Spotlight on a student: Nour Wahba

Heating and cooling systems are supposed to regulate temperature based on reading the room, but flaws in design mean they often miss the mark, wasting huge amounts of energy.

PhD student Nour Wahba is working on a new control model that she hopes will stop systems from blasting rooms too hot or too cold – providing a more comfortable environment for occupants, and smarter energy-efficiency for buildings.

We ask Nour to tell us more about her model, and plans for a patent to put her research into action.

In simple terms, can you tell us what your research is about?

I work on control modelling for heating, ventilation and air conditioning, or what we call HVAC.

Conventionally, HVAC in indoor environments is managed based on a single thermostat reading that tells us how warm or cool a space is, with system supply adjusted accordingly. But there are several problems with this: a single reading provides only a limited perspective on conditions in a zone, and is not representative of room dynamics in temperature. This causes delays between zone demand and system supply – and ultimately wastes a lot of energy.

My research aims to more fully describe interactions in and between zones to ensure HVAC systems can meet heat load requirements, and optimise system performance by reducing delays between demand and supply. This improves efficiency, meaning that less energy is wasted in the process.

OK, now give us the technical terms!

Through my research project, I have developed a framework with Computational Fluid Dynamics combined with a thermal comfort index, to account for zone variations. This part of the research feeds the control model system identification of the nonlinear thermal comfort model, which includes a reduced order model having universal linear parameters.

My research more fully describes the zone interactions with interpretable mathematical models to define macroscopic indoor thermal conditions for an occupant’s environment, with the integration of a Koopman operator system-based controller.

Why did you choose this area of research? What interests you about it?

While undertaking a bachelor’s degree in building systems design, I became passionate about improving the functionality of buildings, as a way to use less energy and reduce impact on the environment.

Applying my knowledge through work experience, I soon realised that conventional building mechanical design relies on oversizing supply ducts, diffusers, and grills so that a ventilation system meets the maximum demand, constantly.

Not only is this a waste of energy, but it often leads to zones becoming too hot or too cold, resulting in complaints of thermal discomfort from occupants. With such a tangible problem at hand, I thought there had to be a better way. My research questions naturally emerged from there.

What did you study to get here?

I studied Architectural Engineering with a specialisation in Mechanical System Design at the Illinois Institute of Technology in Chicago, USA. I aim to complete my PhD at the University of Melbourne by mid-2023.

Have you received any honours or awards for your work so far, and can you point us to any recent publications?

My PhD is supported by a 2020 Graduate Research Scholarship, which covers three and a half years of research at the University of Melbourne. In 2014, I received a fully funded scholarship from USAID that aims to empower high-achieving females in STEM-related fields in the United States.

In 2021, I had the opportunity to present and publish my work at the International Conference on Applied Energy, with my work chosen as a part of the conference proceedings under the title, Thermal Comfort Simulation for Cold Air Distribution Systems by a User Defined Predictive Mean Vote Index.

I was also involved in a collaborative publication on the use of machine learning for virtual energy assessment of university buildings under COVID-19 restrictions.

What’s the bigger picture? How will your work contribute to the transition to a clean energy system?

I aim to have my control model patented so that it can be applied in real-world building design. The research provides a starting point for comprehensive HVAC system design to meet actual demand, facilitating the transition to smart, energy-efficient buildings.

Further information

Nour is happy to answer questions related to her research, and can be contacted at n.wahba@unimelb.edu.au.