Author: workhouse123
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The , f-chart method
The utilizability design concept is useful when the collector operates at a known critical radiation level during a specific month. In a practical system, however, the collector is connected to a storage tank, so the monthly sequence of weather and load time distributions cause a fluctuating storage tank temperature and thus a variable critical radiation…
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Utilizability method
In the previous section, the f-chart method is presented. Due to the limitations outlined in Section 11.1.5, the f-chart method cannot be used for systems in which the minimum temperature supplied to a load is not near 20 °C. Most of the systems that cannot be simulated with f-chart can be modeled with the utilizability method or its enhancements. The utilizability…
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1 f-chart method and program
The f-chart method is used for estimating the annual thermal performance of active building heating systems using a working fluid, which is either liquid or air, and where the minimum temperature of energy delivery is near 20 °C. The system configurations that can be evaluated by the f-chart method are common in residential applications. With the f-chart method, the…
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Solar ponds
Salt gradient lakes, which exhibit an increase in temperature with depth, occur naturally. A salt gradient solar pond is a body of saline water in which the salt concentration increases with depth, from a very low value at the surface to near saturation at the depth of usually 1–2 m (Tabor, 1981). The density gradient inhibits free…
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Solar updraft towers
The solar updraft tower is a renewable-energy power plant for generating electricity from solar power. The principle of operation of a solar chimney or updraft power plant is that because of its lower density hot air rises and creates a draft. The system consists of a chimney, a solar energy collector and wind turbines. In…
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Thermal analysis of solar power plants
Thermal solar power plants are similar to the conventional ones with the exception that a field of concentrating solar collectors replaces the conventional steam boiler. In hybrid plants, a conventional boiler is also present, operating on conventional fuel, usually natural gas, whenever there is a need. Therefore, the thermal analysis of solar power plants is…
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Dish systems
As was seen in Chapter 3, Section 3.2.3, dish systems use dish-shaped parabolic mirrors as reflectors to concentrate and focus the sun’s rays onto a receiver, which is mounted above the dish at the dish focal point. The receiver absorbs the energy and converts it into thermal energy. This can be used directly as heat or…
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Power tower systems
As was explained in Chapter 3, Section 3.2.4, power towers or central receiver systems use thousands of individual sun-tracking mirrors, called heliostats, to reflect solar energy onto a receiver located atop a tall tower. The receiver collects the sun’s heat in a heat transfer fluid (molten salt) that flows through the receiver. This is then passed optionally…
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Parabolic trough collector systems
Details of this type of collector are given in Chapter 3, Section 3.2.1. As was seen in Chapter 3, parabolic trough collectors are the most mature solar technology to generate heat at temperatures up to 400 °C for solar thermal electricity generation or process heat applications. The biggest application of this type of system is the nine southern…
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Introduction
As was seen in Chapter 1, Section 1.5, solar thermal power systems were among the very first applications of solar energy. During the eighteenth century, solar furnaces capable of melting iron, copper, and other metals were constructed of polished iron, glass lenses, and mirrors. The furnaces were in use throughout Europe and the Middle East. The…