Custom Low-Charge Ammonia System Realizes All-Round Improvements

Custom Low-Charge Ammonia System Realizes All-Round Improvements

Star Refrigeration

Star Refrigeration, a U.K.-based refrigeration engineering company, has manufactured and installed two low-charge ammonia refrigeration systems for a new Lineage Logistics cold storage facility in Great Haddon, near Peterborough in the U.K. This solution offers a number of advantages, including improved efficiency, affordability, and lower running costs.

Lineage is the largest temperature-controlled logistics provider in the world with 200 facilities in seven countries across North America, Europe and Asia. The Peterborough development offers 75,000m(2,648,600ft3) of cold storage space, amounting to 15,000 pallet spaces of frozen warehouse capacity to support Lineage’s plan for growth and the industry’s need for consolidation. 

According to the specifications, Lineage required a 600kW (170.6TR) refrigeration system, designed to achieve a nominal storage design temperature of -24°C (-11.2°F). Running costs were key to the system’s design, with a minimum condenser surface of 4,800m2 (51,667ft2) required to achieve optimum condensing pressures throughout the year. The evaporator absorbed power was also limited to 35kW (9.95TR), while the condenser absorbed power had to be equal to, or less than, 30kW (8.53TR) to maximize efficiency and reduce electrical costs.

Star Refrigeration was able to secure the contract using two independent AF300-S Azanefreezer 2.0 ammonia refrigeration systems. To adhere to the technical specification, Star modified its existing AF300 unit by retaining the existing low-pressure receiver and compressors but upgrading the unit’s condenser and base frame to a larger size. This allowed it to achieve a higher efficiency than that required by the tender, thus reducing running costs.

The use of a larger condenser allowed the facility to operate on 32.2kW (9.16TR) for its evaporators – an 8.1% improvement on the requirement, and just 12.5kW (3.55TR) for its condenser – a remarkable 58.3% improvement. These improvements meant that running costs were significantly decreased over the whole life cycle of the freezers.

“Star Refrigeration was able to respond to the most stringent requests for quality and efficiency and provided a solution that exceeded the technical requirements specified to satisfy the facility’s cooling need,” said Jonathan Baker, Executive Director of Lineage Logistics in the U.K. “We are impressed with the advantages offered by Star’s Azanefreezer 2.0 and the smooth delivery of the project.”

According to a recent press release by Star Refrigeration, results from recent energy performance data analysis for the site indicate that the Azanefreezer 2.0’s annual energy usage is only a third of what is allowed in the U.K.’s “Best Practice” guidelines, meaning that Lineage is set to cut carbon emission by 453 tonnes (507.36 U.S. tons) of CO2 per year as compared to these guideline norms.

Capital costs were also minimized thanks to a few clever tweaks. The Azanefreezer 2.0 is a modular, low-charge, packaged ammonia freezer with a patented low-pressure receiver design, which is unique to Star Refrigeration. Its design allows for a reduction of the system’s ammonia refrigerant charge of up to 80% when compared to traditional pumped recirculation systems. Thanks to the maintenance valves on the Azanefreezer 2.0 unit, as well as the use of reverse-cycle defrost, the hot gas valve stations at each cooler were eliminated, including all the associated ventilation and gas detection components. This is a significant benefit in terms of reducing the risk of refrigerant leakage and simplifying ongoing maintenance.

“Star Refrigeration was able to respond to the most stringent requests for quality and efficiency and provided a solution that exceeded the technical requirements specified to satisfy the facility’s cooling need.” –

Jonathan Baker, Lineage Logistics

The Azanefreezer 2.0 units were assembled at Star’s manufacturing facilities and tested prior to dispatch, which reduced onsite installation times and expenses. It did not require a plant room either, eliminating third-party costs by dispensing with the need for a significant amount of accompanying infrastructure.

Also, the system was designed to have no flanged or mechanical joints within the cold store itself, meaning there are no potential leakage points inside the store. Instead, all valves and mechanical joints are positioned on the exterior of the unit and at heights which make them easily accessible from a maintenance perspective.

This was another great milestone in a long working relationship. Star Refrigeration has been working with Lineage for several decades, having undertaken both new-builds and extension projects for the company in the past.

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