Microchannel Coils

  • MICROCHANNEL COILS

    FOR CONDENSER, EVAPORATOR, AND WATER APPLICATIONS

    Microchannel heat exchanger

HIGH-PERFORMANCE MICROCHANNEL COILS FOR HVAC APPLICATIONS

We offer innovative, next-generation aluminium microchannel heat exchangers that provide high heat transfer performance, excellent flexibility, lower internal volume, and smaller size and weight: features and capabilities not found in traditional finned tube heat exchangers.

Microchannel technology offers improved performance by increasing air-side heat transfer between fins and ambient air, heat conduction between fins and flat tubes, and refrigerant-side heat transfer between tubes and refrigerant resulting in 20 to 40 percent higher overall performance compared to finned tube designs.

Importantly, our microchannel heat exchangers perfectly match any application, be it condenser coil, evaporator, water coil, or coil for use in heat pumps – owing to innovative design based on extensive research and development.

FEATURES AND ADVANTAGES

Microchannel coils present significant advantages over traditional finned tube coil design in every respect, including heat transfer efficiency, operating reliability, environmental safety, measurements, and cost:

  • 20% to 40% higher heat transfer performance
  • Lower airside pressure drops
  • 10% to 30% smaller coil face upon design conditions
  • Up to 60% less weight
  • Higher corrosion resistance
  • Robust construction
  • Less refrigerant charge – up to 60%
  • Optimized raw material cost
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Microchannel air-to-water coil

DESIGN AND STRUCTURE

Microchannel coil is all-aluminum, integrally brazed in a controlled-atmosphere brazing (CAB) furnace; the coil assembly includes the following elements:

  1. Flat, multi-port microchannel tubes and fin strips
  2. Refrigerant inlet manifold
  3. Refrigerant outlet manifold
  4. Refrigerant connections
  5. Reinforcement frame
  6. Mountings

Design Highlights

MICROCHANNEL TUBES AND FINS

The coil design incorporates flat microchannel tubes and fins strips, brazed integrally, and resulting in high heat transfer performance. Depending on the application, tubes can be oriented horizontally or vertically to ensure predictable heat exchanger performance. State-of-the-art fin design, louvered or flat, provides low airside pressure drops and high heat transfer, as well as easier water condensate shedding due to using capillary forces and gravity to pull condensate off the coil.

MANIFOLDS

For evaporator and heat pump coils, an inbuilt DX distributor helps to evenly spread the incoming refrigerant across the width of the coil. This provides assured coil performance and efficient part-load operation. DX distributor eliminates the need for an external distributor with complex piping.

Outlet manifold of condenser coils serves as a mini-receiver, which accumulates and holds the liquid refrigerant, helps to reduce critical refrigerant charge issues, and provides easy system charging. The lower header has an internal outlet baffle, which prevents gaseous refrigerant from leaving the condenser.

REFRIGERANT CONNECTIONS

Microchannel coils are available with different types of connections, and with custom orientations. The special plastic/rubber inserts prevent the contact of aluminium and dissimilar metals to avoid galvanic corrosion.

REINFORCEMENT AND MOUNTINGS

The coil itself is a robust frame that provides airtight flush mounting, thereby eliminating unnecessary framing components while preventing air bypass.

MICROCHANNEL CONDENSERS

Condenser coils can be designed for horizontal or vertical refrigerant flow, in single- or multi-pass configuration for exacting performance.

Condenser coils can be configured in small dimensional increments in height and width, up to as large as 6000x2000mm.

Coil models with design working pressures of 32 bar or 45 bar are available for the full range of refrigerants, including environmental-safe low-GWP mixtures and natural refrigerants.

MICROCHANNEL EVAPORATORS

Direct expansion evaporator coils are based on innovations in refrigerant flow distribution, combined with a water-shedding design with a vertical tube arrangement.

Coils are fit for evaporator and heat pump applications with sizes up to 6000x2000mm and design working pressures at 20 bar, 32 bar, and 45 bar.

Coils are suitable for use with HFC- and lower GWP HFO-based refrigerants, as well as for natural refrigerants.

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DX distributor

Refrigerant Distributor: How It Works

The primary function of the DX distributor integrated into the inlet manifold of the evaporator coil is uniform refrigerant spreading across the length of the coil, over a wide range of operating conditions and equipment designs. The distributor provides:

  1. Liquid/gas separation of the mixture delivered to the distributor
  2. Injection of liquid refrigerant into distributor orifices and creation of pressure drop to propel the refrigerant and to spread out the liquid substantially evenly along the length of the inlet manifold
  3. Injection of liquid refrigerant into the tube chambers
  4. Prevention of refrigerant flow between refrigerant tube chambers before entering the microchannel tube ports

MICROCHANNEL WATER COILS

For water, glycols, and special fluids, we offer microchannel coils that perfectly fit cooling, heating, and general-purpose applications.

Microchannel water coils feature large-diameter manifolds for best performance and increased tube wall thickness to ensure reliable operation and long lifespan.

Water coils are available up to 6000mm wide and 2000mm tall, rated for up to 20 bar.

CORROSION RESISTANCE

The corrosion potential of the all-aluminium microchannel coils is significantly lower than in multi-metal coils as there are no dissimilar metals to initiate galvanic corrosion. This makes microchannel coils an inherently better solution for seashore installations, installations in polluted areas, or any application where corrosion may be a concern.

Microchannel coils require only one braze operation in the controlled environment, significantly reducing the likelihood of leaks when compared to manually brazed heat exchangers.

The advanced technology, accurate material selection, and use of modern braze furnaces guarantees the highest quality of our products, which is confirmed by both SWAAT tests and field experience.

Seawater Acetic Acid Test

In accordance with ASTM G-85 Annex A3 (SWAAT), a test specimen is placed in a chamber and exposed to a changing atmosphere that comprises the repeating cycle at a constant chamber temperature of 49°C:

  • 30 minutes exposure to a continuous indirect spray of acidified (pH 2.8 to 3.0) synthetic seawater solution, which falls-out on to the specimens at a rate of 1.0 to 2.0 ml/80cm²/hour
  • 90 minutes of exposure to high humidity (98%) air​

Numerous corrosion resistance tests demonstrate that performance of microchannel coil drops significantly slower compared to the results for traditional finned tube coil.

SWAAT results: microchannel coils vs finned tube coils

PROTECTIVE COATINGS

While all-aluminum microchannel coils are not subject to galvanic corrosion as traditional multi-metal finned tube coils, some installations may require the highest level of protection. For ensured long service life in petrochemical installations, adiabatic systems, installations in highly polluted areas or maritime atmospheres, we recommend using microchannel heat exchangers with electrocoating protection.

E-coating offers ultimate corrosion and chemical resistance, provides excellent salt spray and humidity resistance, and exhibits outstanding performance over uncoated aluminium.

Selection software

SELECTION SOFTWARE

Microchannel coil selection software includes condenser, evaporator, heat pump, and water coils, making it a complete selection and calculation tool for refrigeration professionals.

The software provides selections and ratings for microchannel heat exchangers which enables the user to select the best-suited product based on several deciding parameters such as heat exchanger application, cooling capacity, refrigerant, evaporation and condensation temperatures, airflow and air temperature and other critical variables in refrigeration systems.

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