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abbasi
20-04-2004, 09:10 AM
:confused:
I have recently made a 3D display refrigerator(double glass on all sides)
The problem i am having is the heat loss through channels.
Can somebody recommend me the design of these four channels(pillars)

Bones
25-04-2004, 07:12 AM
can you get plastic internal channels there? this should stop alot of your heat loss problems, and any posibility of insulating between the internal - external channels, with an insulating compound or insulwool or the likes?

Peter_1
25-04-2004, 12:00 PM
As longs as you prevent a coldbridge, you will not have problems.

We did it also many years ago for a pastry tower for a bakery. Placed the double glasses with their inner glas against each other and assembled it with a silicone kit.
Then in each corner, you will have a square gap. We filled this we a glassfoam and a single heating wire to prevent condensation.
Over that corner, we finally placed a stainless steel corner.
Even the ceiling was in glass and in the bottom in the center was a circular fan (extraction) and on the 4 sides an oultlet grille (close to the glass walls)
Switch on the door that shutted off the fan.

abbasi
26-04-2004, 06:12 AM
As longs as you prevent a coldbridge, you will not have problems.

We did it also many years ago for a pastry tower for a bakery. Placed the double glasses with their inner glas against each other and assembled it with a silicone kit.
Then in each corner, you will have a square gap. We filled this we a glassfoam and a single heating wire to prevent condensation.
Over that corner, we finally placed a stainless steel corner.
Even the ceiling was in glass and in the bottom in the center was a circular fan (extraction) and on the 4 sides an oultlet grille (close to the glass walls)
Switch on the door that shutted off the fan.

Kindly view the attached dwg showing top of channel
initially i used GI as material
but i m gonna switch over 2 Alminum(its K factor is very high)
I hope i can learn from ur advice/experience
Regards

Peter_1
26-04-2004, 06:46 AM
Hello Abbasi,
Just woke up and saw your post.
What is GI?
An important question I forgot to ask: what's the temperature in the cabinet?
It's seems already pretty good.
If we make counters for a temperature around 0C with double glazing then we always forsee a little wire in it t oprevent condensation on the outher glasses.
so what's my opinion: see drawing (didn'tmade lot of efforts to draw it nicely) Green is silicone sealing, yellow is a small piece of plastic to prvent that the glass will touch your corner the blue is the heating wire and the red is a small T- profile (or perhaps you could just kit it wit silicone)
If you kit it from the outside, then you can insert the wire in a 1/4 copper (coming out on the top and bottom of the cabinet) so that it's replacable without removing the outher silicone sealing.

We once made for a double glazing manufacturer a demonstrating project for double glass.
It was a piramide with a footprint of 1 x 1 m.
Each side of the piramide was made of another sort of glass: starting with single glass till the then latets super-isolating glass (special coated)
In that piramide it was appr. -10C to simulate the winter. We had it sprayed inside with artificial snow, there was a snowwman in it made in plastic, Santa Claus on his slee,....
The purpose was that you could feel with your hand (there where stickers on the glasses wit a hand) the cold. The single glass was of course constanly wet.
Try to find a picture somewhere.

Peter_1
26-04-2004, 05:50 PM
The Piramid we made, scanned from an old photo in a leaflet.

abbasi
27-04-2004, 05:01 AM
Hello Abbasi,
Just woke up and saw your post.
What is GI?
An important question I forgot to ask: what's the temperature in the cabinet?
It's seems already pretty good.
If we make counters for a temperature around 0C with double glazing then we always forsee a little wire in it t oprevent condensation on the outher glasses.
so what's my opinion: see drawing (didn'tmade lot of efforts to draw it nicely) Green is silicone sealing, yellow is a small piece of plastic to prvent that the glass will touch your corner the blue is the heating wire and the red is a small T- profile (or perhaps you could just kit it wit silicone)
If you kit it from the outside, then you can insert the wire in a 1/4 copper (coming out on the top and bottom of the cabinet) so that it's replacable without removing the outher silicone sealing.


We once made for a double glazing manufacturer a demonstrating project for double glass.
It was a piramide with a footprint of 1 x 1 m.
Each side of the piramide was made of another sort of glass: starting with single glass till the then latets super-isolating glass (special coated)
In that piramide it was appr. -10C to simulate the winter. We had it sprayed inside with artificial snow, there was a snowwman in it made in plastic, Santa Claus on his slee,....
The purpose was that you could feel with your hand (there where stickers on the glasses wit a hand) the cold. The single glass was of course constanly wet.
Try to find a picture somewhere.



GI means galvanised iron
Sir I used gasket instead of plastic in yellowish region and
what confuses me is positioning of copper wire
(bluish 1)
temp within cabinet 0-10 C

1 thing more i made double glass in an iron frame first by putting glass in it, then used aluminum strip in between (10 mm made in rectangular space usin' plastic angles) then i put second glass on it and filled spaces using silicone and whole assembly was joined to channel of fridge as previously shown.
also data of my fridge is

11 cu ft. refrigerated portion

1. Compressor Danfoss FR11G
2. Condenser coil 2 row (7"x7") 12FPI
3. Evaporator coil 3 row (10"x61/2"x3")
4. Capillary 0.059 dia 4m Length
5. Evaporator Blower (130 CFM)
6. Condenser fan 8" dia (300 CFM)
7. Thermostat Temperature Range (0C-10C)
8. Glass 5 mm thick (1220x590) sq. mm
9. Lights 10 Watt tubes x 2
10. Aluminum strip Width 10 mm Length 48 foot
11. Rubber seal For Glass 8 mm width 50Foot Length
12. Gasket Width 1" Length 56 Foot

Jasper
27-04-2004, 06:53 AM
abbasi
A company i worked for used to manufacture this type of cabinet.
We used to put a low voltage (12v ac) heater tape in between the channel and the glass, the tape is selve limiting so the length does not matter, this is then connected to a 12v transformer.
Hope this helps

Jasper :)

Peter_1
27-04-2004, 10:46 AM
You made the double glass yourself?
That will give troubles Abassi.

Normal double glas (obligated to install in Belgium for new buildings) has a special perforated alu spacing profile betzeen the two glasses.
In that profile, they put silicagel in it and they quickly need the to seal the glass.
Once it's sealed, the silicagel will dry the spacing between the 2 glasses so that dawn (correct word?) is prevented.
The smallest leak between the 2 glasses will allways result in dawn between the glasses and the glass will become white on the inside.

I know this very well because my grandfather and later my uncle was a contractor of glass worker (my grandfather even made those very big , colourful glasses you often see in churches) and when my uncle took over the business, then double glasses were coming up in the then new buildings.

They made them all themselve and I often helped them.

I remember then that I took some silicagel to school and the granules changed from red to blue or vice-versa.
You even could dry them agai when we layed them on the central heating panels. It was like magic.

The tape Jasper mentioned, we call that tracing (perhaps the same word in English) and use it also to prevent that drains ices up in freezers.

The wire we install in the spacing is special made for that. The yuse it also in counters to prevent dawn on the glasses and sometimes around the gasket of a freezer door.

Around the door, we instal a diode between it (cheap transformer) so that it became not that really hot and the lifetime of the wire becomes almost unlimited.

GAsket or plastic, does't make that much difference I think.

And no Sir anymore, it's Peter.

chemi-cool
27-04-2004, 12:02 PM
hello Sir peter,

(I kind of like this combination)

not long ago when silica gel was the only substance used for liquid line driers.

a pain in the "under part" it was to change it.

to the issue, some italian manufacturers uses these heating stripes between the two glasses to keep the moisture away and also keep the inner glass dry as water from the air tend to condensate there.

chemi

frank
27-04-2004, 08:00 PM
Hi Peter

The word you were looking for is dew - where the moisture in the air trapped between the glass condenses due to the low temps.

In double glazing here in the UK the gap between the glass is normally filled with an inert gas such as argon so that no moisture is present - this is why it is called sealed unit glazing.

I really like your understanding of the english language :) and feel embarrased that I only speak one language (fridge of course) :D

baker
28-04-2004, 02:30 AM
Hi Peter

The word you were looking for is dew - where the moisture in the air trapped between the glass condenses due to the low temps.

In double glazing here in the UK the gap between the glass is normally filled with an inert gas such as argon so that no moisture is present - this is why it is called sealed unit glazing.

I really like your understanding of the english language :) and feel embarrased that I only speak one language (fridge of course) :D

Apparently SF6 is often used in double glazing when extra noise insulation is required. This potent greenhouse gas is being fazed out - I don't know what replacement gas will be used.

abbasi
29-04-2004, 05:51 AM
You made the double glass yourself?
That will give troubles Abassi.

Normal double glas (obligated to install in Belgium for new buildings) has a special perforated alu spacing profile betzeen the two glasses.
In that profile, they put silicagel in it and they quickly need the to seal the glass.
Once it's sealed, the silicagel will dry the spacing between the 2 glasses so that dawn (correct word?) is prevented.
The smallest leak between the 2 glasses will allways result in dawn between the glasses and the glass will become white on the inside.

I know this very well because my grandfather and later my uncle was a contractor of glass worker (my grandfather even made those very big , colourful glasses you often see in churches) and when my uncle took over the business, then double glasses were coming up in the then new buildings.

They made them all themselve and I often helped them.

I remember then that I took some silicagel to school and the granules changed from red to blue or vice-versa.
You even could dry them agai when we layed them on the central heating panels. It was like magic.

The tape Jasper mentioned, we call that tracing (perhaps the same word in English) and use it also to prevent that drains ices up in freezers.

The wire we install in the spacing is special made for that. The yuse it also in counters to prevent dawn on the glasses and sometimes around the gasket of a freezer door.

Around the door, we instal a diode between it (cheap transformer) so that it became not that really hot and the lifetime of the wire becomes almost unlimited.

GAsket or plastic, does't make that much difference I think.

And no Sir anymore, it's Peter.


Mr. PETER (i hope this sounds good :) )

I used perforated aluminum spacing with silica gel in it.

Actually problem arouse due to conduction through pillars.
I could only maintain temperature of 6 C instead of 0-4 C.

how can i counter temperature differential.

and 1 more thing

the word SIR was used as a respect for your knowledge else u may take it as a compliment lol ;)

Peter_1
30-04-2004, 07:11 PM
I used perforated aluminum spacing with silica gel in it.
Perfect, cant be done any better. You wont have condensation at the inside now.


Actually problem arouse due to conduction through pillars.
I could only maintain temperature of 6 C instead of 0-4 C. How can i counter temperature differential.

I think that problem will remain the same as long as you stay wit the actual design of the corner.

I know your problem. As you probably read in some threads, we often install cooling systems in vending trucks.
We once had a truck who sells gas roasted /grilled chickens and ribs.
We installed in that van two small cold rooms (0,7 x 1,2 x 2,3 m.) beside each other. The walls are made of special insulated (!?) car panels with a total thickness of 4 cm (5 mm wood, 30 mm PU and 5 mm wood)

The 1st room is beside the grills which are extremely hot. We dont have any problems to hold a temperature of 1C in that coldroom.
The 2nd is installed beside the 1st and has on the first sight a lower heat-load. As soon as the sun comes up and shines on the outer walls , the temperature rises and till noon, the temperature in that cabinet has reached 6C to 10C .
The only difference is that this 2nd room has a double door on the outside and the hinges are made of special U profiles they use on the doors of all standard (not refrigerated) trucks. The water was and still is leaking of the profile around the doors.
Because there was a discussion what was going wrong and whos fault it was, we asked someone with an infrared camera (Thermacam) to take a infrared picture of the outside of the doors.
Cause was immediately proved.
I will try to catch these pictures, perhaps that company still have them somewhere.


and 1 more thing the word SIR was used as a respect for your knowledge else u may take it as a compliment
Im flattered Abbasi but you know what we say here from all those high falling guys : if they have to go to the toilet, they also need to strap down their pants, sit down, do the job and wip of their , whatever grade they may have
When I was in the army 25 years ago , an officer of me said Never underestimate the enemy. Remember that every person you will meet in your live will in some way know something more then you or will be better then you in his specific speciality. Even if its just his character or can walk faster, is smarter, can see better.

So, I just have some experience that can be used in this group and Im not the person that will keep it for himself. Im glad I can share it with other enthusiastic eths like you are.

Attached some sketches I made.
1. is your corner profile. I think that problem cant be solved easily perhaps not at all. You have a massive and heat conductive connection between the in- and outdoor.
3. is how we have done it in the past. The outside corner was made in brushed stainless steel. There was a small heating wire inside I mentioned.
2 is one possible solution I see if you can make some modification on your existing corners
4 is another one but you dont see a gap of silicone on the outside and is an elegant solution