GLASGOW, Scotland, May 13, 2026 /PRNewswire/ — Star Refrigeration has helped J D Wetherspoon and DHL stride forward in energy efficiency and sustainability with the successful upgrade of the frozen storage refrigeration system at their Daventry distribution centre. The installation of Star’s low-charge ammonia Azanefreezer 2.0 has delivered energy savings far exceeding initial projections, cutting 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 192,000 m³J 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.

The business case was compelling. 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 120 kW Azanfreezer 1.0 installed in 2016. Working together, the units now provide a robust, energy-optimised refrigeration solution capable of supporting the facility’s 31,000m³frozen store with exceptional reliability and efficiency. 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 has achieved a remarkable 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-mongh estimate, the project has delivered a payback period of under two years – far faster than projected.

Daniel Johnson, Engineering Manager at DHL, said, “We have analysed the electricity figures before and after the installation, and the results speak for themselves: the new system is saving on average around 617,000 kWh per year. This has produced substantial energy cost reductions and helped us exceed industry efficiency standards. Working with Star Refrigeration has been a very positive experience. Their team took the time to understand our operational demands and sustainability goals, and the new system now provides long-term resilience, efficiency and environmental benefits.”

The refrigeration performance and operational visibility of the site have been further strengthened by Star’s Ethos technology, and AI-driven digital optimisation system that provides real-time monitoring, performance benchmarking, and predictive analytics. Ethos enables Star’s engineering and maintenance teams to identify inefficiencies, anticipate future requirements, and support ongoing energy reductions. Remote monitoring, combined with the expertise of Star’s 30-strong Derby-based team, ensures the system continues to operate at peak performance.

The project represents an important milestone in the evolving UK cold chain landscape, where operators are facing rising pressures to reduce energy consumption, minimise carbon impact, and comply with future environmental regulations.

Aiden Perks, Regional Sales Manager (Midlands) at Star Refrigeration, said, “This project shows what is possible when businesses commit to forward-thinking engineering and data-driven decision-making. The impact at Daventry reduced energy use, lower costs, and demonstrated the value of strong partnerships that place innovation, lifecycle costs, and sustainability at their core.”

With more than 18 months of operational data confirming consistently strong performance, the Daventry facility is now considered one of the most energy-efficient cold stores in the country, offering a powerful example of how industrial refrigeration can support both commercial competitiveness and environmental responsibility.

For more information visit the DHL / J D Wetherspoon refrigeration project case study.