Energy Systems
M. E. Emetere; W. A. Ayara; O. R. Obanla
Abstract
This research focuses on the need for preserving fruits in rural areas to prevent waste. The solar drier is made of vital chambers i.e. the concentrator chamber (that harvests the solar irradiance), the transport pipe (that transports the heat generated by convection) and hanger chamber (where the fruits ...
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This research focuses on the need for preserving fruits in rural areas to prevent waste. The solar drier is made of vital chambers i.e. the concentrator chamber (that harvests the solar irradiance), the transport pipe (that transports the heat generated by convection) and hanger chamber (where the fruits are placed). The temperature within the concentrator chamber and hanger chamber was monitored. The design allowed heat transfer by convection from the collector to the chamber at an efficiency of 92 %. The design allowed the temperature build up in the solar collector to be transported faster through hanger chamber with the help of incorporated detachable low power dc fan. This arrangement makes the dryer to either operate in the natural convection dryer mode (without the fan) or as a forced convection dryer (with the fan attached). It is observed that the forced convection provided higher air in-flow and hence greater drying capability. However, regions with moderate precipitation may have challenges of delayed fruit drying and growth of microorganism over the surfaces of the dried fruit.
Solar Energy
H. Hoseini; R. Mehdipour
Abstract
Solar chimney power plants are plants based on solar thermal power including three parts of collector, chimney and turbine, which is able to produce electrical energy. One of the effective parameters in increasing the power production is the collector angles versus horizon. In the present study, a numerical ...
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Solar chimney power plants are plants based on solar thermal power including three parts of collector, chimney and turbine, which is able to produce electrical energy. One of the effective parameters in increasing the power production is the collector angles versus horizon. In the present study, a numerical analysis of a solar chimney power plant for different angles of the collector (divergent, convergent and horizontal type collector) is proposed. The introduced numerical model uses mathematical models of heat transfer. In this regard, effect of various angles of the three considered collectors on temperature distribution and power production of the solar chimney is evaluated. Divergent type collectors produce more power than convergent and horizontal collectors, as they produce more velocity and mass flow rates. It will be shown that by increasing the angle of divergent-type collector (keeping the inlet height constant), the power production will be increased and the output temperature will be decreased, in a way that the angle variation of 0.8 to 1 will increase the divergent type collector output power by 11 % and will decrease the output temperature by 0.78%. In the other case, when the output height is kept constant and the collector angle changes, performance of the divergent type collector is better than the other two collectors. Power production in a constant mean height is shown to be 3 times and 1.5 times more than the convergent and horizontal collectors respectively.
