Dataset of On-tube local condensation heat transfer coefficient of R134a, R513A and R450A on smooth stainless-steel tube at saturation temperature of 35 and 40℃

These data contain local condensation heat transfer coefficients of three refrigerants (i.e., R134a, R4513A and R450A) on a single, horizontal, smooth stainless tube at saturation temperatures of 35 and 40℃. A custom experimental apparatus was constructed to measure on-tube condensation heat transfer coefficients which consisted of two main parts, the chamber and the condensation tube. Refrigerant was vaporized in the experimental chamber and then condensed on the condensation tube. Two recirculating chillers were connected to the experimental chamber. One supplied cooling water through the condensation tube and the other supplied water used to boil the liquid refrigerant in order to achieve saturation temperatures of 35 or 40℃ . The refrigerant boiled and subsequently condensed on the smooth condensation tube. Thermocouples were installed in the flow to measure temperature at the inlet and outlet of the tube. The condensation tube was machined using electron discharge machining and 1.016-mm-diameter thermocouples(T1-T8) were installed in the tube wall in order to measure heat flux through the wall at two radial positions, β=11o from the vertical and β=109o from the vertical. Four thermocouples (T1-T4) were used to compute heat flux at β=11o, and an additional four thermocouples (T5-T8) were used to compute heat flux at β=109o.
Saturation pressures equivalent to 35 ± 0.5℃ and 40±0.5℃ were monitored in LabVIEW. Steady state was attained when the vapor pressure and temperature variation across the wall were in the range of ±0.34 kPa and ±0.05℃. After steady state was reached, experimental data were recorded for five minutes. Each experimental datapoint is the average of data collected within five minutes, and they include the eight thermocouple wall temperatures, mass flow rate of cooling water, temperature inlet and outlet of cooling water, saturation temperature and pressure of refrigerants. The outer wall temperature varied around the tube, and the measured wall temperatures were used to compute the outer wall temperatures and temperature gradients at radial positions around the tube using a natural logarithm curve fit with the measured wall temperatures as input. These values were used to compute heat fluxes and local heat transfer coefficients were computed using thermal conductivity, heat flux, saturation temperature (determined from the measured saturation pressure) and wall temperatures. Uncertainties of local heat transfer coefficients for each experimental trial were calculated using the propagation of uncertainty method and uncertainties of the instrumentation.