Cold Link Africa October 2020 | Page 18

PROJECT INCORPORATING COLD CHAIN 1 2 3 Cooling of products is done in forced air-cooling tunnels with vertical fixed galvanised steel racking. Each tunnel has three centrally mounted suction fans of 1 000mm diameter, with 5,5kW motors. Each fan motor is fitted with a VFD to vary the fan speeds according to the specific cooling programme and to optimise power usage. From the cooling tunnels, the cooled pallets are transferred into five regular atmosphere cold rooms. Rails for mobile racking have been included in the floor of one holding room for possible installation of a mobile raking system at a later stage. Cooled products are received and dispatched thruough 10 insulated loading bays with vertical roll up doors, docking seals and docking levellers. Four of the loading bays have been separated from the others to handle the dispatch of pallets under the sterilisation programme. Tautliners with un-cooled fruit are off loaded in an undercover drive-thru bay. Compliance with fire regulations required that sprinklers had to be installed in all the cold rooms dispatch/receiving air lock and offices. A further costly requirement of the fire protection system was the installation of two 500 000l water storage tanks and a pump room with two high pressure pumps – one driven by an electric motor and the other by diesel engine to start automatically in the event of loss of grid power during a fire. The sprinkler system is of a two-stage design to prevent a full discharge of water at the start of what could be a small trace of smoke and cause costly and unnecessary damage. In the event of the intensity of the smoke increasing the discharge changes to full capacity. A containerised diesel driven 1250kVa generator, in close proximity to the plant room, powers the refrigeration plant to 1. Safety is a priority and operators are warned about damage that can be caused due to incorrect stacking of racks in the cooling tunnels. 2. Accordance with SANS10147 operating conditions and charge of the ammonia plant is displayed outside the plant room. 3. Three suction fans in a plenum draw air through pallets stacked in racks in the cooling tunnels. 18 www.coldlinkafrica.co.za COLD LINK AFRICA • October 2020