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Feature
THE STRANGEST BATTERIES :
AN ICE MAKER THAT CHILLS A BUILDING
Written by Eamonn Ryan
Today , with the rise of green energy sources like solar and wind , the need for industrial-scale energy storage is becoming ever more vital to make sure there ’ s power even after the sun sets or the breeze dies down .
All photos by Evapco
As night falls over the city , at a gleaming Sandton office tower employees shut down their laptops , grab their mobiles and flood out of the building as the workday ends .
But in the basement , the action is just getting started . Using cheaper overnight electricity from the grid , a large refrigerator chills water mixed with glycol ( a component of antifreeze ) below the freezing point . The system then pumps the mixture into tubing coiled inside each of the tanks full of water . Hovering near zero , the glycol solution freezes the water , effectively storing energy in the form of ice .
The next day , when the building ’ s cooling capacity is about to be breached , the glycol mix flows out of the coils and into a closed-loop air-conditioning system . Combining with water and air , it helps to chill the building for hours during the day — when power is typically pricier . Ice storage systems apart , the electric grid is changing , as concerns about climate change and renewable resources increase . Thermal energy storage is becoming more important to building owners and utilities for their ability to enable growth of renewable energy resources .
An Evapco thermal storage unit in a commercial building
Thermal energy storage :
• Supports renewable energy . A thermal battery system can increase renewable energy use by up to 50 % making renewable resources more effective and affordable 1 . That helps with zero net energy design .
• Supports high performance : To have lowest cost of operation , a building must be agile . A thermal battery system can store clean inexpensive energy , when available , to be used during periods of high demand to help lower the cost of operation .
• Supports grid resiliency : A thermal battery system helps overcome the intermittency of renewable energy . It can store excess energy to be used during times when the sun does not shine or wind does not blow . Additionally , a recent study suggests that these systems do more to help the grid during heat storms than previously thought 2 . This is important for both grid resource adequacy planning and providing proper financial compensation which in turn means more incentives .
HARNESSING THERMAL ICE STORAGE : A SUSTAINABLE SOLUTION FOR ENERGY EFFICIENCY As energy demand surges at an alarming rate , individuals and organisations face mounting pressure to reduce their carbon footprint . A significant contributor to energy consumption is commercial buildings , accounting for 37 % of total energy and over 68 % of electricity usage in the US alone . This issue extends beyond borders , with buildings in China responsible for nearly 30 % of the nation ' s energy use and a quarter of its greenhouse gas emissions , according to the China 2007 Blue Book . The global impact is evident , necessitating solutions that address energy demands that unreliable renewable sources cannot meet , while preserving the environment and ensuring economic feasibility .
Fortunately , a practical and environmentally friendly solution exists : thermal ice storage . This proven technology has been around many years and efficiently stores frozen thermal energy
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RACA Journal I August 2023 www . refrigerationandaircon . co . za