Microtubes provide extremely high performance across a wide array of applications. The ultimate reason for selecting microtubes varies by application, but in all cases, Mezzo provides its customers products with industry-leading performance.
- Mezzo definition of a "microtube": Tube diameter with a diameter 0.2-3.0 mm (with most products between 0.5-2.0 mm)
- Microtube material: Various stainless steels, superalloys, polymers.
- A microtube heat exchanger core consists of two tube sheets (usually planar and parallel) which are connected by hundreds to tens of thousands of microtubes. One fluid flows inside the tubes, the other fluid flows over the outside of the tubes.
- Additional components typically include header tanks, shells, midplates and/or baffles (to support tubes and guide shell-side flow through the core), side plates, etc.
- A variety of proprietary methods are used to join the tubes to the tube sheets.
- A variety of architectures are available (multiple pass crossflow shell side, multiple pass crossflow tube side, cylindrical or rectangular cores, pure counterflow (for cases where extremely high effectiveness is needed), etc.
- Microtube heat exchangers are sometimes termed "primary surface" heat exchangers because they do not rely on fins to transfer heat from one fluid to the other.
Advantages of microtube heat exchangers:
- Simple scaling laws show that microtubes provide significantly more UA/volume (KW/K-m 3 ) than heat exchangers that utilize larger diameter tubes or larger characteristic channel dimensions. The UA/volume scales with tube diameter approximately as 1/D 2 . So, a heat exchanger with 1.0 mm diameter microtubes will have a UA/volume ratio about 100 times greater than a heat exchanger with 10 mm diameter conventional-scale tubes.
- Some in-line patterns that Mezzo uses for its radiator-style applications provide very attractive combinations of high thermal performance, low air-side pressure drop, and excellent resistance to air-side fouling.
- Microtubes are excellent in high pressure applications. The volume, weight and cost savings associated with a compact microtube core in a high-pressure application can be significant.
- Tight packed microtube arrays provide very compact solutions in liquid-liquid applications, and liquid-gas applications. Interestingly, the pressure drops in these products often compares favorably with pressure drops across more conventional manufacturing approaches.
- The thermal conductivity of the tubing usually has minimal effect on overall heat transfer— the thermal resistance through the tube wall is often negligible independent of whether the tube is made of stainless steel or a polymer. Heat exchangers that use polymer tubes are compact and very lightweight.
- "Pure" counterflow microtube recuperators for certain cryogenic applications offer a cost- effective, compact, low-mass solution.
- Superalloy microtubes are available- Mezzo can address high temperature applications.
- Phase Change Material (PCM) heat exchangers made using microtubes typically offer substantial weight savings over alternative designs.