Parabolic trough solar power plants
The sun is an inexhaustible source of energy; with a solar thermal power plant (Concentrated Solar Power – CSP) that covers one percent of the area of the Sahara Desert (300 km x 300 km) the electricity demands of the entire world population could theoretically be covered.
The basic principle of solar thermal power generation is simple: Solar energy heats water which evaporates and steam drives a turbine, which in turn sets in motion a generator for electricity production. Given that the heat can be stored in tanks of molten salt for hours, such a plant generates power even when the sun is no longer shining.
In parabolic trough power plants the sun’s energy is concentrated by parabolic mirrors in a small area. In the focal line of the half-open mirrors, which track the sun’s path, there is a pipe, the so-called receiver. It contains a liquid that serves as heat transfer medium – usually synthetic thermal oil. It heats up and releases the energy via a heat exchanger to water. Temperatures occurred thereby are lower than other steam-powered power plants’, typically between 370 and 550 degree Celsius. The fast start-up times as well as daily start-ups of parabolic trough power plants require special turbines.
As shown in the figure below sunlight is transferred by a parabolic trough solar power plant using parabolic mirrors to a tube carrying a thermal fluid; a distinction is made between two transmission media:
The thermal oil transports the conveyed solar energy at temperatures up to 500 degree Celsius in a closed pipe system to the heat exchanger or power generator. The energy density thereby is not as high as with the transfer medium liquid salt, yet less problematic.
The molten salt allows for higher temperatures and higher energy density which is particularly advantageous to bridge sunless periods and at night times. The efforts and the technical challenge however, to convert salt to the liquid state (liquefy salt), are immense.
The company West Coast Power uses products of renowned manufacturers who are developing the innovative technology for the receiver tubes. Instead of synthetic oil, molten salt passes through these tubes. The advantage of this: while the synthetic oil deteriorates in the course of the constant temperature fluctuations and needs to be replaced after a certain time, the salt remains in the heating circuit. It allows for higher temperatures of up to 550 degree Celsius, and thus contributes to a higher efficiency of the plant. Moreover, the heat in the molten salt can be stored in order to generate electricity at night.
Thermal Energy Generation – Solar Collectors
West Coast Power at this offers standard products of reputable manufacturers, who are closely involved and familiar with the overall concept of the Energy Efficient House.
Electric Power Generation – Photovoltaic
These are solar panels generating electricity from sunlight by use of the photoelectric effect. This type of energy source is ideally suited for stand-alone solutions, sunny regions and/or high mountains. West Coast Power here offers standard products of reputable manufacturers who are closely involved with the overall concept of the Energy Efficient House.