## 4 Results and Discussion  
### Refrigeration Cycle  
Figure 6 compares the refrigeration cycle and COP according to the measurement points during cooling operation at outdoor temperatures of 26 \({}^{\circ}\)C to 36.6 \({}^{\circ}\)C and indoor temperatures of 24 \({}^{\circ}\)C to 26 \({}^{\circ}\)C. The pressure increased as the temperature of the air exchanging heat with the evaporator and condenser increased. During the cooling operation, the pressure increased as the outdoor temperature increased, and the prediction results of the proposed refrigeration cycle measurement method confirmed the same pattern. The evaporator pressure changed proportionally with the change in indoor temperature, and the same pattern is confirmed by the proposed refrigeration cycle measurement method. COP variation with outdoor temperature. It was confirmed that the existing method and the proposed method have similar values. However, the difference in the enthalpy and pressure of the refrigeration cycle was noted, and the pressure and enthalpy were compared and analyzed to confirm the accuracy and reliability of the proposed method. The refrigerant enthalpy and pressure of the refrigeration cycle predicted by the proposed method were compared with the measured values. The outlet enthalpy of the evaporator and the inlet enthalpy of the condenser were lower than the measured values, while the outlet enthalpy of the condenser and the inlet enthalpy of the evaporator were higher than the measured values. The outlet pressure of the evaporator and the outlet pressure of the condenser are lower than the measured values, and the outlet pressure of the condenser and the inlet pressure of the evaporator are higher than the measured values. This is because evaporation and condensation do not follow an ideal isobaric process in an actual refrigeration cycle. In the compression and expansion process, the isentropic and \begin{table}
\begin{tabular}{c c} \hline \hline
**Category** & **Contents** \\ \hline Indoor temperature & 24.1 \({}^{\circ}\)C to 26.5 \({}^{\circ}\)C \\ Outdoor temperature & 26.0 \({}^{\circ}\)C to 36.6 \({}^{\circ}\)C \\ Indoor relative humidity & 50\% \\ Outdoor relative humidity & 40\% to 60\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Operating conditions for accuracy analysis. isenthalpic processes are the same as the theory, and the enthalpy difference at each point occurred due to superheating and subcooling in actual operation. The difference between the measured enthalpy and pressure is shown in Figure 7.  
The range of the predicted data compared to the total measured data was analyzed by box-plot for the six cases based on the outdoor temperature. Figure 8 presents the range of refrigerant pressures and enthalpy measurement data used in the analysis and the refrigerant pressure and enthalpy at the condensation and evaporation inlet and outlet points calculated by the proposed refrigeration cycle measurement method. As shown in Figure 6, the enthalpy and pressure increased with the higher outdoor temperature. The predicted results for both pressure and enthalpy were within the range of the measured results. Therefore, the proposed refrigeration cycle can be used independently of perfor  
Figure 6: Results of refrigeration cycle measurement. mance changes due to outdoor temperature. Figure 8 presents the range of refrigerant pressures and enthalpy measurement data used in the analysis and the refrigerant pressure and enthalpy at the condensation and evaporation inlet and outlet points calculated by the proposed refrigeration cycle measurement method. Figure 8: \(Cont\). Figure 7: Results of enthalpy and pressure prediction. Figure 8: _Cont_. The measured results of the existing refrigeration cycle and the results of the proposed measurement method revealed an up to 0.03 MPa and 0.16 MPa difference in pressure in the evaporator and condenser, respectively, and an up to 11.23 kJ/kg and 17.13 kJ/kg difference in enthalpy in the evaporator and condenser, respectively.