CASE STUDY www.jehall.co.uk Natures Way Invests In Ammonia Plant
Natures Way invests in ammonia plant to increase cooling efficiencies, maximise product freshness and minimise its environmental impact
“NWF has been very pleased and impressed with our appointed contractors, such as J & E Hall, and their ability to work concurrently with the builders to meet NWF aggressive build schedule. We are delighted that we were able to go from breaking ground to manufacturing our first customer product in 38-weeks,” says Richard Sellis, Head of Engineering, Natures Way.
The project was characterised by Natures Way’s philosophy that requires a green solution for all business activities. The company prides itself on its ‘zero to landfill’ approach where as much as possible is recycled including waste water which is used to irrigate crops.
At the heart of the ‘pack house’ is the refrigeration plant When Natures Way the UK supplier of packaged fresh fruit which maintains the required air temperatures in preparation and salads to major retail and food service companies built halls and provides chilled water to the processing equipment. a new processing facility, a refrigeration system using a
natural refrigerant was a critical part of the design criteria. Two HallScrew compressors were installed Natures Way is a major supplier of prepped and ready to eat Salads and Fruit to many of the high supermarket chains and its philosophy from its inception some 16 years ago is The cooling is supplied from a plant room built by J & E Hall characterised by its name. All of its products are fresh and which includes two HallScrew HSO 2035 open drive single natural and the company strives to build a business that screw compressors each sized to provide 60% of the total is in harmony with its environment. cooling duty and each fitted with a Fridgewatch™ compressor controller (one per compressor pack), two evaporative condensers, two stainless steel plate heat Where practical produce is sourced locally and the same exchanger packs - ammonia flooded evaporators sized for ethos was applied to the building of the plant, materials, 60% duty. These indirectly cool the water with a 25% labour and equipment including its critical resource – a state propylene glycol solution which is ultimately used as the of the art central Ammonia /Glycol refrigeration plant secondary cooling medium. supplied by Dartford based J & E Hall International.
The large system volume totalling some 180,000 litres of The south coast was already home to two Natures Way water/glycol eliminated the requirement for a system buffer facilities at Selsey and Runcton when demand for fresh tank. produce required a major expansion. The company acquired a green field site on the outskirts of Chichester which became Natures Way specifications and requirements took into NWF Merston offering 7,500m² of production space. account the future expansion of the site and redundancy against servicing/critical system failures. These considerations The south coast was already home to two Natures Way provided a total cooling capacity at design conditions in facilities at Selsey and Runcton when demand for fresh excess of 2.7 megawatts. produce required a major expansion. The company acquired a green field site on the outskirts of Chichester which became NWF Merston offering 7,500m² of production space.
CASE STUDY www.jehall.co.uk Natures Way Invests In Ammonia Plant cont...
Reducing energy consumption, carbon emissions, energy costs, maintenance and overall costs long term were essential criteria for Natures Way who takes a pragmatic but holistic approach to its business and the environmental impact which has to be minimal.
As a result one of the compressor motor packs is driven by a variable speed drive (VSD) for more efficient capacity control. It enhances the performance of the unit at part load acting as the lead compressor until the load exceeds its maximum capacity. At this point the second, fixed drive pack, automatically takes over to take care of the load and the VSD pack runs to trim the load accordingly. Also the speed of the compressor driven by the VSD can vary from 1000rpm – 2975 rpm and in so doing can reduce the running costs by up to 25% offering a payback on the cost of the VSD in less than 18 months. “Natures Way chose Ammonia, as it was felt it offered the best compromise between capital investment, running costs, The second compressor pack has been designed with soft maintenance and environmental impact,” says Nathan start and capacity control is achieved by means of Bennett Projects Manager at Natures Way. compressor slide valves that provide continuous variable (stepless) capacity control. Part load operation is very The factory’s refrigeration duty is served by a mixture of efficient. water and 25% (by weight) food safe, propylene glycol. This cooling medium, though less efficient than direct The production and storage areas are temperature ammonia is far safer and the system is easier to modify in controlled and some incorporate positive pressure and the future. This medium is pumped through system distribution regular air changes to comply with their customer’s pipe work at -7°C and controlled by valve stations located requirements. in the roof void, to serve in total 43 coolers at ceiling level and a number of different production process requirements. The room cooling in the production and storage areas are supplied by a series of ceiling mounted food grade coolers, Year on year Natures Way is setting a remarkable which are specially coated to prevent any contaminants benchmark for other companies to follow by reducing its adhering. They are controlled and monitored by a energy consumption and costs. sophisticated building management and monitoring system. The company has ambitious growth plans. It has already The whole plant has the capability to be monitored remotely unveiled its own branded Lasting Leaf salads as well as and the system has been designed to reduce on-site man producing leafy bowls and trays. The fabric of the building power and improve maintenance. The plant operates 24/7; and the services-infrastructure has been designed to meet downtime is not an option as a major system failure could these future plans. impact their ability to maintain customer service. The ability to diagnose and affect most repairs remotely saves time and In keeping with its environmental concerns, Natures Way is minimises manual intervention which in turn reduces also actively looking at a number of environmental initiatives maintenance costs. In the event of a serious problem, using biofuels. The company’s environmental commitments J & E Hall engineers are on 24-hour callout. and blue sky thinking characterise a highly successful business.
J & E Hall Limited
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All data printed is believed to be correct at the time of issue and is for guidance only. We accept no liability for any incorrect information supplied. For further technical specification please contact J & E Hall Limited. Ref: Naturesway17.0_0216