... permition,reasonable design, Power conservation by 25%.7.cold-rolled steel plate for shell,phosphating static spraying technique,pleasing shape,rustproof.8 ... permition,reasonable design, Power conservation by 25%.7.cold-rolled steel plate for shell,phosphating static spraying technique,pleasing shape,rustproof.8 ... : 8 hours defrost cycle. Roof installation dual discharge air cooler for cold storage