Low grade temperature waste heat recovery with Organic Rankine Cycle (ORC) was studied as a new renewable and sustainable energy source. In purpose to generate electricity, this study focused on the feasibility of integrated ORC in superheated waste heat recovery from Vapor Compression Refrigeration Cycle (VCRC) with single working fluid. ORC was applied to recover superheated waste heat rejected by the air-conditioning (AC) system. The single working fluid program was performed using Matlab and REFPROP then analyzed on their system behavior. Based on the results of overall coefficient of performance (COP) and environmental factors, R1233zd was found to have optimal system performance when compared to the other five refrigerants, while the “inlet cooling water temperature at AC condenser - ORC evaporating temperature” pair was found to fluctuate the overall COP of the system. The performance of the proposed water-cooled system indicated that it is feasible. Annual energy saving with the integrated ORC-VCRC system using single working fluid was estimated to be 2113.444 kWh, which means around 2.198% of annual energy consumption can be saved.
Figure 1 Configuration of the proposed ORC-VCRC system
Figure 2 Relationships between the inlet cooling water temperature at AC condenser and the COP of the system for both Standalone AC system and AC-ORC system with ambient water temperature in 2019
Figure 3 Monthly energy saving with water-cooled system in 2019