Design of Integrated Geothermal- Solar Based System for Multigenerational Needs in a District Energy System Application

The current thesis proposes an integrated geothermal based multi-generation system including the triple effect LiBr/water absorption system (TEAS), organic Rankine cycle (ORC), air-conditioning system (dehumidification with cooling) and an electrolyzer. The aim of this system is to supply six outputs comprising heating, cooling, dry air, hot water, hydrogen, and power. All the simulations are done by Engineering Equation Solver software (EES). By inputting 500K geothermal water, the energetic and exergetic overall utilization factors (Ɛen and Ɛex) for the completely multi-generation cycle would be 2.467 and 1.097, respectively. A parametric study was conducted indicating that a rise in the environment (ambient) temperature from 295K to 320K leads to an accumulative trend for exergetic coefficient of performance (COPex) while energetic coefficient of performance (COPen) remains constant in TEAS. While, the evaporator temperature rises from 274K to 279K, there is a downward trend for COPen and COPex (from 1.491 to 1.479 and 0.3525 to 0.3145, respectively) as well as Ɛen and Ɛex. By raising the geothermal temperature from 400K to 500K, Ɛen and Ɛex will increase from 2.354 to 2.467 and from 1.055 to 1.105, respectively. Moreover, the rise in geothermal temperature will upsurge the rate of hydrogen production as well as the heat rate in hot water production from 0.004873L/s to 0.005944L/s and from 8.365kW to 112.9kW, respectively. Moreover, environmental impacts, as one of the most designing parameter, are analyzed to find the system irreversibility (exergy destruction) and exergy losses. The parametric simulation is done to check the system in term of environmental suitability. In addition, a comparative study shows that using multi-generation cycle with higher COPen and COPex in comparison with conventional systems is more feasible to design for reaching the six outputs. Keywords: Geothermal, Multi-generation, Energy, Exergy, Overall Utilization Factor, Exergoenvironmental Impact Factors.