RACA Journal June 2016 - Page 29

Feature Thermal ice storage – is it worth it? By Ilana Koegelenberg Despite notable energy savings and a quick return-on-investment, thermal ice storage systems have been slow on the uptake locally because of seemingly high equipment costs – is this a good enough reason? T hermal energy storage is like a ‘battery’ for a building’s air-conditioning system. It uses standard cooling equipment, plus an energy storage tank to shift all or a portion of a building’s electrical power demands for cooling to off-peak, night time hours. During off-peak hours, ice is made and stored inside energy storage tanks. The stored ice is then used to cool the building occupants the next day. Increasing greenhouse gas emissions and rising fuel prices across the globe are the primary reasons behind the efforts to effectively employ systems that aid in generating energy through renewable sources. Demand for thermal energy storage technologies is likely to rise due to depleting energy resources coupled with continuous rise in energy consumption. Thermal energy technologies help reduce consumption of energy and increase energy supply by efficiently using renewable energy sources. In order to meet emission reduction targets, the challenge to engineers to develop clean, reliable energy technologies has never been so pressing. With the global potential for grid energy storage by 2017 expected to account for 185GWh (52GW) of capacity, renewable energy technologies such as wind and solar power both offer potential solutions but the unresolved issue has always been consistency of supply and how to store power generated for use at a later date. That’s where thermal energy storage, and especially thermal ice storage, comes in. For over a decade, TES technologies have been deployed to store energy and this capability is becoming increasingly used to shift peak energy use into off-peak hours. Mediclinic Morningside is considering adding more ice storage tanks to further optimise its HVAC system. The ice storage tanks for Newtown Junction’s Nedbank are located in the basement and reach up multiple levels. Global picture The global thermal energy storage market is predicted to grow at a compound annual growth rate (CAGR) of 18.7% over the period 2014-2020 according to a ‘Global Thermal Energy Storage Market 2015-2020’ report done by Research www.hvacronline.co.za Continued on page 29 RACA Journal I June 2016 27