RACA Journal October 2020 | Page 31

Projects The new mall construction started in 2016, although the planning started more than 10 years ago. It was to open mid-2018, but due to project delays only opened in August 2019. The addition to the existing 87 149m 2 construction makes Fourways Mall the largest mall in South Africa. The design specification was to provide an overall costeffective and practical HVAC system suitable for a modern mall operation. Important design specifications, among others, were: • life cycle costing • system flexibility due to constant tenant churns • Per-tenant energy measurement and billing 1 THE HVAC SYSTEM INFORMATION The concept chosen was a closed-circuit condenser water system with DX water cooled package units, and decentralised un-conditioned fresh air. The main reason this system was chosen was for the system’s relatively low life cycle cost, high level of flexibility and capability of per-tenant billing. The new mall development section consists of the following systems: Central closed-circuit condenser water plant The main cooling tower plant consists of five towers with dry cooling capacity to reduce water usage and allow for partial cooling during domestic water shut-down periods. Closed circuit cooling towers are used to ensure that the water circulated to the DX package units is clean and does not foul the heat exchangers on the DX units in the shops. This ring main consists of more than 8km of piping. 2 RACA Journal 3 RACA Journal 1. An aerial view of the new development with roof plant room on the bottom right. 2. 2097kW Evapco closed circuit cooling tower (eco-ATWB-H 12-4L18-U22). 3. A top view of the cooling tower plantroom layout located on the roof. www.hvacronline.co.za RACA Journal I October 2020 29