Ammonia/ glycol system helps Natures Way save on running costs

In August, Natures Way, a food processing company, installed an ammonia/ glycol refrigeration system at its new plant in the UK. The company regards the ammonia system as the best compromise between costs, safety and environmental impacts.

Natures Way is a supplier of packaged fresh fruit and salads to supermarket and food service companies in UK. In August the company built a new processing facility with an ammonia/glycol refrigeration system on the outskirts of Chichester. The system supplies cooling to a 7.500 m² production space. With the ammonia/glycol refrigeration system, the food processing company is setting a new benchmark for its counterparts to follow by reducing energy consumption and costs.

Ammonia/ Glycol system: the best compromise between costs, safety and environmental impact

When asked the reason behind Natures Way’s choice of an ammonia refrigeration system, Project Manger Nathan Bennett said, “Natures Way chose Ammonia, as it was felt it offered the best compromise between capital investment, running costs, maintenance and environmental impact”.

At the new Natures Way’s new plant, although the cooling medium is less efficient compared to using a direct ammonia refrigeration, it is much safer and easier to modify in the future.

Ammonia evaporators supply 60% of the cooling

The ammonia/glycol refrigeration system is manufactured by Darftord based J&E Hall International. The total cooling capacity of the systems is above 2.7 megawatts.

The key function of the system is to maintain the required air temperature in the preparation halls and at the same time provide chilled water to the processing equipment.

In the plant, the cooling is supplied from a refrigeration room with two screw compressors. Each compressor can provide 60% of the total cooling duty. Each compressor consists of a compressor controller, two evaporative condensers, and two stainless steel plate heat exchanger packs. In the system, ammonia flooded evaporators are sized for 60% duty. These indirectly cool the water with a 25% propylene glycol solution, which is ultimately used as the secondary cooling medium.

Variable Speed Drive saves 25% of running costs

As one of the compressor motor packs is driven by a variable speed drive (VSD), the performance of the unit is greatly enhanced. The speed of the compressor driven by the VSD can vary from 1000rpm – 2975 rpm, which meant that the running costs of the system have been reduced by 25% in less than 18 months.