• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.1
• /
• pp.46-54
• /
• 2002

To investigate the design effects of a heat exchanger on a tube type, a tube circuit and a fin pitch, an experimental study on the heat transfer characteristics of finned- tube evaporators was performed. The refrigerant was R-22. A refrigerant loop was established to measure the heat transfer rate, the air heat transfer coefficient. The experimental results showed that the heat transfer characteristics of the evaporators were affected by the design parameters. And the heat transfer rate of the slit fin was better about 25%, compared to those of the louver fin. In the present experimental range, the heat transfer performance with the straight tube circuit was more remarkable than that of the zigzag tube circuit, as seen from temperature variations of the evaporator exit. $\jmath$-factor on the tube type, the tube circuit and the fin pinch decreased, as increasing Reynolds number.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.15 no.3
• /
• pp.85-100
• /
• 2007

This study presents a short overview of the researches in connection to the fin-and-tube heat exchangers with and without the influence of dehumidification. Contents of this review article include the data reduction method, performance data, updated correlations, and the influence of hydrophilic coating for various enhanced fin patterns. This study emphasizes on the experimental researches. Performance of both sensible cooling and dehumidifying conditions are reported in this review article.

• 한국전산유체공학회:학술대회논문집
• /
• 2004.03a
• /
• pp.183-189
• /
• 2004

The flow and the heat transfer about the cross-flow fin-tube heat exchanger in an out-door unit of a heat pump system has been numerically Investigated. Using the general purpose analysis code, FLUENT, the Navier-Stokes equations and the energy equation are solved for the three dimensional computation domain that encompasses multiple rows of the fin-tube. The temperature on the fin and tube surface is assumed constant but compensated later through the fin efficiency when predicting the heat-transfer rate. The contact resistance is also taken into consideration. The flow and temperature fields for a wide range of inlet velocity and fin-tube arrangements are examined and the results are presented in the paper. The details of the flow are very well captured and the heat transfer rate for a range of inlet velocity is in excellent agreement with the measured data. The flow solution provides the effective permeability and the inertial resistance factor of the heat exchanger if the exchanger were to be approximated by the porous medium. This information is essential in carrying out the global flow field calculation which, in turn, provides the inlet velocity lot the microscopic temperature-field calculation of the heat exchanger unit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.12
• /
• pp.1007-1017
• /
• 2003

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/$m^2$s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.408-413
• /
• 2008

This study presents comparison of the air side heat transfer and friction characteristics in a heating condition between Louver fin-tube heat exchangers and aluminum heat exchangers. Experiments are performed for the Louver fin-tube heat exchangers and aluminum heat exchangers using a calorimeter, which is designed based on air-enthalpy method described in ASHRAE standards. The air velocities its are varied from 0.7 to 1.6 m/s with 0.3 m/s interval. A study result shows that the heat transfer performances of aluminum heat exchangers are $40{\sim}80%$ higher than those of Louver fin-tube heat exchangers per unit volume, mass and heat transfer area.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2011-2016
• /
• 2008

A new method is presented for developing a simulation program which can analyze the heat transfer characteristics of fin-tube heat exchanger. This method is able to describe several types of refrigerant circuit arrangement. The delivery path of air and refrigerant properties is simplified by transforming three-dimensional array into one-dimensional array. By comparing simulated results with experiment results, the deviation was 8.2%. Several fin-tube heat exchangers of different design factors and operating conditions were simulated using this program. It was shown that this program could be used for designing practical fin-tube heat exchangers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.12
• /
• pp.833-843
• /
• 2008

A new method is presented for developing a simulation program which can analyze the heat transfer characteristics of fin-tube heat exchanger. This method is able to describe several types of refrigerant circuit arrangement. The delivery path of air and refrigerant properties is simplified by transforming three-dimensional array into one-dimensional array. By comparing simulated results with experiment results, the deviation was 8.2%. Several fin-tube heat exchangers of different design factors and operating conditions were simulated using this program. It was shown that this program could be used for designing practical fin-tube heat exchangers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.3
• /
• pp.220-229
• /
• 2003

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150~250 kg/$m^2$s with air flows at velocity ranges from 0.6 m/s to 1.6 m/s.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1267-1271
• /
• 2009

In the present study, performance characteristics on environment change of A/C applied fin-tube and PF heat exchangers were experimentally investigated. Capacity and COP changing an outlet air velocity, an indoor/outdoor temperature and a relative humidity were obtained. Air－enthalpy calorimeter was used. As the air velocity, indoor temperature and relative humidity increase, capacity and COP increase. PF A/C has smaller refrigerant weight than the fin-tube A/C. The performance of PF-2 A/C with the squarer fin was more excellent than that of PF-1 A/C with the triangler fin.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2023-2028
• /
• 2008

In present study, the flow field near the fin surface of plate fin - oval tube heat exchanger with delta wing vortex generator was numerically analyzed. As results, the well developed vortex behind delta wing was observed. These vortex can improve heat transfer fin surface behind delta wing vortex generators.