Browsing by Subject "Solar power plants"
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Item Feasibility of photovoltaic cells on a fixed mirror distributed focus solar bowl(Texas Tech University, 1986-08) Calico, Steve EugeneThe object of the Crosbyton Solar Power Project was to design a solar-fossil hybrid power plant to provide electrical power to Crosbyton, Texas. To meet this objective a test facility was built south of town. The power is produced by focusing sunlight to convert water to steam then using the steam to turn a generator to produce electricity. In times of inclement weather, darkness, or breakdown, electricity is provided by conventional fossil fuels. With the advances in photovoltaic cell efficiency and decreases in cost of manufacturing, direct conversion from solar energy to electrical energy could be possible. The purpose of this study is to determine the technical feasibility of solar cells on a fixed mirror distributed focus solar bowl, such as at the test facility at Crosbyton. Most of the research effort was devoted to the design of the receiver. The cells are mounted on the movable receiver, which tracks the sun during the day. The receiver with attached photovoltaic cells is the critical design element in this solar-electric concept. Its shape and size impact the solar concentration on the cells and the cooling requirements. Once the receiver was designed the essential support equipment needed was studied. These support systems provide for the cooling of the cells and conditioning the direct current electrical output from the solar array to be compatible with the load requirements. No estimate of the cost of construction and operation of such a solar system was made. Such an estimate would be needed to determine the overall feasibility of such a system. However, the simplicity of the receiver designed here and the projections of low cost commercially available solar cells indicate that the feasibility of direct energy conversion by solar cells on a distributed focus receiver may become practical in the near future.Item Reflection characteristics at large incident angles with reference to solar bowl(Texas Tech University, 1988-05) Trahan, Markham RayA computer code was developed for the Crosbyton Solar Power Project to calculate the optical concentration along the receiver of the Crosbyton Solar Bowl. The predicted values have been in agreement with the observed data during the middle period of the solar day. However, optical flux distributions along the receiver in the mornings and afternoons have been found to be approximately 8 percent below what was predicted for the system. The purpose for this investigation is to identify the cause(s) for this discrepancy. To account for these discrepancies, a set of simple experiments were performed in the lab using the same kind of mirrors which are mounted on the solar bowl. The data analysis and calculations show that a significant quantity of this discrepancy is due to the focusing defect caused by two properties of back surface reflecting mirrors. They are surface defects introduced during the manufacturing process, and internal reflections between the glass/air interface and the back reflecting surface. These properties have significant effect at large incidence angles.Item Strategy of operation and theme for control of a solar-fossil hybrid electric plant(Texas Tech University, 1982-12) Watson, Karan LeaThe Crosbyton Solar Power Project has proposed a design for a solar-fossil hybrid electric power plant. This plant will utilize ten Solar Gridirons and a fossil fuel boiler to produce 5 MWe on a steady and reliable basis. Before the final design for this plant can be made, detailed operational procedures must be defined. This study considers strategies, methods, and procedures for operating and controlling the Solar Gridiron. Specifically, two elements of sclar boiler operation were investigated. The first effort was to develop a basis for selecting the solar boiler operation modes for use under various conditions. A mode is defined by the state of the fluid exiting the boilers. A criterion for switching from one mode to another, in order to improve plant performance, is referred to as a solar boiler operational strategy. For this study several strategies were investigated in an effort to find procedures which provide the most effective capture and utilization of solar energy for the plant. Several strategies were found which improve the expected plant performance. However, the final decision between these strategies must ultimately incorporate economic considerations beyond the scope of this study. The second effort related to boiler operation, considered in this study, dealt with control of the fluid through the boilers. A control system providing rapid, yet safe, control of the solar boilers is fundamentally different than a control system for a fossil boiler. For fossil boilers, an operator can control the firing rate to produce the amount and q u a l i t y of steam desired. For solar boilers, solar availability directly influences the boiler output, and there is no way to effectively control the solar power reaching the Gridiron. An effective and versatile control scheme for the solar boilers, developed daring this study, is described in detail.