Energy Saving with Liquid Pressure Amplification in a Dairy Plant

The Dairy sector is one of the major refrigeration energy users in the food industry. Significant energy and financial savings can be achieved by adopting new refrigeration technologies and practices. One such technology which has been available on the market for direct expansion evaporator vapour compression systems for a number of years but has not as yet found wide application is Liquid Pressure Amplification (LPA).The 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. Operation at lower pressures also increases the refrigeration capacity of the system enabling it to cope with increased load demands. LPA can be applied to new refrigeration plant and as a retrofit to existing plant. LPA also enables the use of liquid injection into the discharge line of the compressor whichdesuperheats the refrigerant vapour before entering the condenser. This increases the capacity of the condenser, which in turn enables operation of the plant at lower condensing temperatures.This case study considers the application of a LPA and liquid injection to a cold store at a dairy plant in Northern Ireland. Before the application of the technology the cold store haddifficulty maintaining temperature during periods of high ambient temperatures, with a drift of 5°C from design. The main aim of the case-study is to investigate the performance of theLPA technology as installed at the plant and estimate the energy savings and environmental performance of the system.

Download full Case Study Energy-Savings-through-liquid-Pressure-Amplification-in-a-Dairy-Plant