Right now, it’s just a patent application and computer model. Nonetheless, researchers are currently working toward building a physical prototype for validation. If this works, hospital HVAC systems could get an energy-efficient makeover featuring a 100% fresh outdoor air supply. Learn more about membrane technology and the team behind the idea.

The Team and Opportunity Behind New Hospital HVAC Systems

The team behind the patent are Purdue University engineers David Warsinger, Andrew Fix and James Braun. HVAC systems that rely entirely on fresh outside air are safer and healthier, but also costly. Their goal is to create a fresh air system that isn’t uneconomical.

“Most people don’t realize the complexity of a modern HVAC system,” said Braun, the Herrick Professor of Engineering and director of the Center for High Performance Buildings at Purdue in a WBIW article. “There’s a specific sweet spot for humidity in an indoor environment—between 40 and 60%.” In other words, people aren’t comfortable when humidity levels are below 40%. Similarly, if indoor humidity levels are above 60%, the risk for mold and other problems increases.

To clarify, the team understands that in large indoor environments like hospitals, open windows are not a solution. Coupled with the fact that 40% of energy costs goes toward dehumidifying incoming air, and therein lies the opportunity for better technology.

What Is Vapor-Selective Membrane Technology?

Historically used to filter or separate liquid or gas forms, membrane technology is the backbone of this engineering idea. The main benefit of membrane technology is that it works without the addition of chemicals, with relatively low energy-use and easy well-arranged process conductions. For this reason, the Purdue researchers are proposing vapor-selective active membrane energy exchangers for hospital HVAC systems.

“The membrane is the key,” said Fix, a Purdue doctoral student in mechanical engineering. Using vapor-selective membranes, water vapor passes through the membrane when a pressure difference is applied, simultaneously blocking the air. To clarify, the membrane helps reduce the load on the system motors and compressors responsible for the refrigeration cooling cycle.

How It Improves Hospital HVAC System Energy-Efficiency

In theory, and currently completely based on computer models, vapor-selective membranes shows a savings of up to 66% in energy costs. This would benefit large hospital buildings, particularly those located in areas with hot and humid summer weather.  

Should membrane technology move from concept to completion, hospital HVAC systems will improve on many fronts. Feasibly introducing 100% outdoor air into any large indoor space is exciting news for the HVAC industry. For now, we wait and see what happens. Interested in learning more? You can stay up-to-date on this project here.