Solar thermodynamic energy

In an energy-conscious world, SI provides a direct relationship among mechanical, electric, chemical, thermodynamic, molecular, and solar forms of energy. AH power ratings are given in watts. 

See also Animal and Human Energy Batteries Con-seivation of Energy Nuclear Energy Solar Energy Thermodynamics Units of Energy. 

Rosen, M.A., 1992. Appropriate thermodynamic performance measures for closed systems for thermal energy storage, ASME J. Solar Energy Eng., 114, 100-105. 

The theoretical solar conversion efficiency of a regenerative photovoltaic cell with a semiconductor photoelectrode therefore depends on the model used to describe the thermodynamic and kinetic energy losses. The CE values, which consider all the mentioned losses can generally only be estimated the full line in Fig. 5.65 represents such an approximation. Unfortunately, the materials possessing nearly the optimum absorption properties (Si, InP, and GaAs) are handicapped by their photocorrosion sensitivity and high price. 

Ideally, all photons with a wavelength of about 900 nm or shorter should be harvested and converted to electric current. This limit is derived from thermodynamic considerations showing that the conversion efficiency of any single-junction photovoltaic solar converter peaks at approximately 33% near the threshold energy of lAeV.1 2 There are numerous ways to convert the solar radiation directly into electrical power or chemical fuel. The silicon solar cell is the most efficient in this respect. Nevertheless, the capital cost of such devices is not attractive for large-scale applications. 

De Vos, A. Endoreversible Thermodynamics of Solar Energy Conversion, Chapter 6, Oxford Science Publishers, Oxford, 1992. 

A.W. Adamson, University of Southern California You mentioned a thermodynamic limitation to the efficiency of conversion of solar energy to useful work. This is an interesting point, and I would like to hear more about it. I can see an entropic effect in terms of the following hypothetical cell for the system A = A, where A is the excited state of species A ... 

Ikegami, Y. and A. Bejan. On the Thermodynamic Optimization of Power Plants with Heat Transfer and Fluid Flow Irrreversibilities. J Solar Energy Engr 120 (2) 139-144 (1998). 

From a consideration of thermodynamics, solar energy conversion by means of photoinduced charge separation followed by water splitting is a feasible process. 

A. De Vos, Endoreversible Thermodynamics of Solar Energy Conversion, Oxford University Press, Oxford, 1992 R. S. Berry, V. A. Kazakov, S. Sieniutycz, Z. Szwast, and A. M. Tsvihn, Thermodynamic Optimization of Finite-Time Processes, John Wiley Sons, Chichester, 2000) P. Salamon, J. D. Nulton, G. Siragusa, T. R. Andersen, and A. Limon, Energy 26, 307 (2001). 

Incident solar energy is absorbed by the surface water of the oceans. Ocean surface temperatures in excess of 26°C occur near the equator. Pure water has a maximum density at a temperature of 4°C. The chilled water tends to settle to the depths of the ocean. The combination of the warmed ocean surface water and cold deep ocean water provides the thermodynamic condition needed to operate a heat engine called ocean thermal energy conversion (OTEC). A typical closed-cycle OTEC Rankine cycle using a working fluid such as ammonia or a freon is suggested. 

Blank, D.A. and Wu, C., Performance potential of a terrestrial solar-radiant Ericsson power cycle from finite-time thermodynamics. International Power and Energy Systems, 15(2), 78-84, 1995. 

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