Experimental evaluation of desuperheating and oil cooling process through liquid injection in two-staged ammonia refrigeration systems with screw compressors

This paper examines the problem of achieving desuperheating through liquid injection in two-staged refrigeration systems based on screw compressors. The oil cooling process by refrigerant injection is also included. The basic thermodynamic principles of desuperheating and compressor cooling as well as short comparison with traditional method with a thermosyphon system have also been presented. Finally, the collected data referring to a big refrigeration plant are analyzed in the paper. Specific ammonia system concept applied in this refrigeration plant has demonstrated its advantages and disadvantages.

► An experiment was setup during a frozen food factory refrigeration system reconstruction and adaptation.
► Desuperheating and low-stage compressors oil cooling process were investigated.
► Efficiency of compression process and high-stage compressors functioning were examined.
► Evaporation temperature reduction has great influence on the need for injected liquid refrigerant.
► Several cases in which desuperheating and oil cooling process application are justified were determined.