The basic premise of most energy efficient homes is that they prevent the outdoor environment from seeping into the home, creating HVAC efficiency and reducing power consumption. The goal is to seal air inside the home and keep outside air outside, but that has presented a new problem – air quality problems due to lack of ventilation.
A research team from Purdue University has attacked this problem by presenting a concept known as the “BioWall” to improve air quality in such airtight homes.
The BioWall is an air filter consisting of shelves of plants built into a wall and attached to a home’s HVAC system. Built-in systems provide light and water. A fan behind the unit draws air into the BioWall and through the growth media where microbes in the plants’ roots process volatile organic compounds. The plants also remove carbon dioxide from the air. The cleaned air then returns to the home’s HVAC unit for heating or cooling.
The current prototype has been in place in a home near Purdue University since 2016. The home is a joint venture between Purdue and Whirlpool Corp. It is a retrofitted, net-zero energy, water and waste house. The 1920s era home near the Purdue campus is used by graduate students to monitor a host of incorporated novel energy-saving technologies.
Data from the prototype shows it has the potential to reduce HVAC energy consumption by up to 25 percent because less outside air is required for ventilation. The research team plans to develop a pre-commercialization prototype within the next year.
The team is still investigating which types of plants would work best. The team is also discussing the possibility of establishing maintenance agreements as a potential commercialization effort so the plants could be regularly monitored and plant trays could be swapped out depending upon the season.
The idea for the BioWall originated from Purdue’s participation in the 2011 Solar Decathlon sponsored by the U.S. Department of Energy. The program challenges collegiate teams to design, build and maintain solar-powered homes that are energy-efficient, cost-effective and attractive to potential buyers. Purdue’s purpose-built, solar-powered house featuring an early version of a BioWall took second place overall in the national competition.
The team is currently seeking licensing agreements and partnerships to establish a distribution network.
Grants from the U.S. Environmental Protection Agency, the Department of Energy and the American Society of Heating, Refrigerating and Air-Conditioning Engineers have assisted the research.