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Feeze
14-04-2005, 02:07 PM
Hi all,
I have been quoted for freezer room panels by 2 different suppliers.Their prices are about the same.
Supplier A offered polyurethane panels 80mm thick and
supplier B offered polystyrene 60DV 150mm thick.
The room is to be used as a holding room for frozen chicken,
room temperature -18deg c.
Room size 18*14*7m high.
A foglift will be used in the room.
A concrete floor with polyurethane 80 mm for the polyurethane room or alternatively a polystyrene insulation of 150mm 24DV for the polystyrene room.
What are the pros and cons of the 2 different rooms

chemi-cool
14-04-2005, 03:48 PM
Hi Feeze.

SA is a hot place like Israel. You will need for this temp, at least 150MM walls.

The difference is in the heat conductivity and strength.
Polyurethane panels are made in a different way, the mixture is being poured into the space of the two metal sheets and the whole thing is under high pressure to hold it from expation.

Polystyrene is simply two metal sheets glued to it under pressure.

Heat transfer wise, polyurethane is much better.
For the room size you have discribed you will need an outside steel constuction to hold it.

We only use the polystyrene fo temps above 0c and insulated roofs.

Chemi :)

SNi
15-04-2005, 06:32 AM
Hi Freeze

In you place i would use only PPU panels with thickness 150-170mm. otherwise condensate can appear outside.
In Russia average temperature in summertime +32C (+35C for south) we always use PPU-150mm. panels for outdoor freezer stores & rooms.

Feeze
18-04-2005, 07:53 AM
I have been told that polyurethane panels of 80mm thickness is equivalent in insulation to polystyrene of 150mm.
If this is the case then it should not be a problem to use the polyurethane 80mm or am I missing something?
Polyurethane panels have a tendency to become saturated with water if the panels are not well sealed.
Polystyrene panels have the problem where rats burrow into them and build a nest if they are not well sealed.
Are there any other comments that will help me make an informed decision as to which panel I should choose?
Note these rooms are to be erected in a warehouse so the roof panels will will be supported by hanging cables and the freezer room floor will be the same level as the outside floor.
Maximum summer temp 34 deg c, average summer temp 28deg c.
Thanks,
Feeze

SNi
18-04-2005, 12:20 PM
In my previous message i told about freezer stores which located on open air.
In my opinion you should use polyurethane panels, but thickness 100mm. seems more suitable for your case than 80mm.
Polyurethane panels have water absorbance in 100% relative humidity a maximum of 0.2 volume percent. You can also use butyl mastic as moisture barrier for the outer edge of the joints.

Feeze
19-04-2005, 07:08 AM
In my previous message i told about freezer stores which located on open air.
In my opinion you should use polyurethane panels, but thickness 100mm. seems more suitable for your case than 80mm.
Polyurethane panels have water absorbance in 100% relative humidity a maximum of 0.2 volume percent. You can also use butyl mastic as moisture barrier for the outer edge of the joints.
SNi,
Thanks for replying.
Why have you opted for polyurethane?
Why do you you suggest 100mm instead of 80mm, is it because of higher strenght for the height or because of better insulation or both?
The thicker insulation will bring the price up.
Cheers,
Feeze.

PobodysNerfect
20-04-2005, 02:51 AM
Freeze,

In my opinion 80 mm polyurethane is way to little. Have you done any calculation of operation cost with different insulation thickness?

Some prefer polystyrene in the floor due to the compression creeping factor.

What do you intent to do to prevent frost heave?

Regards,

Jan

Servicefrigo
20-04-2005, 05:32 AM
Hay
If you chose a thickness 150 mm poliurethane you will win a customer or more. The size of equipment wil be much smaller and the total costs also.
Calculate your self.

SNi
20-04-2005, 08:15 AM
Hi Freeze
I use polyurethane panels because company where i work produces polyurethane panels & doors, so i don`t have choice :)
I think that difference between heat loss through panels of 100mm. thickness & panels of 80mm. thickness would be around 15% or something like that, you can easily check it:
K-value for panels of 100mm. thickness is 0.22W/m2K
K-value for panels of 80mm. thickness is 0.28W/m2K
Maybe this difference will allow you to use smaller compressor, condenser, evaporator and reduce the energy cost.
Polyurethane panels of any thickness are not strenght enough to hold the load (and polystyrene panels too) so you should made for your room framework or fix wall insulation panels to existent walls.

Peter_1
21-04-2005, 08:34 PM
Hay
If you chose a thickness 150 mm poliurethane you will win a customer or more. The size of equipment wil be much smaller and the total costs also.
Calculate your self.
Much smaller??? No... some milliwatts :p

Servicefrigo
22-04-2005, 05:58 AM
Peter1

This time I don*t beleve you.How about the maintenace,energy cost after instalation.You can explain all benefitts to the owner and I am sure he will chose a bigger thicknes.