New camera system detects building air leaks in real time

That’s why the team came up with a new, innovative solution. 

The new method 

This innovative air leakage detection system is based on an 1860s method known as "schlieren photography," which is a fluid flow capturing mechanism. 

This technique is commonly used to visualize airflow around aeronautical items. It entails observing subtle changes in the backdrop of a series of photographs to visualize leaking air with a different temperature than the surrounding air. When viewed against the façade of a structure, this temperature differential creates a mirage.

“Even though this mirage is too small to be seen with the naked eye, it can be imaged by a camera. The mirage looks just like wavy patterns you might see rising up from the pavement on a hot day or in the hot exhaust of a car tailpipe,” explained Philip Boudreaux, a lead ORNL researcher, in a press release. 

Measurement of leakage 

In addition to visualizing the leaks, the team is working to find a way to measure the amount of such leakages. 

“We’ve also developed custom software for real-time visualization of the leak with algorithms that measure the velocity and flow rate,“ said Boudreaux.

This feature is specifically beneficial for locating and prioritizing the places that require the most urgent sealing. 

“Being able to triage the biggest leaks saves time and allows for the energy reduction and carbon burden of buildings to be quickly addressed,” added Boudreaux. 

According to the statement, up to 130 million buildings in the United States absorb nearly 40 percent of the country's overall energy supply. As a result, decreasing needless energy usage is critical for achieving sustainable energy targets. The team expects that this invention will help them achieve this goal. 

The team applied this technique to visualize leaks in three cladding materials: brick, vinyl siding, and concrete masonry blocks. They conducted visualization experiments in both sunny and overcast lighting conditions.

The visualization studies demonstrated that leaks could be spotted when the temperature differential on the concrete block and brick claddings was as low as 54 to 59 degrees Fahrenheit (12 to 15 degrees Celsius).

“We were able to get a sufficient temperature difference between the air around the leak area and the ambient air. Through ongoing research, we intend to get that leak detection temperature limit down to 5 degrees Celsius,” he said.

ORNL's air leakage detection system was showcased as one of seven new technologies at the lab's recent Technology Innovation Showcase, featuring products that are nearing commercialization.