ISECO Engineering Services

The Melbourne Market in Epping handles the majority for fresh produce entering the city.

This impressive 28,000sqm facility built in 2013 is one of the few sites of this type with 124 tenant loads served from a centralized refrigeration system. The system was carefully chosen to provide a low global warming potential and energy efficient system, using ammonia refrigeration ( GWP =0) , evaporative condensers and a glycol secondary refrigerant . Capacities are big , in the order of 2.4MWr with three screw compressors each with 750 kW variable speed drives.

Because this was such a departure from the traditional model of every tenant having their own air cooled synthetic refrigeration system, the market management sought a review of the systems now that they have been operating for a few years to determine if they were operating efficiently and if improvements could be made.

Iseco performed extensive reviews of the system configuration, SCADA and energy bills and BMS logs as well as maintenance records and reports from the maintenance contractors.

Our findings concluded that the central plant system was indeed operating efficiently, delivering a 26% improvement over equivalent air-cooled systems at peak load and a massive 50% reduction in peak electricity power input.

The recommendations included:

• Review of tenant operational practices to reduce individual tenant loads -tenant loads represent 65% of the total consumption compared to only 17% for the central plant
• Compressor and secondary glycol pumping control loading changes to reduce system overshoot in response to load changes
• Improved BMS /Power monitoring to provide all data on one platform to enable better benchmarking and day to day tracking of energy usage