Case studies

Poultry Producer / Germany

Planning / Implementation / Main components

Kältetechnik Dresen + Bremen GmbH


Ammonia (NH3)

System start-up


A leading poultry producer required an economical and environmentally friendly refrigeration plant for processing its products. Kältetechnik Dresen + Bremen, a German builder of refrigeration plants, installed this particular ammonia plant.


The new production facilities, with a total floor space of approx. 5,000 m², were to be equipped with a number of different refrigeration and processing rooms. The spectrum of required temperatures extended from -30°C to 7°C.


Kältetechnik Dresen + Bremen built a three-stage ammonia refrigeration plant with a glycol cycle. Four screw compressors and one piston compressor were used to control the various temperature level requirements of the system, which was charged with 2,850 kg of ammonia. The deep-freeze warehouse and the shock-freeze rooms with a refrigeration output of 410 kW at -40°C are directly supplied with ammonia. An ethylene glycol cycle with a flow temperature of -12°C cools the production rooms, e.g. filleting, fresh storage and packaging rooms, and an integrated ventilation system with a total refrigeration output of 2,190 kW. In a spray humidified chilling tunnel that is also linked into the cycle, roughly 9,000 chickens per hour are cooled down to a temperature of 2°C.

Technical data:


Type of facility

Three-stage ammonia plant



Refrigerant volume

2,850 kg

Secondary refrigerant

Ammonia/ethylene glycol

Refrigerating capacity

deep-freeze warehouse/quick-freeze rooms: 410 kW
production rooms: 2,190 kW

Refrigerant temperature

deep-freeze warehouse/quick-freeze rooms: -40 C°
production rooms: -12 C°

Main components

Screw compressors, piston compressors, air coolers

Special features / Comments

One special feature of this refrigeration plant is mist humidification, to prevent loss in product weight, and a sliding temperature scale that takes its cue from the product temperature. The production rooms are kept at 4°C by air coolers operated in conjunction with a ventilation system. After wet-cleaning, the production rooms can be dehumidified and dried in a very short time at a constant temperature thanks to “intensive humidification” via the custom-built air coolers.



Dresen + Bremen GmbH
Norbert Hackmann
Waller Esch 3
D-49594 Alfhausen

Phone: +49 (0)5464 9 61-00
Fax: +49 (0)5464 96 10-20
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