Pick 'n Pay Eastport
CLIENT: PICK 'N PAY
DATE: MARCH 2023
LOCATION: EASTPORT, GAUTENG
SIZE: 45 000m
PROJECT DESCRIPTION
This facility is one of the largest, if not the largest, chilled distribution centres in South Africa. The overall site measures 360 000m , of which 150 000m is distribution area. 45 000m of that is the chilled distribution area, and forms the portion of the development that AMC was involved in. AMC completed the design, tender and site supervision of the Refrigeration and Insulated Structures, as well as the HVAC to all ancillary buildings.
THE DESIGN
The ammonia plant is a 7.2 MW installed refrigeration plant with a total of 9.2 MW of heat rejection to the evaporative condensers.
The plant is divided into two suction regimes, namely minus 8.75°C and +3.25°C, to optimise energy efficiency. The -8.75°C system is a 4.5 MW chilled glycol system supplying the 2°C rooms with cooling, while the +3.25°C system is a 2.15 MW plant supplying the 14°C and chocolate box rooms with cooling.
The additional high stage capacity is utilised to economise the medium (-8.75°C) plant by means of open flash economising in the high stage vessel.
The heat from the spaces (with the future ambient area incorporated) is removed by means of 80 coils of 74 kWR each in the 2°C space, 24 coils of 76 kWR each in the 14°C space and four coils of 73 kWR each in the chocolate box.
The waste heat recovery from plant is designed for a peak heat recovery of some 317 kW, although initially only 200 kW will be recoverable due to the plant capacity ramping up over the life of the facility. This waste heat is utilised to warm the water to the crate wash plant.
There is provision for a heat pump, utilising the discharge gas from the primary ammonia plant and compressing it to 70°C saturated conditions in order to generate hot water, in future, if required.
Due to safety, and as a result of the size of the facility, the decision was taken early on in the design phase to use secondary refrigerants in the field and limit the ammonia charge to the plant room. Noting the congestion in the roof void and the travel distances, it was a prudent decision, and greatly increased the safety aspects of the overall facility and roof void.
Rainwater harvesting forms a key component to the overall system and facility design. This rainwater is treated to a high quality, to make it suitable for use in the evaporative condensers, as well as site potable consumption. This greatly reduces potable municipal water consumption while also providing a large back-up water source, requiring municipal water as back-up / top-up only.
Of the total 350 000m , site area, 250 000m is utilised for water harvesting. The total estimated water consumption for the whole site is 125 M litres, of which 69 M litres are consumed by the refrigeration plant. Although a total of 133 M litres is available for harvesting during a year, due to peak rainfall and demand mismatch it effectively results in a total amount of harvested water that can be consumed on site of 75 M litres per annum.
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