Energy Analysis for the Ahuachapan and Berlin Geothermal Fields, El Salvador

Abstract

This paper in based on the results obtained from the exergy analysis done in the Ahuachapan and Berlin geothermal fields. Plotting the thermodynamic conditions of both fields on the Molliere diagram and computing the specific exergy index (SEI) the fields are classified on the medium high exergy zone. Also, the analysis of the characteristic curves by comput the utilization efficiency ratio at higher wellhead pressure related to the maximum flow conditions, indicates that higher wellhead operation can improve the thermodynamics in a production well. The study of the output characteristics curves from all the production wells in the Ahuachapan field, shows that the low enthalpy wells AH- 1 and AH-24 can improve its thermodynamic conditions if they operate under higher pressure. The utilization energy (exergy) at wellhead conditions has been considered to compute the utilization efficiency (É?u) of the geothermal field power plant system instead of the extracted thermal energy. The reported production data over 1998, gives a values of 41 % for Ahuachapan (condensation system). As comparisson, in the Berlin geothermal field where two wellhead unit of 5 MW (back pressure system) are operated, is observed a utilization efficiency of 21 %.