The current work examines how refrigerant R410A condenses in the condenser of a split air‑conditioning unit of type TOSOT with a capacity of 1.5 ton. The unit was operated at outdoor temperatures up to 47.4 °C. The study combines experimental measurements with fully three‑dimensional (3‑D) and transient numerical simulations carried out in ANSYS Fluent to resolve the evolution of flow regimes, void fraction, and condensation heat transfer inside the 4 mm internally finned copper tubes. For the simulation tasks, a Volume of Fluid (VOF) framework is adopted, and the k‑ω SST turbulence model together with the Lee condensation model is used to track the vapor–liquid flow along the entire condenser tubes. The tests were carried out under realistic summer operating conditions in July and August. Eight runs were chosen as representative cases. The outdoor temperatures ranged between 31.0 °C and 47.4 °C. These conditions produced discharge pressures from 23.6 bar to 34.2 bar and saturation temperatures from 37.9 °C to 54.0 °C. The data revealed that, as the outdoor temperature rose, the condenser tube temperature and discharge pressure increased, while both the Coefficient of Performance (COP) and the exergy efficiency declined. The set of axial temperature sensors installed along the condenser tube made it possible to distinguish the circuit’s three regions: desuperheating, condensation, and subcooling sections. The refrigeration coefficient of performance decreased from 3.424 at 31.0 °C to 2.189 at 47.4 °C, while the estimated whole-coil average overall heat-transfer coefficient, 𝑈𝑜,avg, ranged from 9.15 to 19.74 W/(m²·K). The exergy analysis showed that the exergy efficiency ranged from 0.423 to 0.383, while the total exergy-destruction rate ranged from 1.025 to 0.968 kW. The compressor was the principal source of irreversibility, with an estimated exergy-destruction rate of 0.355–0.332 kW, followed by the capillary tube at 0.315–0.303 kW. The condenser and evaporator contributions ranged from 0.24 to 0.226 kW and from 0.115 to 0.107 kW, respectively. These results indicate that improving compressor efficiency, reducing capillary-tube throttling losses, and improving condenser airflow and heat-transfer performance are the most relevant measures for improving second-law performance under high ambient temperatures. Four transparent tubes made from polycarbonate were used to replace copper sections with the same internal diameter. These rigid tubes, with a wall thickness of 3 mm, were used for flow visualization and to allow image recording. The average local film thickness and liquid holdup values were estimated from the flow images for each section using an image‑enhancement procedure. Along the condenser pathway, the annular film had an average liquid height of about 0.3 mm to 0.4 mm, increasing at the condenser outlet to 1.2 mm to 1.8 mm depending on the mass flow rate for each test. The liquid height decreased as the refrigerant mass flow rate increased. In general, flow patterns were observed for all test conditions that progressed from vapor at the condenser inlet to annular flow and then to wavy-annular structures at the condenser outlet. Stratified regimes were not observed within the investigated conditions. The combined relative uncertainty associated with tube temperature, pressure, and the estimated whole-coil average overall heat-transfer coefficient remained generally below 5%, and the corresponding standard deviations of temperature and pressure stayed at ±0.21 °C and ±0.8 bar. The measured standard deviations indicate a high level of measurement repeatability Computational Fluid Dynamics (CFD) is applied to predict the flow structures. The simulation represents one of the six parallel condenser paths studied in the current work. The tube length of 8.914 m is simulated and divided into nine axial segments. Meshing is applied for each segment, resulting in about 0.8 million cells, which can adequately resolve the interfacial structures. For this model, boundary conditions were prescribed from the experiment at an outdoor temperature of 37.4 °C and inlet and outlet pressures of 28.5 bar and 28.1 bar, respectively. The vapor enters at a temperature of 77.6 °C and a saturation temperature of 45.8 °C. A mesh‑independence study was carried out by examining three kinds of mesh sizing: coarse, medium, and fine grids, with the assessment performed under steady‑state conditions. The results showed that the difference remained within 3.5 % along the tube and below 1 % at the inlet, indicating satisfactory spatial resolution for the medium mesh. With a deviation constrained to within 15 % along the tube, the resultant CFD model replicated the axial trends of the R410A flow. For the current tube design and operating conditions, inertia and surface tension effects clearly dominated according to the dimensionless numbers based on the Bond, Froude, and Weber criteria. In the absence of stratified flow, annular and wavy‑annular patterns were formed inside the condenser tubes, in line with the prior estimation. The CFD model produced an outlet liquid holdup value of 0.34 and also captured the decline in vapor quality and void fraction from the inlet to the outlet. The behavior of R410A condensation in the condenser tubes is investigated in the current work under the hot climate of Zakho city. The flow behavior is coherently described by the experimental tests and the validated CFD models. The study explains how heat transfer and the performance in the condenser of a 1.5‑ton air‑conditioner are impacted by external temperature, mass flux, and flow-regime changes. The information gathered from the current study serves as a foundation for optimizing condenser designs in high‑ambient locations and for applying the same strategy to other eco‑friendly refrigerants with properties similar to R410A, such as R32 and R454B.