Recent advantages in laser fabrication of micro-channel heat exchangers

2017 ◽  
Vol 48 (3-4) ◽  
pp. 205-209 ◽  
Author(s):  
M. Mehrpouya ◽  
S. Emamian
Keyword(s):  
Heat Exchangers ◽  
Micro Channel ◽  
Laser Fabrication

Performance Evaluation of a Window Room Air Conditioner With Micro-Channel Condensers

2000 ◽  
Author(s):  
Man-Hoe Kim ◽  
Clark W. Bullard
Keyword(s):  
Performance Evaluation ◽  
Heat Exchangers ◽  
Micro Channel ◽  
Performance Tests ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Baseline System ◽  
Inlet Conditions ◽  
Core Volume ◽  
System Characteristics

Abstract The performance evaluation for a residential window air conditioning system with micro-channel condensers has been performed. First, a series of wind-tunnel calorimeter tests are conducted for two different prototype micro-channel heat exchangers. The measured heat transfer and pressure drop characteristics for the heat exchangers are then compared to four conventional finned round tube designs, which were obtained using a validated simulation model for identical air and refrigerant inlet conditions. Finally, two prototype micro-channel condensers are installed in the system and system performance tests are conducted. System characteristics such as capacity, energy efficiency ratio, and suction and discharge pressures and temperatures are presented, compared to those for the conventional system. Refrigerant charge amount for a window air conditioner with a micro-channel condenser is decreased by 35%, and the condenser core volume and weight can be reduced by 55% and 35%, respectively, compared to the conventional baseline system.

Heat and Mass Transfer Design of a Silicon Carbide Micro-Channel Heat Exchanger

2003 ◽  
Author(s):  
Merrill A. Wilson ◽  
Michele Bullough ◽  
Kriston Brooks ◽  
Kurt Recknagle
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Unit Volume ◽  
Micro Channel ◽  
System Efficiency ◽  
Uniform Temperature ◽  
Power Cycles ◽  
Ceramic Recuperator ◽  
Improve Heat Transfer ◽  
Higher Temperature

Efficiency and emissions of advanced gas turbine power cycles can be improved by incorporating high-temperature ceramic heat exchangers. In cooperation with the DOE, a highly effective microchannel ceramic recuperator for a microturbine is under development. In this recuperator, the use of microchannel architecture will improve heat transfer and provide a more uniform temperature distribution. This will result in overall higher productivity per unit volume compared to conventional hardware. The use of ceramic for the recuperator will allow higher temperature operation than available in conventional microturbines. Based on a model for a typical microturbine, these changes may improve the overall system efficiency from about 27% to over 40%.

scholarly journals Random Amplitude Fatigue Life of Electroformed Nickel Micro-Channel Heat Exchanger Coupons

1998 ◽  
Vol 5 (2) ◽  
pp. 103-110 ◽  
Author(s):  
Larry Byrd ◽  
Michael P. Camden ◽  
Gene E. Maddux ◽  
Larry W. Simmons
Keyword(s):  
Fatigue Life ◽  
Heat Exchangers ◽  
Solid Material ◽  
Specimen Thickness ◽  
Micro Channel ◽  
Amplitude Data ◽  
Electroformed Nickel ◽  
Suitable Form ◽  
Number Of Cycles ◽  
Cycles To Failure

The use of micro-channel heat exchangers (MCHEX) with coolant flow passage diameters less than 1 mm has been proposed for heat flux, weight, or volume limited environments. This paper presents room temperature, random amplitude,ε−N(strain versus number of cycles to failure) curves for MCHEX coupons formed by electroplating nickel on a suitable form. These coupons are unique in two aspects; the microstructure formed by electroplating and the presence of holes as an integral part of the structure. The hole diameters range from approximately 10% to 50% to the specimen thickness. The fatigue life of electroformed nickel can be estimated from constant amplitude data using the formulation presented. The heat exchangers with channels parallel to the coupon direction have a lower fatigue life than the solid material.

Thermal analysis of micro‐channel heat exchangers with two‐phase flow using FEM

2005 ◽  
Vol 15 (1) ◽  
pp. 43-60 ◽  
Author(s):  
Pradeep Hegde ◽  
K.N. Seetharamu ◽  
G.A. Quadir ◽  
P.A. Aswathanarayana ◽  
M.Z. Abdullah ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Heat Exchangers ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase

Pressure drop characteristics of cryogenic mixed refrigerant at macro and micro channel heat exchangers

Cryogenics ◽  
2012 ◽  
Vol 52 (12) ◽  
pp. 689-694 ◽  
Author(s):  
Seungwhan Baek ◽  
Sangkwon Jeong ◽  
Gyuwan Hwang
Keyword(s):  
Pressure Drop ◽  
Heat Exchangers ◽  
Micro Channel

Design and Evaluation of Copper Metal Foams in Cold Plates

2006 ◽  
Author(s):  
Donald E. Floyd ◽  
Mark J. Topolski ◽  
Jeff Darabi
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Metal Foams ◽  
Micro Channel ◽  
Cfd Analysis ◽  
Copper Metal ◽  
Cold Plates ◽  
Impinging Flow

This paper present an analytical and experimental investigation of the performance of metal foams in an impinging flow application. Microstructures of the foam as well as the foam-to-solid braze interface are presented. Aditionally, the effects of brazing procedure on the performance of the heat exchanger are investigated and the results are compared to CFD analysis assuming perfect braze joints. Finally, the results are compared to commercially available micro-channel heat exchangers.

Design and Development of a Low-Cost, High Temperature Silicon Carbide Micro-Channel Recuperator

2005 ◽  
Author(s):  
Merrill A. Wilson ◽  
Kurt Recknagle ◽  
Kriston Brooks
Keyword(s):  
Heat Transfer ◽  
Silicon Carbide ◽  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Ceramic Materials ◽  
Micro Channel ◽  
Micro Channels ◽  
Micro Turbine

Typically, ceramic micro-channel devices are used for high temperature heat exchangers, catalytic reactors, electronics cooling, and processing of corrosive streams where the thermomechanical benefits of ceramic materials are desired. These benefits include: high temperature mechanical and corrosion properties and tailorable material properties such as thermal expansion, electrical conductivity and thermal conductivity. In addition, by utilizing Laminated Object Manufacturing (LOM) methods, inexpensive ceramic materials can be layered, featured and laminated in the green state and co-sintered to form monolithic structures amenable to mass production. In cooperation with the DOE and Pacific Northwest National Labs, silicon carbide (SiC) based micro-channel recuperator concepts are being developed and tested. The performance benefits of a high temperature, micro-channel heat exchanger are realized from the improved thermal efficiency of the high temperature cycles and the improved effectiveness of micro-channels for heat transfer. In designing these structures, the heat and mass transfer within the micro-channels are being analyzed with heat transfer models, computational fluid dynamics models and validated with experimental results. As an example, a typical micro-turbine cycle was modified and modeled to incorporate this ceramic recuperator and it was found that the overall thermal efficiency of the micro-turbine could be improved from about 27% to over 40%. Process improvements require technical advantages and cost advantages. These LOM methodologies have been based on well-proven industry standard processes where labor, throughput and capital estimates have been tested. Following these cost models and validation at the prototype scale, cost estimates were obtained. For the micro-turbine example, cost estimates indicate that the high-temperature SiC recuperator would cost about $200 per kWe. The development of these heat exchangers is multi-faceted and this paper focuses on the design optimization of a layered micro-channel heat exchanger, its performance testing, and fabrication development through LOM methodologies.

Thermo-Mechanical Design of a High-Temperature Silicon Carbide Micro-Channel Heat Exchanger

2003 ◽  
Author(s):  
Merrill A. Wilson ◽  
Steven M. Quist
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Mechanical Design ◽  
Mechanical Degradation ◽  
Micro Channel ◽  
Power Cycles ◽  
Microchannel Heat Exchanger ◽  
Operating Environments

Efficiency and emissions of advanced gas turbine power cycles can be improved by incorporating high-temperature ceramic heat exchangers (see Figure 1). In cooperation with the DOE, preliminary development and testing of SiC based structures has been completed. This program has focused on four initial areas: thermo-mechanical degradation as a function of the chemical operating environments, design of a layered microchannel heat exchanger, thermo-mechanical testing and analysis of these structures, and fabrication development through rapid prototyping techniques.

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