Seward Refrigeration Ltd were awarded the installation contract, to supply, install and commission a brand new ammonia/glycol system for a factory extension in the Midlands. The plant provides 690kw providing glycol at -10°c/-5°c feeding evaporators in a large blast chiller, despatch area, chill area, chill stores and two air handling units in high care/low care areas. Evaporator defrosting is achieved via a warm glycol circuit, recovering free heat from a Vahterus desuperheater installed on the discharge line of the Sabroe twin pac.
Installed was an ammonia/glycol, Sabroe twin pac, comprising of 2 x Inverter driven SMC 108LV reciprocating compressors. The pack provides a duty of 670kw, glycol off -10°c, glycol on -5°c, condensing @ +32°c / +21°c wet bulb. To reject the compressor(s) THR we installed a Baltimore VXC condenser, including inverter driven fan motor, controlled on discharge pressure.
The plant is controlled by an RDM plc, including 3G modem allowing our engineers and staff to dial in remotely if any fault alarms are raised. All compressor motors, blast chill evaporator fans and condenser fan are driven by Danfoss FC103 Inverter drives reducing power consumption during low load conditions. The control strategy for the system was designed and programmed in house.