Research: A New Model for Demand Flexibility in HVAC Systems

July 26, 2022 by Stephanie Leonida

Researchers from Carnegie Mellon University created a new model for predicting demand flexibility in building HVAC systems.

At Carnegie Mellon University’s (CMU) Department of Civil and Environmental Engineering, a Ph.D. student by the name of Elvin Vindel led a team of researchers to create a heating, ventilation, and air conditioning (HVAC) system model for demand flexibility. The model has the potential to allow power grid operators and building managers to manage or balance the power demand and reduce energy consumption.

Along with Vindel, Professor Mario Bergés and Professor Burcu Akinci from the department of Civil and Environmental Engineering co-authored the paper, which was published in BuildSys '21: Proceedings of the 8th ACM International Conference on Systems for Energy-Efficient Buildings, Cities, and Transportation.



Image used courtesy of Pixabay


What Is Demand Flexibility?

Demand flexibility is defined by the ability of a building to use different sources of energy to meet heating and cooling demand.

Demand flexibility is one of many building design features that contribute to a building's sustainability. It can help buildings save money on their energy bills and reduce their carbon footprint by using less energy than they otherwise would need.


Keeping Cool

Cooling down need not only apply to the world at large, but to systems that we use almost every day and perhaps take for granted. According to the International Energy Agency (IEA), using electric fans and air conditioners contributes 20% globally of  total building electricity use today.

“Growing demand for air conditioners is one of the most critical blind spots in today’s energy debate. Setting higher efficiency standards for cooling is one of the easiest steps governments can take to reduce the need for new power plants, cut emissions and reduce costs at the same time,” said IEA Executive Director Fatih Birol.

While AC systems cool air in homes and other buildings, HVAC systems heat, ventilate, and cool them. As populations increase and the climate warms further, AC and HVAC systems are expected to grow in usage all over the world.

The “U.S. HVAC systems market size was valued at USD 16.54 billion in 2021 and is projected to grow at a compound annual growth rate (CAGR) of 5.6% from 2022 to 2030,” according to Grand View Research report.

Both AC and HVAC systems are needed in hospitals, schools, corporate buildings, and other industrial settings to keep people and machinery cool. However, as demand for these systems continues to rise, there remains a need to manage energy consumption and reduce carbon footprint to benefit the environment.


A New Model for Keeping Cool and Staying Green

According to CMU, existing models for estimating the demand flexibility of commercial buildings are not accurate enough in producing predictions and so are not suitable for grid services. Accurate models should integrate both the occupant preferences and diversity/heterogeneity in the building population.

The CMU research team used data generated from building automation systems through sensors and smart meters “to define this flexibility as a property of the installed mechanical system.” This is the basis of the researchers’ new model, which, aims to more accurately predict demand flexibility for troughs in demand.



Image used courtesy of Pixabay


Since its creation, the researchers have “tested the model on simulations of three buildings under varied climates across the U.S.”

The CMU team is planning to conduct more tests on real-world HVAC systems this summer to validate their latest research findings.

With the new model, grid operators and building managers could work with each other to reduce energy consumption and balance demand. Building occupants would be able to keep cool to their preferences and the green energy transition would be able to progress on, “full steam ahead!”


Feature image used courtesy of Pixabay