Wang aims to reduce energy consumption through AC&R systems


Fatima Farha, MechSE Communications

Xiaofei Wang joined the MechSE faculty last semester as a research assistant professor. After completing a PhD in engineering thermophysics in 2012 at Xi’an Jiaotong University in China, Wang came to the University of Illinois to undertake postdoctoral training. She previously served as an assistant professor at Henan University, where she taught courses in controls and applied math.
“My classroom instruction was always about measurement, control, and mathematics,” she said. “I started to appreciate the importance of deeply understanding what you control. We learn all this high-level control and measurement, but I really wanted to understand the fundamental mechanisms of how the systems worked—especially thermal systems.”
While Wang was working on her PhD and assisting her adviser with controlling experiments in his lab, she realized she could combine her knowledge and experience in controls with her interest in thermophysics. 
Her current research is primarily focused on heat transfer, fluid flow, phase change, and energy systems. Some of her doctoral research was based on computational work, and she has also done some modeling. But her research focus is experimental, and it is directed at fundamental research with implications on energy conservation, power-generating systems, and air conditioners and refrigeration.
“I want my work to have an impact on energy conservation and sustainability—new ways to use energy more efficiently and renewable energy sources,” she said. 
Her current experimentation focuses on understanding two-phase flow morphology in complex, unsteady liquid-vapor flows in air-conditioning and refrigeration systems. She is exploring a new pulsed-flow system, and knowing the flow regime is important to controlling the flow distribution, optimizing the refrigerant charge, and exploiting the unsteady heat transfer enhancement for improved system performance.
Wang is also interested in two-phase flow regimes for falling film heat exchangers used in air conditioning, as well as in a range of energy conversion, desalination, and petrochemical systems. 
“A clear understanding of these flows in real heat exchangers is challenging, because we rely so heavily on experiments. We are exploring some new ideas to better understand what underlies these regime transitions. We hope to develop transition criteria with broader application that might find more general application, without relying so heavily on experiments,” she said.
One goal of her research is to reduce energy consumption in residential and commercial buildings, much of which is attributed to air conditioning and refrigeration. She hopes to achieve this by increasing the coefficient of performance (COP) of these systems. For air conditioning, the COP is the desired air-cooling effect divided by the energy consumed to achieve that effect.
“If we can enhance the heat transfer between the air and the refrigerant, the system’s COP will increase, and we do not consume as much electrical power to meet the needs of the building occupants.” Wang said. “Even a small increase of system COP can be a big deal for energy conservation, because the AC&R system is a big part of energy consumption.”
As she continues with her research, Wang said she would like to pursue teaching, and she also hopes to expand her lab team.