FREEZER CALCULATION for STRONG USERS

Hello,

I Have a Freezer room, (-18) 125m X 48m X 12m Height

There is only one automatic fast door opening 300times/week 4m X 3m

the are outside the door has always 20C and the freezer always -18C

The isolation is polyurethan Panel 23cm

How can i calculate the looses because of the door ?

ASHRAE provides an air exchange method for an open door.

Moisture ingress is more important than the heat ingress

Why not install air curtain on the inside of the door?
It will eliminate the cold air from going out and keep the moisture out.