Best Overall Supermarket Refrigeration System

[Coorsman777]

I need some opinions..

What do you feel is the best way to design a super market system? I need to compare price of purchase and install. Cost of energy to operate. Cost to maintain. Complexity to perform repairs. Carbon footprint.

Currently we use a centralized DX system with R-507 which has been working great for us for the past 10 plus years and had a very low cost of ownership. But with things being what they are and high GWP rating of this gas and the possibility looming of a tax on GWP rating here is the US I need to explore other options. I know all my European, aussie and NZ friends on here have plenty of experience with F-gas regs.

I'd like to hear comments on 407 systems, secondary glycol and CO2. DX loop systems CO2 and F-gas.

I need info to present to my company's ownership and get their direction and which way we would like to proceed in the future and any opinions on here are greatly appreciated.

I am hoping this is a good conversation starter with a bunch of opinions.

Thanks

[RONB]

Hi Coorsman
Here in the UK the various supermarket chains have adopted a lot of differing systems.
We have transcritical Co2 DX systems,subcritical Co2 DX systems, which are cascaded with either 404a,407a or 407f. Some are using pumped liquid Co2 with a 400 series refrigerant to cool the Co2 through a plate heat exchanger or similar. Some are using integral cases with PHE condensers with a dry air glycol condensing medium. We also have a lot of 400 series DX systems in use as well.

[Coorsman777]

Hi Coorsman
Here in the UK the various supermarket chains have adopted a lot of differing systems.
We have transcritical Co2 DX systems,subcritical Co2 DX systems, which are cascaded with either 404a,407a or 407f. Some are using pumped liquid Co2 with a 400 series refrigerant to cool the Co2 through a plate heat exchanger or similar. Some are using integral cases with PHE condensers with a dry air glycol condensing medium. We also have a lot of 400 series DX systems in use as well.

Thanks for the reply.

Which one of these options would you recommend?

[RONB]

They all have their pluses and minuses. The transcrit /subcrit systems especially on LT are a lot cheaper to run as they use a lot smaller compressor. The Co2 is more " environmently" thought of,but the very high operating pressures can be a problem. There are no so called short cuts in the servicing of these plants as they will bite back if not treated with respect. A few of the UK major supermarkets are using Co2. Some are full Co2 (HT & LT) ,some are 400 series HT and Co2 LT,the others are as I said in my previous reply. The integrals on HC gases with PHE condensers are also being used but HC gases have their own inherent problems e.g a Big Bang ! At the end of the day it is always up to the end user as to what kind of system is used. But until something better comes along I think Co2 is probably the one to go for.

[Tesla]

It is possible to reduce the carbon foot print to zero. They could build the shopping area underground with car parking at ground level and solar panels to shade the cars and ground. The low temp stock in the centre of the floor and med temp around the low temp. Supermarkets also need to look at using oil less compressors as the oil costs on efficiency. The cabnets have not advanced in years compared to ac applications. Just a few ideas there.

[Magoo]

Roof top mounted multi temp.. ammonia glycol systems with absolute minimal ammonia charge. Not difficult at all. The current CO2 multi what ever systems are aload of old rubbish generated by equipment suppliers and refrigerant manufacturers. If you were a manufacturer of a semi hermetic, you would balls out to design an overly complicate multi gas system to sell your compressors and added complex crap

[Magoo]

I have to think sometimes with all the global crap etc., and major manufactures of AC equipment are pumping out all this VRf Vr what ever refrigerant systems, like truck loads of refrigerant in circultion in a simple bleedin'air con system. Have they actually heard of or at least considered WATER or even GLYCOL as a secondary refrigerant and minimizing actual refrigerant charges.,we as an industry just go along with the flow and whinge constantly about everything ferbatum but clip the ticket in the process, the "who cares about the next generation syndrom policy ", continues. I really like and love my children and at my age grand children and would like to think that when I cark it that I leave some sort of a reasonable place to live.
Time to wake up people as an industry, driven by us, not the friggen conglomerates and corporations.
grump session is now over.

[Grizzly]

Bad Hair Day, Magoo?
I was day dreaming whilst driving the other day on a similar veign.
Who challenges the more ridiculous decisions made in the name of health and safety?
If not us!
(Good point all the same.)
Grizzly

[RONB]

I haven't done much AC work for a few years but even so the end user still holds all the aces. A chilled water/ glycol system may be more expensive on initial install and subsequent maintenance with pumps,pipe work,specialist lagging etc and you are still using a refrigeration system with a slightly less refrigerant charge to chill the water. A VRV/VRF is probably a much easier system to install and maintain and maybe somewhat cheaper to install as well, but on a large building the refrigerant charge is going to be greater than on a chilled water system and as I have said at the beginning of the reply it is still up to the end user as to what the type of system they want. And nine times out of ten it will be the cheapest option that will win. If we want to leave a world worth living in we are at the mercy of the man who is paying the bill at the end of the day.

[cadwaladr]

so with all the big bang /high pressure best to build the supermarkets miles away from houses,so we can use lots of fuel to get there! oh but not to worry we can fill up when we are there plus get as many loyalty points so can do it all again fantastic!!!!!!!!!

[RONB]

That's the thing about the green issue one fairly good solution is always cancelled out by another. Why don't we all just tell them to shut all the supermarkets, let every one cook in their high rise offices, and open a window if they are hot. Lets go back 100 years and live off the land,give our gas guzzlers up and all die at 50 from TB!!!!!! Nothing in life is perfect and sometimes something has to give.

[cadwaladr]

well my mum + dad did that lived thru ww2,and smoked drank ,dad grew veg + stuff on his allotment mum had 11 kids and died at 96 and could still go to the toilet on her own,walking was tough in her later years what a pity there was not a supermarket around in her time she would have lived forever,if your theory was right i could not answer,look to the east my friend and see how long people live without tesco+friends!!!!!!!!!!!!!!!!!!!!!!1

[cadwaladr]

the term green,hard to describe but progress is not always described as beneficial to all,rant over wheres my r12 lol.

[THE DUDE]

R-744 is showing up at a slow pace in the U.S. but I think it will be big in the future with Carbon Tax,GWP and who knows what else is on the Horizon. R-744 is a Safe bet for avoiding future issues but Cost is obviously a consern. Most major MFG's in the U.S. have products for R-744 now and more on the way. The Advansor CompSuper looks like a Solid System.
But for now here are some things I would look at
* Racks (in a machine house) centrally located with a lower GWP HFC like a 407 Series
* Common loop Piping on non HG racks
* A Microchannel Condenser
* Surge Receiver
* Secondary System for the MT with a Fluid Cooler for Low ambient climates
* Condensing Units for W.I. Boxes located far from the Racks
Or
* Frozen H2O ( R-718) as this will be the only Refrigerant we will be able to use in few years due to all the Bureaucratic nonsense.:D

[750 Valve]

I disagree with quite a few here in relation to Co2, the sub critical systems are really simple - I can't for the life of me fathom the criticism of these systems - they could't get any simpler.

If it were my store I'd have a liquid recirc Co2 system for MT/HT, DX Co2 for LT with an Ammonia high stage system in a container on the roof. I see this as a pretty good trade off between energy efficiency, reduction of environmental impact and reduction of refrigerant cost. If I had to I'd trade the R717 high stage for a more traditional refrigerant and go with R407F (definitely not R134a!).

[RONB]

A few years ago 404a was supposed to be the business. Now that's getting very bad press and is going to be phased out due to its GWP. How long before someone comes along and says 407a/f have to go the same way.What will we be using to cascade subcritical systems with then? HC gases. I think transcrit Co2 is the only long term option available at the present time,and all engineers will have to be retrained in the operating and servicing of these plants they have their own inherent problems as well .

[Coorsman777]

It seems that we here in the states are about 10 to 15 years behind Europe and Aus on the green refrigeration. I am just trying to identify what the best next step to recommend to my company is. I believe the CO2 transcritical would be the best option but I do not this the climate here makes it viable. We average around 1500 hours above 70F. I am thinking the CO2 cascade would be the best option but I also think it may be cost prohibitive also. I also have a tough time moving towards a system that will use excess energy as I believe a secondary will. Thank you all for the valuable info on this.

[chillerman2006]

I have to think sometimes with all the global crap etc., and major manufactures of AC equipment are pumping out all this VRf Vr what ever refrigerant systems, like truck loads of refrigerant in circultion in a simple bleedin'air con system. Have they actually heard of or at least considered WATER or even GLYCOL as a secondary refrigerant and minimizing actual refrigerant charges.,we as an industry just go along with the flow and whinge constantly about everything ferbatum but clip the ticket in the process, the "who cares about the next generation syndrom policy ", continues. I really like and love my children and at my age grand children and would like to think that when I cark it that I leave some sort of a reasonable place to live.
Time to wake up people as an industry, driven by us, not the friggen conglomerates and corporations.
grump session is now over.

very well put Mr Magoo

R's chillerman

[chillerman2006]

It is possible to reduce the carbon foot print to zero. They could build the shopping area underground with car parking at ground level and solar panels to shade the cars and ground. The low temp stock in the centre of the floor and med temp around the low temp. Supermarkets also need to look at using oil less compressors as the oil costs on efficiency. The cabnets have not advanced in years compared to ac applications. Just a few ideas there.

some good points mate

R's chillerman

[al]

Display cases should be full glass door, look at using back load cold rooms with doors?

Packs, use what is currently freely available, yes CO2 is probably going to be a large part of the future, but if you blaze a trail will the cost of investment in training and R&D give a reasonable payback? (given that CO2 etc is pretty mainstream in the UK, there has been very little takeup here), standard recip based packs on 404a make up (in my experience) most of the stock here.

Whatever you install, put your energies into making it leak free!

al

[Silhouette]

As a commissioning engineer working with most of the major supermarkets here in the UK, I would go for the Advansor Compsuper system on Co2. It's a DX system, transcritical booster pack, having used these for the past two years I can say that it is one of the simplest systems I have worked on using R744.

Hope this helps!
Mel.

[cold.man]

I must agree I spend alot of time working with CO2 packs Advansor and SCM. I have found the Advansor packs alot better we have alot less issues with these compared to the SCM. Its still hard to call what systems the supermarkets will be going for in the next 5 years, will be interesting to see which way they go.

[Coorsman777]

Just got my first quote back for a R407A system versus our typical R507 system. The system cost increase from 507 to 407A is almost 10% not to mention 407A is 20% more per pound. But atleast with a 407A system the utility bill will be more expensive. Going "green" seems like it financially makes sense......

[crackertech]

We are getting our first co2 store this year.:D

[THE DUDE]

[QUOTE=Coorsman777;273418]Just got my first quote back for a R407A system versus our typical R507 system. The system cost increase from 507 to 407A is almost 10% not to mention 407A is 20% more per pound. But atleast with a 407A system the utility bill will be more expensive. Going "green" seems like it financially makes sense......[/QUOTE
Thanks for going "Green" The Manufactures and Chemical Companys thank you too:o

[THE DUDE]

We are getting our first co2 store this year.:D
Do you know what type of R-744 it is? I would like to check out a Transcritical Booster system, None around MN yet.

[mad fridgie]

It would seem that you are all making the same mistake. As do most designers. All they can see it what is in front of them and what they been been sold.
The application determines the best design, in many case the equipment is chosen with out understanding the application.
So with a supermarket you need to know cooling and heat load profiles changes daily, weekly and yearly. Changes in ambient and and electrical and other energy tariffs.

[Silhouette]

Hi Mad Fridgie,
As always you are correct, but we were asked for our opinion on what we thought were the best supermarket systems! The supermarkets in the UK have been greatly concerned over the last few years regarding energy consumption, GWP, Carbon footprint etc. etc. and so the suppliers have had to prove their worth and design systems that do what they say they can. The supermarkets are very proactive at countercharging energy costs back to installers if the system does not come up with what they were expecting!!

[Silhouette]

Hi Coorsman777,
Advansor are now owned by Hill Phoenix and so will be rolling out equipment across the USA! I'm sure if you give them a call they can fill you in with any details you require.

[mad fridgie]

Hi Mad Fridgie,
As always you are correct, but we were asked for our opinion on what we thought were the best supermarket systems! The supermarkets in the UK have been greatly concerned over the last few years regarding energy consumption, GWP, Carbon footprint etc. etc. and so the suppliers have had to prove their worth and design systems that do what they say they can. The supermarkets are very proactive at countercharging energy costs back to installers if the system does not come up with what they were expecting!!

And there lies the problem, (I have recently had to reverse engineer many UK supermarket applications, so gained a bit more insight). Many methods improve but only minor, in the application field!

So lets go real left field for a moment. (but really is not left field)

Lets look at load, more during the day, less at night.
Ambient generally speaking higher higher during the day, lower at night.
Power price, higher during the day, lower at night.

So this leads to a thermal storage system, even though on a simple performance the efficiency is less than that of a DX system, but depending upon the difference on the above stats, is could be on average more efficient.

Tanking this a bit further, the thermal store could be within prep areas so all heat gains to the store are useful.

The cabinets could also be with an enclosed place, (part of the above), so again the losses/gain are contained.

What is the biggest load in supermarket refrigeration? Moisture!

So lets get rid of the DX coils, and have the air passing through the thermal fluid. The fluid will absorb the moisture. If the thermal store was a binary ice system, the excess water could be frozen out, and removed and be used for liquid sub cooling.
Of course no need for any defriost (medium temp).
The LT systems, could use the thermal store to cond, nothing to new in that. But the area in which there are held could be de-humidified, reducing frost load and defrost requirement.

Nothing new really, but very large savings (the refrigeration could be any of the refrigerants mentioned above, but would lean towards a small packaged NH3 plant)

[Coorsman777]

After some extensive research on this subject I have come to a conclusion. I weighed an R507 DX system versus a R407A DX system and a Co2 Cascade system with R407A highside. I compared the current install price and cost of equipment, energy costs to run and any possible tax implications. I used $.50(USD) per 100 GWP for tax on the refrigerant and $20(USD) per ton of CO2 and a 10% to 15% leak rate, which we easily meet each year. I have to honestly say that with those figures that the R507 DX system is still the best long term option. With the energy efficiency loss and extra cost to install it would take close to 20 years to pay for added cost of a CO2 system. Please let me know if any of my numbers seem off, but these are the amounts that have proposed is legislation.

[Tesla]

I like your ideas Mad
This would create a cooler space for the customers (and give the chicks fripples) with the dryer atmosphere. Thinking outside the square again I came up with this one. Considering the checkouts are automated now with machines and places like paknsave I have seen customer product scanners - there is no need to display products on the shelf. There would be a display of empty packages on shelf, the customer gets a scanning pen and scans the products they want. Then just like in automated warehousing a robot picks all the product for the customer and moves it on a travellator to the customers bin/bags automatically. Then when the customer has completed their shop they go to a collection area to pay and pick up their products. This way we can get rid of all those staff who are underpaid anyway. This method would eliminate all theft and waste heat load from open cold doors etc. Just have cool rooms which are auto loaded by the pallet prepacked from the warehouse. Could even have the drive through version. From what I have seen of supermarkets they are in the caves with technology and ripping us all off on cost. This might be a little too advanced for the supermarket cave though?

[Magoo]

Hi MF and Tesla.
definitely the thermal mass storage system is the way of the future, taking advantage of off peak power charges, and smaller trimming systems during high seasonal peak load periods.
Educating designers is the first hurdle. Who seem to design around demand loads that has the larger proportion of system idle at night. What really annoys me is that hundreds of Kgs of refrigerant is in circulation, as for rack systems and dozens of compressors and what ever, defies belief. Although if I sold compressors , copper pipe and refrigerant I would design systems like that as well. Mr Grocer the supermarket owner does not anything different, he makes money what ever which way.
definitely small charge ammonia systems, roof top mounted