Solar plants

For desorption the vapor desorbed from the silica gel has to be condensed. For this reason a low temperature heat sink is required. The hydraulics of the plant provides two heat sinks a 10 m3 rain water cistern and the thermal solar plant. With these heat sinks two desorption modes could be carried out a desorption with simultaneous condensation of the vapor an a second mode in which the desorption and condensation were not done simultaneously. If desorption and condensation of the vapour occur at the same time, then the condensation heat is rejected via the rain water cistern. The condensation heat can also be removed by the solar plant when the desorption and condensation operation are discontinuous. In this case the solar plant heats up the adsorber during daytime but no condensation is done. The condensation take place through the solar system during the night given correspondingly low outside temperatures. 

McGovern RJ, McSorley R, Bell ML (2002) Reduction of landscape pathogens in Florida by soil solarization. Plant Dis 86 1388-1395. doi 10.1094/PDIS.2002.86.12.1388 McLean KL, Swaminathan J, Stewart A (2001) Increasing soil temperature to reduce sclerotial viability of Sclerotium cepivorum in New Zealand soil. Soil Biol Biochem 33 137-143. doi 10.1016/S0038-0717(00)00119-X... 

Polizzi G, La Rosa R, Arcidiacono C, D Emilio A (2003) Effects of innovative films in soil solar-ization for the control of soil-borne pathogens. Acta Hort (ISHS) 614 805-811 Porras M, Barrau C, Romero F (2007a) Effects of soil solarization and Trichoderma on strawberry production. Crop Prot 26 782-787. doi 10.1016/j.cropro.2006.07.005 Porras M, Barrau C, Arroyo FT, Santos B, Blanco C, Romero F (2007b) Reduction of Phytophthora cactorum in strawberry fields by Trichoderma spp. and soil solarization. Plant Dis 91 142-146. doi 10.1094/PDIS-91 -2-0142... 

Yogev, A., Kribus, A., Epstein, M., Kogan, A. 1998. Solar tower reflector systems a new approach for high-temperature solar plants. Int J Hydrogen Energy 23 239-245. 

The decontamination of polluted waters by photocatalytic treatment has been suggested as a viable, low-cost, and environmental friendly technique. The possibility of using solar energy as well as low-cost technology pushed to develop solar plants based on this process. The field results are very encouraging [1]. 

Rankine Cycle. The sleam-Rankine cycle employing steam turbines has been the mainstay of utility thermal electric power generation for many years. The cycle, as developed over the years, is sophisticated and efficient. The equipment is dependable and readily available. A typical cycle (Fig. 21) uses superheat, reheat, and regeneration. Heat exchange between flue gas and inlet air adds several percentage points to boiler efficiency in fossil-fueled plants. Modern steam Rankine systems operate at a cycle top temperature of about 800 K with efficiencies of about 40%. All characteristics of this cycle are well suited to use in solar plants. 

Electric Generation Geothermal Plants Wind Plants Solar Plants Hydroelectric Plants Coal Plants Gas Plants... 

Minero, C., Pelizzetti, E., Malato, S., Blanco, J. (1993) Large solar plant photocatalytic water decontamination degradation of pentachlorophenol. Chemosphere 26, 2103-2119. 

A 354 mW thermal solar plant at Kramer Junction in the Harper Valley in California that has been in operation since 1985 (courtesy of NREL/DOE). (Top) This is one of nine solar electric energy-generating plants at Kramer Junction, California and it uses parabolic troughs to collect the Sun s energy. (Courtesy of National Recoverable Energy Laboratory-NREL/DOE.) (Bottom) In the receiver tubes, hot oil transports the concentrated solar heat to steam boilers, which drive the turbine generators. 

Other installations include one by a Spanish company named Acciona Energy, which recently started up a 64-mW solar thermal power plant near Boulder City in Nevada. This company is also planning two thermal solar plants in southern Spain (50 mW each) in Palma del Rio for an investment of 0.5 billion euros. 

Therefore, even if an installed solar-hydrogen power plant costs 1 billion more than a regular solar plant, this is still under the costs of state-of-the-art nuclear or fossil power plants of the same size range. If the solar collector cost is estimated at 3,000/kW, the life expectancy of the equipment at 25 years, and the interest on investment at 5%, the unit cost of electricity generated will be about 12tf/kWh. This cost is already competitive with fossil-generated peak electricity costs and even with nonpeak electricity prices in some areas. (In June 2007, in Connecticut in my household, we paid 18.9 /kWh for our electricity.)... 

In order to determine the solar plant area requirement for the above described power plant if it is located in southern California, one can assume that Figures 1.28 and 1.29 accurately give the average yearly insolation as about 2,600 kWh/m2/year. If the efficiency of the solar collectors is 20%, the collectors could be arranged on a square with 2.5 mi sides (6.5 mi2 or 16.6 km2). Naturally, if the plant is located in the equatorial zone (such as the Sahara or on a floating island), the area requirement would be less. For example, if the insolation in the selected area is 3,000 kWh/m2/yr and the solar plant efficiency is 30%, the radius of a circular plant would be about 1 mile, while in the temperate zone, with 1,500 kWh/m2/yr insolation and a 15% efficient system the required radius would be about 2.0 miles. 

Gimenez J, Curco D, Queral MA. Photocatalytic treatment of phenol and 2,4-dichlorophenol in a solar plant in the way to scaling-up. Catal Today 1999 54 229-243. 

A. Yogev, A. Kribus, M. Epstein and A. Kogan, Solar Thermal Reflector systems A new approach for high-temperature solar plants, Int. J. Hydrogen Energy 26 239-245 (1998). 

Hydrogen can be extracted from a range of sources since it is in almost everything, from biological tissue and DNA, to petroleum, gasoline, paper, human waste and water. It can be generated from nuclear plants, solar plants, wind plants, ocean thermal power plants or green plants. 

These solar plants are being tested to evaluate their desirability. One area of concern is how the output from the plants can be integrated into the electric power grid. The midday peak of production does not mesh well with the peak demand that occurs late in the afternoon. On some days, clouds prevent any operation. On other days the power drops quickly when clouds drift in fiont of the collectors and comes back abruptly when the clouds drift on past. These transients cause dramatic thermal expansion and contraction shocks to the system. Accommodating for these shocks produces design challenges and reduces the system lifetime. 

A lot of thermochemical cycles have been proposed in literature [4, 67, 68], potentially able to exploit the high-temperature energy coming from nuclear or concentrating solar plants (CSP). 

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