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A REVISED SOLAR TRANSFORMITY FOR TIDAL ENERGY RECEIVED BY THE EARTH AND DISSIPATED GLOBALLY: IMPLICATIONS FOR EMERGY ANALYSIS
Citation:
Campbell, D E. A REVISED SOLAR TRANSFORMITY FOR TIDAL ENERGY RECEIVED BY THE EARTH AND DISSIPATED GLOBALLY: IMPLICATIONS FOR EMERGY ANALYSIS. Proceedings of the 1st Biennial Emergy Analysis Research Conference: Emergy Quality and Tranformities, Gainesville FL, September 2-4, 1999.
Description:
Solar transformities for the tidal energy received by the earth and the tidal energy dissipated globally can be calculated because both solar energy and the gravitational attraction of the sun and moon drive independent processes that produce an annual flux of geopotential energy in elevated ocean water. I assume that the available geopotential energy of the world oceans is the same regardless of how it is made; therefore, the transformity of the annual geopotential energy flux generated by solar emergy should be approximately equal to that generated by the gravitational attraction of the sun and moon. This approximate equality is plausible, because the maximum power principle implies that in the long run the transformity of a product created by any process will approach the lowest thermodynamically possible value. The annual emergy contributed by solar radiation (3.93 E24 sej y-1) and the earth's deep heat (4.07 E24 sej y-1) was divided by the difference between the geopotential energy generated annually in the world oceans and the tidal energy dissipated annually in shallow water (21.4 E 19 J y-1 -5.2 E19 J y-1) to obtain a transformity of 24259 sej J-1 for the part of the ocean's total potential energy generated by the solar heat engine, if solar emergy is the only important emergy source and 49383 sej J-1 if both the solar heat engine and the earth's deep heat contribute. Using the assumptions given above, the transformity of the tidal energy dissipated globally is also approximately 24259 sej J-1 or 49383 sej J-1. The solar emergy used up globally by the dissipation of tidal energy is then 5.2 E19 J y-2 multiplied by 24259 sej J-1 or 49383 sej J-1 equaling 1.26 E24 sej y-1 or 2.58 E 24 sej y-1, respectively. The transformity of the gravitational energy of the sun and moon received by the earth is then 1.26 E24 sej y-1 or 2.58 E24 sej y-1 divided by 8.515 E19 J y-1 which equals 14797 sej J-1 or 30159 sej J-1, respectively. Because the earth's deep heat makes a negligible contribution to determining variations in the geopotential of the world oceans except on long time scales, e.g., more than 1.0 E4 years, the solar transformity for the tides based on solar emergy alone is preferable for emergy analyses on short time frames, e.g., less than 10,000 years. These revised solar transformities for tidal energy establish new planetary baselines for emergy analysis, 9.26 E24 sej y-1 for short (<1.0 E4 y) and 10.58 E24 sej y-1 for long period processes (>1.0 E4 y). Spatial and temporal guidelines to avoid double counting in determining the emergy basis for local phenomena were suggested based on implications of this analysis.