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Chapter 19 - Energy Access for Development
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- By Shonali Pachauri, International Institute for Applied Systems Analysis, Abeeku Brew-Hammond, Kwame Nkrumah University of Science and Technology, Douglas F. Barnes, Energy for Development, Daniel H. Bouille, Bariloche Foundation, Stephen Gitonga, United Nations Development Programme, Vijay Modi, Columbia University, Gisela Prasad, University of Cape Town, Amitav Rath, Policy Research International Inc., Hisham Zerriffi, University of British Columbia, Touria Dafrallah, Environment and Development Action in the Third World, Conrado Heruela, United Nations Environment Programme, Francis Kemausuor, Kwame Nkrumah University of Science and Technology, Reza Kowsari, University of British Columbia, Yu Nagai, Vienna University of Technology, Kamal Rijal, United Nations Development Programme, Minoru Takada, United Nations Development Programme, Njeri Wamukonya, formerly United Nations Environment Programme, Jayant Sathaye, Lawrence Berkeley National Laboratory
- Global Energy Assessment Writing Team
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- Book:
- Global Energy Assessment
- Published online:
- 05 September 2012
- Print publication:
- 27 August 2012, pp 1401-1458
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Summary
Executive Summary
Key Challenges
A quarter of humanity today lives without access to any electricity and almost one-half still depends on solid fuels such as unprocessed biomass, coal, or charcoal for its thermal needs. These people continue to suffer a multitude of impacts detrimental to their welfare. Most live in rural villages and urban slums in developing nations. Access to affordable modern energy carriers is a necessary, but insufficient step toward alleviating poverty and enabling the expansion of local economies.
Even among populations with physical access to electricity and modern fuels, a lack of affordability and reliable supplies limits the extent to which a transition to using these can occur. Those who can afford the improved energy carriers may still not be able to afford the upfront costs of connections or the conversion technology or equipment that makes that energy useful.
Beyond the obvious uses of energy for lighting, cooking, heating, and basic home appliances, uses for purposes that might bring economic development to an area are slow to emerge without institutional mechanisms in place that are conducive to fostering entrepreneurial activity and uses of energy for activities that can generate income. Without the expansion of energy uses to activities that generate income, the economic returns to energy providers are likely to remain unattractive in poor and dispersed rural markets.
Significant success has been achieved with small pilot projects to improve energy access in some rural areas and among poor communities in urban areas. But subsequently, less thought is focused on how to scale-up from these small pilot and demonstration projects to market development and meeting the needs of the larger population.
Optimum plane diffusers in laminar flow
- Hayri Çlabuk, Vijay Modi
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- Journal:
- Journal of Fluid Mechanics / Volume 237 / April 1992
- Published online by Cambridge University Press:
- 26 April 2006, pp. 373-393
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The problem of determining the profile of a plane diffuser (of given upstream width and length) that provides the maximum static pressure rise is solved. Two-dimensional, incompressible, laminar flow governed by the steady-state Navier-Stokes equations is assumed through the diffuser. Recent advances in computational resources and algorithms have made it possible to solve the ‘direct’ problem of determining such a flow through a body of known geometry. In this paper, a set of ‘adjoint’ equations is obtained, the solution to which permits the calculation of the direction and relative magnitude of change in the diffuser profile that leads to a higher pressure rise. The direct as well as the adjoint set of partial differential equations are obtained for Dirichlet-type inflow and outflow conditions. Repeatedly modifying the diffuser geometry with each solution to these two sets of equations with the above boundary conditions would in principle lead to a diffuser with the maximum static pressure rise, also called the optimum diffuser. The optimality condition, that the shear stress all along the wall must vanish for the optimum diffuser, is also recovered from the analysis. It is postulated that the adjoint set of equations continues to hold even if the computationally inconvenient Dirichlet-type outflow boundary condition is replaced by Neumann-type conditions. It is shown that numerical solutions obtained in this fashion do satisfy the optimality condition.
Laminar separation in buoyant channel flows
- Vijay Modi, F. K. Moore
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- Journal:
- Journal of Fluid Mechanics / Volume 177 / April 1987
- Published online by Cambridge University Press:
- 21 April 2006, pp. 37-47
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A slow moving flow in a duct emerging into a quiescent negatively buoyant environment may separate from its inner wall prior to the lip. Buoyancy accelerates the flow, curving the streamlines within the duct away from the walls. The resulting deceleration at the wall may be sufficient to provoke separation. The problem of the location of this separation point in a two-dimensional channel is studied. A potential-flow model is examined first to explore the large-Reynolds-number behaviour. The form of the potential-flow description in the vicinity of the assumed location of separation is characterized by the presence of a square-root singularity in the pressure gradient at the wall. This permits use of the ideas of viscous-inviscid interaction, proposed by Sychev (1972), to determine the separation location as a function of Froude and Reynolds numbers. Results obtained in the high-Reynoldsnumber limit show that the channel flow separates at shorter distances from the entrance as Froude number is reduced.