Hydrogen technology in Sub-Saharan Africa: Prospects for Power Plants

Hydrogen as an energy vector could be one of the solutions to the crucial energy crisis in sub-Saharan Africa. A technological review is done in this paper as a first attempt to foster research and development on the subject. It shows the hydrogen technology disadvantages and difficulties regarding its usage in Africa, and explores ways to better tackle them. Concepts are also discussed by showing the benefits of hydrogen introduction in sub-Saharan African countries on their economy through the increase of their electrification coverage and the reduction of electricity shortages witnessed in these countries. Ideas of systems hybridization including hydrogen fuel cells are presented, discussed and adapted to the sub-Saharan context. Methods of overcoming possible risks, technologies that could be adopted now and on-going research on the subject are finally performed

CIFEM2018 Conference Proceedings

International audienc

Performance analysis of a K2CO3-based thermochemical energy storage system using a honeycomb structured heat exchanger

International audienceThe application of thermal energy storage using thermochemical heat storage materials is a promising approach to enhance solar energy utilization in the built environment. Potassium carbonate (K 2 CO 3) is one of the potential candidate materials to efficiently store thermal energy due to its high heat storage capacity and costeffectiveness. In the present study, a 3-dimensional numerical model is developed for the exothermic hydration reaction of K 2 CO 3. The heat produced from the reaction is transferred indirectly from the thermochemical material (TCM) bed through the walls of the honeycomb heat exchanger to a Heat Transfer Fluid (HTF). A parametric study is conducted for varying geometrical parameters of the honeycomb heat exchanger. The obtained results indicate that the reaction rate and heat transport in the TCM bed strongly depends on the geometrical parameters of the heat exchanger. Reducing the cell size of the honeycomb heat exchanger up to a certain level provides better thermal transport as well as improved reaction rate of the TCM bed. The results of this study provide detailed insight into the heat release processes occurring in a fixed bed of K 2 CO 3. The study is useful for designing and optimizing thermo-chemical energy storage modules for the built environment

Thermal synthesis of a thermochemical heat storage with heat exchanger optimization

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Analysis of Hybrid Energy Systems for Telecommunications Equipment: A Case Study in Buea Cameroon

The considerable expansion of telecommunications infrastructure in non-electrified areas has led to massive consumption of non-renewable energy sources by diesel generators. The promotion of renewable energy technologies as an alternative to these diesel generators is until now confronted with the problems of Capital Expenditures and system reliability. The hybridization of fossil fuels with renewable energies would make it possible to find a better quality/cost/environment ratio for the supply of off-grid telecommunication base stations (BSs).This paper presents the analyses of eight different hybrid energy systems dedicated for telecommunications equipment with a BS antenna as case study. The techno-economic analysis of hybrid energy system comprises solar, wind and the existing power supply. All the necessary modelling, simulations, and techno-economic evaluations are carried out using the assessment software package HOMER (Hybrid Optimization Model for Electric Renewable). The result shows that adding solar PV to the existing system is the optimal option. For the site studied powered by grid and diesel generator, the hybrid PV-diesel-grid with storage battery system is the best optimal system configuration for the chosen antenna with an initial capital cost of 34,619$, a Net Present Cost (NPC) of 55,588$ and a Cost of Energy (COE) of 0.39$/kWh

Performance analysis of a thermochemical based heat storage as an addition to cogeneration systems

International audienceA closed thermochemical heat storage system based on pure salt hydrate, namely SrBr2·6H2O is developed and its performance, numerically investigated. This paper focuses on system development as an addition to existing micro-combined heat and power (cogeneration). The originality of this work lies in the fact that it models the coupled heat and mass transfer with chemical reaction on a 3D geometry to be closed to reality. Besides, a reaction front model is also developed, in order to determine optimal parameters (bed porosity, bed thickness kinetic behaviour) and thermal power, required for system efficiency. Then, sensitivity of permeability and thermal conductivity on the reaction efficiency is numerically demonstrated, leading to some recommendations for future prototype development. Results exhibit a theoretical reactor energy storage density of 115 kWh m−3, storage capacity of 61 kWh, thermal efficiency of 78% (at 90% of reaction conversion) and COPth of 0.97, highlighting system performances. An average output temperature of 52 °C is numerically obtained. A comparison simulation-experiment is then performed and discussed, showing encouraging results, even if limited at lab-scale. Performances are quite similar, consolidating the idea that, waste heat from cogeneration can be re-used with 78% of efficiency