Explore Hydro's all-aluminum micro-channel heat exchangers for HVAC&R. Lower refrigerant charge, less space, easier recycling and improved corrosion resistance than conventional copper coils.
Hydro supplies dedicated high corrosion resistant alloys for micro-channel construction: 9170 and 9153 for most applications, and 9108 where higher strength is needed. Headers and manifolds typically use VIA Balance 3K50 (3903-R) or FA7905 for a balanced corrosion match with the tube, while FA7850 is available for higher-strength applications. Tubes can be supplied with flux/clad coating, which carries the flux, filler material needed for brazing and/or Zinc, removing the need for a separate fluxing station on the customer's production line.
Aluminum micro-channel heat exchangers can require as little as 7% of the refrigerant charge of a comparable copper tube-and-fin condenser while using around 28% of the required space. Compared with conventional copper-based designs, aluminum micro-channel heat exchangers offer significant advantages in weight, cost and recyclability. aluminum tubes can be up to 35% lighter than comparable copper tubes, while aluminum tube-based heat exchangers can weigh around 50% less than equivalent copper heat exchangers.
A micro-channel coil is built from three main components: multi-port extruded (MPE) tubes, headers or manifolds, and corrugated fins. MPE tubes are flat aluminum extrusions with multiple parallel internal channels, typically 7 to 120 mm wide, 1 to 10 mm high, and 0.1 to 0.6 mm wall thickness, giving a large internal surface area in a very compact footprint. The tubes, headers and fins are joined by controlled atmosphere brazing (CAB), an oven-based process that produces a metallurgical bond rather than the mechanical bond used in tube-and-fin coils. Because there is no mechanical tube-to-fin contact to degrade over time, a micro-channel coil maintains its rated heat-transfer capacity and energy efficiency longer than a mechanically expanded tube-and-fin coil.
Combining micro-channel tubes with welded aluminum manifolds allows you to exploit the potential that an all-aluminum solution provides. This technology allows your company to:
Micro-channel condensers have a better capacity-per-core-volume ratio, lower refrigerant-side pressure drop, lower air-side pressure drop, higher coefficient of performance (COP), and lower refrigerant charge than conventional tube-and-fin heat exchangers. aluminum is the most viable solution for increasing efficiency while reducing overall costs. In essence, it just got less expensive to be more environmentally friendly. It is also immune to formicary corrosion, which is estimated to cause up to 10% of premature indoor heat exchanger failures. By eliminating the mechanical fin-to-tube bond, micro-channel heat exchangers help maintain rated heat-transfer performance and energy efficiency over time.
Yes. Aluminum can replace copper in tube-and-fin heat exchangers, micro-channel heat exchangers, line sets and many other HVAC&R applications when the alloy selection, coating system and joining method are matched to the operating environment. Aluminum can also be used with ammonia refrigerants, unlike copper.
The HVAC&R industry is increasingly replacing copper components with aluminum because aluminum can offer lower material costs, weight reduction, improved corrosion performance in all-aluminum systems and enhanced recyclability.
Although copper has higher thermal conductivity, the tube material contributes only a small portion of total heat transfer resistance in a tube-and-fin heat exchanger. For matched geometries, the difference in overall heat transfer coefficient between copper and aluminum tube designs is approximately 1%.
Formicary corrosion is a failure mode that affects copper heat exchangers. It is estimated to account for around 10% of premature indoor heat exchanger failures. Aluminum is immune to formicary corrosion and does not experience this failure mode.
