The iconic Mutual Place design criteria called for an energy-efficient chilled water air-conditioning system that would contribute towards attaining a 5-Star Green Star rating, while also maintaining office indoor environmental conditions as required by the client (22.5 ± 1.5°C and NC40 acoustic levels in general office areas). Rickard is proud to have supplied our VAV Swirl and constant volume diffusers that contributed to the energy efficiency of the building. The diffusers are managed and integrate with the BMS through our state of the art MLM system.
By Deo du Plessis of Spoormaker & Partners
The iconic new Old Mutual headquarters in Sandton features a state-of-the-art HVAC installation that combines the elements of energy efficiency, practicality, comfort, and feasibility.
The 12-storey 5-Star Green Star building was designed by LYT Architecture following years of various feasibility schemes. A complete glass façade, narrow aspect ratio, and unique shape all contribute to a true landmark building while also providing unique challenges to the mechanical design and installation. In addition to the top structure, an eight-level super basement provides underground parking and service areas to Mutual Place and future buildings on the same precinct.
The design criteria for Mutual Place called for an energy-efficient chilled water air-conditioning system that would contribute towards attaining a 5-Star Green Star rating, while also maintaining office indoor environmental conditions as required by the client (22.5 ± 1.5°C and NC40 acoustic levels in general office areas).
Ventilation requirements involved adhering to strict fire rational ventilation requirements as well as SANS fresh air regulations, while providing a system as flexible as possible to future tenant changes. Some of the interesting design challenges inherent to the building design included the limited roof plant space available, coupled with the significant thermal load and ventilation requirements, as well providing occupant comfort to various pause areas in an unconditioned multivolume atrium with feature ceilings.
The HVAC system at Mutual Place features a high-efficiency air-cooled chiller plant at roof level, providing chilled water at 8°C and hot water at 45°C to an energy-efficient four-pipe network of decentralised variable air volume (VAV) air handling units (AHUs) in plant rooms on every floor.
Two 1 200kW cooling-only chillers supply the cooling demand, while a 900kW heat pump chiller addresses the heating load, with both loads measured and controlled in real-time. The heat pump chiller can also be coupled to the chilled water system with automatic control valves, should the cooling demand require it. A dedicated 90kW data chiller connected to the same network provides cooling to IT-critical areas after hours, thereby avoiding energy wastage and reduced lifetime associated with running large chillers at low load. A primary-secondary pumping arrangement circulates chilled and hot water, with variable speed pumps efficiently supplying the AHUs with chilled/hot water to meet the thermal demand.
Article published on HVACR Online