Any one built a low temp (-25F) walk-in freezer using Icynene or poly foam? Issues are framing, thermal breaks, condensation, etc.
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Any one built a low temp (-25F) walk-in freezer using Icynene or poly foam? Issues are framing, thermal breaks, condensation, etc.
I just signed on to this forum to ask the same question.
I am looking to build a fairly large freezer. What is the downside to using the polyeurthane spray foam sandwiched between two metal skins? Seems to me the same as those panels only cheaper.
Hi,
I'm also new to this forum. Maybe this can help.
Normally prefabricated panels are used for good results. If you are trying to make your own 'sandwich' panels then it's a bit tricky. Proper panel joints, straight or angled, leaks, etc, are all quite difficult if you don't have proper tools.
Ham Bone, in my experience spray foam is not a good idea for a sandwich panel. You have to use liquid mixture, but still you need to be careful to avoid trapped air.
If the intent is to erect a structure for below freezing temperatures you only have two real alternatives; using premanufactured and insulated metal panels, or, to use prefabricated concrete, insulated panels.
The concrete option is used for very large structures and offers an additional advantage. The higher mass of the concrete walls slows down the heat gain into the freezer. When the sun is hitting the wall during the afternoon hours, the heat does not reach the inside of the freezer until after the sun has almost set.
In effect, you are using the concrete as a thermal mass to mitigate the heat transmission rate into the freezer. The net impact is the refrigeration load does not reach a peak as fast, or as high as it will with metal insulated panels.
Any and all joints have to be very carefully sealed to prevent moisture intrusion or air. Thermal breaks are very important at the ceiling and wall to floor interface.
The floors should be concrete with sufficient insulation under the concrete. A floor warming system is required to prevent the floor from frost-heaving. The floor warming system usually consists of flexible plastic piping installed under the floor. A warm glycol is circulated through the tubing to keep the floor slightly warm.
A freezer structure is not a home build idea if you want any chance of success.;)
Dan, Ham, also a good day to you;)
The largest one we ever built was +/- 150 x 100 x 30 ft
We're installing in April a freezer walk-in in The Netherlands of 18 x 18 x 12 ft with a concrete floor.
The only reason I can see to use on site spray foam construction is to save money. This must be a small freezer you are thinking of, a large freezer would cost a fortune in labour to foam blow on site.Quote:
Originally Posted by Dan McMahon
In general the more labour that can be done on large scale production floor the less the end product will cost, peolpe do not invest in large machines and production processes unless their is a reason. Cost effeciency is the reason:)
If you site blow your cold store the quality will be lower than a factory and you will not have a fire rating.
Two good reasons for not getting insurance. No insurance and companies can not use your cold store and you cannot store product, unless you are rich enough to self insure, but if you were that wealthy you would not be building home made cold stores:D
Buy the panels after checking with your insurance company and what they want (may require a bit of negotiation) shop around for a price and hire in a good team to install the panels, (check their previous jobs)
The panel market is extremely competitive, some companys are pulling out of the food market, simply becase they can't make money.
If you have ever seen frost heave you will know why proper construction is important. I have seen whole walls 200' long pushed more than 6" just because moisture penetrated the vapour barrier and I have heard of a floor lifting 3' in the middle and pushing the racks through the ceiling, simply because the under floor heating went off
Enough said I think:confused:
Kind Regards Andy.:)
why would you need a freezer in the Netherlands, i thought it snowed over there permenantly.brrrrrrr.:cool:Quote:
Originally Posted by Peter_1
Quote:
Buy the panels after checking with your insurance company and what they want (may require a bit of negotiation) shop around for a price and hire in a good team to install the panels, (check their previous jobs)
Good point. after the collapse of a burning coldstore on the fire brigade about 12 or 18 months ago the insurance of foam based rooms has rocketed in the uk.
Look once here http://www.refrigeration-engineer.co...ead.php?t=2981Quote:
Originally Posted by Andy
Euhhh...the Netherlands aren't somewhere in the Artic Circle, you know.Quote:
Originally Posted by slingblade
Mean temperatures are warmer then where you live.
my mistake, i was thinking of sweden.
We are currently building a 60'x48'x21' subzero freezer here in KY. This is the third unit we have built w/o issue. We do not use the floor warming system stated above, but insteal raise the freezer above grade several feet and install an array of vent tubes above grade that go the entire width of the building allowing for heat conduction through the soil and allowing for some thermal expansion.
I do have a question. With external units this size, we install steel substructures for snow loading and holding the building to the ground in high winds. We have always set soild oak blocks in the floor insulation which were anchored to the foundation/sub floor and then attached our ironwork to the blocks, in essence using the blocks as a structural member and thermal barrier.
Has anyone found a better way to secure inner framework to the ground without creating a thermal conduit?
put a steel frame around the outside anchor that to the ground?
Doesn't help with snow load, but it would help with keeping it down! lol. I have heard that someone is making polymer blocks to use instead of wood, but I have yet to find the manufacturer. Just thought someone may have ran across something. We've considered making our own from UHMW PE...
I must add, Iceman and the others are correct... the only way to build a freezer is with pre-made materials, be it styrene/styrofoam panels or the precast concrete that is foam filled. Moisture control plays such a key roll in maintaining structure that it is not worth the chance of having voids in panels and joints. I have seen a roof torn loose from a wall because there was an ever so small air gap in the corner.. moisture came it, froze, expanded, and the process repeated until the structure came apart!
And then there is always the dreaded floor heave! We built a 20 below freezer for a local grocery supplier that was designed to have an access door to the adjacent building. Everything worked well for several years until they decided to turn the adjacent room into a cool room for sort and pack. This would not have been a problem, but the employees started leaving the dividing door open most of the time. It was not long until the floor in the cool room froze and its floor heaved and buckled! The freezer of course remained intact.
Besides moisture problems, insurance problems, and lack of thermal consistency, another issue to consider in the homemade vs pre-made panel is rigidity. A person can walk across an end supported 40' 6" pre-made panel without fear. Are you willing to do that with your homemade panel? There is a company now in Florida that is building premade house kits using 3" and 4" styrofoam panels that require no internal frame; they are totally self supporting!
In short, don't waste your time or effort trying to build your own panels. You can purchase panels, hardware, edging, and sealants for less than $7/ sq. ft.