Conversion during ongoing operation of an ammonia refrigeration system from single-stage to two-stage compression with dry expansion + pump operation, as well as retrofitting of a heat recovery system
Cooling capacity after conversion: approx. 2,600 kW
Refrigerant: ammonia (NH₃)
Special features: Conversion to two-stage refrigeration during operation, retrofitting of a heat recovery system
As part of the expansion of production space, we planned and supervised the conversion of an existing NH₃ refrigeration system in a logistics center with a deep-freeze and normal refrigeration system. The aim was to convert from a single-stage to a two-stage refrigeration system and to integrate additional cooling surfaces – without interrupting production and without interrupting ongoing operations.
Technical highlights of the converted refrigeration system
- Two-stage NH₃ refrigeration:
Conversion from a single-stage freezer circuit to an energy-efficient two-stage system. A newly integrated medium-pressure circuit (-10 °C) will in future supply all standard cold rooms (+2 °C to +12 °C) and significantly reduce the load on the deep-freeze circuit. - Combination of direct evaporation and pump operation:
Normal cooling areas are supplied via air coolers with direct NH₃ injection. The deep-freeze rooms remain in proven pump operation. - Refrigeration capacity and NH₃ charge:
Total capacity increased to around 2,600 kW, of which approx. 1,600 kW in deep-freeze and 1,000 kW in normal refrigeration. The NH₃ filling quantity was increased to approx. 6,300 kg. - Waste heat recovery and redundancy:
The heat recovered from oil and compressor cooling is used efficiently. Excess energy is dissipated via recoolers. In addition, a redundant compressor was installed to safeguard the deep-freeze system. - Conversion in existing buildings without interrupting production:
All system conversions and extensions were planned and coordinated in such a way that there was no disruption to ongoing operations. Critical interventions were carried out outside regular working hours.
Our services at a glance
- Planning the conversion from a single-stage to a two-stage NH₃ refrigeration system
- Design and selection of all refrigeration components
- Integration of a new intermediate circuit (-10 °C) incl. separator and planning of the piping enclosure
- Planning and coordination of conversions without production downtime
- Heat recovery concept and expansion of recooling and compressor capacities
- Preparation and monitoring of the approval procedure in accordance with the Federal Immission Control Act (BImSchG)
Refrigeration technology with vision
This project demonstrates our expertise in dealing with complex conversions in existing buildings. The challenge of converting a running production operation without interruption and at the same time significantly increasing the energy efficiency of the refrigeration system was successfully solved through close coordination, precise planning and a great deal of experience.
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