In a strategic investment to improve efficiency and sustainability, J D Wetherspoon has upgraded its Daventry distribution hub with Star Refrigeration’s state-of-the-art Azanefreezer 2.0. The investment to replace their ageing refrigeration system with a modern, energy-efficient low charge ammonia design system was made on the advice of J D Wetherspoon’s long standing logistics partner, DHL.
Star Refrigeration’s low-charge ammonia system saves nearly £200K annually at DHL / J D Wetherspoon distribution centre in Daventry
Background
DHL is a global leader in logistics with a strong focus on sustainability. As part of its extensive network, the company operates a 192,000 m³ warehouse on J D Wetherspoon’s behalf in Daventry. The facility stores food, drink, and consumables, serving as a national distribution hub for the large British and Irish pub chain.
Star Refrigeration and DHL share a longstanding partnership, with Star providing maintenance for the chilled and frozen storage areas at the site for over a decade. The facility is divided into three main areas, including a 31,000 m³ frozen store, a 24,000 m³ chilled store, and a 137,000 m³ ambient store.
Installed in 2004, the existing frozen store system was functional but was becoming increasingly costly to maintain. The logistics firm partnered with Star Refrigeration to present the business case for replacing the traditional ammonia pump circulation refrigeration system with a more future-focused alternative.
Star Refrigeration’s maintenance team produced an analysis of the total cost of ownership, including service, ammonia hazard assessments and component upgrade costs. Forecasts indicated the costs over the 2024-2027 period would amount to approximately £400,000 for necessary upgrades, with an additional £180,000 in projected running costs for power, water, water treatment, and maintenance requirements.
As part of J D Wetherspoon’s and DHL’s commitment to achieving net-zero emissions by 2050, the companies opted to replace the ageing system with a highly energy-efficient, low charge ammonia Azanefreezer 2.0. This upgrade supported their ISO 14001 and 9001 environmental and quality assurance management objectives, cutting carbon emissions while driving greater efficiency.
Daniel Johnson, Engineering Manager at DHL, said, “Star Refrigeration has been a valued partner at our Daventry site for many years, providing maintenance support for our refrigeration equipment across our chilled and frozen storage areas. After seeing the benefits of the first Azanefreezer 1.0 operating alongside the ammonia pump circulation system, and following a careful review of Star’s cost analysis of the ageing plant, a decision was taken to invest in the latest Azanefreezer 2.0 upgrade.
“This allowed us to avoid over half a million pounds in service, maintenance, and running costs, reduce our annual energy bill, and make significant progress towards our customers’ sustainability goals.”
Peace of mind and a sustainable future
With the new system now operational for over 18 months, the consistent results continue to validate the investment decision. The combination of the AF290E and existing AF120 Azanefreezers provides a robust, efficient, and environmentally sound cooling solution that will serve the business needs for decades to come.
Star Refrigeration maintains the optimal performance of the site’s refrigeration systems through weekly data collection via remote monitoring, supported by a dedicated maintenance team of over 30 staff based at its Derby office. This gives DHL peace of mind, knowing that their customer receives the highest level of aftercare and support.
Real-time data from the Azanefreezers is captured through Star Data Analytics advanced ‘Ethos’ technology, an AI-driven performance optimisation and smart monitoring system. Ethos delivers in-depth analysis of energy use and component efficiency, predicts future energy requirements, and runs ‘what-if’ scenarios to enable continuous operational improvements. The use of Ethos technology, combined with targeted maintenance interventions informed by live operational data, has been proven to deliver significant energy savings and reductions in carbon emissions for many cold chain businesses across the country.
With the UK cold chain under pressure to reduce energy consumption, the J D Wetherspoon / DHL site is now a model of what net zero aligned logistics infrastructure can look like. This successful collaboration demonstrates how companies can transform operational challenges into opportunities for innovation, cost savings, and CO2 emission reductions, ultimately contributing to a cleaner, safer future.
Daniel Johnson, Engineering Manager at DHL, said,
We have run the electricity figures before and after the new refrigeration plant installation, and our findings are that the new system saves on average 617,000 kWh per year. This has delivered substantial energy cost savings and helped us exceed industry efficiency standards.
Working with Star Refrigeration has been a very positive experience. They’ve been proactive, knowledgeable, and always ready to support us throughout the project. The team took the time to understand both our operational requirements and our broader sustainability ambitions, and helped us deliver a future-proof temperature-controlled storage facility that supports not only our own Net Zero Strategy but also that of our customers.
We’re proud to be able to offer this kind of sustainable value to our customers as part of our commitment to greener logistics.
Sustainable Solution with Low Life Cycle Costs
Building on the success of the 120 kW Azanefreezer 1.0 installed in 2016, Star Refrigeration proposed adding a new Azanefreezer 2.0 unit to work seamlessly alongside the existing unit, delivering the additional capacity needed to maintain cold store operations.
The new modular Azanefreezer 2.0 met DHL’s requirements as a future-proof solution. With a predicted lifespan of over 25+ years, the system delivers 290 kW of cooling at -22°C and operates with an ammonia charge of just 220 kg, therefore improving safety and environmental concerns. The air-cooled system design eliminates the need for water usage and associated treatment costs, while advanced intelligent control systems optimise efficiency, resulting in a significant reduction in monthly energy bills.
The installation process required careful planning and execution to avoid disruption to daily operations. The Star team decommissioned the old ammonia plant in stages, employing a phased approach to remove each of the existing three evaporators during the winter period, when demand on the system was lower. This methodology allowed DHL to maintain continuous operation of the freezer throughout the installation without any loss of temperature or disruption to operations.
Energy Performance and UK ‘Best Practice’ Benchmarking
The results have so far exceeded all the initial projections. While the original business case estimated monthly savings of £5,000, actual energy cost reductions have been reported at £16,500 per month, more than three times the anticipated amount, delivering a return on investment in under two years.
Through improvements in energy efficiency and reductions in carbon emissions, the new refrigeration system enables Wetherspoon to progress toward its Scope 1, 2, and 3 emissions targets – a goal that is increasingly important across the supply chain.
An energy usage analysis for the 31,000 m³ facility revealed an energy consumption rate of 19 kWh/m³/yr, nearly 17% lower than the UK’s ‘Best Practice’ benchmark, which is reported at 22.9 kWh/m³/yr.
DHL’s refrigeration system significantly outperformed the UK’s most stringent ‘Best Practice’ benchmark for cold stores of comparable size, a standard met by only a small number of sites nationwide, placing the facility among the country’s most energy efficient.
Star Refrigeration’s low-charge ammonia system saves nearly £200K annually at DHL / J D Wetherspoon distribution centre in Daventry
| Client: | Wetherspoon/DHL |
|---|---|
| Location: | Daventry |
| Sector: | Temperature Controlled Storage & Distribution |
| Service: | Installation Manufacture |
| Equipment: | Azanefreezer 2.0 |
| Refrigerant: | Ammonia |
Global leader in logistics
Azanefreezer 2.0
Future-proof solution