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The latest refrigeration technology for Kaufland

Kaufland logistics centre in Möckmühl: One of the most modern logistics centres for deep-frozen goods (TIKO) and fresh produce

Line of Busi-ness:

Commercial Refrigeration

Application: Supermarket cooling

Country / City: Germany / Möckmühl

Fluid: NH3, Glycol

Product: Ceiling air cooler DGN, insulat-ed unit cooler GIKS, wall/ceil-ing aircooler GGN, wall/ceilingaircooler GGHN, drycooler GFH,condenser AGVH

Europe's biggest logistics centre for deep-frozen goods (TIKO) and fresh produce hasbeen constructed within just one year next tothe A 81 motorway in Möckmühl, near Heil-bronn. A wide range of refrigeration logisticsand meat dissection innovations are plannedto give Neckarsulm-based Kaufland Stiftung &Co. KG a market advantage for several years.The refrigeration concept, which is consid-ered to be unique within specialist circles, wasplanned in close collaboration with the Kau-fland construction/shopfitting business areaand the Brunnenkant engineering office inWiesloch.

The company that built the system wasthe Mannheim branch of York IndustriekälteGmbH & Co. KG. The company, which is partof the globally successful York refrigerationgroup, specialises in the development and in-

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stallation of cutting edge refrigeration systemsfor a variety of industries. The insulated unitcoolers that were specially developed for thelogistics centre were supplied by Güntner, aswere the brine coolers, the condensers andthe drycoolers. Not only was Möckmühl thebiggest individual order so far in Güntner's his-tory, but it was also one of the company's great-est challenges with regard to technical speci-fication, adherence to extremely tight deliverydeadlines and the use of well thought-out sup-ply logistics.

Completeness by omission

One of the most modern logistics centres fordeep-frozen goods (TIKO) and fresh producewas created in Möckmühl in accordance withthe saying "take the latest refrigeration tech-nology, optimise it until it is simple and prac-tical, subject the different variants to absorp-tion costing and then implement it in the fieldwithin a few months". This was possible be-cause optimisation and simplification are toppriority at Kaufland and on the agenda at alldecision-making levels. To put it simple, Kau-fland wants to provide the best possible qual-ity at the lowest prices. Since other chains al-so work in accordance with this principle, Kau-fland sees its market advantage in logistics,particularly in the deep-frozen goods and freshproduce area. A novelty in the industry is thata meat factory and refrigeration logistics havebeen combined for the first time and closelyinterlinked under one roof at the Möckmühl lo-gistics centre.

At a glance: With 12 Güntner type AGHV NH3condensers on the roof, the Kaufland logis-

tics centre is perfectly equipped for the future.

Extraordinary refrigeration concept

The high strategic value of refrigeration logis-tics forced new measures to be used when de-signing the refrigeration systems. "Similar toother industries, we also developed complete-ly new concepts for our refrigeration systems",says Rolf Semelink, area manager at Kau-fland construction/shopfitting business areaand among other things, responsible for the re-frigeration systems. "We did not make our de-cision easily and viewed a large number of ref-erence sites, visited specialist trade fairs andobtained advice from specialist planners". Incollaboration with the Brunnenkant engineer-ing office in Wiesloch, which specialises in foodrefrigeration technology, a refrigeration con-cept was created that will be unique in Euro-pean refrigeration logistics for years to come.Semelink: "Europe will never see the likes ofthis kind of system again. Together with Mr. Re-hberger from the Brunnenkant engineering of-fice we have subjected different system vari-ants to absorption costing and not just lookedat the energy costs but also checked envi-ronmental aspects, examined the maintenancecosts and included the consequential costs ofcertain systems in the equation".

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Narrow aisle warehouse for deep-frozen goods at -28 ºC: Specialcombination of ventilation ceiling and insulated unit coolers

After about two years of operating experienceRolf Semelink came to the conclusion that "Thesystem runs perfectly, just like we imagined.The Brunnenkant office and York Industriekälteas the system contractor performed excellent-ly. Particularly Michael Broser, the York projectleader, made a major contribution to creatingthis top class, extremely modern refrigerationsystem".

View of the refrigeration centre: Installation of ten NH3 com-pressors with total refrigeration capacity of about 7,910 kW

York only had four months to install the mam-moth system consisting of ten NH3 compres-sors, 140 aircoolers and 25 insulated unit cool-ers. There is about 14 km of pipeline for coldbrine and NH3 alone! In order for the refrigera-tion systems to go online on schedule, York de-ployed four site foremen and about one hun-dred fitters, with a certain amount of 2-shift op-eration.

“Only NH3 is economical on this scale”

"As far as the refrigerant was concerned it wasclear from the start that there was little flexibil-ity”, says Semelink. “In this performance seg-ment only NH3 comes into question. That is themost economical and therefore cheapest solu-tion as far as we are concerned”.

Impression of the insulation cooler: View from insulation cool-er via open defrosting flap into the narrow aisle warehouse

A two-stage NH3 system has been installedconsisting of six high-pressure compressorswith a total refrigeration capacity of 5,400 kWat –11/+45 ºC, two low-pressure compressorswith a total refrigeration capacity of 1,100 kWat –9/-39 ºC and nine air-cooled condenserswith a total condensing capacity of 6,700 kWwith a tk of +45 ºC.

The cold brine is cooled in the associatedplates and delivered to the heat exchangers us-ing two frequency-controlled pumps per brinecircuit. For example, ten insulated unit coolersin the fruit and vegetable area and other insu-lated unit coolers in the fresh produce area aresupplied with the cold brine. Several rooms inthe meat factory are also supplied with cool-ing via another brine circuit. As well as thetwo-stage system a so-called eco-system hasbeen installed, consisting of two compressorswith a total refrigerating capacity of 1,360 kWat –19/45 ºC, three aircooled condensers witha total condensing capacity of 1,940 kW witha tk of 45 ºC and the associated separatorsand plates, that provide cold brine for the freshproduce chamber and the meat factory. Here,too, the brine is distributed using two frequen-cy-controlled pumps for each refrigeration cir-cuit.

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100

Cost

75

50

25

Air-cooled condensersand drycoolers

Wet cooling towers

Year

1st Qu

arter

2nd Qu

arter

3rdQu

arter

4th Qu

arter

Operating cost comparison for supercooling plant

The warm brine defrosting system proved tobe particularly economical in the brine system.The warm brine is produced by the compres-sor oil coolers and buffered in a store with a

volume of 16 m3. When the stores are charged,the excess heat is used to heat the ceiling cav-ity. Depending on the operating conditions, ex-cess heat can be led outside via the two glycolcoolers, but this procedure rarely occurs.

The brine insulated unit coolers are defrostedvia a variable PLC program in accordance withthe specific requirements, and the aircoolersin the meat factory are defrosted by the build-ing conducting equipment. Since each aircool-er is individually defrosted, the temperature inthe room does not increase. The temperatureof the deep-frozen goods is unaffected by thisdefrosting process.

The biggest air-cooled refrigeration systemin Europe

Rolf Semelink particularly emphasized themaking of the decision as to whether thedrycooling of the two NH3 refrigeration systems(direct cooling for deep-freeze, brine coolingfor fruit, vegetables, fresh produce and meatfactory) could be achieved more economical-ly using wet cooling towers or air-cooled con-densers. “That was a lengthy decision, sincewe included many secondary aspects such aspower costs, availability of cooling water, watertreatment and disposal of sludge water in ourconsiderations”, says Semelink.

Fresh produce areaThe air intakes of the in-sulated unit coolers wereplaced just beneaththe insulated ventilationceiling with air ducts.

In spite of having a large installation area, ad-ditional steel scaffolding on the roof to supportthe drycooler and longer pipelines with a largerdiameter, the absorption costing has convinc-ing benefits for air-cooling. “However, someengineering companies advised us not to dothis. But we are certain the air-cooled systemwas the correct choice, which has been backedup by the operating statistics”. The coolingplant at the Kaufland logistics centre consistsof twelve Güntner AGVH air-cooled NH3 con-densers. There is also a GFH air-cooled glycolcooling tower unit with capacity of 2 x 880 kW.

Insulated unit coolers and ventilation ceil-ings

Kaufland was taking a new direction by equip-ping the deep-freeze, fruit and vegetable ware-house and the meat factory with air coolers. In-

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stead of fitting individual aircoolers to walls orthe ceiling, Kaufland decided on Güntner insu-lation coolers that blow their air directly into aprism-shaped stainless steel ventilation ceiling.This keeps the premises free of supply pipes,air coolers and air ducts. “In all deep-freezeand fresh produce warehouses that are ap-proximately 8 or 18 metres high we originallyused the combination of insulated coolers andair distribution ducts developed by the Brun-nenkant engineering offices”, says Semelink.“This solution is also the result of absorptioncosting including friction points between logis-tics on the one hand and possible maintenancework on the aircoolers on the other”.

Function diagram of GIKS insulated unit cool-er with radial fan in cooling operation ...

The following arguments led Kaufland to acombination of insulated coolers and a venti-lation ceiling:

• Excellent air distribution over the en-tire surface of the ceiling

• Also easy to adjust after installation• Low noise generation by air flow/fans

(important for legal reasons)• No restriction to goods movements• The maintenance work that is needed

on the insulated unit coolers can becarried out at normal room tempera-tures outside the deep-freeze/refriger-ation warehouse.

• No dust deposits on ducts, aircoolersor pipelines

• Simple, rapid defrosting of insulatedunit coolers by closing air intakes/out-lets

"Here, too, we were able to fall back onthe comprehensive know-how of our planner.Mr. Rehberger from the Brunnenkant officeachieved an extraordinarily economical solu-tion with a combination of insulated unit cool-ers and a ventilation ceiling that also has anattractive appearance”, says Semelink.

Defrosting the insulated unit coolers

The Güntner insulated unit coolers installed atKaufland were prepared in the factory so thatthey only had to be connected to the air ductsystem. The NH3 insulated unit coolers are de-frosted using hot NH3 gas, controlled by a YorkPLC. The defrosting tank is heated separately.This is the only way to ensure that defrost wa-ter back-ups do not occur because of blocks ofhoar frost sliding down.

... and in defrosting.

The brine insulated unit coolers are defrostedin the heat exchanger coil using warm brine(25 ºC) and in the tray using electrical power.Here, too, the tray is preheated so that the out-let does not block with ice. In all insulated unitcoolers, defrosting always takes place with theflap to the cooling compartment closed. In or-der to prevent unnecessary steam formationduring defrosting, the coil defrosting tempera-ture is recorded and defrosting stopped imme-diately if the coil temperature exceeds 5 ºC.

After the defrosting process a dripping periodtakes place and then the freezing period. Assoon as the coil temperature has reached anappropriate value the flap to the cooling com-partment opens and the insulated unit cooleris ready for operation.

The following insulated unit coolers are in-stalled:

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• 4 air coolers of type GIKS25-45/626/2-1100 for NH3 direct

evaporation in flooded operation, eachwith 200 kW of refrigerating power atan evaporation temperature of –37ºC and a room temperature of –27 ºC(TIKO 1), set up for hot gas defrosting.

• 1 of same type for TIKO 2 with refrig-erating power of 90 kW at –37/-27 ºC

• 1 of same type for TIKO 3, switchablefor positive storage at t = +4/+2 ºCand +10/+12 ºC

• 2 of same type for TIKO 1 chamberwith refrigerating power of 70 kW atan evaporation temperature of –9 ºCand a room temperature of–2/+4 ºC

• 3 insulatied coolers for brine circuitI, each with 170 kW of refrigeratingpower and chamber, designed on coldbrine with –7/-2 ºC and a room tem-perature of +4 ºC; the hoar frost in thecoil is defrosted using warm brine.

• 14 insulatied coolers for brine circuitsII and III, each with refrigerating powerof 150 kW for supplying the fresh pro-duce warehouse and the fruit and veg-etable area

All other refrigeration rooms in the refrig-eration logistics and the meat factory areequipped with slimline unit coolers with differ-ing power and design temperatures. The ma-jority of these aircoolers are defrosted usingwarm brine, and the trays have electric heat-ing. In many cases an air heater is installed forroom drying. A total of 140 aircoolers are de-ployed in the Möckmühl logistics centre.