Defrost in supermarkets

[bernard]

Hi all

I am interested in what systems supermarkets use and what types of defrost is most common gas or elec.

Can someone also explain how the gas defrost works and what would you most commonly find in tescos

Or if you could pass on any links to web sites regarding supermarket refrigeration

Many thanks

Bernard

[Mark]

Hi

HT cases (0-3) say mostly use off cycle defrost by cycling LLSV off for a predetermined air temperature or coil temperature or time.(depends on software used)
LT cases (-18 - -25) say use electric defrost methods by means of finned or rod type heaters.(depends on software used)
Hot gas defrost uses discharge gas from pack to defrost,saturated gas defrost uses gas from the top of the reciever(full explanation/discussion of sat gas defrost in supermarket forum).
The prefered method being electric defrost less controls,less wiring installation times cut,commissioning time less turnover of store quicker .
I cant speak about all tescos equiptment they like many other stores in the supermarket arena have and will continue to use a method which maximizes profits and keep breakdowns to the minimum.

Best regards Mark

[bernard]

Hi Mark

I am familiar with the elec and hot gas its the sat/gas I need more info on.As you suggested I,ll search the forum.

Regards Bernard

[chemi-cool]

hi guys,

an interesting paper about supermarket refrigeration and defrost systems.

http://www.ornl.gov/sci/engineering_...per_Vasile.pdf

chemi

[Mark]

Hi Bernard

Most sat gas sites have been refitted. There are a few about

Best regards Mark

[Mark]

Hi chemi

How are you finding the supermarket work.....ok?

Best regards

Mark

[chemi-cool]

hi mark.

to be honest, I didnt get there yet. too much work in one rubber factory

700KW trane chillers with a lot of problems. hope to finish it in a couple of days and get to the supermarket.

I will post a picture of the place when I get there.

chemi

[Mark]

Ok chemi

Have fun.

Mark

[Andrew Pribora]

Hi, all

we in Russia use electric defrost in SM - everywhere! for Plus Temp and Low Temp Cases.

BR

Andrew

[NIKO]

Dear Bernard,

for what concerns Belgium (DELHAIZE, CARREFOUR):
It used to be electric defrost as of cabinet temperature of 0°C down to -25°C, with fixed defrost hours (eg : 1.00; 07.00; 12.00; 20.00). This to make sure that no defrosts were activated during the opening hours of the supermarket.
Nowdays electric defrost is still the most common method but since the controllers have been evolving quite rapidly these last years, defrosts are monitored much more closely and activated only when absolutely necesarry !

Niko

[chemi-cool]

hi niko,

do you have experience with Dixell i-chill?


chemi

[NIKO]

Sorry Chemi, but I don't know the Ichill instruments from Dixell. However I took the time to download some doc from the internet and it seems like a basic chiller controller to me...

What's the problem ?

I do know DIXELL well though. I used to be the first distributor outside Italy for their products. As you might know the founders of Dixell are ex-ELIWELL people and I still know them quite well. To be honest, from a technology point of view, they have been quite advanced since they started about 7 years ago (the company was still called SAE at that time).

Bye,
Niko