The Feasibility of using Biomass for Energy for a Typical (African) Rural Community

To evaluate the biomass potential to provide thermal energy to drive an absorption refrigeration system, a computer aided model was developed. The subroutines that constitute the model agree with ASHRAE standards and reflect the underlying thermodynamic principles, but introduces a shorter method of analysing Aqua Ammonia absorption refrigeration cycle by eliminating the need for finding the specific volume from charts or computation of the rigorous parameter components of the equations of state. Parametric evaluation from the model shows that at constant evaporator, condenser and absorber temperatures, the COP decreases with increase in generator temperature. The COP ranges between 0.84 for generator temperature of 60◦ C and 0.76 for 90◦ C, beyond which the variation is insignificant. The concentration of the refrigerant exiting the generator is dependent on the solution mass flow and temperature, and varies between 0.9 to 0.98 for the simulated data. This quantity is usually assumed to be 100%. The biomass consumption varies with generator temperature and the flow of hot water, but also depends on the fuel density, load and heating hours, as well as the efficiency of the biomass combusting system. The rationale a typical (African) rural community with access to biomass is based on the characteristics of these communities; one of which is the access to renewable energy in a dimension that is apt to support the production and efficient utilisation of the energy to a large scale, and the need for a refrigeration system that demands little or no extra energy but capable of conditioning indoor climate to suit human comfort, maintain and support the viability of agricultural seedlings and medical drugs in healthcare facilities and related amenities. The conventional vapour compression refrigeration systems, although efficient, use refrigerants that are not environmentally friendly and high energy consuming. The study highlights some of the limitations of the uptake, and efficient utilisation of renewable energy in the region. It also presents a review of energy in the region from a global and historical perspective and focuses on the influence on the regional economy from a state of the art review of the literature. It shows the relation between energy access and economic development. Causality study shows that this might be unilateral or bilateral, but the influence of one on the other does exist. The theory of biomass for energy was explored to highlight measures of enhancing the energy yield of a biomass species, suitability and selection.