What is the difference between a chilled water coil and a DX coil?

A chilled water coil uses water, or a water–glycol mix, from a chiller as the cooling medium. A DX (direct expansion) coil evaporates refrigerant directly inside its tubes. Chilled water systems suit larger buildings served by a central chiller plant.

How many rows do I need?

Most comfort cooling coils have 4 to 8 rows. Humid tropical climates and high latent loads often call for 6 rows or more. Send us your airflow, entering air conditions and water temperatures and we will recommend the right depth.

Can you make a replacement for my existing AHU coil?

Yes. We build to the fin size, casing, rows, circuiting and connection positions of your existing coil so the new one fits the original housing. Follow the measuring steps on this page, or send photos and we will guide you.

Can the coil run on glycol?

Yes. Coils can be selected for ethylene or propylene glycol mixtures. Glycol transfers heat less effectively than water, so the coil is sized to make up the difference.

What face velocity should I design for?

Up to 2.5 m/s (500 fpm). At higher velocities condensate can be blown off the fins and carried into the ductwork.

Which materials suit coastal or corrosive locations?

Cupro-nickel or stainless steel tubes, paired with copper or stainless steel fins, give the best corrosion resistance. Tell us about the site and the water quality and we will suggest a combination.

What information do you need for a quotation?

Airflow, entering air dry-bulb and wet-bulb temperatures, chilled water supply and return temperatures, fin dimensions or available space, number of rows if known, and connection size and type.

Chilled Water Coils

Cooling and dehumidifying coils for air handling units, fan coil units and fresh air units. Built to your dimensions, or matched to the coil you are replacing so it slides straight into the existing unit.

Rows: 3 to 12

Tube outside diameter: 3/8", 1/2", 5/8"

Fin spacing: 4 to 16 fins per inch

Tube joints: Hand-brazed, silver alloy

Cool, dry air from chilled water

A chilled water coil is a finned-tube heat exchanger. Chilled water from the plant flows through the tubes, and warm air passing over the fins gives up its heat. Because the fin surface runs below the air's dew point, the coil removes moisture as well as heat.

Most coils have 3 to 12 rows of tubes. More rows give more cooling and dehumidification from the same face area, with a higher air-side pressure drop. Standard and custom designs are available for new equipment and for retrofits.

Where they are used

Air handling units (AHU), new builds and retrofits
Fan coil units (FCU) and blower coil units
Fresh air and pre-cool air handling units (PAU / FAHU)
Data centres and computer room air handlers (CRAH)
Hospitals, cleanrooms and pharmaceutical plants
Hotels, offices, shopping malls and factories
Process cooling, including water–glycol systems

Typical design conditions

Parameter	Metric	Imperial
Entering air (return or outdoor)	24–35 °C	75–95 °F
Chilled water supply	5.5–7 °C	42–45 °F
Water temperature rise	≈ 5.5 K	≈ 10 °F
Maximum face velocity	2.5 m/s	500 fpm
Rows	3 to 12

Above 2.5 m/s, condensate can be blown off the fins into the duct. Every coil is selected for your actual airflow, air conditions and water temperatures.

Built to fit, built to last

Drop-in replacement

We match fin size, casing, rows, circuiting and connection positions, so the new coil slides into the existing housing without modifying the unit.

Wide choice of materials

Copper, stainless steel, or aluminium tubes, with aluminium, copper, stainless steel fins.

Corrosion resistance

Copper fins and stainless steel options for coastal sites, aggressive water and hygiene-critical areas.

Glycol ready

Selections for ethylene or propylene glycol mixtures. Glycol lowers capacity, so the coil is sized to make up for it.

Hand-brazed joints

Tube joints are brazed by hand with silver-bearing alloy for strong, leak-tight connections.

Drainable designs

Non-freeze tube arrangements for coils that must drain completely, for example during seasonal shutdown or maintenance.

Replacing an existing coil

Send us these details and our engineers will confirm a replacement that fits the original housing.

Measure the fin areaFin height and fin length of the finned section only, not the casing.
Measure the casingOverall height, length and depth, plus flange widths.
Count the tubesRows deep in the direction of airflow, and tubes per row on the face.
Record the connectionsSize, type, thread standard, and which side they are on when you face the airflow.
Take photosThe whole coil, the nameplate and the connections, with the unit make and model.