DX Evaporator Coils

Direct Expansion Evaporator Coils for Precision Cooling

Direct Expansion (DX) Evaporator Coils are an efficient HVAC/R cooling solution, because they cool air directly using refrigerant. Precision Coils manufactures direct expansion coils made with copper sweat connections, and customers can choose between standard or hot gas distributor options.

Choosing the Right DX Evaporator Coil

When ordering new DX Evaporator Coils, let Precision Coils’ expert team guide you through the selection process. Certain specifications are critical for DX coils to operate properly, and the experience of our staff ensures your coils will function with maximum efficiency. These are the factors to consider when selecting DX coils:

Cooling Capacity: The cooling capacity of the DX coil must match the cooling load of the entire HVAC/R system for the coil to operate efficiently.
Refrigerant Type: Select a DX coil compatible with a refrigerant that meets your HVAC/R system’s design requirements and local environmental regulations.
Fin and Tube Materials: Standard DX coils are constructed with copper tubes and aluminum fins, but for applications in corrosive environments, all-copper coils or an epoxy coating may be required.
Circuiting and Rows: Our DX coils are constructed with the proper number of rows and correct circuiting for optimum refrigerant distribution and cooling performance.
Airflow Configuration: DX evaporator coils can be built to accommodate horizontal, vertical or universal airflow, and our staff ensure the correct coil design is chosen for the layout of your HVAC/R equipment.

Direct Order Entry in PC Select

Precision Coils products can be purchased directly from PC Select using Direct Order Entry (DOE). DOE offers accelerated order processing and faster access to order acknowledgements, sales order numbers, and estimated ship dates to complete projects efficiently. Contact your sales representative to set up an account.

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Applications of Direct Expansion Coils

Given their smaller footprint compared to other HVAC/R systems, DX coil systems are used to cool smaller spaces. Some of the applications for DX coils include:

Residential HVAC Systems
Air Handling Units (AHU) for Small Commercial Spaces
Refrigeration Cases and Coolers
Variable Refrigerant Flow HVAC Systems
Split HVAC systems
Rooftop Packaged Units

Benefits of DX Evaporator Coils

Compact Design: DX coil HVAC/R systems occupy less space than chilled water systems, making DX systems ideal for buildings with space constraints.
Energy Efficiency: In HVAC/R applications with variable cooling loads, DX evaporator coils maintain efficient operation.
Precise Cooling: When cooling needs change rapidly, DX coils quickly adjust to maintain consistent temperature and humidity.
Cost-Effective Installation: DX coil HVAC/R systems eliminate the need for chilled water piping and a central chiller plant, lowering installation costs.

How Direct Expansion Cooling Works

DX cooling works by circulating refrigerant directly through an indoor evaporator direct expansion coil, where it evaporates and absorbs heat from the indoor air. The refrigerant then travels to an outdoor compressor and condenser, releasing the heat and condensing back to a liquid to repeat the cycle. This closed-loop process efficiently cools a space by removing heat and moisture. DX systems eliminate the need for chilled water loops because they are self-contained and cool air directly using refrigerant.

Refrigerant Compatibility and Circuiting

Refrigeration systems rely on a precise combination of refrigerants, engineered distributors, and specific circuit configurations to achieve efficient heat transfer. Refrigerants are classified by chemical composition and safety based on toxicity.

Common Refrigerant Types

Chlorofluorocarbons (CFCs)
Hydrochlorofluorocarbons (HCFCs)
Hydrofluorocarbons (HFCs)
Hydrofluoroolefins (HFOs)
Natural Refrigerants

Refrigerant Safety Classifications

A1 (non-toxic, non-flammable)
A2L (non-toxic, mildly flammable)
A3 (non-toxic, highly flammable)
B1 (toxic, non-flammable)
B2 (toxic, mildly flammable)
B2L (toxic, flammable)
B3 (toxic, highly flammable)

A refrigerant distributor is a component located after the expansion device and before the evaporator coil.
It receives a mixture of liquid and vapor refrigerant from the metering device and distributes it evenly among the evaporator circuits to ensure maximum efficiency. Circuit configurations in the evaporator are designed to optimize heat transfer based on capacity and load. There are a few configurations: multi-circuit, pass arrangements, and DX.

Coil Configuration Options

HVAC coil configurations are critical for managing heat transfer efficiency, protecting internal components, and enabling proper airflow. Coils are specialized components designed to transfer heat between the refrigerant fluid and air. Fin density refers to the number of heat-transfer fins per unit length on a coil.
Coil connection types include direction expansion coils, chilled and hot water coils, and steam coils.

Matching DX Coils to System Capacity

Matching direct expansion coils to system capacity requires balancing the evaporator coil’s capacity with the condensing unit’s total capacity at a specific saturated suction temperature. A properly matched system ensures efficient cooling, adequate dehumidification, and prevents issues, such as compressor short cycling.

A dx cooling coil is a heat exchanger where refrigerant evaporates directly, cooling the air passing over the coil fins. Proper operation relies on balancing airflow, controlling refrigerant superheat via a metering device and accurately calculating the load to ensure efficient moisture removal and heat transfer.

Typical Applications

DX systems are widely used in HVAC for direct cooling and are commonly found in residential split systems, commercial rooftop units, packaged terminal air conditioners, and process cooling. They are ideal for small-to-midsize buildings, data centers requiring precise temperature control, and temporary climate control for events due to lower installation costs.

We know DX evaporator coils the way only experts can. By partnering with Precision Coils to manufacture your DX coils, customers can be certain of the exceptional performance, efficiency, and longevity of our heat transfer products. We also offer chilled water coils and booster coils.