## 2 Description of Combined Systems  
Figure 1 shows schematic of combined system with single evaporator in VCR cycle. The system basically aims at transferring turbine power produced in ORC to the compressor of VCR to acquire refrigeration. System uses the same working fluid in both of the combined cycles. Compression occurs in compressor. Then, heat is transferred to ambient under constant pressure in the condenser. Fluid expands in expansion valve under constant enthalpy. Lastly, fluid draws the heat of the ambient to be refrigerated while passing through the evaporator under constant pressure and VCR cycle is completed. In an organic Rankine cycle, pumping is achieved in the pump. Then, fluid is heated with hot water waste heat source under constant pressure in the boiler. Expansion occurs in the turbine and gained turbine power is transmitted to the compressor. Finally, heat is given to ambient under constant pressure in condenser and ORC cycle is completed. Assumptions made for thermodynamic analysis are as follow. * Cooling load is 2 kW. * Fluid is saturated vapor at the outlet of evaporator and boiler while being saturated liquid at the outlet of both of the condensers [3; 10; 11; 13]. * 15 \({}^{\circ}\)C temperature difference was assumed to be between boiler and waste heat source [13; 20]. * 5 \({}^{\circ}\)C temperature difference was assumed to be between evaporator and refrigerated space [13; 21; 22]. * Ambient temperature and pressure are 25 \({}^{\circ}\)C and 101.325 kPa, respectively. * Heat sink temperatures of both of the condensers are equal to ambient temperature. Input values and ranges of operational parameters used in combined a ORC-single evaporator VCR cycle are given in Table 2. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Working** & **Chemical** & **Molecular** & \multirow{2}{*}{**NBP (\({}^{\circ}\)C)**} & \multicolumn{2}{c}{**Critical**} & \multirow{2}{*}{**GWP (100**} & \multirow{2}{*}{**ODP**} & \multicolumn{1}{c}{**Fluid**} \\
**Fluid** & **Compound** & & & & & & **Type** \\ \hline R134a & CH\({}_{2}\)FCF\({}_{3}\) & 102.3 & \(-\)26.1 & 101.1 & 1370 & 0 & Isentropic \\ R600a & CH\({}_{4}\)(CH\({}_{3}\))3 & 58.12 & \(-\)11.7 & 134.7 & 20 & 0 & Dry \\ R1234 ze(E) & CHF\(=\)CHCF\({}_{3}\) & 114.04 & \(-\)19 & 109.4 & 6 & 0 & Isentropic \\ R227 ea & CF\({}_{3}\)-CHF-CF\({}_{3}\) & 170.03 & \(-\)16.3 & 101.8 & 3580 & 0 & Dry \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Properties of working fluids. Figure 2 shows a schematic of the combined system with dual evaporator in VCR cycle. System targets transmitting turbine power gained in ORC to the compressor of VCR to achieve refrigeration. Cooling loads of evaporators were selected to be consistent with similar studies. The system uses the same working fluid in both of the combined cycles. Compression occurs in the compressor. Then, heat is transferred to ambient under constant pressure in condenser. After the condenser, fluid divides into two branches to achieve refrigeration mission in two different evaporators. Fluid expands in the second expansion valve under constant enthalpy and passes through the second evaporator to draw heat of the ambient to be refrigerated under constant pressure. Then, fluid expands in the third expansion valve under constant enthalpy to have the same pressure with fluid flowing from other branch at the entrance of mixing chamber. On the other hand, fluid expands in the first expansion valve under constant enthalpy and passes through the first evaporator to draw heat of the ambient to be refrigerated under constant pressure. Fluids flowing from two branches mix in mixing chamber and are directed to compressor. Thus, VCR cycle is completed. In the organic Rankine cycle, pumping occurs in the pump. Later, temperature of the fluid increases by heating it with hot water waste heat source under constant pressure in the boiler. Expansion happens in the turbine and turbine power is given to compressor.