European turntable for fruit and vegetables Pfalzmarkt ... · Air-cooled condensers preferred It was relatively easy to decide what kind of condensers to use to recool the refrigerant.

REF017_V1_2005_EN Page 1

European turntable for fruit and vegetablesPfalzmarkt Mutterstadt uses cooling logistics

The typical regional building style characterises the Pfalzmarkt in Mutterstadt.

Line of Busi-ness:

Industrial Refrigeration

Application: Fruit and Vegetable Cooling

Country / City: Germany / Mutterstadt

Fluid: R404A

Product: Wall/ceiling unit cooler GHN,Floor mounted air cooler GSN,Condenser GVH, Receiver GBH,Control panel GWS, Controlmodule GDRD, Pressure sensorGWS

With production of more than 120,000 tonsof fruit and vegetables on an area of morethan 12,000 hectares by about 2,100 collec-tively organised members, the Pfalzmarkt inMutterstadt is one of Europe’s leading pro-duction and distribution centres. Since the de-mand for fresh fruit and vegetables is contin-uously increasing because of the expansion ofthe EU, the storage and operating area that wasset up in Mutterstadt in 1987 was recently in-creased from about 15,500 m2 to 45,300 m2.About 1/3 of new building no. 2 is used as a


storage, loading and unloading area for fruitand vegetables and 2/3 of the building is usedby empties and returnable crate provider Eu-roPool System International (Germany) GmbH.

When the VOB tendering took place, the orderfor the refrigeration system was placed withHeddesheim company Schulz Kälte- und Kli-matechnik GmbH. Although a large number ofmanufacturers and distributors competed tosupply the air coolers, condensers and refrig-erant containers, the order went to Güntner.According to refrigeration system constructorKlaus Schulz: “The proposed Güntner prod-ucts with their specific equipment featureswere the most suitable for the planned coolingconcept.”

First cool the goods, then load them

The collectively organised members of thePfalzmarkt had already decided to expandthe cooled loading/unloading and storage areaat the Mutterstadt site before EU legislation178/2002 concerning the traceability of per-ishable goods came into force. Decisive for theconstruction of new building no. 2 was not justthe area for loading, unloading and intermedi-ate storage of fruit and vegetables that was sourgently required, but specific cooling of thegoods supplied by the surrounding producersduring commissioning for the individual cus-tomers. Since the EU directive came into forceon 1st January 2005, customers and distribu-tors have required the perishable goods to bepre-cooled to a certain core temperature, e.g.5 °C for fresh vegetables.

Upright evaporator model S-GSN 080/408 withprotection guard in rapid refrigeration room.

Collectively organised fruit and vegetableproducers help to make the decision

The topic of cooling has played an importantpart with the members of the Pfalzmarkt co-operative, even before the new EU legislationcame into force. For the majority of agricultur-al producers, the cooling of their goods is thekey to greater value creation. The expectationsof the cooling equipment in the new hall weretherefore extremely high. Jürgen Hutzler fromVR-Bauregie GmbH, Eschborn, as the repre-sentative of the clients who are responsible forthe construction of the new building, explainsthe farmers’ situation as follows: “Strong emo-tions are often in play when fruit and vegeta-bles are being sold. The subject of cooling is aparticularly hot potatoe.

The Pfalzmarkt logo is a symbol of good qual-ity, well beyond the borders of Germany.

Almost every farmer has his own ideas aboutwhat should be cooled and how it shouldbe cooled. It was therefore a difficult deci-sion to make. In the past, the quality of theproduce was obviously frequently affected bylack of cooling, meaning that it could not besold.” Thomas Schlich, the managing directorof Pfalzmarkt eG, explains the cooling problemas follows: “The products have a wide varietyof cooling requirements. Some of them reachtheir core temperature quickly, such as lettuceand radishes, and others take longer. We needthe technology to cool our products to the re-quired core temperature as quickly as possiblewithout causing damage, so that the time be-tween delivery, commissioning and transporta-tion is kept as short as possible."


Bernd Schulz (left) and Klaus Schulz: “If Güntner says thatthe equipment will be there on day X, that is when it arrives.”

The formation and support of a work groupconsisting of six agricultural producers and anexpert adviser from the “Dienstleistungszen-trum Ländlicher Raum“ (Rural Service Cen-tre – DLR) in Neustadt showed how impor-tant the subject of cooling was being taken bythe Pfalzmarkt management. However, the re-sults of the work group were more or less thesame as those of engineering office that wascommissioned to plan the refrigeration system(Brunnenkant, Wiesloch). According to Dr. Hol-ger Kettenmann, the project leader of the engi-neering office specialising in food refrigeration:“It was important to all participants that opti-mum use was made of the limited space situa-tion and that enough cooling power for storageand commissioning was available. This is whyour ideas were fairly similar.” A multifunctionbuilding with the following critical values wascreated:

• Approximately 11,000 m2 of the15,500 m2 building is used by return-able crate provider EuroPool SystemInternational (Deutschland) GmbH asa store and for cleaning plastic crates.

• Approximately 4,300 m2 of buildingspace is cooled, divided into

• 10 continuous loading rapid refriger-ation rooms (width x length x height= 7.25 x 14.5 x 4.5 m) for cooling thegoods delivered by the farmers from30 °C down to 5 °C,

• 10 rapid refrigeration rooms (width xlength x height = 7.20 x 8.90 x 7.00m) for cooling and storing fruit andvegetables from 30 °C to 5 °C,

• approximately 2,400 m2 of cooledcommissioning area for room temper-atures of between 2 °C and 12 °C, de-pending on what is being stored,

• each with 2 entry and exit locks withhigh-speed doors.

Flowchart of refrigeration system at Pfalzmarkt, Mutterstadt

For lack of space, there are three modi-fied high-efficiency evaporators, model S-GHN066C/27-E, with integrated 90° air deflection,concealed upwards headers and automaticallycontrolled defrost flap in each of the ten con-tinuous loading rapid refrigeration rooms. Theyare installed at the long sides of the room, di-rectly beneath the ceiling, so that the maxi-mum storage space is available and the first-in-first-out concept can be adhered to.

The ten rapid refrigeration rooms for the short,medium and long term storage of appropri-ate types of fruit and vegetables (so-calledlong turning screw machines) have GüntnerSGSN080/ 408 upright evaporators attachedto the front. These are made to measurewith integrated defrosting flaps and a blow-outchannel with a 90° bend. Three 6200 kg insu-lation coolers that are preferred by the Brun-nenkant office and manufactured by Güntnerare used for cooling the central commissioningarea. These are directly connected to air ductsand provide draught-free, homogeneous andlow-noise air distribution over the entire com-missioning area using optimised air outlets.


Risk analysis speaks in favour of an R 404Asystem

Two R404A combination systems, one with650 kW and one with 720 kW of refrigeratingcapacity, are used for refrigeration. The origi-nal intention was to use NH3 as the refriger-ant. However, the client and the planner de-cided to use R404A refrigerant, which was forsafety reasons in order to protect employeesand because of the possibility of damage to thestored goods if NH3 escapes. This also meansthat the BImSchG (federal law for the protec-tion against immissions) approval procedure isnot required.

The temperature trends in the refrigeration roomsare continuously recorded and documented.

Air-cooled condensers preferred

It was relatively easy to decide what kind ofcondensers to use to recool the refrigerant.Kettenmann: “Because of the problems with

the existing evaporative condensers, the clientwas clearly in favour of air-cooled condensers.”The following arguments were decisive for thesolution that was implemented:– No need for water treatment– Performance remains constant, since littlesoiling occurs.– Hygienic operation without the risk of watervapour or legionella incidence– Extremely low maintenance costs comparedto cooling towers.A total of four Güntner axial condensers fromthe new product line are installed with Günt-ner support profiles. Two devices of type GVH090.1 A/2x5-N(D), each with 500 kW capaci-ty, and two GVH 090.1 A/ 2x6-N(D) with 625kW are installed above the machinery house.All condensers have epoxy-coated fins.

Dr.-Ing. Holger Kettenmann from the Brun-nenkant engineering office: “Our ideas and thoseof the producers were not dissimilar at the end.”

Because of the space-saving base of the re-frigerant receivers with a capacity of 1,200litres, all condensers are supported on 1,400mm legs, which differs from the standard ver-sion. Since the four S-GBH 1200 refrigerantreceivers are also supplied by Güntner, thestructural coordination of neighbouring com-ponents was provided by a single source. Forservice purposes and in the event of unfore-seen breakdowns, the refrigerant receivers canhandle the entire refrigerant volume of therespective refrigeration circuit. The Güntnerswitch cabinet system beneath the equipmenthas also been integrated into the locality ina user-friendly way. All condensers have themodular switch cabinet system GWS 50-70 be-


neath them, each with a GDRD 87U digital con-troller module, including a GSW 4003/F pres-sure sensor for independent fan control de-pending on the condensation pressure.

Thomas Schlich, managing director of Pfalzmarkt eG forfruit and vegetables in Mutterstadt: “With building no.2 we are making a contribution to improving the cool-ing chain between the producer and the consumer.”

On-time delivery

When the order was sent to Schulz with theobjective of starting installation within no morethan four weeks and completing the work fourweeks later, it became clear to managing direc-tor Klaus Schulz that such tight delivery dead-lines could only be met in collaboration witha partner such as Güntner. “The order wasplaced with Güntner at the beginning of March2005 and the units were on site at the begin-ning of April, exactly on the specified dates andat the required times. With a total of 15 trucks,11 of which arrived on one day alone, it was areal masterly performance.“ The refrigerationsystem constructor found Güntner’s option ofsupplying the equipment ready for installationto be particularly efficient, meaning that theair coolers could be directly unloaded from thetrucks using a fork lift or special fork lift andinstalled and secured in the planned locationimmediately. “It only took 10 minutes to installan aircooler. This delivery service from Günt-ner saved us a great deal of time, of course,”remarks Klaus Schulze appreciatively.

Jürgen Hutzler, VR-Bauregie GmbH, Eschborn: “Thesubject of cooling is a particularly hot potatoe withthe farmers. The decision concerning the refrigera-tion concept was not exactly an easy one to make.”

Insulated cooler with independent controller

More and more insulated coolers are beingused to cool large areas in fresh produce lo-gistics. In combination with ventilation ceilingsor air ducts with optimised air outlets, they arefar superior to other types of aircoolers withair throw nozzles with regard to thermal com-fort. In order to make installation as easy aspossible, Güntner insulated coolers are now -supplied with preinstalled, tested switch cab-inets. They are fully equipped with an ener-gy supply, power units and all of the neces-sary control components. The control systemis independent, but external control values canoptionally be used. User guidance is provid-ed in plain text, and is available in German,English, French and Spanish. Up to 24 coolerscan be interconnected in one or more controlcircuits (refrigeration rooms). The internal ex-change of data between the coolers takes placevia a CAN bus system. The following bus sys-tems are available for communicating with abuilding control system or other higher-ordersystems.

• Profibus DP/V1 (Siemens S7 etc.)• Interbus• Ethernet TCP/IP 10 Mbit• Ethernet TCP/IP 100 Mbit• DeviceNet• CAN open• MOD-BUS• LON-BUS (BACnet-kompatibel)


The Pfalzmarkt system is incorporated into thehigher-order MSR system (TECO, Wurm) viathe CAN bus.

All units are equipped with a switch cab-inet for independent condenser control.

Which air cooler for which product?

The axial condensers (model GVH 090.1)are positioned above the machine rooms forthe refrigeration equipment and the BHKW.

Each type of fruit and vegetable has its opti-mum storage temperature and humidity. Forexample, tomatoes become damaged at a stor-age temperature of 0 °C, but at 2 to 3 °C thereare no problems. Lettuce should have a coretemperature of 5 °C before it is transported.There is an optimum storage temperature foralmost every fruit or vegetable that can only beexactly controlled in exceptional cases, sincethe refrigeration rooms are used for a mixtureof the above items. The humidity also plays apart in the quality assurance of fruit and veg-etables. Whereas the ideal relative humidity forfresh vegetables is about 95 %, apple skinstend to start rotting at this value.

Continuous loading rapid cooling room withGüntner S-GHN storage room coolers. Wettingtakes place manually using fixed spray nozzles.

Onions and potatoes prefer a relative humidityof 80 %, which is even dryer. The Pfalzmarktalways attempts to use temperatures that pro-vide the best possible conditions for all storedand commissioned produce. In order to pre-vent vegetables that have been heated by thesun during delivery from drying up, farmers of-ten use a water hose. The produce is also wet-ted by “eye judgement” in the new hall, i.e.each batch is individually assessed and wettedusing spray nozzles that are built into the ceil-ing. Since the cooling store has to be used fordifferent items, there is no point in having anevaporator that is specially tailored to a par-ticular item. The following generally applies tofruit and vegetable storage:

The commissioning area is cooled using an air conduc-tion concept that was developed by the Brunnenkant -

office: the cooling is provided by insulated coolers.

• Evaporators with large surfaces and alow Dt do not remove as much mois-ture from the air, therefore preventingthe produce from drying out.


• The evaporating temperature for thefresh produce area should not be lessthan -8 to - 10 °C.

• The air throw should be adapted tothe geometry.

• Electronic expansion valves shouldbe used if possible to control the -cooling area temperature as accurate-ly as possible. This will allow the de-sign-based hysteresis of thermal ex-pansion valves to be reduced to ± 0.5K (Danfoss AKV20/1 electronic ex-pansion valves are used in the Pfalz-markt).

• The air in cooling buildings containinglarge numbers of employees shouldbe provided via air ducts if possible.Advantages:

° Slow air speed / no draughts° Less noise emission for em-

ployees° More agreeable climate despite

low room temperatures° Good air distribution° Produce does not dry out as

much° Central treatment of cooled air

in insulated coolers that are in-stalled outside the rooms thatare being cooled; thereforeeasier maintenance outside thestorage area

A refrigerant receiver installed beneath each con-denser that can hold the entire volume of re-frigerant of the respective refrigerant circuit.

European turntable for fruit and vegetables Pfalzmarkt ... · Air-cooled condensers preferred It was relatively easy to decide what kind of condensers to use to recool the refrigerant.

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