Department of Architecture and the Built Environment The University of Nottingham
“Regeneration and Urban Sustainability for Slums in Brazil Case Study: Rio de Janeiro – Favela da Rocinha”
By Andreia Pereira de Sousa
A dissertation submitted in partial fulfilment of the regulations for the degree of M.Sc. in Renewable Energy and Architecture,
Abstract The informal human and spontaneous settlements continue to grow more than the formal city. The migration for the big cities is the main reason of the rise of clandestine houses that trigger the slums, not only creating human, economic, social and urban problems, but also energetic and ecologic issues for the human health environment. The aim of this work is to examine the construction methods and the energy use pattern of slum-dwellers in the Favela da Rocinha in Brazil in order to investigate the key factors for sustainable development. Considering the specific social-economic aspects it is recommended the use of low-cost local materials and simple construction strategies easily applicable by the slum dwellers, Since the slums are usually self-built. The thermal analysis suggests that the standard chaotic structure of cement and brick can be substantially improved only by insulating the shell and by integrating energy efficient designing concepts for natural ventilation. Particularly, the energy demands for cooling can be reduced up to 6 times, stressing the great potential for sustainable improvement of the slums-dwellings. Also, the use of low-cost green roofs can effectively control the microclimate, improving the slum-dwellersâ€™ quality of life. Investigating the wind power potential in Rio de Janeiro case study, this analysis highlights that the instalment of 81.25 MW wind capacity can cover the total yearly energy demands. Besides, an estimated payback time of nine years indicates the feasibility of the instalment in terms of both environmental and economical aspects. The solutions proposed in this research represent an effective strategy in order to achieve a sustainable development with the use of efficient construction methods and renewable energy systems that are able to reduce the carbon emissions, improve the quality of life and contribute to urban regeneration.
The study for Regeneration and Urban Sustainability for the slums in Brazil, by using a case study as an example to follow, for Rio de Janeiro, the Favela da Rocinha, was followed in two main steps: First, is directed at the regeneration and sustainability for the Brazilian slums is the consideration and implementation of passive strategies in architecture, not only for the existing constructions but also for further upgrading that the slums can take in future. This principle must be followed according to the climate conditions, and especially to what is feasible according to the low cost and availability of solutions, considering the economic and social situation of the Favelas. Changes will be transmitted by knowledge, so the own self-builders, that is in majority the own living communities can apply and live by the principles and benefits of passive strategies, that was already confirm to have a significant effect not only on human thermal comfort, and in minimizing the needs of cooling. It is considered to be effective for reducing the energy consumptions of the houses, and for minimizing the use of mechanical devices for cooling, like air conditioned, fridges or fans. Chapter 5 describes the difference between the values of heat gains and human discomfort in a typical house of the case study, the Favela da Rocinha, and the improvement of the results by minimizing this values by 55% average the implementation of some low cost passive strategies, such as bulk thermal insulation for the exposed elements of the dwellings, mostly the external walls and roofs. Using bright colors on exposed elements in order to help the reflection of solar radiation and avoid the absorption and transmission of the heat for the inside also improves the results on reducing the energetic consumptions and achieving thermal human comfort temperatures. The second main part of implementation for this study, as for a governmental investment, is the consideration of a grid connected wind farm installation nearby the site location, in order to supply all the electric demands of the Favela da Rocinha dwellings, around 38.000 (IBGE, 2008) using the wind power, that was proved from the present author analyses to have feasible optimum conditions to cover this needs by installing around 65 big scale wind turbines, of 1.25MW of power regeneration and blade diameter of 64m, that are described in chapter 7. this investment is considered feasible by taking the present authorÂ´s results from the economic analyses calculated (see chapter 8), where show that the installation of a wind farm will be able to provide the total electrical consumption of the site plan, but also will get the investment return within 9 years, where considering the average lifetime of a wind turbine of 15 years,(Suzlon, 2010) this form of energy will be not only a form of solving economic problems of energy utilization and illegal use of electricity from the grid, but also is a clean and inexhaustible form of energy generation, without fossil fuels consumption and zero carbon emissions. (Boyle, 2004)
Figure 9.1 ÂŠPhotoshop, 2009 Photomontage Rendering of Favela da Rocinha, with Passive Strategies and Wind Farm Implementation Proposal (Vicenti, 2009)
Over generations the problem of the illegal settlements, presented in the form of slums, or favelas, in Brazil cities has remained without an effective solution. The idea of removing the slums and destroying the settle dwellings, by moving the inhabitants to social blocks of buildings in present authorÂ´s opinion is not a solution for the illegal housing and settlement for two main reasons. First, the action of eradicating of this urban shanty settlements will not regenerate the original forest and green places, but instead, the probability is that it would be taken over by new constructions, given continuation to the inner-city, where high, multi-storey buildings from the modern and develop world take place as a sign of potential, power and industry and economic development are the most important for the new urban world of big cities as centre of opportunities, competition and capital power. Second, the exponential growth of birth rate plus the migration to the big urban centres, following job and opportunities, cannot be controlled it by only changing places and moving people that has formed a new kind of society that rise from the informal cities, and are already functioning as communities. These facts cannot be ignored, but instead, they are an integral part of the main concerns and implementations for regeneration and sustainability of the slums of Brazil.
Figure 9.2 ÂŠPhotoshop, 2009. Photomontage Rendering of Favela da Rocinha, with Passive Strategies/ Low cost Green Roofs Implementation proposal. (Romario 2009)
The consideration of low cost green roofs seems to be not only an urban environmental solution for the visual impact, but also will be a crucial constructive element on dwellings that will permit to reduce the heat island effect, that is caused in dense urban areas, helping to create a protective and drainage layer for absorbing and help on water runoff from the strong tropical rains, that can be fatally dangerous not only for the dwelling structure, but also in the floods of land. Another benefit of the green roofs implementation will be the microclimate effect, by helping to absorbing the solar radiation, and reduce the heat transmittance of heating for the inside of the constructions, and the photosynthesis effect of the vegetation by absorbing the carbon dioxide and releasing oxygen to the atmosphere, low cost green roofs are effective considering as a crucial aspect for the urban regeneration and sustainability of the Brazilian slums.
Figure 9.3 ÂŠPhotoshop, 2009. Photomontage Rendering of Favela da Rocinha, with Passive Strategies and Wind Farm Implementation proposal (Coletivo Favela em Foco, 2010)
In conclusion to what was explored in this dissertation, there are feasible considerations regarding the aims for regeneration and urban sustainability for Favela da Rocinha, also greater extensions for the Brazilian slums in general, if based on the same principles. As we can take the best application from the idea of transmitting the knowledge of efficient strategies and performances of passive strategies in constructions focusing in the basic human needs and still remain in a steady balance with nature, not in a destructive way, of ignoring the existing issues that took place with a industrialized world, changing lifestyle societies and urbanism from generations of human development. The solutions is not to solve the problems with only social, housing or legacy solutions, but to find the solution with the own problem, by upgrading in a regenerative way, without the need of total destruction. This study proposal is not only focusing in one single element of study, as only in passive strategies or wind energy, but by following an interdisciplinary route, as general part of possible solutions combining and integrating what is considered to be feasibility considering the present reality were global, urban and shanties are growing without control. Shanty people fight for rights of minimum human conditions, they ask for water, electricity, sanitation, health and education.
Most of the people and operational organismâ€™s do not realize about the importance and effective effects that the eco-sustainable and regenerative considerations can have as a benefit on increasing human comfort and energy efficiency. These measures may not solve all the problems faced by the shanty towns, but leads to a way of possible Favela upgrade that have been putting in practice in considering the acceptance of this reality of new urban world of squatter settlements. â€œThink globally but act locallyâ€? (Architecture for Humanity, 2006)