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
A detailed study showed that there was potential to reduce energy
consumption by over 30%, the installation of Liquid Pressure Amplification
(LPA), Inverter control of condenser fans and recommissioning was
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 fitted
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.