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Case study

Delhaize New Fresh 2Zellik, Belgium

NH3/CO2 refrigeration for new

Delhaize distribution centre in Zellik

The Delhaize Groups key position in the food industry is the result of gradual growththat goes back more than 140 years. Continuing this growth, Delhaize decided toexpand its existing distribution centre in Zellik in 2007 with an additional 150,000m ofloading and unloading bays and a warehouse. This will be operational in 2009.

The new building consists of an automated warehouse with the northern and southernloading and unloading bays continuously refrigerated at a temperature between +1Cand +3C. In order to make best use of the storage space, a technical corridor had tobe installed above it to accommodate the refrigeration installation.

The new building had to be refrigerated using a cooling system running on the naturalcoolant ammonia. The volume of ammonia had to be limited to the machine room andthe condensers. Cold transport had to occur through a secondary cooling medium

such as glycol or CO.

Delhaize works hard to limit its energy consumption and this is also evident in thenew, environmentally friendly depot. The depot roof is equipped with 6,000 m ofphotovoltaic cells that generate 306 MWh each year. A cooling system based on

NH/CO rather than glycol will also go some way to helping the environment. The

depot is also insulated extremely well and 12,000 m of water will be recuperated in areservoir each year.

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Challenges

The entire 150,000m new building needed to be air conditioned. Thewarehouse and the loading and unloading bays needed to be refrigerated at atemperature between 1C and 3C. Everything needed to be carried out asredundantly as possible.

Delhaize feels very strongly about the environment and the surrounding areaand therefore wanted a solution that was as energy efficient andenvironmentally friendly as possible. A comparison between glycol and COalso had to be taken into consideration.

Johnson Controls Solutions

Following analysis, it appeared that a NH3/CO2 refrigeration installation wouldbe more energy efficient than a NH3/glycol installation. Not only canevaporation take place at -8C instead of -10C, which limits the energy costs(15% annual savings), but the one-off capital outlay is also significantly lower.Tie all of these systems together through a central monitoring station viaa Johnson Controls Metasys building management system to facilitatecost savings and accelerate project installation.

Following the specifications, Johnson Controls Industrial Refrigeration BELUXinstalled a machine room that works with a natural refrigerant that does nothave an impact on the environment or contribute to global warming; namelyammonia. Furthermore, it was decided to limit the refrigerant to the machineroom, in order to eradicate product contamination risks and personnel safetyrisks.

CO2 was chosen as a secondary refrigerant in order to transport the cold towhere it is required. This CO2 is cooled to a liquid via a thermosyphonsystem (separator with two NH3/CO2 plate heat exchangers underneath) by

evaporating ammonia.

To cool the warehouse, Johnson Controls Induref installed eight air handlingunits in the technical corridor above, each with a capacity of 100 kW. Theloading and unloading bays were fitted with 36 coolers ranging from 17 kW to

50 kW.

To compress the ammonia, Johnson Controls used three SABROE SAB193Lscrew compressors. One of these compressors is frequency controlled, whichmore easily enables the customer to react to the supply and demand ofcooling without having to compromise on efficiency. In total, the compressorsprovide 2,438 kW at -8C/35C.

Two BAC CXV309 axial evaporative condensers condense the ammonia. Acooling unit was also installed to cool the CO2 buffer tank during a standstill.

Everything is controlled by S7 PLCs. Various touch screens enable easycontrol of the installation.

The existing WINCC supervision system was expanded, enabling the

customer to store and analyze histories if required and to manage alarmslinked to the installation.

Results

The customer now has a more reliable, energy efficient and environmentally

friendly refrigeration installation based on NH/CO. Compared to a NH3/glycol

installation, Delhaize saves 924 MWh of energy each year and the capitaloutlay was + 5% lower than for the NH3/glycol solution.

Opting for a NH/CO installation enables Delhaize to make savings both in

terms of investment and exploitation.

Three SAB193L compressorsproduce the refrigeration.

The NH3/CO2 separators with

the CO2 pumps underneath.

Air handling units in thetechnical corridor above thewarehouse provide the requiredcooling.

CASE STUDY DELHAIZE ZELLIKINDUSTRIAL REFRIGERATION BELGIUMCSST-09-096DU by WB