Geothermal-based freshwater production by humidification-dehumidification and evaporating desalination units integrated with a CCHP system: Energy and exergy analysis

Ever-increasing demands of energy and freshwater along with the good potential of geothermal energy in the northern regions of Iran, make it affordable to design and implement a renewable-based multigeneration system to harvest this energy resource. In this study, the energy and exergy analysis of a desalination system integrated with a combined cooling, heating, and power (CCHP) system based on geothermal energy is conducted to calculate the production capacities, to identify the advantages and disadvantages of the proposed system from the exergy viewpoint, and finally to investigate the impacts of the critical parameters on the system’s performance. The system employs a humidification-dehumidification (HDH) cycle and an evaporating separator based on an absorption heat transformer (AHT) to generate freshwater. Also, a LiBr-water absorption chiller and a heating unit are utilized to provide the cooling/heating demands. Finally, an organic Rankine cycle (ORC) is used to generate power. The results reveal that the maximum exergy destruction occurs in absorber 1-separator (ABS1-SEP) and absorber 2 (ABS2). Moreover, offering the power, heating, cooling, and freshwater generation capacities of 78.4 KW, 6.25 MW, 4.99 MW, and 3837.6 L/h, respectively, this system has got the energy and exergy efficiency of 60.55% and 17.05%, in summer, and 70.58% and 43.59%, in winter, respectively. The parametric study shows that the maximum value of energy efficiency is achievable with the ambient temperature of 295.26 K.

Geothermal-based freshwater production by humidification-dehumidification and evaporating desalination units integrated with a CCHP system: Energy and exergy analysis Keywords:

Absorption chiller , Absorption heat transformer , Desalination , Exergy Analysis , Geothermal energy , Humidification-Dehumidification , Multigeneration , Organic Rankine cycle