Ammonia chiller exceeds expectations
13th May 2026
UK: The installation of Star Refrigeration’s low-charge ammonia Azanefreezer 2.0 has delivered energy savings far exceeding initial projections at a food distribution hub in Daventry.
The successful upgrade of the frozen storage refrigeration system at the DHL Wetherspoon distribution centre is said to have cut annual electricity use by more than 600,000kWh, reducing costs by nearly £200,000 per year, and lowering carbon emissions by 123 tonnes.
The project forms part of a long-term partnership between Star Refrigeration and DHL, who operate the 192,000m3 J D Wetherspoon distribution hub. Faced with rising maintenance costs and an ageing refrigeration plant originally installed in 2004, DHL sought a future-proof, environmentally responsible solution capable of supporting both firms’ net zero goals. A comprehensive technical and financial analysis conducted by Star demonstrated the limitations of the existing pumped-circulation ammonia system and outlined the efficiency, safety and lifecycle benefits of upgrading to a modern, low-charge ammonia design.
Forecasts suggested that maintaining the old plant would incur approximately £400,000 in upgrade costs between 2024 and 2027, with a further £180,000 expected in running costs. By contrast, the Azanefreezer 2.0 offered a system with no water usage or associated treatment requirements, advanced intelligent controls, and a significantly lower ammonia charge of just 220kg, improving both safety and environmental performance.
The new 290kW system was designed to operate alongside an existing 120kW Azanefreezer 1.0 installed in 2016.
To minimise disruption to operations, Star implemented a phased decommissioning of the old plant during winter, allowing the freezer to remain fully operational throughout the installation.
Since the upgrade, the site is said to have achieved a 17% improvement beyond the UK’s best practice benchmark for cold storage facilities of a comparable size. With annual energy savings more than triple the original £5,000-per-month estimate, the project has delivered a payback period of under two years – far faster than projected.
DHL engineering manager Daniel Johnson confirmed that the new system is saving on average around 617,000kWh per year, compared to the old system.
The addition of Star’s Ethos AI-enabled, data-driven performance monitoring and energy management system provides real-time monitoring, performance benchmarking, and predictive analytics.
“This project shows what is possible when businesses commit to forward-thinking engineering and data-driven decision-making,” said Star Refrigeration’s regional sales manager (Midlands) Aiden Perks.”
The full project video can be viewed on Star Refrigeration’s YouTube channel.
