Microchannel Coils

  • MICROCHANNEL COILS

    FOR CONDENSER, EVAPORATOR, AND AIR-TO-FLUID APPLICATIONS

    Microchannel heat exchanger

HIGH-PERFORMANCE MICROCHANNEL COILS FOR HVAC AND REFRIGERATION

Microchannel coil technology delivers superior HVAC performance through enhanced heat transfer across three critical zones: optimized air-side exchange between aluminum fins and ambient air, maximized thermal conduction between fins and flat tubes, and improved refrigerant-side transfer within multi-port tubes. These engineering advances result in a dramatic 20-40% increase in overall system efficiency compared to traditional finned-tube heat exchangers.

Kaltra’s advanced microchannel coils revolutionize thermal management with industry-leading heat transfer efficiency and corrosion protection. These precision-engineered heat exchangers excel in multiple applications, from refrigerant condensers to evaporators and fluid coils. By combining superior thermal performance with compact design and lightweight aluminum construction, Kaltra’s microchannel coil technology consistently outperforms traditional finned-tube heat exchangers in efficiency, longevity, and reliability.

ADVANTAGES AND BENEFITS

Microchannel coils perfectly fit today’s HVAC equipment requirements, providing numerous improvements over traditional heat exchangers:

  • 20–40% higher heat transfer performance
  • Reduction in fan power thanks to lower air resistance
  • Ability to operate in harsh environmental conditions thanks to exceptional resistance to corrosion
  • 10–30% space savings and up to 60% lower weight
  • Refrigerant charge reduction up to 60%
  • Optimized manufacturing costs
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Microchannel air-to-water coil

DESIGN AND STRUCTURE

Microchannel coils are all-aluminum, assembled for integral brazing in controlled-atmosphere furnaces (CAB). Main components include:

  1. Flat multiport microchannel tubes
  2. Refrigerant inlet manifold
  3. Refrigerant outlet manifold
  4. Refrigerant inlet/outlet connections
  5. Reinforcement frame
  6. Mountings/fixtures

Design Highlights

MICROCHANNEL TUBES AND AIRSIDE FINS

Microchannel coil design incorporates flat microchannel tubes and airside fins, delivering high thermal efficiency through brazed joints. The coil designs allow horizontal or vertical tube orientation for optimized performance across applications. Advanced louvered fin geometry ensures minimal air resistance while maximizing heat transfer, with superior condensate management through enhanced gravity and capillary action.

REFRIGERANT MANIFOLDS

The refrigerant distributor, integrated into the inlet manifold of evaporator coils, ensures uniform refrigerant distribution across microchannel tubes, optimizing coil performance at full and partial loads without requiring external distribution systems or complex piping arrangements.
The bottom outlet manifold of condenser coils with vertically oriented tubes functions as an integrated mini-receiver, managing liquid refrigerant accumulation and optimizing system charge. A strategically positioned baffle prevents refrigerant vapor from exiting the condenser, maintaining optimal system efficiency.

REFRIGERANT CONNECTIONS

Coils can be configured with different connection orientations, types, and materials, including ones made from copper, aluminum, or stainless steel, with special attention paid to preventing contact with dissimilar metals and avoiding corrosion issues.

REINFORCEMENT AND MOUNTING FIXTURES

The coil design allows airtight flush mounting with a wide selection of mounting options, eliminating unnecessary framing components while preventing air bypass. For enhanced robustness, reinforcement beams can be added to the coil construction.

MICROCHANNEL CONDENSERS

The microchannel condenser range features heat exchangers with horizontally or vertically oriented multiport tubes, available in single or multiple pass designs. The condensers are compatible with a wide range of refrigerants, including HFCs, HFOs, and natural refrigerants, and support working pressures of 32 or 45 bars.

Kaltra offers an extensive range of multiport tubes, fin types, and fin pitches, with customizable condenser dimensions up to 6000mm x 2000mm. Featuring multiple options for refrigerant connections, mounting configurations, and protective coatings, Kaltra’s microchannel condensers can be fully optimized to meet specific customer requirements.

MICROCHANNEL EVAPORATORS

The cornerstone of microchannel evaporator efficiency lies in uniform refrigerant distribution across multiport tubes. Kaltra’s innovative engineering achieves peak efficiency at full and partial loads through precision-engineered features: integrated refrigerant distributors, optimized pressure drop control through specialized port design, and scientifically calculated geometrical ratios for width, height, and manifold dimensions.

These evaporator coils deliver exceptional heat transfer with multiple refrigerant options, supporting HFC, HFO-based, and natural fluids.

MICROCHANNEL WATER COILS

Microchannel water coils deliver superior thermal performance in single-phase applications through precision-engineered tube port and manifold geometries. These industrial-grade heat exchangers feature reinforced construction and comprehensive corrosion protection, with specialized coatings protecting both exterior and interior surfaces.

Available in vertical and horizontal tube configurations and sizes up to 6000mm x 2000 mm, the water coils are suitable for use with water, glycols, oils and special fluids.

CORROSION RESISTANCE

The corrosion potential of all-aluminum microchannel coils is significantly lower than that of 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 highly 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 precise-temperature braze furnaces guarantee the highest quality of our products, which is confirmed by both SWAAT tests and field experience.

Sea Water Acetic Acid Test (SWAAT)

The SWAAT test is conducted to evaluate the corrosion resistance of aluminum alloys under exposure to acidified synthetic seawater spray, high humidity, and elevated temperatures. This test also assesses how different surface treatments impact corrosion behavior.

In accordance with ASTM G85 Annex A3 (SWAAT), a test specimen is placed inside a chamber and subjected to a repeating exposure cycle at a constant chamber temperature of 49°C, consisting of:

  • 30 minutes of continuous indirect spray of acidified (pH 2.8–3.0) synthetic seawater solution, which settles on the specimens at a rate of 1.0–2.0 ml/80cm²/hour
    90 minutes of exposure to high-humidity (98% RH) air
  • Multiple corrosion resistance tests confirm that microchannel coils maintain performance significantly longer compared to traditional finned-tube coils, highlighting their superior durability in harsh environments.

Multiple corrosion resistance tests confirm that microchannel coils maintain performance significantly longer compared to traditional finned-tube coils, highlighting their superior durability in harsh environments.

SWAAT results: microchannel coils vs finned tube coils

ANTI-CORROSION COATINGS

While all-aluminum microchannel coils are naturally resistant to galvanic corrosion, certain installations in harsh environments may require enhanced corrosion protection. To ensure long service life in maritime atmospheres, highly polluted zones, and other C4/C5 corrosivity areas, additional protective coatings are recommended.

Among the various anti-corrosion treatments available—such as e-coating, trivalent chromium process (TCP) coating, and nanoscale trichrome treatment—electrophoretic epoxy coating provides the highest level of corrosion and chemical resistance, with proven durability of 6,000+ hours in SWAAT testing.

MCHE selection software

SELECTION SOFTWARE

MCHE selection software offers a comprehensive solution for refrigeration professionals, covering condenser, evaporator, heat pump, and air-to-fluid coils. This all-in-one selection and calculation tool simplifies the design and optimization of microchannel heat exchangers for a wide range of applications.

With advanced capabilities, the software allows users to select and rate microchannel heat exchangers based on critical parameters such as application type, cooling capacity, refrigerant, evaporation and condensation temperatures, airflow, and air temperature. These detailed options ensure precise product selection and optimal system performance in refrigeration systems.

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