capacity rating for freezer

i would like to know watts/m2 or m3 for freezer design, the room is 1.5m x 1.1m x 2.3m high =3.8m3 have been told 1600w .does it make a big difference to the capacity if only 3" styrofoam panels are used? is 421w/m3 high usage enough capacity mainky storing pre frozen products (frozen chips etc) and about the only thing not frozen when it goes in is bread. also keep in mind high ambients lately here in australia 40+c does this make a difference to rating?

icemakerman.

1.temp for freezer application is typically from -18C to -23C.
2.you can use 4inch P.U.panel the above temperature.3inch polysterne not design for freezer application.
3.one good reference for refrigeration calculation is chandler refrigeration engineering manual,for capacity ratings.

regards,