Dr Edwin Tso is currently an Assistant Professor of School of Energy and Environment at the City University of Hong Kong (CityU). He received his Bachelor’s degree in Mechanical Engineering (1st class), MPhil degree in Environmental Engineering and PhD degree in Mechanical Engineering from The Hong Kong University of Science and Technology (HKUST) in 2010, 2012 and 2015, respectively. He was awarded the Fulbright – Research Grant Council (RGC) Hong Kong Research Fellowship in 2014, and studied at the University of California, Berkeley (UC Berkeley) in 2015. Upon returning to Hong Kong from UC Berkeley, Dr. Tso worked as a Research Associate at the Department of Mechanical and Aerospace Engineering (MAE), HKUST from 2015 - 2016, before he was promoted to the rank of Research Assistant Professor (2016 - 2018). While at HKUST, Dr. Tso was also a Junior Fellow at the HKUST Jockey Club Institute for Advanced Study (2016 - 2018). In September of 2018, Dr. Tso joined CityU as an Assistant Professor, and his research focuses on understanding the fundamentals of heat transfer, energy conversion, and engineered materials. He strives to integrate theory and experiments to create innovative solutions for enhancing thermal management, built environments, space cooling and refrigeration, micro-droplet manipulation, and energy-efficient building technologies, making a great and global impact by addressing the biggest needs and issues in our world.

Abstract

Development of Cooling and Ventilation Systems for Cavern Sewage Treatment Works

To support social and economic development in Hong Kong, the Relocation of Sha Tin Sewage Treatment Works to Caverns is implemented so as to release the existing site for other uses. Mechanical ventilation is necessary in the cavern in order to deliver adequate fresh air and dilute indoor air pollutants. As the volume of space in the caverns is huge, peak fresh air supply rate around 400 m3/s via tunnel portals and supply fan plants is required, consuming a large amount of energy/electricity.

To reduce the energy/electricity consumption of the cavern ventilation system, a demand control ventilation (DCV) system is proposed that can maintain acceptable indoor air quality while minimizing the energy consumption. Specifically, the dominant air pollutant can be used to indicate the demand for fresh air. By controlling the dominant air pollutant and the indoor temperature to the desired levels, most of the other air pollutants can also be maintained at acceptable levels to achieve acceptable indoor air quality and thermal comfort.

Apart from the DCV systems, an energy efficient cooling system is also needed in the carven for cooling energy-saving. Adsorption cooling systems (ACSs) are more environmentally friendly, energy saving, have fewer moving parts and lower noise level and vibration compared to the traditional vapor compression systems. Therefore, an ACS with waste heat capturing system for use in cavern is also designed and discussed in this talk.

Last, we will also present the synergic effect combing both the ACS and DCV systems in the cavern. It is expected that the energy efficiency of the proposed cooling and ventilation systems can be further enhanced, resulting in significant energy-saving and cost reduction.