geothermal power plant projects in central america - Orkustofnun

Second, condensation of the working fluid vapor can be calculated as̅ = (h −h ) (34)where h is the enthalpy of the working fluid in a saturated vapor state, where the pinch point inthe condenser is located. Figure 18 shows the thermodynamic T-s diagram of the process.FIGURE 18: T-s diagram of an ORC cycle (Isopentane) with regeneration4.2 Simulation and optimizationCentral America is a small geographic region divided politically into many territories. There existsimilar economic and climatic conditions for the design of geothermal plants. However, geothermalreservoir and well properties differ from site to site and, as such, require serious attention during thedesign process as they are critical parameters for optimization. In this analysis, power plant models forCentral America were designed based on the technical parameters which do not change from case tocase and on the similar climatic conditions of the region.The methodology applies the fundamental principles of thermodynamics to the components of thecycle and to the cycle itself to form a system of non linear equations as developed in Section 4.1. Theoptimization process was solved by using the mathematical environment called Engineering EquationSolver (EES) which also evaluates thermodynamic properties and solves a system of non linearequations.The optimization process was done over three types of energy conversion systems: single flash (SF),double flash (DF) and organic Rankine cycle (ORC). For each of these cycles design variables andconstraints were defined. The optimization constraints were applied by setting boundaries on eachvariable. In this analysis, the optimization process was carried out on the design variables using adirect search algorithm called the grid search method.According to Rao (2009) the method involves setting up a suitable grid in the design space, evaluatingthe objective function at all the grid points, and the point corresponding to the best objective functionvalue is considered the optimum solution. The power output optimization process was repeated severaltimes in each case for different resource temperatures and mass flows.4.2.1 Assumptions and limitationsSimulation of the models of the energy conversion systems described in Section 4.1 requiredassumptions for a wide range of behavior of the geothermal system and technical characteristics of thepower plant equipment. Table 3 gives a summary of assumptions used as input in this analysis. Someimportant assumptions not used as input for the analysis are:22