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Project and roofing specialists ensured that insulation materials met performance criteria while remaining cost-effective and practical to install. Through innovative design choices, including decentralised ventilation, free cooling integration and strategic insulation enhancements, the HVAC system met both compliance requirements and financial objectives. The result was a cost-effective, energy-efficient solution tailored to the store’ s unique operational needs.
The insulation strategy for Dhlamini Junction, given the climatic zone of the project, required an R-value of approximately 3.2 for the roof assembly to comply with the SANS 10400-XA energy efficiency standards. This assembly consisted of the roof sheeting, insulation material, thermal breaks, ceiling void and ceiling board.
To achieve the necessary R-value, the project required a 135mm thick Factorylite Glasswool insulation layer. This type of insulation was chosen for its thermal properties and compliance with fire safety standards, ensuring that it was non-combustible and safe for public spaces.
One of the key challenges in implementing this insulation system was the risk of compression, which significantly reduces its thermal efficiency. Typically, insulation is laid over steel purlins before the roof sheeting is installed on top. The weight of the roof naturally compresses the insulation, specifically at purlin interface, diminishing its effectiveness. The final solution involved using an 80mm thick Factorylite insulation layer paired with 50mm XPS( extruded polystyrene) spacers. Apart from reducing the Glasswool compression, the spacer also acts as a thermal break to inhibit conduction from the roof sheeting into the building’ s steel structure. This solution not only optimised thermal performance but also ensured durability and ease of installation, aligning with the overall cost and energy objectives of the development.
The location is designated a‘ cold climate’ zone, enabling the mall ' s HVAC system to utilise natural cooling to cut costs in summer months. Motorised dampers on the fresh air intake, linked to an external louvre system, automatically adjust based on indoor and outdoor temperatures. When conditions allow, the dampers open to bring in cool air, reducing mechanical cooling and enhancing efficiency. During winter, or heating mode, fresh air is limited to baseline compliance values.
A key aspect of the design was ensuring proper pressurisation of each store. For instance, in Shoprite, the extraction system for bakery and deli areas required dedicated makeup air systems, but this alone was insufficient. Balancing the fresh air intake and exhaust ensures a slight positive pressure, preventing dust ingress and maintaining indoor air quality.
Dedicated fresh air and exposed ducted hide away installation at Easy Build Hardware complete with white faced roof insulation. During economy cycle operation, when up to 75 % fresh air is introduced, the potential for over-pressurisation is mitigated by integrating relief dampers. These were installed on the smoke extract fans, allowing excess air to escape while preventing unwanted air ingress.
The project utilised an LG VRF system, chosen for its energy efficiency and adaptability. The system features ducted hideaway indoor units in standardised sizes( 15kW, 22kW and 28kW), allowing for scalability based on store size. Each store is coupled to a dedicated condenser set. The VRF system operates using variable-speed compressors, which
gradually increase capacity instead of running at full tilt immediately. This results in reduced energy consumption, better load matching and extended equipment lifespan.
The LG AC Smart BMS was implemented for centralised monitoring and control. The system provides real-time insights into unit performance, set points and compressor activity. An integrated generator mode was also included, which disables condensers during generator operation to
Aerial view of fire and domestic water storage tanks and pump room including generator and elevated outdoor AC Plant Area 4.
Image by © RACA Journal Image by © RACA Journal www. refrigerationandaircon. co. za RACA Journal I July 2025 35