Energy and exergy based evaluation of the renovated Afyon geothermal district heating system

• Energy and exergy analysis of renovated Afyon geothermal distinct heating system (NAFJET) was performed.
• Engineering Equation Solver (EES) was used for energy and exergy calculating.
• The exergy destruction in the overall system was quantified and illustrated using exergy flow diagrams. Energy and exergy efficiencies of the overall system were found to be 46.17% and 60.63%, respectively.
• Thermodynamics results of an investigated system compared with other geothermal distinct heating system (GDHS).

In this study, the exergy and energy analyses of the Renovated Afyon Geothermal Heating System (NAFJET), which was completely renovated in the Afyon province of Turkey between the years 2011–2013, were conducted. The exergy destruction in the overall geothermal district heating system (GDHS) was quantified and illustrated using exergy flow diagrams. Both energy and exergy flow diagrams were presented for comparison purposes. The analyses revealed that the exergy destruction in the system took place particularly due to the exergy of the thermal water (geothermal fluid) re-injected, the heat exchanger losses, the losses of all pumps and pipeline loses, accounting for 15.94%, 12.44%, 5.52% and 5.52% of the total exergy input to the system. Both energy and exergy efficiencies of the overall system were investigated, and they were found to be 46.17% and 60.63%, respectively.