Unilever / Czech Republic

Planning / Implementation / Main components

Bohemiachlad spol. s.r.o.

Refrigerant

Ammonia (NH₃)

System start-up

2003

Unilever, one of the world’s largest vendors of everyday consumer goods, needed to expand the production capacity at its Czech headquarters near Prague. The contractor Bohemiachlad built a refrigeration system that uses the natural refrigerant ammonia.

Demands

Unilever needed to increase the refrigerant capacity up to 3 MW at short notice for the extended production. The aim was to minimise the refrigerant charge while maximising the cooling output.

Solution

Bohemiachlad installed a central dry expansion ammonia system with a refrigerant volume of just 100 kilograms in circuit of one plate heat exchanger. The secondary refrigerant is chilled by the heat exchangers. The refrigerating system chills cold water from 10°C to 3°C. The refrigerant evaporating temperature is about 0°C, and the condensation temperature is 35°C. The plant has a refrigerating capacity of 3 MW, making it one of the largest systems with dry expansion in Europe.

Type of facility

Dry expansion ammonia system

Refrigerant

NH₃

Refrigerant volume

100 kg

Secondary refrigerant

Chilled water

Refrigerating capacity

3 MW

Main components

3 screw compressors controlled by 3 frequency converters, 3 plate heat exchangers, 2 condensers

Special features / Comments

All of the processes are monitored and centrally controlled by a computerised control system.