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Gally
31-08-2012, 01:03 PM
Hi all I am an apprentice and in the progress of my 3rd year block of tafe. My teacher has handed out an assignment to do a report on supermarket cabinets and cases, as I only work on air-conditioning I am finding this a rather difficult task.

He has given the following topics to cover:
1. Meat display case
2. Fruit and vegetable display case
2. Dairy display case
4. Jumbo freezer
5. Reach-in freezer cabinet
6. Reach-in refrigerator cabinet
7. Deli display case

I am doing a description on the construction of the cases eg open/closed, single deck, triple deck etc, this part it straight forward.

There are certain topics he would like us to cover:
1.product storage type,temperature/humidity/air velocity
In this section I am covering the storage temps for the products, what the humidity should be for the product and the fan speed (lower or higher fan speed to suit the humidity for the product) straight forward.

2. Method of controlling temp in case/cabinet
This section I am having trouble finding information for, for what I have found and just using my head each case/cabinet could use either pump down, LP, EPR, solenoid valve and probe, depending of the manufacture's design am right? although there would be certain cabinets that would not use certain valves for such a reason?


3. Complete details of method of defrost including, type of defrost, fan operation during defrost and typical defrost initiation and termination.

This section is much he same for me as section 2, I have been able to find some pretty good info (in my text books) on types of defrost and fan operation but no info on what methods would be used on what case.

If anyone could help out and share some of the knowledge/experiences picked up over the years or if anyone has any good information that could help me out with the topics I am having trouble with, it would be much appreciated?

I have spent some time now browsing Google for information and most of it is trying to sell products. (not much help)

Rob White
31-08-2012, 01:28 PM
.

Most of us will be willing to help.

You have been honest and you are doing the correct thing.

What I would suggest is you give specific details on areas you
are struggling with and then the guys from here will feed back to
you and offer advise as you require it.

Regards

Rob

.

THE DUDE
31-08-2012, 11:55 PM
When I was getting started I purchased a used ASHRAE Refrigeration Handbook. That was a VERY good investment for me as I still reference it 14 yrs later. It covers a large range of info, but most of what you need should be in there.

Done it all
11-09-2012, 09:43 AM
Humidity is not really an issue except for produce or service cabinets where products arent packaged. Google for humidity/ temp requirements for fresh products.
Most supermarket cabinets are on a rack system and use solenoids on liquid line to pump down, temp is controlled on supply air. Off cycle defrost is normal except for freezers or sometimes meat cabinets. EPR is used where evap temp needs to be specific due to humidity or cabinet design specs.
In open cabinets fans on for defrost, in rooms or glass door cabinets fans off.
This is quick answer to long question. Try going to a local company who works on this stuff for more detailed info.