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After nearly five years of research and development, Illinois Institute of Technology College of Architecture Assistant Professor Youngjin Hwang, along with Associate Professor Alexandros Tsamis and Professor Theodorian Borca-Tasciuc of Rensselaer Polytechnic Institute, has proposed an environmental control system that transforms a building’s heating and cooling processes and more easily adapts to global climate change.

In July 2024, Hwang and his team received a United States patent for a novel climate-adaptive, dynamic, opaque-building-envelope system called HydroSIP. This system is designed for application across all opaque building elements, including exterior and interior walls, roofs, foundations, and floors. Through a unique, double-sided hydronic layer—which transfers heat through flowing water—embedded within the building envelope, the system can adapt its thermal resistance based on changes in climate.

“This means there are hydronic loops on both the exterior and interior surfaces of the envelope,” says Hwang. “These double-sided layers can be coupled to flow water within this closed circuit, thereby directly transferring the heat from one side to the other. Or the hydronic circuit can be decoupled and each layer on the building’s surfaces can work individually.” The system is also made for harvesting energy. Due to the hydronic layer on the exterior surface of the building wall, it can directly harvest solar energy from the exterior surface. In this way, the building envelope becomes an active, flexible component of energy management, rather than simply an insulated barrier between inside and out. Theoretically, a building’s exterior walls could send either heat or cooling to the interior as needed.

In the description of their patent, the team highlights that the building industry consumes nearly 40 percent of the U.S.’s primary energy and is thus a significant contributor to carbon emissions. They go on to describe that the opaque building envelope affects 25 percent of total building energy use, which translates to 10 percent of the U.S.’s primary energy use. This data suggested to Hwang and his partners that advancing opaque envelope technologies could play a significant role in reducing energy use in buildings and help them adapt to potential changes in climate.

With the patent for the technology secured, Hwang and his team have been collaborating with students, faculty, and researchers across both Illinois Tech and Rensselaer to work on validating the system, including testing a prototype of the technology in a room-sized artificial weather chamber. The weather chamber is designed to simulate 95 percent of the U.S.’s history of weather data. By artificially generating this weather data through the chamber, they will be able to test the dynamic performance of the proposed system across various climates.

If the proposed system works as intended, Hwang says, buildings will essentially have the ability to automatically adapt to the weather changes and, in turn, reduce heating and cooling energy use, therefore reducing the overall impact of the building industry on the built environment.

“Instead of relying on mechanical systems, we propose a whole new paradigm for heating and cooling,” says Hwang. “We believe that if a building envelope has the ability to collect energy sources while dynamically adapting its thermal resistance, we should be able to heat and cool a building by the ambient renewable energy sources available.”