AGU’s renovation project was broken down into four categories of high performance design strategies that collaboratively help the building to reach net zero energy goals. They are generation, absorption, reclamation, and reduction. The building’s hydroponic phytoremediation (hy-phy) wall, which is also known as a living plant wall or green wall, is one of a handful of reclamation strategies being used across the project that will help reduce the building’s overall energy usage. AGU and the project team worked closely with Nedlaw Living Walls to design its green wall for the space.
Living walls are well known in sustainable design not only for their aesthetics, which improve building occupants’ well-being, but also for their potential to improve the indoor air quality. But, not every green wall is a hy-phy wall. AGU’s green wall will serve as an indoor air biofilter reclaiming air in the building, drawing it in through the root systems of the plants where it is filtered air quality for building occupants, and recirculating the clean air through the building. AGU’s wall is hydroponic because the plants will be suspended in a growing media that allows the plant to gather nutrients through water and air, rather than traditional soil. Some green walls use containers to suspend traditional soil. The “phytoremediation” part of the name refers to the use of plants for removing contaminants from the air.
The hy-phy wall functions sort of like the nose hairs of the building. It will work in concert with the dedicated outdoor air system with exhaust air heat recovery (DOAS) as part of the building’s ventilation. The DOAS conditions and delivers outside air to the building but the hy-phy wall allows the building to reduce the amount of outside air needed by recycling indoor air through the DOAS. This collaboration between the ventilation system and living wall system reduces the energy needed to circulate fresh air throughout the building.
The building is equipped with an Air Quality Monitoring System (AQM) which will detects gasses both in the “return” i.e., recirculated air which travels through the Hy-Phy wall and the outside air supply. These two sources (recirculated and fresh air from outside) of air are mixed and together provide supply air to enhance thermal comfort and air quality. The added benefit of the hy-phy wall means that the treated air can have fewer contaminants than the air outside and may already be at a comfortable air temperature.
Craighton Ellingsworth, President of GreenWall Source, the green wall installer for AGU’s building renovation, explains the process in the video below.
AGU’s hy-phy wall is actually six distinct green walls traversing the six occupied floors of the building (including the basement level) and will feature more than 400 plants. The plants are non-pollen producing, and range from multiple species of Ficus and Dracaena, to a species of palm.
The plants will receive all the lighting they need to survive from LED lighting above each system. But, as you can imagine, the amount of plants on the wall will require a lot of water to sustain. Irrigation for the green wall will come from the building’s 11,300-gallon water cistern, another reclamation strategy for AGU’s net zero building that will capture rainwater from the roof for flushing toilets and irrigating the green roof and wall.
AGU’s hy-phy wall is a highly anticipated design feature for staff who are looking forward to moving back into the building and it will be a showstopper for visitors.
- Hydroponic Living Plant Walls
- Grondzik, W and Kwok, A. (2015) Mechanical and Electrical Equipment for Buildings. Wiley: Hoboken, NJ.