RACA Journal May 2020 | Page 36

Feature 1 2 1. 2. 36 spoiled produce, a decline in productivity.” How an ice thermal storage system would work during load shedding is; “During Stage 4 load shedding conditions the ice will keep the chilled water at the design temperature of 6°C instead of the chillers, without using any power to produce cooling. The only power required will be to run the chilled water pumps and air handling equipment fans. However, the pumps and fans use a fraction of the chiller power requirement and can therefore comfortably be supplied by a renewable source such as solar panels.” Vermeulen says that if it is designed for such at the time of construction, then, yes it could provide a good solution. However, “if it is designed for Stage 2 and then, for a period, stage 4 becomes common occurrence, the cooling will be compromised so it has be designed for a worst-case scenario. In theory, load shedding is with us for another year so to invest additional capital for such a short-term benefit would not be practical.” Muller says that a thermal storage design shouldn’t be focused on load shedding, “the key is return on investment with regards to energy saving.” RACA RACA Journal I May 2020 The ice found in the coils that is melted during the day. The size of a thermal storage system can start from 200 tons generating about 700kW. There is no limit to the size. www.hvacronline.co.za