Recycled paper could cool buildings without electricity, researchers say | New

A team of researchers from Northeastern University have created a durable material that can cool buildings without the need for conventional air conditioning systems. Led by Associate Professor Yi Zheng of the University’s College of Engineering, the team developed a “cooling paper” made from 100% recyclable paper, intended to cover the roofs of houses, warehouses and apartment buildings. of offices, as well as to be incorporated in the construction of new buildings.

The “cooling paper” reduces heat gain in two ways. The light color of the paper reflects warm sunlight from a building, similar to the Purdue University ultra-white paint we talked about earlier this year. Meanwhile, the porous microstructure of the natural fibers of the cooling paper absorbs the heat generated inside the building, from electronic sources, cooking and the human body, and re-emits the heat to the outside.

The experiment began with Zheng, an expert in nanomaterials, who observed buckets of waste paper and asked how this waste could be reused as composite materials. Using a high-speed mixer, Zheng made pulp from the waste paper before reforming it into a water-repellent “cooling paper” for lining buildings.

By testing the paper’s cooling ability under various temperature and humidity conditions, Zheng and his team found that cooling paper could reduce a room’s temperature by up to 10 degrees Fahrenheit. The team also found that the material can be used, exposed to sunlight and weathering, then pulped again and reformed in a new iteration without losing any of its cooling properties. “I was surprised to get the same result,” Zheng said. “We thought there would be maybe 10 percent, 20 percent loss, but no.”

Zheng sees the material as a sustainable method of reducing energy bills and fighting climate change. “The ultimate goal is to reduce global warming,” Zheng says. “The starting point is to reduce the use of carbon-based materials and also to reduce global warming.” The research has now been published in the journal of the American Chemical Society Applied materials and interfaces.

Cooling paper is the latest in a series of research breakthroughs by materials science teams in recent months. In June, the Worcester Polytechnic Institute developed a new method of producing concrete with self-healing capabilities to enhance the durability of concrete structures. In May, researchers at the University of Kassel in Germany published their findings on the potential of smart glazing to transform the energy use of buildings. Meanwhile, Snøhetta recently announced details of its partnership with Norwegian startup Saferock to develop net zero concrete for the future of construction.