Case Study Energy Efficiency -Liquid Pressure Amplification

A Norlake Walk-in-Freezer used for the storage of serum at the J Hillis Miller Health Centre, University of Florida, Gaineville,Florida had to maintain a temperature -30 ºC with a maximum temperature of – 20 ºC .

The two chillers operating on R502 dump the extracted heat into the main chilled water circuit (8 ºC ). One chiller should have been on standby, but to achieve satisfactory operation the flow of chilled water to the condensers wasrestricted so that the head pressure was maintained at 15.5 bar and even at this condition flashing occurred in the required time.

This reduced the system capacity so that it was no longer able to meet the requirement to maintain – 20 ºC with one chiller operatingand one on standby. A LPA® Liquid Pressure Amplifier was installed and the head pressure was reduced to 8.2 bara. The capacity of the system increased by 58% and there was a 37% reduction in compressor amperage, reducing the energy consumption by 60%. The savings are exceptionally large in this case because of the use of chilled water as a dump. This does however show the potential for energy savingavailable in many systems by the removal of head pressure control.

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