The LPA was recently installed on the following refrigeration system at Food Town, Takapuna, New Zealand through the Power New Zealand Energy Partnership Program.
The cooling system runs 24 hours a day to provide cooling for the products stored in the store.
The liquid pressure amplifier is a pump, patented by Hy-Save Incorporated of Portland, Oregon, USA and marketed by Hy-Save Australia. The pump is a semi-hermetically sealed unit incorporating a magnetically coupled impeller. Because the motor and impeller are physically separated, motor burnout will not contaminate the refrigerant line, and if the motor does fail, the system will continue to operate.
The LPA can be retrofitted into existing systems, or designed into new equipment for commercial refrigeration and air conditioning.
In traditional systems the liquid must be sub-cooled to eliminate evaporation of refrigerant ("flashing") in the liquid line. The LPA provides extra pressure in the liquid line and allows the pressure of the compressor to be lowered. The increased liquid line pressure eliminates liquid line "flash" gas, resulting in improved efficiency and increased cooling capacity.
In the way the LPA allows the head pressure to be floated with the ambient air temperatures, providing the following benefits:
Increased refrigeration capacity
Using the LPA, it may be possible to further enhance system performance by injecting a small amount of the pressurized liquid refrigerant into the hot discharge line of the compressor. Liquid injection desuperheats the refrigerant, improving the efficiency of the condenser.
Liquid injection is more suited to systems working in warmer climates, or at high loads.
The system was tuned by the usual refrigeration contractor to extract the best possible efficiency from the system.
The system's energy consumption was recorded for six days before and after the LPA, using the Altech Controls datalogger associated with the refrigeration system. This monitored the total system energy consumption, i.e., compressor and cooling fans.
The tuned system cooling capacity was measured before LPA installation using an ETM 2000 refrigeration analyser. Real-time data was verified before analysis recording.
The cooling capacity was measured over a sufficient time frame to enable a range of system loading and ambient temperatures to be considered for extrapolation into an annual operating profile.
The simple payback on total expenditure is approximately 12 months, with an net present value of approximately NZ$36,870 over a ten year equipment life. Due to this success, Food Town is now conducting a nationwide store installation program.