Rooftop+Farming

Green roofs allow us to restore ecological value of open space, especially in densely developed and populated urban centers. Incorporating a green roof into our design allows us the opportunity to mitigate other impacts of our construction practices. One major advantage of a green roof is its capacity to manage stormwater and runoff. As a result of new land use practices, cities in the U.S. today are in increasing numbers facing over-stressed sewage systems with stormwater management problems. Due to rapid and pervading development, tree cover and green space is ever-dwindling. These fast-disappearing green spaces are nature’s way of managing stormwater and surges, and by installing a green roof we can accomplish stormwater retention and runoff control. Depending on rain intensity and greenroof soil depths, runoff can be absorbed between 15-19%. Furthermore, rooftop vegetation absorbs pollutant from rainwater; heavy metals and other contaminants are bound in the soil instead of being discharged into groundwater/streams/rivers. Rooftop gardens may also be implemented in such a way as to moderate air temperatures in urban landscapes, which are commonly elevated due to the prevalence of concrete and asphalt, which act as reflectors, absorbing some energy and redirecting it to other surfaces. This phenomenon often leads to a “dome” of higher temperatures over cities. Economically, overall building energy costs can be reduced due to the greenroofs’ natural thermal insulation properties. There are countless other advantages to the implementation of green roof technology, and as a result of the emergence of integrated green roof/PV technology, building a green roof does not necessarily come at the cost of installing solar panels.
 * Green Roof Overview**



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**Natural Fusion**
 * Ecologically responsible
 * Provides a refuge and a natural respite from the otherwise dense and urbanized setting
 * Economically responsible
 * Can be integrated with solar panel technology without sacrificing energy needs

Penn State’s 2009 entry in the solar decathlon, Natural Fusion, was based on the concept of integrating the elements. The team focused on maximizing daylight and passive solar gain in its design, and thus employed lerestory windows and tri-fold doors on the southern façade, which provide daylight throughout the year. Especially notable was their use of green roof integrated photovoltaics, which combines a photovoltaic system with plants to help remove excess heat from the roof. In order to do this, they used a type of solar panel that allowed for 360 degrees of solar collection, thus the ability to support plant life below. The plants also reflect light upwards, towards the underside of the panels. Additionally, the team employed an innovative, cylindrical, thin-film PV material to maximize sunlight collection.



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 * Innovative use of green roof integrated photovoltaics, allowing for both a green roof and ample solar panel space
 * Their main power system was on their roof

**Liuzhou Concept for Rooftop Farming** William McDonough is a globally recognized leader in sustainable development, and has specialization in the area of industrial and urban development. One of his most recent projects includes a design for an urban structure in Lizhou, Guangxi Zhuang Autonomous Region, People's Republic of China. The design is structured to maximize social engagement throughout the community and create a sense of commonality within an urban setting. The design further promotes walking and interacting with the environment with its multitude of parks, paths and trails. Furthermore, this project is centered around the concept of rooftop farming.This project is still only in the conceptualized stage and construction on this design has not yet been undertaken.



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 * Focused on community
 * Rooftop farming is an integral part of the design