Star Refrigeration has installed a 290kW (82.4TR) low-charge ammonia (R717) system in a warehouse in Daventry, England, for British pub operator J D Wetherspoon.
The 192,000m3 (6,780,416ft3) warehouse stores food, drink and other consumables and serves as a national distribution hub for the chain. The facility is divided into three areas: a 31,000m3 (1,094,754ft3) frozen store, a 24,000m3 (847,552ft3) chilled store and a 137,000m3 (4,838,109ft3) ambient store. The facility is operated by DHL on behalf of J D Wetherspoon.
The new low-charge ammonia system replaced an ammonia pump circulation refrigeration system installed in 2004. Star said the current system would have required upgrades from 2024 through 2027 at a cost of £400,000 (€464,116/$529,620) along with an additional £180,000 (€208,852/$238,329) in projected costs for power, water, water treatment and maintenance.
Technical details: The manufacturer installed an Azanefreezer 2.0 to complement the already operational Azanefreezer 1.0, which was installed in 2016 and has a capacity of 120kW (34.1TR).
- The new 290kW unit provides cooling at −22°C (−7°F) for the warehouse’s frozen store and has an ammonia charge of 220kg.
- The Azanefreezer 2.0 is air-cooled, which eliminates the associated water costs of the previous system. The system has a lifespan of more than 25 years, and it is expected to deliver a return on investment in under two years, according to Star.
- Star carried out the installation in phases to ensure the warehouse’s daily operations would not be disrupted.
Simply the best: Star Refrigeration said the system, which has been operating for 18 months, has a specific energy consumption (SEC) value of 19kWh/m3/yr. SEC is measured in kilowatt-hours per cubic meter per year with the volume defined as the total warehouse’s refrigerated volume.
- This is nearly 17% lower than the U.K.’s best practice benchmark of 22.9kWh/m3/yr. The benchmark was developed by Andy Pearson, Managing Director at Star, and presented to the International Institute of Refrigeration (IIR) in 2019.
- A modern and well-maintained cold storage facility of 100,000m3 (3,531,466ft3) should have an SEC of 10kWh/m3/yr for the refrigeration system, while for a 500,000m3 (17,657,333ft3) facility, the SEC could be less than 5kWh/m3/yr, per Star’s benchmark.
- The new unit reduced energy use by 600,000kWh annually, resulting in savings of £200,000 (€232,253/$264,679) while cutting 123 metric tons of CO2 emissions per year.
By the numbers: There were an estimated 5,700 industrial sites worldwide using low-charge ammonia as of December 2025, according to the ATMOsphere report “Refrigeration: Commercial and Industrial Refrigeration with Natural Refrigerants.” ATMOsphere is the publisher of NaturalRefrigerants.com.
- In addition to Star, Australia’s Scantec Refrigeration Technologies is a notable name in the low-charge ammonia industry. In January 2026 Scantec delivered a 1.13MW (321TR) low-charge direct expansion (DX) ammonia system for a cold storage facility located in Melbourne.
- In 2025 Denmark-based Danfoss touted its NeoCharge system as a “shortcut to low-charge ammonia” that could save operators of DX systems up to $200,000 (€175,000/$199,737) annually by lowering the recirculation ratio in recirculated systems.
