Thermodynamic Analysis of a Half-Effect Absorption Cooling System Powered by a Low-Enthalpy Geothermal Source

Abstract

A thermodynamic analysis of a half-effect absorption cooling system powered by a low-enthalpy geothermal source was carried out. This paper presents modeling of the half-effect absorption cooling system operating with an ammonia/lithium nitrate mixture and based on the first and second laws of thermodynamics, using as energy inputs real data from two geothermal wells located at Las Tres Vírgenes volcanic complex, Baja California Sur, México. Plots of coefficients of performance and exergy efficiency against condenser, evaporator, and generator temperatures are presented for the half-effect cooling system. The results showed that the system was able to operate at generation temperatures between 56 and 70 °C, which were supplied by the geothermal wells in order to produce cooling at temperatures as low as −16 °C, achieving coefficients of performance between 0.10 and 0.36, while the exergy efficiency varied from 0.15 to 0.40 depending on the system operating temperatures.

Keywords

• half-effect absorption system
• geothermal source
• low enthalpy
• thermodynamic analysis