Kent based AGA, provide fruit storage services to a number of major UK retailers. They have the capacity to store over 7,500 bins totalling around 2,500 tonnes. Cold Storage facilities are provided for the short-term storage of top fruit (below 3°C) - for longer term storage, fruit is stored in a refrigerated low oxygen-controlled atmosphere to reduce degradation.

Orchard’s initial investigations confirmed AGA’s secondary cooling system had traditionally used a salt brine secondary refrigerant (heat transfer fluid). Based on previous experience with brine chillers, Orchard suspected they were looking at a significant corrosion issue.

Consultants, design engineers and installers are more than aware of the potential pitfalls of a brine (salt) based cooling system. While aqueous salt solutions could initially be perceived as a cost-effective option, they can be the cause of expensive, potentially catastrophic failures after a relatively short period of time.

With a reputation for being a high maintenance option, salt-based brines are particularly corrosive if they are not kept in check. Recommended corrosion inhibitors must be added and monitored (along with pH levels) on a regular basis to prevent an acid condition occurring in the system.

The full extent of the damage to system components became evident following a system drain-down, with strainer and isolating valves being particularly corroded and in need of replacing.

The damaged internal working parts of the circuit were swapped out and Orchard recommended charging the cooling system with Hydratech’s Coolflow DTX.

Unlike salt-based heat transfer fluids, non-toxic Coolflow DTX has low corrosivity. It is also formulated with long-life multi-metal and multi-function inhibitors (which exceed ASTM & BS corrosion standards), to prevent internal corrosion, scaling and biological fouling.

The innovative hybrid glycol was introduced in 2010 as a high-performance secondary refrigerant, suitable for replacing propylene glycol and salt brines in food and cold storage cooling systems.

The list of Coolflow DTX adopters is now extensive and includes a host of well-known companies from the food and beverage sectors including, Hovis, DairyGold, Morrisons, Diageo, Thatchers Cider, Molson Coors, BrewDog, Eli Lilly and Co-op.

DTX based coolants are also used in a variety of industrial and commercial sectors, where non-toxicity and low environmental impact are high priorities. End users and contractors from these sectors include, Honeywell Aerospace, Aggreko (Temperature Control Division), Daikin, BMW, Siemens, Mercedes, J&E Hall, Star Refrigeration, GE Aviation and AMEC.

Orchard’s engineers flushed the system with clean water several times to achieve a neutral pH and introduced the Coolflow DTX. As a result of the retrofit - from salt brine to DTX - Orchard are confident the glycol-based system will provide AGA with a more reliable, efficient system.

Hydratech has established a close working relationship with the UK food supply chain over the last 20 years. From crop storage and distribution to retail display, the UK’s leading formulator of hybrid glycols and secondary refrigerants has helped the likes of Waitrose and Sainsbury’s improve the performance, efficiency and energy consumption of their refrigeration systems.

For more information on Hydratech’s Coolflow range click here