Air-cooled screw chiller

New chillers for Arla dairy processing plant

Processing of milk products requires the correctly designed process in order to attain end products of the highest quality. Processing of milk involves pasteurization, a technique that destroys pathogens in milk and makes it safe to drink. Pasteurization necessitates the use of chilled water to cool down the milk after the heating-up process to prevent the deterioration. During the cooling process, the pasteurized milk has to be cooled to 0°C. Thus, the production of chilled water for dairy processing operations is a vital part of producing safe and high-quality consumer products. Tight thermal control is also a crucial requirement for dairy processing facilities.

Chilled water plant at Arla which served dairy production facility for over two decades required a replacement with the new, energy-efficient and environment-safe equipment.

The new chilled water plant was to provide a supply water temperature of no higher than -5°C, while the return temperature was expected to be above 20°C. Kaltra engineers have conceived a two-stage cooling solution which included glycol chillers piped in series for cooling the water first from 25 to 10 degrees and then from 10 to -5 degrees. The overall performance of the plant consisting of five air-cooled screw chillers was 120 cubic meters of 35% propylene-glycol solution cooled down to -5°C per hour.

After the detailed assessment, Kaltra offered a number of energy-saving options, including extra condensers to keep the condensing temperature as low as possible, close approach flooded evaporators, and electronically-commutated fans. Kaltra technicians also selected the chillers with unequal capacities to maintain plant efficiency at various heat loads. New flooded type evaporators with low plant-side pressure drop installed on Lightstream Screw chillers also promote significant savings of energy on plant pumps. Optimal cooling plant operation which has great impact on energy efficiency has been ensured by sequence control based on the chilled water return temperature. Kaltra engineers considered the possible control strategies and selected the optimum alternative after extensive study, analysis, and running the model across the full range of operating conditions.

As a result of these improvements, including the impact of optimum control strategy, the overall energy consumption of cooling facilities at Arla drops, saving electricity and money as much as 40%.

The new equipment has appropriate warranties in place and a maintenance agreement for on-going periodic servicing.

Kaltra is an HVAC engineering and manufacturing company headquartered in Germany. We offer a wide range of innovative cooling products for industrial, commercial, and mission-critical applications, such as data centers, clean rooms, contaminant-free areas, processing plants, and other facilities where the reliability and energy efficiency are key factors. Kaltra’s cooling equipment range includes precision cooling systems, air-cooled, free cooling and water-cooled chillers, evaporative cooling solutionsdry coolers, and condensers.

For more information on Kaltra and its products call +49 911 715-32021 or visit