Ethnic food manufacturer reduces energy consumption by 30%
With refrigeration consuming 40% of their electricity, a leading supplier of ethnic supermarket chilled and frozen ready meals approached Excalibur to advise on how energy efficiency could be improved.
A detailed study showed that there was potential to reduce energy consumption by over 30%, the installation of Liquid Pressure Amplication (LPA), Inverter control of condenser fans and recommissioning was proposed.
The modifications would allow the refrigeration system to operate at low discharge pressures, often referred to as floating head pressure, increasing refrigeration capacity while reducing absorbed power.
LPA is installed into a manifold on the outlet from the liquid receiver; refrigerant is then pumped to the expansion valve, providing good quality liquid refrigerant during low head pressure operation.
Inverter control of condenser fans provides accurate discharge pressure using the entire condenser surface area. Settings are continually adjusted in relation to external ambient temperature and refrigeration demand, optimising energy efficiency for any conditions.
The design incorporates a number of features to ensure that no single point of failure could affect production.
An initial pilot installation was undertaken to a refrigeration pack tted with 4 Copeland reciprocating compressors operating on R404a, with a capacity of 340kW, and a 10 fan air-cooled condenser.
The pack was monitored prior to modification to establish a base line performance. Installation was completed and the monitoring repeated to show the improvements in efficiency.
An energy reduction of 36% was achieved, this represented a cost reduction of over £25,000 / year, a return on capital of less than 18 months, and a 128 tonne reduction in CO2 emissions.
The success of this project convinced the client that significant cost reductions could be achieved and Excalibur were instructed to modify a further 5 systems, which have demonstrated a similar reduction and a return on investment of less than 2 years.
Steven Pye, Operations Director at Wholesale Power UK Limited, undertook energy surveys at the sites following the modifications and reported that the sites were delighted not only with the performance and the associated reduction in consumption, costs and emissions, but also with the quality of the installations.