Snacks by Ditsch

Planning / Implementation / Main components

YORK Deutschland GmbH

Refrigerant

ammonia (NH₃)

System start-up

1999

Ditsch, a wholesale bakery, sells specialties including salt pretzels, pizzas and croissants. To ensure that products are always fresh, the bakery supplies its branches with frozen raw products, which are baked on the premises as needed.

Demands

To ensure consistent top quality in the freezing and chilling of the pre-formed dough.

Solution

The production system uses both a low pressure (-40 ºC) and a medium pressure refrigeration cycle (-10 ºC). The refrigerant used is ammonia. The sensitive fermentation cooling and air conditioning is handled by an indirect refrigeration cycle using glycol water as a secondary refrigerant. Heat is recovered using plate heat exchangers, and can be used to heat service water. The use of ammonia makes this refrigeration process both environmentally friendly and economical.

Type of facility

pumped recirculation plant

Refrigerant

NH₃

Refrigerant volume

3,800 kg

Secondary refrigerant

Ethylene glycol / water

Refrigeration plant

Low-pressure stage: 2 ammonia screw compressors

Model SAB 202 SM, at -40 ºC/-10 ºC Refrigerating capacity 490 kW, 2,950 RPM, drive motors 75 kW each, liquid separator 700 kW with 3 refrigerant pumps

High-pressure stage: 2 ammonia screw compressors

Model SAB 163 HF, at -10 ºC/+35 ºC Refrigerating capacity 1,240 kW, 2,950 RPM, drive motors 200 kW each, discharge gas desuperheater 130 kW, liquid separator 1,600 kW with 2 refrigerant pumps

Condensers

1,800 kW evaporative condenser, with section for cooling the 280 kW oil cooler glycol / water

Heat recovery

via the 280 kW oil cooler plate heat exchangers; used as service water

Cooling consumers

Low-pressure cycle (-40 ºC)

180 kW cold store, continuous-flow freezer 1 x 170 kW, 1 x 120 kW, 1 x 114 kW, entry cooler 5 x 10 kW

Medium-pressure cycle
(-10 ºC)

a variety of cooling units 100 kW, fermentation cooler 140 kW, 400 kW brine cooler plate heat exchanger, indirect cooling: product cooling, ice water production and air conditioning.

Controls

Visualised system on PC with BUS system for communication and data capture, microprocessor controls and monitoring Model UNISAB for the compressor