Grocery Coolers/Freezers: Power

[Keri_WW]

I'm designing a grocery store which has the typical merchandising coolers and freezers strewn throughout the store. I'm slightly baffled at how to provide power for these things...

From what I can tell looking at the various cutsheets, they have evaporators, condensers, fluorescent lighting, door heaters, anti-sweat heaters, and fans. The owner is purchasing a used "condenser rack" from a Wal-Mart (houses a 480 main panel, step-down transformer, 208v panels, all of the condensers and evaporators, and various controls).

My best guess is to provide (1) floorbox for the 120v loads (lighting and fans), powered from one of the 208v panels in the rack. Is it ok to jump from unit to unit, or do I need to provide a circuit for each (loads aren't very large)? Should I also provide an empty floorbox with conduit back to the rack for connections to condenser/evaporator, or is this considered refrigeration piping and out of my scope?

What about disconnecting means? Do I need to have disconnects for the 120V being brought in? If so where do I put it... within site?

These designs have to be pretty common considering the number of grocery stores out there, so if any of you have experience in either designing or installing these systems, please help me! What is common practice?

Thanks,
Keri :grin::grin:

 

[iwire]

OK some generalizations here.

We don't bother with a floor box, run down the walls if you can or just stub a conduit up under the case and use flex from the stub to the case junction box.

The case lights, fans, and anti condensate heaters are not run from the rack power.

Generally you will run a switched circuit for the lighting and that can jump to as many cases as the current of each allows.

The fans will be on a constant circuit and that circuit usually jumps case to case

The anti condensate heaters often run on another constant circuit but sometimes will be run through a controller for them that saves power.

You may have Defrost termination controls that run between cases and racks, often there are solenoids in the field that need to be wired.

The rack power will generally run the control circuits and the compressors.

Somewhere outside will be condenser fans and they may be powered from the rack or may just be controlled from the rack

I have to be honest this could be a nightmare if the owner is piecing this system together without a professional. There is so much to consider.

 

[iwire]

These designs have to be pretty common considering the number of grocery stores out there, so if any of you have experience in either designing or installing these systems, please help me!

To give you an idea, the stores I work on are single floor stores and often the prints run 20 to 26 pages. At least 6 or 8 of those will be just pages of details on refrigeration wiring.

 

[Keri_WW]

Bob,

Thanks for the info, very helpful! So for the fans and anti-condensate heaters, how do you take care of a disconnecting means?

I guess I wasn't clear enough when I said "rack". The owner purchased a large enclosure (44' x 7') that houses the low/high temperature racks, piping, controls, and a couple of panelboards and transformer. From their old cuts, they were pulling circuits from these panels to feed the lights, etc.

What size conduit would you typically run from the rack to a group of coolers/freezers for the refrigeration piping? I think at most we have 6 grouped together....

Thanks,
Keri

 

[augie47]

Congratulations. I think you have taken the step beyond "used restarurant equipment" . I hope it's a T&M job,

 

[iwire]

I have never seen all the power pulled from the racks but anything is possible. If you have frozen food cases often they use electric defrost elements in them and that power often comes directly from the racks. Often 12' of frozen food case would require a 30 amp 3 phase 208 volt circuit for electric defrosting.

As far as circuiting, the lights and fans are small loads but that does not mean you want to load them up to the max. If they lose the fans they lose the product so you don't want a problem in one case to take down all the circuits.

The way I see it done is the electrical circuits are broken up to match the refrigeration circuits.

So if refrigeration circuit 'A1' is a meat display made up of 4 or 5 cases one fan circuit will feed that group of cases. One lighting circuit will feed that group, etc.

We run no less then 3/4" to a single case and if it is a long line up it will be multiple runs of 3/4" or 1".


We do not install disconnects at the cases. The lights are not required to have a disconnecting means and the fans are individually cord and plug connected.

The anti condensate heaters that may actually be a problem.


Here is a typical refrigeration rack.

 

[iwire]

Congratulations. I think you have taken the step beyond "used restarurant equipment" . I hope it's a T&M job,

LOL you got that nailed, getting these stores up and running with all new matched equipment it a fun challenge.

Getting a hodge podge of used equipment up and running would be very tough.

 

[peter d]

I have never seen all the power pulled from the racks but anything is possible.

You probably know better than me, but I'm pretty sure WalMart has one or two prefabs on the roof that takes care of all the refrigeration cases in that part of the store. Not sure how the prefab is set up but it looks like that's what this customer has purchased. So, this prefab is set-up for WalMart's needs..it might be difficult to make it work for anything else without major modification.

 

[iwire]

You probably know better than me, but I'm pretty sure WalMart has one or two prefabs on the roof that takes care of all the refrigeration cases in that part of the store. Not sure how the prefab is set up but it looks like that's what this customer has purchased. So, this prefab is set-up for WalMart's needs..it might be difficult to make it work for anything else without major modification.

I have actually not worked in a super Walmart yet but I have no doubt they use prefabbed pods for the refrigeration.

My first thought when he said it was a used Walmart Rack was about the control system and if it came with the rack as part of the sale, if it has a program, can the program be modified? How badly hacked up is the wiring on it.

 

[peter d]

Is that Chugs cart in the background?

 

[Keri_WW]

We do not install disconnects at the cases. The lights are not required to have a disconnecting means and the fans are individually cord and plug connected.

The anti condensate heaters that may actually be a problem.

The Hussman RL 3Dr and 5Dr freezer cuts that I have list an MCA and MOCP for the fans and anti-sweat heaters together. Its high enough to where you wouldn't put more than one on a 20A circuit. If I wanted to combine them into one circuit, I'd need a larger breaker, but wouldn't I also need a disconnecting means for each piece? I'm slightly confused on this aspect!

I'm worried that if I just show a couple homeruns from the freezers for all of the required loads, that it won't pass when it goes through review.

Thanks again for the help and tips
Keri :grin::grin:

 

[Fulthrotl]

OK some generalizations here.

We don't bother with a floor box, run down the walls if you can or just stub a conduit up under the case and use flex from the stub to the case junction box.

The case lights, fans, and anti condensate heaters are not run from the rack power.

Generally you will run a switched circuit for the lighting and that can jump to as many cases as the current of each allows.

The fans will be on a constant circuit and that circuit usually jumps case to case

The anti condensate heaters often run on another constant circuit but sometimes will be run through a controller for them that saves power.

You may have Defrost termination controls that run between cases and racks, often there are solenoids in the field that need to be wired.

The rack power will generally run the control circuits and the compressors.

Somewhere outside will be condenser fans and they may be powered from the rack or may just be controlled from the rack

I have to be honest this could be a nightmare if the owner is piecing this system together without a professional. There is so much to consider.

i never did that much of the new grocery store dance, and it looks like bob
sure has, and having it all spelled out like this makes me remember why my
head hurt trying to relocate a gondola case in a store once...

if you are at the design from the ground up stage, consider avoiding putting
conduits between cases, for common loads if at all possible. if you have
conduits from each location back to your chiller room, and at some point
the store configuration changes, or you eliminate a case, or you have to
troubleshoot, it's one thing.... otherwise, those feed thru conduits going
here, there, and everywhere, are not your friend.

i moved a microbrewery once, and all the schematics were in german....
and it was ok, as long as you could be the one doing the tagging,
photographing, and disconnecting... but if the equipment just shows up
on a skid, cut with a sawzall from whatever building it came from, i'd just
want to run and hide.

but this..... just reading it gives me a contact headache.... :smile:
good luck to you on this one.... it doesn't sound like much fun.

 

[peter d]

i never did that much of the new grocery store dance, and it looks like bob
sure has, and having it all spelled out like this makes me remember why my
head hurt trying to relocate a gondola case in a store once...

A few years back myself, Iwire, and 7 other guys had to do an emergency job at a supermarket. Floor stripper had made its way into walker duct for the produce cases and the wires shorted out.

One of the cases we refed by going overhead to the electric room and down a boxed-in column, and under the case. That was the one I was assigned to. I have to say my head was spinning making sure I kept track of all the circuits Bob mentioned earlier in the thread - multiple circuits each of constant power for fans, switched power for lights, constant power for receptacles, and 208 volt power for solenoid valves. You absolutely did not want to get any of those crossed up. Bob has a good story of a company that didn't keep track of stuff when they moved gondolas.

 

[K8MHZ]

I have actually not worked in a super Walmart yet but I have no doubt they use prefabbed pods for the refrigeration.

My first thought when he said it was a used Walmart Rack was about the control system and if it came with the rack as part of the sale, if it has a program, can the program be modified? How badly hacked up is the wiring on it.

I think they do, using Tyler designed equipment. The Meijer store I just finished did and there were some guys on the job talking about the WalMart they just did.

I totally agree with the statement about getting the system up and running. It is the norm for brand new equipment to have techs and specialists spend a few hours programming and de-bugging the system before it all can be rendered functional.

If the refrigeration equipment is not connected to a data bus along with the HVAC equipment you may have problems with wash out that will be a nightmare to correct. If you have several coffins on the same control loop and only one gets washed out, how do you correct for that?

How do you plan on testing equipment designed for air to flow around a full case of product, when you have no product? In short, while empty the cases may appear to be defective when in reality they are not.

Be especially aware of the many different configurations of defrost termination. Some use simple temp probes and a relay (DTR). Some use current sensors that feed information to the Einstein and then is controlled by said computer. Some use defrost termination switches that send either an on or an off signal back to the computer, which in turn controls the defrosters. Some cases are totally self contained and all that needs to be done is to run power for them. We had to deal with all of the above on a brand new installation at the Meijer store.

We had a brand new case catch fire, the anti sweat heater shorted out and spewed forth it's magic smoke the first time we turned it on. We had a case labeled for 208 that had 120 volt solenoids on it from the factory. More magic smoke.

We had panels both in the pre fab room and on our free standing units with incorrect labels on them.

Wiring up a decent sized computer controlled refrigeration system NEW isn't for your average rope puller. I wouldn't attempt using used equipment before going start to finish on at least one new installation.

 

[Kba-rapc]

As a retired owner of a mechanical service company, I had at least 15 years experience working on Wal-Mart and Sam's equipment. Their systems, at least the ones we serviced, are a little different than the one shown in the picture and all we saw used Carlyle compressors. If you have one of their typical rack houses, there is no wiring interconnecting the actual rack and the refrigerated cases such as defrost wiring, fans, lights, terminations, etc. All of these functions are controlled by the Novar controller, mounted on each individual rack with sensors located in each refg. circuit (1 per case with 1 per circuit being designated as the master to control defrost, temp, etc and the others just monitor temp). All of their rack houses had all of the breaker panels factory installed in them for all fans, lights, anti-sweats, defrost, etc. Defrost contactors are energized from a relay located on a computer board which is located towards the right end of each individual rack wiring panel.