Urban Space Station (USS)
to boldly go where no greenhouse has gone before
USS adapts CLOSED SYSTEM design developed for SPACE STATIONS to an urban agriculture facility optimized for the unique constraints of an urban GREEN ROOF
coupling open ecological systems with closed systems engineering; mutualistic host-parasite relationship; increasing CO2 fixation; waste air cycling; increasing density; no additional structural retrofitting;
open ecological services of
Space: the final frontier.
Urban Space Stations (USS) are designed to explore the frontier of urban space: the roofs, specifically the rising movement to green them, and the simultaneous demand for better building performance. Greenroofs are a relatively new if not the final frontier of Urban Space, and are being colonized at an alarming rate for promised energy conservation benefits and other environmental services many with all or at least some part are also intended as an for urban agriculture resource.
However, greenroofs are designed under competing agendas usually listed together as if entirely compatible. This produces the misunderstanding that all benefits are associated with all greenroofs rather than revealing the tradeoffs , conflicts and real costs and design decisions involved.
The conflicting design agendas of green roofs can be grouped under 4 main approaches:
1) Providing a vegetated layer with minimum maintenance and additional infrastructure while maximizing the environmental services delivered to
a. the specific building and
b. the local neighborhood and city environs.
The building enjoy increased roof membrane life; sound and thermal insulation, hence reducing energy expended on heating and cooling;. The local neighborhood and city effects includes improved airquality; stormwater retention, reducing and delaying runoff (and NY this can reduce the combine Sewarge overflow events and the associated environmental cost); reduced heat-island effect; particulate capture; hyper-accumulation of heavy metals; reducing external building temperature and associated public health benefits. 80-90% of the insulation can be achieved with a 3-4” of soil and a selection or monoculture of sedum. This provides minimal hardy vegetation is popular because it requires no irrigation in the dessicated context of a roof, is usually with the structural constraints without having to sister beam or reinforce, yet provides the same CO2 fixing and particulate capture as other vegetation that require more soil.
2) Providing habitat and nutritional resources for diverse organisms and plants; enhancing and maximizing urban biodiversity. This is the most understudied of the greenroof functions, and requires a complex model of interdependent organisms, challenging design that can exploit the uneven structural capacity of roof space (i.e. dense shrubby habitat for birds can be built around the edges while grassy plains and browsing territory cover the span to create a differentiated set of habitats. It also requires a ecosystems approach, rather than the imagistic work of landscape architects, or the popular planting strategies of most gardeners. There is little formal literature to draw on in the vo vocabulary of most green roof enthusiasts.
3) An outdoor greenspace as an amenity for social gathering and leisure activities. This view sees greenroofs as event spaces that typically have tremendous views; and include leisure or pedagogical facilites to service substantial human occupancy. Platforms that can support human traffic limit the foliage footage and linearyly decrease the leaf area for CO2 fixing. This can be a valuable space that provides some interaction with urban ecology, however it does not maximize these. is not only bars, but can serve pedagogical agendas; leisure> this is a common tension for urban parks
4) An urban agriculture resource designed to provide substantial food production; and thereby minimizing the externalities of distribution (40% of commercial traffic is trucks delivering food). As in many vegetable gardens the food sources for insects, the birds that feed on them are seen as pests. This usually requires a substantial coverage of at least 6 and usually more than 12 inches of soil.
This list is arranged in ascending order of costs and measurable benefits. In my No documented designs satisfy these multiple goal.
The primary financial incentive for green roofs is cited as the energy savings they provide although many will mention aesthetic aspects. With these priorities it makes it difficult to justify more than 3-4” of soil, as shown in the graph. With respect to air quality, capturing particulates and fixing CO2 depends on the surface area of foliage, i.e. ground cover can fix similar amounts of CO2 as a tree or shrubby form with the same leaf surface area, yet not require structure, irrigation, or maintenance.
The design of greenroofs for esthetics and leisure usually conflicts with low maintenance, and with expectations. “Its not a green roof, it’s a brown roof” was a comment from one visitor expecting the green expanse more like a golf course than the challenging overexposed roof vegetation, the array of hardy but scrappy prairie plants and sedums among the roof machinery, and the exposed soil which itself provides VOC fixing. Greenroofs defy the esthetic expectations set by familiar urban parks and cultivated gardens greenspaces. In my experience touring greenroofs with people, even the most intensive and preened greenroofs are esthetically disappointing to most people. These are neither gardens, nor lawns, nor golfcourses. The infrastructure to manage soil moisture is an additional cost few can justify, and even so produces a fragile lawn space not suitable for human traffic.
Habitat provisioning and the support of a diverse array of insects, birds, microorganisms, and plants requires close engagement with species interdependencies. This has received much less attention in the literature. Urban ecology is a relatively new science and there is relatively little information on designing for biodiversity in urban contexts, particularly at the scale of a roof. Some valuable design guidelines have been developed for the neighborhood level and urban planners, but these requires a coordinating body. Incentives to conjoin island for a significant ecological impact.
What is the value of diverse urban habitats? Quantifying the value of habitat provisioning is difficult. The view ecosystems as realestate for nonhumans conflicts with essentially tenets of exculisonary property rights, and is be definition an externality. The . A full cost-benefit analysis from this point of view is forthcoming (presented at GR). The research opportunities, and the opportunity to significantly change the urban landscape in this respect are underexplored. And is a fractious territory In sum that birds—the urban birds that Audubon society refer to a “junk” birds, and beyond; provide critical services: maintenance and cleanup; nutrient cycling some length, In sum, the argument for doing so is that catering to
however, designing habitats to accommodate provides environmental services that have not been include din the cost –benefit analysis: . This is approximated by the use local natives, which conflicts again with the monolithic layers, load distribution. Fragmented “islands” already address a limited number of clients
By far the most demanding of all the oft listed benefits of greenroofs is the food production. Significant food production and variety demands soil at least 12” and ideally more in addition to irrigation; and other equipment for ongoing maintenance; regular access. The particulate matter capture on microgreens conflicts with food use (though not entirely). While new buildings could be , the cost of sistering beams and structural reinforcement> Three and two largely conflict. This is the tension that the USS facility addresses.
hence it is called a space station .... for urban space.
The structural approach addresses the constraints of a roof space, focusing the additiona load on the columns and masonry walls where extra loading can be easily accommodated without any additional structure or retrofitting. This approach to strategy also maximizes the use of open span that can provide habitat. It lifts the Space station off the roof so that a semi shaded space is provided underneath and another habitat to differentiate from other full exposed areas on the roof. the “legs” position all load on masonry walls and columns, while maximizing the open vegetation and habitat provisioning on the roof; and capturing more radiative heat energy.
Shape is motivated to maximize radiative heat and internal thermal distribution: for climate control in intensive agriculture.
The USS systems approach is designed to decouple the open ecosystems services from a closed system approach (controlling inputs and maximizing outputs) to urban agriculture. This allows the maximization of each independently, in which much of the space can be allocated to the complex open ecology, poorly controlled yet empirically monitiored.
The relationship to the building.
This USS is designed to use the CO2 enriched air from output of HVAC system; produced by human and machine occupancy of the building.
grey water cycling etc, to take on the closed systems design from space stations.
and energy harvesting adapts the systems engineering involved in Space Station design to pressing urban issues. The space station is designed to generate it own energy and can provide energy to the building it rests upon. in the form of parasitic mutualism.