Stanford University Exchange Program

by Lili Yu

2020, this year has been engraved on my mind forever because of the COVID-19. Everything including my daily life and doctoral study in Japan changed suddenly and dramatically. However, the scholarship from the Friends of UTokyo, Inc. did really help me through the tough period by supporting me with better electronic devices and internet access to join global online lectures. As usual, the scholarship will be used for overseas short-period exchanges in high-level universities, which I planned before was Stanford University. COVID-19 results in the pandemic worldwide and I had to give up my original plan and turned to online lectures. However, it turns out to be a more productive and efficient way to broaden my research horizons and communicate with more leading scientists in my research field.

My research is mainly about the mass and heat transfer in HAVC (heating, ventilation, and air conditioning) systems for Net-Zero-Energy buildings at system-scale, device-scale and material-scale. With the development of human life and society, the energy generation, consumption and related environmental problems have been hot issues for decades. The total energy demand will continue to increase up to 2060. In addition, there are around 20 to 30 years left before the world exceeds the CO2 emission budget to keep the global average temperature rise below 2 ˚C with a 50% probability as introduced in the Stanford Global Energy Dialogues. Therefore, we must take actions now to realize our NZE (net zero energy or emission) society. Moreover, 30% of the electricity consumed in buildings is used for space heating and cooling and over 50% of final electricity demand is consumed by the global building sector. Therefore, the improvement of HAVC is critical for the development of the NZE buildings. I am following two online lectures: the Stanford Global Energy Dialogues and MIT International Colloquia on Thermal Innovations. I can get a whole picture of the global energy innovations from different aspects including science, engineering, business, law, finance and human behavior to solve different energy challenges in history and now. For example, Chad Holliday in the Stanford Global Energy Dialogues mentioned that the greenhouse gas emission decreased about 17% after different levels of lockdowns in the world. However, the mass production of vaccines in the future will require new supply chains and factories, which will result in climate change. Therefore, the simple lockdown or carbon tax are not the appropriate ways to deal with the climate problems thoroughly. We need to try and develop step by step instead of ‘one size fits all’. As said by Chad Holliday, energy is the golden thread in the COVID-19 world. On the other hand, MIT International Colloquia on Thermal Innovations focuses more on novel techniques about energy conversion, storage, transport and utilization in details which stimulates new ideas for my research. I have been working on the optimization of air dehumidification systems by ANN and GA. Prof. Jiang pointed out that decentralized HAVC systems with improved devices and AI techs may be the future direction, which guides my thoughts for the optimization of HAVCs in building or larger scales. In addition to presentations of top scientists from all over the world, the online lectures also provide the opportunities to hear different voices and communications from students, faculty, post-docs, industry and government in the Q & A section.

The most impressive lecture for me is Dry is the new cool: advanced dehumidification research for high performance cooling. As my Ph.D. topic is mainly about optimization of parameters for air dehumidification systems and the mass transfer in porous solid desiccants which are used for dehumidification. Therefore, this cutting-edge technology introduced by this lecture including moisture control for comfort & health, innovations in liquid and solid desiccant technology for HVAC and novel liquid desiccant-membrane dehumidification with integrated radiant cooling inspired me in my future research. Especially the research on dehumidification rate, which studied the limiting factor during the dehumidification process and showed that it actually changed with the adsorption time. The initial dehumidification is very fast but with the surface saturation increasing, the pressure difference between the bulk air and the particle surface is decreasing and it becomes the limiting factor. This shed a light on my recent experimental results of adsorption rate of a novel solid desiccant M. S. Gel.

As I have mentioned before, this year is quite different, perhaps, for all people. Though I cannot join the exchange program in person and may miss more interesting campus life because of COVID-19, the online lectures turn out to be not bad. More choices of various lectures are provided this year and I can easily take what I want. COVID-19 leads to remote work and study, which actually shortens the distance among people on the internet. However, COVID-19 brings huge challenges to the world, and neither one country can escape that. We witnessed the lockdown and recovery of Hubei province. Chinese people united as one and got through the disaster. Japan also started lockdown later and I stayed home for about four months. My daily life is gradually returning to normal now. The period of staying home was anxiety and inconvenient, which makes me cherish our normal life.

However, the COVID-19 can also be a moment to start our new life. The economic recovery after the pandemic will be an opportunity for us to try new patterns and society organizations. For example, remote work can be more popular and the development of the digital economy will be accelerated. Moreover, different policies will be implemented for economic recovery, such as the ‘go to travel’ and ‘go to eat’ campaigns in Japan. New jobs will be created during this recovery and we should be positive about our future but remember this lesson. There is a vaccine for the COVID-19 but no vaccine for our life and environment. We need to take action now for the future! Different solutions and attitudes of different countries to COVID-19 have been shown this year. We cannot require all countries to follow the same rules to deal with COVID-19 and also some other problems such as sustainable environment issues, disarmament, fishing regulations, traffic regulations and taxation. It’s better to seek common points while reserving differences to deal with international problems of this characteristic.