Performance Analysis of a Coupled System based on Organic Rankine Cycle and Double Effect Absorption Refrigeration for Waste Heat Recovery in Data Center

During data center operation,it generates a significant volume of low-grade waste heat.To recover waste heat,a coupled system including solar collector,double effect absorption refrigeration and organic Rankine cycle is proposed.The system performance is analyzed in detail.For the organic Rankine cycle,five organic working fluids(R245fa,R245ca,R123,R11,and R113) are selected.R245fa,R113 and R245ca obtain the maximum net power output,thermal efficiency and exergy efficiency,respectively.In the double effect absorption refrigeration system,the evaporation temperature,condensation temperature,and generation pressure affect the COP and exergy efficiency.When the generator pressure is unchanged,the COP increases with increasing evaporation temperature and decreasing condensation temperature.When the COP reaches 1.3,the COP slightly decreases as the evaporation temperature or condensation temperature changes.Similarly,the exergy efficiency of refrigeration systems exhibits the same trend as the COP,and the exergy efficiency maximum value appears at approximately 0.32.A new performance indicator,rPUE,was defined to evaluate the data center power utilization efficiency.The flow distribution ratio and heat source temperature were optimized with multi-objective optimization.When the mass flow distribution rate is 0.6 and the heat source temperature is 441.5 K,rPUE and the total unit production costs of the system obtain the optimal solution.