Based in Victoria, Australia, Nestlé’s Packenham Food Processing Plant produces a wide range of frozen and refrigerated meals. Though upgrading parts of their industrial refrigeration system the plant improved their overall energy efficiency performance.
In a case study released by the Energy Efficiency Exchange – a joint initiative of the Australian, state and territory governments – Nestlé revealed how they had achieved their results.
1. An energy audit was undertaken. This identified that the largest refrigeration system was running well below optimum level with more compressors running that necessary, more start/ stop operations occurring than necessary, and some compressors running with only partial load.
So, energy efficiency was definitely below optimum and it was decided that the energy management system and control system of the refrigerator required upgrading.
2. The lowest refrigeration temperature (-42°c) was only needed for one process but was currently being used widely by the refrigerator. Consequently another low-level temperature (-36°c) was added for all other processes, thereby reducing energy consumption.
3. The control system was upgraded from automatic to a logic controller system that could regulate the loading and unloading of compressors and also manage the stop/ start functions. This reduced the overall run hours of the compressors by 18%.
4. Variable speed drives were installed onto the condenser fans creating further energy savings.
Although Nestlé identified that their processes and energy consumption were not at optimal efficiency they chose not replace their entire system with a new, modern industrial refrigerator. Instead they chose to pinpoint the exact areas of weakness and address those parts with updated technology and management systems. This approach delivered both significant energy efficiency improvements, and an excellent return-on-investment timeframe for the plant.
• Refrigeration system electricity consumption reduced by 16%.
• Compressor run hours reduced by 18%. This increases the life span of the asset and reduces maintenance costs.
• Overall site energy consumption reduced by 6%.
• 840 tonnes of carbon avoided per annum.
• Project costs recovered within 6 years.