Thermodynamic analysis of a trigeneration system based ongeothermal energy

In this study an integrated system for the simultaneous production ofpower, fresh water and hydrogen based on geothermal energy isproposed. In this thesis, Kalina cycle is used due to the variabletemperature of the ammonia water mixture in the two-phase region andits ability to be closely aligned with the temperature of the hot source. Inaddition, reverse osmosis and proton exchange membrane electrolyzertechnologies have been used to produce fresh water and hydrogen in theproposed system. The results showed that in a basic condition, the energyand exergy efficiency of the proposed system are ۳۰.۲۶% and ۲۳.۱۵%respectively. Moreover, the amount of the power produced by the systemis ۶۰۶.۳ kW. Furthermore, the amounts of hydrogen and fresh waterproduced by the system are ۰.۰۰۴ g/s and ۴.۰۹۸ kg/s, respectively. Theresults showed that the main contribution to the irreversibility of thewhole system is related to the Kalina subsystem. With the increase of thegeothermal fluid temperature, the energy and exergy efficiencies of thesystem decrease while the amount of hydrogen and fresh waterproduction rate increases.

Keywords:

Geothermal , Kalina cycle , RO unit