New technology to increase the energy efficiency of district cooling systems

A new invention that improves the energy efficiency of district cooling systems (DCS) has shown that it can improve energy carrying capacity by three times compared to a traditional cold water storage system and achieve cost savings of more than 10% annually. The test, which was completed in August 2021, was carried out in one of the Keppel Infrastructure (KI) district cooling systems in Singapore in the Changi Business Park.

This technology solution for thermal energy storage (TES) uses a new phase change material (PCM) that can store and release cold energy when changing between liquid and solid state. The stored cooling energy is gradually released in a district cooling system in order to mitigate cooling load peaks in commercial buildings. This solution was jointly designed and developed by the National University of Singapore (NUS) and Keppel DHCS Pte Ltd (KDHCS), a wholly owned subsidiary of KI. The project was funded by the Energy Market Authority in 2018 as part of their Energy Resilience Grant Call.

The NUS research team has also developed a laboratory-based refrigeration recovery system that utilizes refrigeration energy released as a by-product when liquefied natural gas is converted back to its gaseous state to generate electricity. The recovered cooling energy can be stored and released, similar to an energy storage system, in order to compensate for energy demand and supply if necessary. One example is balancing intermittent power from renewable energy sources such as solar energy to maintain the reliability and resilience of Singapore’s power grid.

Ralph Foong, Deputy Chief Executive of the Energy Planning and Development Division at EMA, said: “The close collaboration between industry, research community and government has enabled the development of this innovative solution to improve the efficiency and resilience of our energy sector.” EMA is proud to have supported this project, which offers a more energy efficient solution to meet the significant energy consumption for cooling in Singapore’s warm tropical climate. With such new technologies and innovations, we can build a more sustainable energy future for Singapore. “

“The TES technology can be compared to a battery that stores thermal energy and can release it again at the desired time. Our new TES system was specially developed and constructed to close the gap between local cooling supply and energy demand. It enables the redistribution of cooling energy so that peak load requirements can be covered in an energy-efficient manner. The integration of the new TES technology in KDHCS district cooling systems offers enormous potential for success for low-energy concepts in order to cover Singapore’s cooling needs. This innovation marks a significant milestone in our progress towards a sustainable future, ”said the project’s lead researcher, Associate Professor Ernest Chua of the NUS Department of Mechanical Engineering.

Chua Yong Hwee, Executive Director of New Energy at Keppel Infrastructure, said, “We are delighted to be working with NUS and EMA to successfully develop this new technology. This is in line with Keppel’s Vision 2030, which places sustainability firmly at the center of the corporate strategy. The novel TES solution will improve KDHCS ‘ability to meet Singapore’s cooling needs in a more energy-efficient manner through a new and better heat storage material and the recovery and use of cooling energy that would otherwise have been lost. This innovation can also potentially help reduce grid disruptions as more renewable sources are integrated. “

As part of the EMA’s Energy Resilience Grant Call in 2018, grants totaling S $ 15 million were awarded to seven energy innovations to strengthen the resilience of Singapore’s power system and energy markets.

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