Energy Analysis of a Thermodynamic System Combined Organic Rankine Cycle and Absorption Cooling System for Power and Cooling: Effects of Pressure and Temperature

In the current economic, energy and environmental context, the implementation of technologies using renewable energies as a source of power electricity and cooling production is very beneficial insofar as it allows the reduction of pollution and the cost of fossil fuels. Senegal has a sunshine potential well distributed across the country for irradiation varying from South to North between 1850 KWh/m²/year and 2250 kWh/m²/year. It is one of the best solar potentials in the world. Systems operating on the organic Rankine cycle ORC and the absorption cooling system ACS are innovative and sustainable technologies for the exploitation of low enthalpy renewable energy sources. In this present work, the thermodynamic analysis of a combined ORC and ACS system for power electricity and cold production is carried out numerically using the Engineering Equation Solver (EES) software. R245fa and water-lithium bromide mixture are used as working fluid for ORC and ACS respectively. The results obtained at the ACS subsystem level show that the COP of ACS decreases when the absorption temperature increases. This reduction goes from 0.83 to 0.55, i.e. a reduction of 0.28 for a variation of absorption temperature from 27°C to 45°C. The COP has stabilized for generator temperatures above 95°C and is in the range of 0.7 to 0.8. These fluctuations are due to the irreversibility at the level of the components of the system. For the ORC subsystem, the turbine power and ORC condenser power decrease as the ORC condensing pressure increases. Thus, the turbine power goes from 235 kW to 200 kW and the ORC condenser power goes from 80 kW to 60 kW.