Energy Savings through Liquid Pressure Amplification in Refrigeration Systems

The Liquid Pressure Amplification (LPA) technology utilises a refrigerant pump in the liquid line after the receiver to maintain a high enough pressure differential across the expansion valve to compensate for the pressure drop in long liquid lines. This allows the condenser pressure to be varied in line with variations in the ambient temperature leading to lower discharge pressures during periods of low ambient temperatures and lower compressor power consumption. This paper considers the application of LPA to a vapour compression refrigeration system for a chilled cold store in a dairy plant. The analysis has shown that the use of LPA in conjunction with liquid injection can lead to in excess of 10% energy savings over and above the savings that can be achieved with floating head pressure alone.