WHAT IS AN ECO-EFFECTIVE REGENERATIVE BUILDING?
As we move towards a future where climate change and environmental overshoot will challenge the ecological and economic health of our cities, I believe we will need to design and build our buildings am often asked "what is an eco-effective regenerative building?" There is a great deal of dabate now going on in the architectural community on this question. The Whole Building Design Guide website has a very good article on "Living, Regenerative, and Adaptive Buildings," however, given the inherent broadness of words "eco-effective" and "regenerative" there will continue to be lots of room for interpretation.
In our explorations of regenerative design at DIALOG's Toronto studio (the design firm I am a principal in), we understand eco-effective regenerative buildings as buildings that not only aim for the lowest possible carbon and water footprints, but also ones that provide the necessary physical and technical support for green infrastructure including green walls, green facades, and green roofs. We think that eco-effective regenerative buildings should be designed and engineered to significantly reduce their operational water and energy demand, reduce their upstream material and energy footprint, and improve their surrounding environment by restoring a site's natural hydrology and providing animal and plant habitats.
WHY DESIGN AND BUILD THEM?
Dense, populous cities require significant quantities of natural capital necessary to generate the ecosystem services required to support the necessities of life and support a sustainable economy. The production of oxygen, purification of water, pollination of plants and adsorption of stormwater are some of the more important ecosystem services that green infrastructure can provide. Green infrastructure such as green roofs, green walls and green facades contribute to the generation of all of these ecosystem services. As we intensify both the density and population sizes of our cities to meet growing size of cities worldwide, we will also need to intensify our provision of green infrastructure to support the natural capital that produces these ecosystem services. Cities have not typically been thought of as the location for natural ecosystems, but to be truly symbiotic, cities will need to effectively incorporate the green infrastructure required to support and generate key ecosystem services.
HOW IS A REGENERATIVE HIGH-RISE DESIGNED?
To transform our cities into Symbiotic Cities we will need to design and engineer our buildings to not only provide for their functional, programmatic requirements, but to also become the generator of ecosystem services. Buildings will need to be designed to collect and store rainwater; provide the necessary structure to support extensive and intensive green roofs; and provide for extensive areas of green facades and green walls.
Specific design elements to create a regenerative building that more symbiotically integrates into a city’s natural ecosystems would include:
Extensive use of “green façades”, green roofs and green balconies: To provide an infrastructure for the growing of plant material that will not only screen a building from the summer sun, but also provides a resilient screen (created by the stainless steel mesh structure that supports the plant materials) against high speed projectile debris produced during extreme weather events. This green façade also provides natural cooling for the building in summer by means of natural evapotranspiration by the plant material, which reduces the air temperature between the screen and the building façade.
Production of Environmental Services: A green façade and extensive use of green roof remove CO2 from the air, and produce oxygen through photosynthesis. This micro-ecosystem also helps clean the air, and provide habitat for micro to macro organisms.
Reduced glass to wall ratio: Designed for high energy efficiency and including glass-to-wall ratios of between 30 to 40% to reduce energy lost through glass.
Natural ventilation: Designed to take advantage of natural ventilation using operable windows. Most interestingly, because the green façade acts as a buffering wall, the higher wind velocities higher up the building that would typically prevent the use of operable windows, are reduced to a manageable level.
Human Waste Water Re-processing: Designed to include an “eco-machine” or other biological waste water reprocessing system to re-process waste water produced by the buildings inhabitants through biological means. Waste water would be processed into clean water and recirculated into the toilets and urinals in a closed loop virtually eliminating the use of potable water for waste water processing.
Rainwater Retention and Use: Rainwater would be stored for use in charging the closed-loop waste water system, as well as for irrigating the green façade.
Use of Infinitely Recyclable Materials: To reduce the hugely negative impact resource extraction has on the natural environment, designed as far as possible to be constructed with materials that could be infinitely recycled. The three key building materials would therefore steel (for structure), glass and aluminum (for building envelope).
Use of Wood: FSC Wood would be used wherever possible, as it is a sustainable carbon sequestering material. Floor slabs would be designed as CLT (cross laminated timber) decks––which are fire resistant, durable, and are naturally beautiful.
Heating and Cooling: Radiant heating and cooling––the ventilation and heating/cooling systems would be decoupled to reduce energy needs and mechanical sizes (e.g.. fans, shafts, and ducts)
Heat Recovery: Heat recovery from exhaust air as well as discharge of this air through the underground parking to reduce ventilation costs
Daylight Harvesting: Photocell control of lighting to maximize benefit of daylight harvesting in combination with external solar shading provided by the “green screens” on southern exposure, as well as the minimization of glazing on east and west exposures
Participant in an Ecodistrict: It is important to note that buildings should also be considered as potential integral parts of larger ecodistricts that provide the opportunity for a disctrict with many buildings and infrastructure components to work together to reduce material and energy use and increas natural capital.
Concept rendering of DIALOG's Eco-Effect High Rise Prototype designed by Craig Applegath, Steve Sestic, and Tom Svilans.