Additively Manufactured Two-Phase Heat Exchanger Design Offers 30% to 50% Performance Improvement

Additive Manufacturing, aka 3D Printing

     According to Wikipedia:

“3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer control, with the material being added together (such as plastics, liquids or powder grains being fused), typically layer by layer.”

     One huge advantage of additive manufacturing (AM) is the speed at which parts can be created, without the normal intermediate steps. MIT Sloan senior lecturer Thomas Roemer called it going directly from digital to physical:

“With additive manufacturing, much of the supply chain’s intermediate steps are removed. “The speed at which you can get to a single part is much faster,” said Roemer, since people can send a design directly from their computer to the 3-D printer.”

     Additive manufacturing allows the production of small amounts of something in a cost-effective way. It allows better control of the weight of objects produced. It allows for better production of customized products as well as prototypes for experiments. It has been used to develop advanced prosthetics and other synthetic biological components.

 

New Two-Phase Heat Exchanger Offers Significant Performance Improvements

     In April, TechXplore reported on a new additively manufactured heat exchanger that offers 30-50% performance improvements, according to a paper in the International Journal of Heat and Mass Transfer. TechXplore notes that heat exchangers are used in many products, including HVAC systems, refrigerators, cars, ships, aircraft, wastewater treatment facilities, cell phones, data centers, and petroleum refining operations, and there are billions of them in use globally. One of the paper’s authors, Bill King, noted that the basic design and mechanical geometry of heat exchangers have not changed in decades. The reason for the lack of innovation is that they have been subject to limitations of the manufacturing process.

“Precise design of the three-dimensional shapes within these devices can optimize trade-offs among three key factors: the rate of heat transfer, the amount of work that must be applied to achieve the transfer, and the size of the heat exchanger. But the traditional manufacturing methods have meant that many desirable shapes were unachievable in practice.”

     King also noted:

“We can link large passages for fluid flow that promote easy fluid motion, with small passages that promote high heat transfer. So we can make things that have three-dimensional shapes that allow fluids to be mixed and routed in unconventional ways."

     The result of the new design is improvements in heat transfer of 30-50% over previous designs with the same power usage. The volumetric and gravimetric power density of the heat exchanger is increased. The heat exchanger is lighter and more compact.

     According to another one of the paper’s authors, Nenad Miljkovic:

"This results in a higher level of performance, and also enables the integration of high-power devices in mobile applications like cars, ships, and aircraft, which classically could not be achieved with state-of-the-art heat exchanger technology."

The team developed modeling and simulation tools that allow them to test “tens of thousands of possible configurations with different sizes, shapes, and ways that flows would move back and forth within the heat exchanger.”

Two companies involved in energy efficiency, Creative Thermal Solutions Inc. and TauMat Inc., worked with the researchers.

      The new water-cooled condenser design uses the HFC refrigerant R134a as the condensing working fluid. The modeling and simulations developed utilize computational fluid dynamics (CFD). The authors note that improvements in heat exchanger performance could significantly impact global energy consumption. Two-phase heat exchangers are required for use in refrigerators and air conditioners. Refrigerant condensation is the second phase. Additive manufacturing offers the ability to create intricate geometries for complex two-phase heat exchange. Modeling and manufacturing single-phase heat exchangers is much easier, but additive manufacturing allows the modeling and manufacturing of two-phase heat exchangers to be optimized. Reducing the refrigerant flow velocity allows for better heat transfer.

“By reducing the refrigerant channel width and flow area in each pass, the mass flux increases for each channel section. Increased mass flux compensates for the increased density and helps maintain a nearly constant refrigerant velocity throughout the condensation process.”

     The figures below show the condenser design and the segmentation procedure, respectively.

     The next two figures shows the refrigerant side-channel chevron architecture and the wavy fin architecture of the water-side channels.

     The domain and boundary conditions are shown below, followed by photographs of the setup, including magnified photos.

     A schematic of the experimental setup is shown below.

     The researchers also modeled the design with different refrigerant working fluids, including several with much lower global warming potential (GWP) such as isobutane, propane, and R1234yf.

     The authors note:

“The present paper introduces an innovative water-cooled heat exchanger made of AlSi10Mg, which incorporates miniature 3D-enhanced surfaces tailored for optimal heat transfer efficiency, harnessing the capabilities of AM.”

     The paper’s conclusions emphasize that the design methodology may be expanded to enable better additively manufactured heat exchangers for further design improvements.

“The design methodology may enable other two-phase heat transfer and flow devices that can be manufactured with AM and used for next-generation energy systems. The novel condenser design leverages internal 3D structures enabled by AM, which cannot be made using conventional manufacturing methods.”     

“The research underscores the significant thermal-hydraulic performance and volumetric power density gains achievable through AM techniques, providing a robust framework for future heat exchanger designs.”

 

 

References:

 

Additively manufactured heat exchanger beats out traditional designs. Science X staff. TechXplore. April 17, 2025. Additively manufactured heat exchanger beats out traditional designs

Additively manufactured compact water-cooled refrigerant condenser. Omar M. Zaki, Robert A. Stavins, Mario Wenzel, Andrew Musser, Darin Sharar, Stefan Elbel, Nenad Miljkovic, and William P. King. International Journal of Heat and Mass Transfer. Volume 244, July 2025, 126836. Additively manufactured compact water-cooled refrigerant condenser - ScienceDirect

Additive manufacturing, explained. Rebecca Linke. MIT Sloan. December 7, 2017. Additive manufacturing, explained | MIT Sloan

3D printing. Wikipedia. 3D printing - Wikipedia