## 1 Introduction
Working fluids were toluene for ORC and ammonia/carbon dioxide couple for cascade refrigeration cycle. They observed that boiler temperature in ORC is the most important parameter effecting COP and exergy efficiency of system. The highest COP was found to be 0.79 and the highest exergy efficiency was detected 31.6% in the system. [PERSON] et al. [14] investigated three systems that were single ORC, combined ORC-Ejector Refrigeration Cycle and combined ORC-Absorption Refrigeration Cycle. They determined that exergy efficiency of ORC first increases then decreases with increasing boiler temperature. They also detected that a combined uncoupled system with absorption refrigeration gave a better result than the system with ejector in terms of exergy efficiency. Thermodynamic analysis of combined ORC-VCR system using low GWP working fluids was carried out by [PERSON] et al. [15]. They used four hydrocarbons that were R290, R1270, R600a, and R600. They designated that R600 gave the highest COP with 0.4696. They also found that thermal performance increases with increasing boiler exit temperature and evaporator temperature and decreases with increasing condenser temperature. [PERSON] and [PERSON] [3] performed theoretical energy and exergy analysis of an integrated ORC-VCR system benefited from waste heat. R600, R245 fa, R123, R600a, and R141b were used in the study. They determined that R141b shows better performance than R245 fa, which is frequently used in ORC systems. In addition, they found that increase in condenser temperature causes a dramatic decrease in thermal and exergy efficiency of the system. [PERSON] [2] investigated performance of integrated ORC-VCR system using R245 fa, R1234 ze(E), R600, R236 fa, R290, R236 ea, RC318, R1270, R1234 yr, and R600a as working fluids. He observed that high boiler and evaporator temperature as well as high turbine and compressor isentropic efficiency increase performance of the system but decrease total mass flow rate. R600 and R245 fa gave almost the same COP value but R600 was selected to be the best candidate because of environmental issue of R245 fa. Another similar study was performed by [PERSON] and [PERSON] [16]. They used Refrop and Matlab software to calculate thermodynamic properties and performance of a combined ORC and ejector refrigeration cycle. R245 fa was utilized in the system. Results revealed that efficiency of the system can increase with increase in boiler and evaporator temperature and decrease in condenser temperature. [PERSON] and [PERSON] [17] made thermal performance analysis of a combined ORC-VCR system used for air conditioning purpose. 49 different working fluid couple were evaluated using R134a, R123, R245 fa, R134 ze(E), R1234 yf, isobutane, and butane. R134a was selected as the best working fluid for ORC and isobutane for VCR. They determined that the boiler has the highest exergy destruction rate in ORC. [PERSON] and [PERSON] [18] analyzed a cogeneration system composed of an ORC and ejector refrigeration cycle. They used mixtures of R245 fa and R600a fluids with different mass fractions. They found out that using of mixture instead of pure working fluids gives better performance. Mixture consisting of 40% of R245 fa and 60% of R600a performed better refrigeration effect. It is certain that there is need for analyzing performance of different combined ORC powered systems and different working fluids used in these systems. This paper presents energy and exergy analysis of two combined ORC-VCR systems. For the first system, ORC was combined with classical VCR cycle having single evaporator. Using the same parameters and working fluids, a second system that is a combination of organic Rankine cycle and dual evaporator refrigeration cycle was designed. Performance of four different working fluids that were R1234 ze(E), R227 ea, R134a, and R600a were evaluated in the study. Attention was paid to use isentropic or dry working fluids. Properties of working fluids are given in Table 1[19].