will do the rest.

/snip/

Slavko

I think you need to do a little more testing and a little more calculating.
5 minutes? at 200 watts input?? (optimistic) is not going to get you a usable
cool box. If? you could pump down to a few millibars in 5 min, so your water boils, then
the pressure goes up again - so you have to keep pumping.

Sounds like you did as physics class quite a few years ago: is that the way it was?

:-)

Brian W

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S, Simon Quellen Field pi?e:

I am not clear on why you think idling a car is out of the question.

Just don't have space for car. I park it far away of lodge. And is not so quiet.

Unlike running my whole farm during a power outage, all you need

to do is run a fridge until you have replaced the energy you lost by

opening the fridge door. If you keep the fridge in the car, then any

driving you do should be more than enough to get it cold again.

I dissagre.. The fridge in house turn's on for few minutes every half hour. (but it's good one!) the cheapo is even worse. But my problem isnt power outage but lack of power. I had inverter in home to use it with car to power deep frezer in home if necesary. In the lodge that is for constant use.

An idling engine 10 meters from the house will not make a noticeable

noise.

can't park 10m away. (Can wery close or far away)

The $250 fridge and $50 inverter are probably cheaper than any

homemade solution using a vacuum.

I hope to make it under $300

Cooling a liter of water by one degree costs you a?kilo-calorie?(one food calorie),

assuming your cooling method is 100% efficient. The vacuum fridge you describe

will be lucky to be 10% efficient. So to cool 5 liters from 30 degrees to 7 degrees,

you need 5 * 10 * (30 - 7) = 1,150 calories of food if you want to do this by hand

using a hand pump.

Haha. I'm not crazy. I need to evacuate system down to pressure and then leave it here. The zeolite in container will adsorb the water wapour and make operation continous. The problem come when zeolite saturate. Then I need to regenerate it. It can be done with sun, woodstove, or anithing capable to heat to 200 centigrade. After that I need to reassemble all thing and evacuate again. As I calculated I need to regenerate aprox twice a week. (When come to lodge and before I leave it - if I wan't to be in cold state)

Looking up the calories for various activities, we find that 1,150 calories is?

3 hours of walking briskly, or running 13 kilometers in 1 hour and four minutes.

Trying to expend 1,150 calories squeezing a hand pump with one hand will

take the better part of a day. I have one of those hand pumps, and I can pump

it for perhaps 10 minutes before my hand is too fatigued to continue. So you

will need a lot of friends to help you. But they will eat a lot, so you need a bigger

fridge, and then...

Misleading. I (hope) need to pump under 5 minutes. The zeolite will do the rest.

If you are going to use human power, you are much better off using a bicycle

with a generator, and powering the $250 fridge from that. It will still take 1.33

hours of bicycling.

Again misleaded...

BUT...
Simon thanks. Your calculations and effort to write that post is great. You just miss that I need to evacuate system not to pump to all the watter evaporate.
... and I my lodge I wan't as much stuf to be green. No gass generators and similar alowed.

So please again let's stay on topic. I know that this is possible as I already tested it. (borrowed pump) So just need cheap pump. probably hand operated. the volume of system is aprox 5L and need vaccum of aprox 10mBar. (7.5 torr).? Thanks.

Slavko

I am not clear on why you think idling a car is out of the question.

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S, o1bigtenor pi?e:

On Wed, Jun 8, 2011 at 1:12 AM, Slavko Kocjancic <eslavko@...> wrote:

S, o1bigtenor pi?e:

Is suggested the Icyball because if YOU can silver solder you can make a system which is very cheap to run. As I am a professional welder its not too hard for me. It is a possible solution!

I don't have equipment for silver soldering, just for soft soldering. IcyBall seems atractive but the presence of ammonia take me off. Long ago I checked that topic and found a lot of problems with that and accidents. So I avoid that. But thanks for sugesstions.

Slavko.

You use a small propane torch for the 'soft solder'? - - and the same for silver solder (tin solder is at about 600 F and silver solder is at about 850 F) both of which are a lot cooler than arc welding.

Re: ammonia - - think potent window cleaning stuff. I farm too and have worked around the high potency stuff. Have not found it too hard to work with and would rather work with that than R-13 (or 13a or 134 or 131 or any of the the other organochlorofloro compounds).

Darald

It's not the amonnia itself. The high pressure AND ammonia freak's me out.

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S, brian whatcott pi?e:

There is a perfectly green way of keeping food cool; it comes free - only sweat equity is needed.
It's called an ice house.
Briefly; you dig a hole and line it with insulating natural materials, and provide it with a tight
insulating door.?? In Winter, the cellar is loaded with ice and snow, and in Summer, the door is opened as seldom as possible.

If this won't do it for you, need to find a lawn mower engine, and replace the valves with flap valves and a big handle and flywheel.

Brian W

That's best one... Just It's little bulky. I already think in that way (near). To make isolated box underground and then with coil of salty watter pump heat to kitchen small box. As I remember calculations give me something around 5 cubic metres of ice. Just little to much. The underground watter cistern give me near constant 17 centigrade but that's not enought. Just need little coller.

About lawn mover engine. Just don't have one.
But I look at this thing..

its small cheap auto compressor.
I don't know much in pneumatic but compresor is rated 250PSI (17BAR) and that seem to much. So I try to be realistic and get 130PSI (8.9 bar) as real value.
So if I isolate input port then that small one can pull 1bar(atmosphere)/8.9Bar=0.112Bar. So this 112mBar is stil to high. What if I attach another one in series? If that works then in theory I can get 112mBar/8.9=12,6 mbar. How series pump works? Is this correct aproach? If yes then that cost me 16 Eur total..

Slavko

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On 6/8/2011 1:35 AM, Slavko Kocjancic wrote:

/snip/
And I have cabin/lodge (don't know correct english term) and running car on idle there is out of question. Possible to run inverter to run vacuum pump but not all the day for runing fridge.
using good regular fridge and inverter is cheapest. But running car to power it makes it to expensive and anyoning.
if powered with solar panel we need at least 200W panel and at least 100Ah battery. too bulky and expensive for my option.
Otherwise I want 'green' solution in my little place.

/snip/

There is a perfectly green way of keeping food cool; it comes free - only sweat equity is needed.
It's called an ice house.
Briefly; you dig a hole and line it with insulating natural materials, and provide it with a tight
insulating door.?? In Winter, the cellar is loaded with ice and snow, and in Summer, the door is opened as seldom as possible.

If this won't do it for you, need to find a lawn mower engine, and replace the valves with flap valves and a big handle and flywheel.

Brian W

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S, Simon Quellen Field pi?e:

An inverter, a car, a few extra gallons of fuel, and a cheap small

refrigerator.

""

""

""

During power outages here up on the mountain, I used to idle my truck

while it powered an inverter. That powered the house all day, including

a large standard refrigerator. For a little refrigerator like one of the above,

you won't need a 1,000 watt inverter -- more like 200 to 300 watts at most.

And at night, you don't need to power the fridge at all, since the door will

be closed all night.

-----

Well look the last link. there is cittation...
Almost all refrigerator and freezer models reviewed in this article were priced more than $1,000, with the Tundra TJ85 at $1,600, the Norcold DE-61T at $1,200, the SunDanzer DCF225 at $1,100, the Sun Frost RF-12 at $2,100, and the Sun Frost RF-16 at a whopping $2,800. You may be able to find slightly lower prices if you shop around, but all are quality-built low-energy appliances and far exceed the energy performance of lower-cost models you find locally. Since these models are fairly large and some weigh in excess of 300 pounds, they must be shipped to you by truck freight, so expect another $200 for crating and shipping costs.

And I have cabin/lodge (don't know correct english term) and running car on idle there is out of question. Possible to run inverter to run vacuum pump but not all the day for runing fridge.
using good regular fridge and inverter is cheapest. But running car to power it makes it to expensive and anyoning.
if powered with solar panel we need at least 200W panel and at least 100Ah battery. too bulky and expensive for my option.
Otherwise I want 'green' solution in my little place.