Entropy production and optimization of geothermal power plants

Abstract

Geothermal power plants are currently producing reliable and low-cost, base load electricity. Three basic types of geothermal power plants are currently in operation: single-flashing, dual-flashing, and binary power plants. Typically, the single-flashing and dual-flashing geothermal power plants utilize geothermal water (brine) at temperatures in the range of 550-430 K. Binary units utilize geothermal resources at lower temperatures, typically 450-380 K. The entropy production in the various components of the three types of geothermal power plants determines the efficiency of the plants. It is axiomatic that a lower entropy production would improve significantly the energy utilization factor of the corresponding power plant. For this reason, the entropy production in the major components of the three types of geothermal power plants has been calculated. It was observed that binary power plants generate the lowest amount of entropy and, thus, convert the highest rate of geothermal energy into mechanical energy. The singleflashing units generate the highest amount of entropy, primarily because they re-inject fluid at relatively high temperature. The calculations for entropy production provide information on the equipment where the highest irreversibilities occur, and may be used to optimize the design of geothermal processes in future geothermal power plants and thermal cycles used for the harnessing of geothermal energy. 234

Optimized Piston Motion for an Alpha-Type Stirling Engine

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Can Earth as a Level 1 Civilization control Plate Tectonics and eliminate Earthquakes by harnessing the Energy of the Planet?

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“…The larger portion of this heat (30TW) is generated by radioactive decay in the core and mantle. This difference (14TW) implies that the Earth cools continuously, mainly through the oceans and specifically the mid ocean ridges [5,6].…”

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ETA-Graphics—an interface to endoreversible thermodynamics

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