Thermal-Fluid Characteristics of an Automotive Radiator Used as the External Heat Exchanger in an Auto Air Conditioning System

2005 ◽  
Author(s):  
Amir Jokar ◽  
Mohammad H. Hosni ◽  
Steven J. Eckels
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Thin Plate ◽  
Air Conditioning ◽  
External Heat ◽  
Air Conditioning System ◽  
Louvered Fins ◽  
External Heat Exchanger ◽  
Fluid Characteristics

The thermal-fluid characteristics of an automotive radiator, used as the external heat exchanger in an auto air conditioning system, are experimentally analyzed and discussed in this article. The radiator in this study is a compact heat exchanger with parallel rectangular minichannels and louvered thin-plate fins. A 50% glycol-water mixture flows through the minichannels with staggered surface enhancements on the walls. On the other side, air flows through the radiator openings with the louvered thin-plate fins sandwiched between the minichannels. Single-phase heat transfer and pressure drop correlations for glycol-water flow within the minichannels and for air flow through the louvered fins are obtained and presented. The Wilson plot technique is applied to find the heat transfer coefficients on both the glycol-water and air sides. The frictional pressure drop for the glycol-water flow within the minichannels is also obtained using the Fanning equation. The uncertainty estimates for both measured and calculated parameters are then presented, and finally the results are plotted, discussed and compared with the relevant previous studies. These results show that the heat transfer rate is increased in the glycol-water side due to the surface enhancements in comparison with smooth rectangular channels. The heat transfer is enhanced on the air side as well, as compared with the flat smooth surfaces, due to the use of louvered fins.

RESEARCH OF HEAT TRANSFER AND PRESSURE DROP CHARACTERISTIC OF CONCAVO-CONVEX PLATE

2013 ◽  
Vol 21 (02) ◽  
pp. 1350012 ◽  
Author(s):  
AKIRA KANEKO ◽  
MASAFUMI KATSUTA ◽  
YUKI HAMANO
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Performance Improvement ◽  
System Performance ◽  
Air Conditioning ◽  
Parallel Plates ◽  
Pump System ◽  
Air Conditioning System ◽  
Heat Pump System

For an automobile air-conditioning system, performance improvement of the heat exchanger is needed to fit in the change of refrigerant and heat pump system. In this study, the heat transfer and pressure drop characteristic of air flow between parallel plates with concavity and convexity is grasped, and the possibility of using a fin-less heat exchanger is considered analytically. And it has been shown that a fin-less heat exchanger has the possibility of increasing performance compared to a conventional heat exchanger, which uses a corrugated louver fin.

3D Computational Analysis of Thermal and Hydraulic Performance of Louvered Fin Heat Exchanger With Variable Louver Angle and Louver Pitch

2016 ◽  
Author(s):  
Abdulkerim Okbaz ◽  
Ali Pınarbaşı ◽  
Ali Bahadır Olcay
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flow Characteristics ◽  
Hydraulic Performance ◽  
Double Row ◽  
Louvered Fin ◽  
Goodness Factor ◽  
Fluid Flow Characteristics ◽  
Louvered Fins

In the present study, 3-D numerical simulations on heat and fluid flow characteristics of double-row multi-louvered fins heat exchanger are carried out. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles in the range of 20° ≤θ≤ 30°, louver pitches of Lp = 2,7mm, 3,5mm and 3,8mm and frontal velocities of Uin between 1.22 m/s and 3 m/s. The results are reported in terms of Colburn j-factor, Fanning friction factor f and area goodness factor j/f based on louver angle, louver pitch and Reynolds number. To understand local behavior of flow around louvered fins and heat exchanger tubes, flow visualization results of velocity vectors and stream-lines with temperature counters are presented. It is investigated that increasing louver angle enhances convective heat transfer while hydraulic performance decreases due to increased pressure drop. The flow noticeably behaves louver directed for all louver angles The flow can easily travel between different fins. This case study has been done to design and manufacture an industrial louver fin heat exchanger.

Experimental Study on Compact External Heat Exchanger for a 4 MWth Circulating Fluidized Bed Combustor

2013 ◽  
Vol 448-453 ◽  
pp. 3259-3269
Author(s):  
Zhi Wei Li ◽  
Hong Zhou He ◽  
Huang Huang Zhuang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cooling Water ◽  
External Heat ◽  
Circulating Ash ◽  
Fluidized Bed Combustor ◽  
External Heat Exchanger

The characteristics of the external heat exchanger (EHE) for a 4 MWth circulation fluidized bed combustor were studied in the present paper. The length, width and height of EHE were 1.5 m, 0.8 m and 9 m, respectively. The circulating ash flow passing the heating surface bed could be controlled by adjusting the fluidizing air flow and the heating transferred from the circulating ash to the cooling water. The ash flow rate passing through the heat transfer bed was from 0.4 to 2.2 kg/s. The ash average temperature was from 500 to 750 °C. And the heat transfer rate between the ash and the cooling water was between 150 and 300 W/(m2·°C). The relationships among the circulating ash temperature, the heat transfer, heat transfer rate, the heat transfer coefficient and the circulating ash flow passing through the heating exchange cell were also presented and could be used for further commercial EHE design.

Effects of horizontal tube arrays on heat transfer in an external heat exchanger

2020 ◽  
Vol 181 ◽  
pp. 115964
Author(s):  
Runxia Cai ◽  
Boyu Deng ◽  
Xin Tao ◽  
Yi Zhang ◽  
Hairui Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Horizontal Tube ◽  
External Heat ◽  
Tube Arrays ◽  
External Heat Exchanger

Ground Source Heat Pump Air Conditioning System of Vertical Geothermal Heat Exchangers Heat Transfer Process and Design Calculation Method

2013 ◽  
Vol 291-294 ◽  
pp. 1728-1734
Author(s):  
Shao Qing Liang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Air Conditioning ◽  
Scientific Basis ◽  
Heat Transfer Process ◽  
Design Calculation ◽  
Geothermal Heat ◽  
Air Conditioning System ◽  
Ground Source ◽  
Geothermal Heat Exchanger

Geothermal heat exchanger is an important part of the GSHP air-conditioning system and different from other traditional air-conditioning systems. This article through to the geothermal heat exchanger heat transfer performance analysis and the design, derived from the geothermal heat exchanger length calculation formula, for actual engineering construction to provide a scientific basis.

The Development of Performance Prediction Methods for an Automotive CO2 A/C Cycle

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Akira Kaneko ◽  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Performance Prediction ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Refrigeration Cycle ◽  
Air Conditioning System ◽  
Lubricant Oil ◽  
C Cycle ◽  
Simulation Results

In previous research, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times, and finally, we have substantial database including the effect of lubricant oil. Moreover, the maldistribution of two-phase in an evaporator can be also predicted from the experimental database. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned database. This paper describes the refrigeration cycle performance prediction of each element (e.g., an evaporator, a gas-cooler, and so on) by a simulation using substantial database and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and, in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling capacity successfully within ±10% for A/C system simulation. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling capacity and pressure drop for evaporator simulation, respectively.

Numerical Simulation of the Flow Boiling Heat Transfer Performance of R134a in a Microchannel Evaporator With Louvered Fins

2011 ◽  
Author(s):  
Justin J. Gossard ◽  
Andrew D. Sommers
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Flow Boiling ◽  
Control Volume ◽  
Cooling Capacity ◽  
Heat Exchanger Design ◽  
Microchannel Tubes ◽  
Louvered Fins

The need for more compact and more efficient heat exchangers in the aerospace, automotive, and HVAC&R industries has led to the development of heat exchangers that utilize minichannel or microchannel tubes coupled with louvered fins. Minichannel and microchannel heat exchangers exhibit enhanced heat transfer with a minimal increase in pressure drop over conventional round tube, plain fin heat exchangers often with a significant reduction in the required refrigeration charge and overall heat exchanger size. This paper presents the development and validation of a finite volume, steady-state evaporator model to be used as an aid in heat exchanger design and analysis. The model focuses on evaporator geometries that include minichannel and microchannel tubes with louvered fins and headers. Multiple published correlations provide the user with options for calculating the air-side and refrigerant-side heat transfer and pressure drops within the control volume. Once the model was validated, it was then briefly used to study the effects of maldistribution of refrigerant within the inlet headers on the cooling capacity and refrigerant side pressure drop.

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