I had a major customer coming to ask me the reasons for certain settings that we used on their supermarket refrigeration system controls. i was totally stumped and could only reply that was the market norm...

Anyway, the questions he posed me were:

1. What is the basis behind the temperature settings for frozen food (currently using -20oC to -18oC)? Is there any guidelines from any organization which states that certain food have to be kpet at certain temperature?

2. Why 4 defrost cycles a day? I know that countries with lower humidity are using 2 to 3 defrost a day. But being in Singapore (read HOT AND HUMID), we have even up to 5 defrost a day. Again, is there any guidlines for this?

So, Can anyone here please help me before my customer comes up with more questions to torment me??

Thank you.