Showing posts with label water. Show all posts
Showing posts with label water. Show all posts

Water in Hong Kong


Passing by the drainage system of Hong Kong island, I am starting to think about water issues in Hong Kong (HK), a city highly dependent on water supply from outside. One third of Hong Kong's surface is developed as water catchment area which is not enough to meet high water demand, even despite average annual rainfall in HK amounts to about 2400 mm. Therefore Hong Kong imports about 70 % of its water needed for industry and private use.
There are systems in place which help to reduce water dependency, such as a seawater toilet flushing system and several desalination plants. From a landscape perspective it is interesting that in Hong Kong even ocean bays (or arms) have in the past been fenced off from seawater and are now used as freshwater reservoirs. When it comes to water large scale landscape interventions have always been possible.
From a design (research) perspective it would be interesting which up-to-date (green) infrastructure measures could be inserted into the landscape of Hong Kong to harvest rainfall and mist and to which extent they would help to alleviate outside water dependency. 

Scaping the Connecticut River

Last week I got the chance to participate in the 2011 riverscaping learning lab which was held in Springfield, MA and dealt with potentials of understanding the landscape along the Connecticut river between Springfield and Turner Falls as one entity, one region. Thereby regional dynamics may be fostered to develop strategies for the unique landscape along this stretch of the Connecticut river.
 For a first impression I post some panorama images (click to enlarge!) and shots from the bus tour we did to understand the landscape along the Connecticut river.

Springfield. Beautiful and wide waterfront with problems of accessibility and reputation.

Holyoke. Amazing industrial building stock where a computing center will invest because of green energy potentials.

Holyoke. Partly refurbished waterfronts and vast empty building stock.
Hadley. Issues of accessibility to the mostly privatized waterfront.

Turners Falls. Great industrial structure with uncertain future.

This autumn there will be a 'design laboratory' following to develop 'interpretative installations' for specific sites along the Connecticut river in Springfield, Holyoke, Hadley and Turners Falls to allow 'understanding the River as a catalyst for change and growth, and to create connections between communities, ecosystems, and economies along the River.' Follow the developments on the riverscaping homepage to know about the competition.

Terreform's Self-sufficient Skyscraper

Recently I visited terreform, a non-profit dedicated to research into the forms and practices of just and sustainable architecture and urbanism, located in Manhattan, NYC.  I wanted to find out more about a specific project, the 'self-sufficient skyscraper', which terreform presented during the 2010 Venice Biennale in the US 'workshopping' pavilion. 
Terreform's contribution to the US pavilion at the Venice Biennale 2010. [image courtesy of terreform] 

In relation to a 'self-sufficient skyscraper', I was interested in questions of how to achieve self-sufficiency, technological feasibility, social implications and a research-based design process integrating life-cycle concepts.   
The 'Self-sufficient Skyscraper' is part of terreform's ongoing investigation 'New York City (Steady) State' about the possibility of New York city becoming entirely self-sufficient within its political boundaries. The issues concerned in the study are: food, energy, water, waste, movement, buildings, air and climate. 
'New York City (steady) State' features urban prototypes for (almost) closed loop systems at different scales, such as, the districts, neighborhoods, building blocks, barges on the water or detached single family houses. 
The self-sufficient skyscraper extends this investigation to the realm of high rise buildings. In a nutshell, the project can be described as a habitable and sociable vertical urban farm in the dimension of a skyscraper. 
The 'Self-sufficient Skyscraper' is a re-use proposal for the Verizon building North of the Brooklyn bridge landing in Manhattan. The building is conceptualized to house 500 people and follows the approach of creating vertical neighborhood supported by an agri-cultural production system which is largely closed (in terms of water and resource cycles) and tied to on-site energy generation (solar and biomethane) and minimized energy consumption (food, building and lifestyle needs). The 'self-sufficient skyscraper' houses various urban functions to support the social life in the city. Residential uses, farming areas, commercial floors, institutional programs as well as adaptable spaces are featured to bring the self sufficient skyscraper to life.
Diagram of water and waste cycles (click to enlarge). [image courtesy of terreform]

As a habitable vertical farm, the building is a homage to Dickson Despommier, advocate of the vertical farm concept. The agricultural layout integrates aeroponics for growing of vegetables (at lower water demand), aquaponics producing proteins (tilapia sp., the 'queen' of farmed fish) and small scale chicken husbandry (open air).

Agricultural concept for the self-sufficient skyscraper and technologies used (click to enlarge). [image courtesy of terreform]

The farming area of the building is calculated based on a dietary energy intake of 2000 kcal/person/day assuming a half-vegetarian low-fat diet for the residents. This conceptual approach reflects the discussion of how to mitigate the 'developed' countries' carbon and ecological footprint by limiting dietary energy uptake to a more modest level. This would result in a reduction of the footprint of the 'developed' world, which is currently over-feeding itself and wasting huge portions of the food energy available. Such a reduction will not necessarily be a limitation in terms of quality of life, rather a healthy alternative to increasing obesity and food-related illnesses. 

 Diagram of energy generation and use (click to enlarge). [image courtesy of terreform]

The 'self-sufficient skyscraper' features some interesting examples of green technologies and strategies. Most of the technologies in the project are market-ready at hand and could therefore be integrated in building in the near-term future. This could happen either in a rather condensed way as a vertical, almost machine-like urban farm (as the project described here), or as extensions and benign parasites for existing urban structures. In this sense the 'self-sufficient skyscraper' is a feasibility study for high-density urban farming.

The 24 levels of the building feature three water cycles, each with a 'living machine' (biofilter) for a cluster of eight floors, to clean the water before being recycled. The system is modeled after John Todd's version of the living machine, called the 'eco-machine'.
Detail view of an 'eco-machine' designed by John Todd Ecological Design for indoor wastewater treatment. [image by John Todd Ecological Design]

Wind turbines are integrated on some floors of the building to generate a fraction of baseline energy use. Wind Turbines for small scale urban applications are market ready but their real energy generation capacity still needs to be assessed. 
Vertical axis wind turbine (VAWT) for urban application. [image and turbine by Urban Green Energy]

Helium balloons coated with photovoltaics are designed to power the biggest part of electrical energy for the building. The concept was suggested in 2007 by Geotectura for the 2007 re:volt competition about how to power an urban block. The approach seems intriguing and technically feasible but will have to be developed further to solve problems of wind and directional positioning. 

Experimental prototype for a photovoltaic helium balloon within the 'SunHopes' project of geotectura. [image by geotectura]

Methane digesters are market-ready and widely used. Urban applications and integration of methane digesters into buildings has yet to be adopted on a larger scale. We still waste huge amounts of nutrients (and thereby energy) by uncoupled nutrient cycles leading to dangerous nutrient levels in the natural environment. 

 Diagram showing basic function of an anaerobic biogas digester to manage human feces (separation important!) [image by Unesco via PlanningPool]



Scheme for a methane digester integrated in an agricultural system to produce fuel gas and fertilizer. [figure by John Fry]

Aeroponic farming is widely used in commercial farming worldwide and by a community of small scale farmers interested in pushing climate and spatial limits to urban agriculture. Aeroponics can create a good income for urban farmers by producing cash crops with limited space in urban settings.
Aeroponics support root growth and nutrient uptake by plants leading to high growth rates at a lower water demand than conventional plant growing. [image by trendgrinder]
Aquaponics unifies fish cultivation with hydroponic plant growing in a symbiotic system (nutrients traded for the cleaning of water). The concept is applied in community-based gardens in the US and worldwide.
 Scheme for an aquaponic system to cultivate tilapia sp. and various vegetables. [image by UVI Aquaculture Program]

Next to the above mentioned technologies and strategies, the 'self-sufficient skyscraper' as well features state of the art green building technologies such as passive ventilation and double facades to lower energy demand of the building. 

Technically the self-sufficient skyscraper is less utopian as in its social and economic functioning (Do New Yorkers really want to become part-time farmers? (I tend to answer: Yes, for enough of them to potentially fill a vertical farm.) How can a vertical farm compete economically with non-stacked farming practices?).
The economic feasibility of the 'self-sufficient skyscraper' has not been assessed yet but possible starting points for such a project would be public funding as a lighthouse project or a project run by a cooperative. As stated above, urban farming of cash-crops, especially if grown organically, can bring significant revenue.

The project of terreform shows that architects and designers have an important role in re-shaping imaginary representations of our society, especially under scenarios of diminishing resilience of ecological systems and limited energy availability. The 'self-sufficient skyscraper' can therefore be an opportunity to exemplify state-of-the-art green technologies, urban farming practices and social narratives so they may be discussed and further developed. This conversation will ideally be informed by wonder and excitement to nourish a debate about patterns of our food and energy consumption which sits at the very heart of issues such as climate justice, public health or social and environmental justice.

During my research for this post I didnt find any evidence of how efficient vertical urban farms are (energy and auxiliary input versus food output) if you take into account the construction process of the farms and on-site energy inputs. I still miss a full life-cycle assessment (in terms of energy) comparing vertical farms with for example community gardens or rooftop gardens. Nevertheless the concept is intriguing, provocative and obviously very attractive for designers who want to go green. It will have to be discussed what form of urban farm is the most efficient and in which way can and will society be part of such an endeavor. This discussion should only be teasered here, I will elaborate on that in a subsequent post focusing on vertical farm projects which have been proposed for NYC.

Gravitation Water Vortex Power Plant

The other day I stumbled upon a fascinating small scale hydropower plant - the 'gravitation water vortex plant' - as developed by the Austrian engineer Franz Zotloeterer, who holds the patent for the turbine technology. 
The plant is transforming the mechanical energy produced inside a water vortex and  has great potential for small scale installations. The maximum energy output for this technology is estimated to be about 150 kW at an efficiency of about 70% and a minimum falling height of 0,7 meters.  [source]
 
The main pros of the 'gravitation water vortex plant' are: 
- No regulation system necessary.
- Minor flotsam is able to pass the turbine.
- Fish can pass the plant in both directions.
- The water gets aerated leading to better microbial growth and breakdown of nutrient charge in water. 
- The low falling height allows a better integration into the landscape. 


Because of the above reasons this type of hydro power can be realized in relatively flat landscapes, integrated into river restorations (with synergistic effects) or included in wastewater treatment plants. 
One may as well think about planning small gravitation water vortex power plants as being integrated in urban graywater discharge sewers. There they could create electricity used in pumping rainwater during storm events.
Three types of grid integration are presented on Zotloeterer.com: 
- Parallel operation mode (direct injection into public power grid)
- Surplus energy into grid (energy not used by owner of plant is injected into public power grid) 
- Isolated operation mode (energy is exclusively used by plant owner and stored in other means, eg hot water etc.)

There are several pilot projects in place already which demonstrate the feasibility of this technology.

Obergrafendorf, Austria.
Zotloeterer Inc. installed a pilot 'gravitation water vortex power plant' in Obergrafendorf, Austria, in 2006 . 
The installation cost about 60.000 € and produces about 7,5 kW. 




Schöftland, Switzerland. 
The first gravitation vortex power plant in Switzerland was inaugurated in 2010. The plant produces about 15 kW at an annual production of about 90000 kWh supplying 50 households with electricity.