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 .
From an office HVAC perspective there are multiple different systems serving the satellite offices in terms of ventilation and air conditioning . The main office block has a highly efficient VRF system as well as a rooftop package unit for large open areas such as the canteens . Satellite offices and remote areas are served by means of cost-efficient split units .
Rainwater harvesting forms a key component of 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 and provides a large back-up water source requiring municipal water as backup / top up only .
Of the total 350,000m 2 site area , 250,000m 2 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 are 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 the site of 75 M litres per annum .
ELECTRICAL ENGINEERING Site Bulk Power The site is fed from council with a supply capacity of 7,100kVA at 11kV ( MV ) connection .
The client then has a full ( 100 %) backup step-up 11kV generator farm , with 5x 2,000kVA / 1,600kW generators in sync ( n + 1 redundancy system ). Generators are fed from a ± 84,000L diesel bulk underground tank .
There is a full ( 100 %) UPS backup throughout the site for all Red dedicated socket outlets for IT and server rooms .
dam which is utilised for harvesting has a capacity of 3,500m 3 .
The collected rainwater is being pumped from this pond / dam to a filtration plant where it is filtered and pumped back into an underground concrete storage tank . The storage tank is located below the parking area of the development and has a total storage capacity of 1,000m 3 ( 1,000,000 litres ).
The stored , filtered water is then being pumped and reticulated to the various site operational activities such as the refrigeration plant and water closets within the various buildings .
SUSTAINABILITY The DC will be applying for an Edge Certification for its commitment to incorporating green and sustainable practices . The facility will harvest all its rainwater through on-site attenuation dams as well as a one million litre storage tank . This water will feed domestic supply as well as the refrigeration system running the perishables building . Excess water from the refrigeration and crate wash facilities will be recycled for washing of the Pick n Pay truck fleet , while waste heat generated from the refrigeration plant will be harnessed to heat water for the crate wash . The solar system , included onto the Dry Goods roof , is expected to be ± 3MWp , consisting of around 5,500 PV modules and produce ± 4,781,000kWh of electricity .
CONCLUSION The Pick n Pay Inland 2 Distribution Centre is a mammoth achievement from both a design and engineering perspective and sets the bar high on what can be achieved with Industrial facility construction in South Africa .
Lighting There is 100 % full LED lighting throughout the site . There is a DALI lighting automation system with sensors in the warehouses ( occupancy in aisles and daylight harvesting in open areas ).
Lighting designs were carried out via software simulation for maximum efficiency , required lux levels and low power output . The office lighting is controlled via standard motions sensors and master switch system at reception .
CIVIL ENGINEERING Rain Water Collection The rain water is collected by means of open channels and underground pipe systems where it is collected and discharged into a recessed attenuation and storage pond / dam . The portion of the pond /
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