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monsker
07-04-2006, 08:24 AM
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.

coolman
07-04-2006, 08:16 PM
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.

The temperature at wich food has to be preserved is usually on the pakkage this is usualy the maximum temperature at wich it is safe to sell the food up till maximum selling date wich is also on the pakkaging.

Defrost is usually prescribed by the manufacturer of the equipment at a certain temperature and relative humidity.
Normally we start of with these settings and depending on the situation give less or more defrost periods to obtain maximum efficiency.

regards Victor

chillin out
07-04-2006, 08:20 PM
Victor said it all,

Temp is set to whatever product dictates (-18 to -20 is ok ice cream should be a little colder)

Defrost should be set up to the individual circumstances.

Chillin:) :)

US Iceman
07-04-2006, 09:29 PM
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 guidelines for this?

The US display cases I am familiar with are designed for a certain inside space temperature and humidity. The case cooling capacity and subsequent defrost times (frequency and duration) are determined by this set of conditions.

If the defrost frequency or durations exceeds the norm (what the cases were designed for), perhaps you should investigate the air conditioning system for the store also.

If you can remove the humidity with air conditioning equipment it is much cheaper than using the refrigeration system. Less defrosts and less run time for the compressors. A Win-Win situation.

chillin out
07-04-2006, 10:02 PM
oooo moderator...

Congrats on the promo.

Chillin:) :)

US Iceman
07-04-2006, 10:44 PM
Thanks Chillin.

Now if I can only find a superb avatar like yours.

My eyes hurt... :p

tonydeith
07-04-2006, 11:24 PM
Hi monsker


Usually case temps are dictated by either EHO (enviromental health) or product specs. If a major supermarket retailer they generally have their own specs for setting ht or lt cases.

Defrost settings for cases are normally recomended by the case manufacturer, unless ambient surroundings dictate otherwise, but we try to keep to the customer/manufacturer specs.


Regards

Tony.:)

Dan
08-04-2006, 02:12 AM
Hi, Monsker.
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?

Regarding defrosts, the most common mistake is increasing the frequency of defrosts when you should simply be increasing the duration of the defrost. If you are fighting the problem of evaporators icing up, you have a duration problem. If you are seeing the product warming up before the next defrost, you have a frequency problem.

I am in Tampa, Fl which is also hot and humid. We can get by with only one defrost in a frozen food glass door case and in the single deck frozen food cases often referred to as "islands" or "coffin" cases.

We have many walk-in freezers operating with only 2 defrosts per day. To say it in different words:

If you are experiencing a diminished air flow where the product becomes warmer, and you see a heavily frosted (snowy) evaporator, you should increase the frequency of defrost.

If you are experiencing a diminished air flow where the product becomes warmer, and you see an iced-up evaporator (refrozen frost), you should lengthen the duration of the defrost.

monsker
10-04-2006, 02:18 AM
Hi guys,

Thank you so much for all your replies and help you have given me. I truly appreciate it.

These information will certainly prove useful when i meet up with my clien again. Once again Thank you.

But if there are any new information, i definitely wouldn't mind more of them! :)