How One Ethnic Food Maker Reduced its Energy Use by 30 Per Cent

An ‘ethnic food manufacturer’ recently approached Excalibur to ask how they could increase their energy efficiency when making chilled and frozen foods for supermarkets.

Excalibur, an energy management business, after studying the challenge, realised they could reduce the manufacturer’s energy consumption by 30%. The solution they proposed was using modifications to the existing systems, including Liquid Pressure Amplification (LPA) and Inverter control of condenser fans before re-commissioning the system.

As a result, the refrigeration system could operate with low discharge pressures (or floating head pressure) which allows increased refrigeration capacity and reduced absorbed power.

The solution involves installing the LPA into a manifold, which is on the outlet from the liquid receiver.

Then, refrigerant is pumped to the expansion valve. This provides ‘good quality’ liquid refrigerant in low head pressure operation. Inverter control of condenser fans provides accurate discharge pressure using the entire condenser surface area. The settings are adjusted in relation to external ambient temperature and refrigeration demand, which optimises energy efficiency for any conditions.

The design uses a number of fail-safe features to prevent any production downtime. The pilot installation scheme was on a refrigeration pack fitted with four Copeland reciprocating compressors operating on R404a, with a capacity of 340kW, and a 10 fan air-cooled condenser.

The results?

• Energy Reduction – 36%

• Money Saved – £25,000 a year

• Return on Capital – 18 months

• Carbon Emissions – Reduced by 128 tonnes

“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,” said Steven Pye, operations director at Wholesale Power UK, who carried out the energy surveys.

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