RACA Journal June 2016 - Page 51

Projects 1 potential for damage relative to that of the refrigerant type CFC11 which has an ODP of 1 and is the most damaging of the CFCs. The ODP is defined as the total change in ozone per unit mass when the substance has reached a steady state in the atmosphere. The atrium heating is provided by underfloor hot water PEX pipes. Insulation is installed below the slab to reduce heat loss to the outside ambient during cold months. HVAC system selection With regards to cooling method, we considered various types of air-conditioning systems, all of which were chilled water, air-cooled systems with variable air volume air handling units and fan coil units. Three different options of no ice storage, partial ice storage and full ice storage were examined and the final system that was selected was the partial ice storage system. With regards to the heating method, we considered various types of air-conditioning systems as follows: 1. Option 1: Electrical heating on all air handling units and fan coil units. 2. Option 2: Hot water, air-heat pump system with variable air volume air handling units and fan coil units, with no hot water storage. 3. Option 3: Hot water, air-heat pump system with variable air volume air handling units and fan coil units, with hot water storage. The final system selected was option 3. www.hvacronline.co.za 2 3 1. 2. 3. Inside the new Novartis head office. The ice storage tanks. Most of the HVAC equipment is located on the roof. RACA Journal I June 2016 49