Built for the rooms that never stop running

The NKH Series is Muller's industrial unit cooler for high-duty refrigeration: cold storage warehouses, distribution centres, freezer rooms, seafood and meat processing halls, and process industry rooms where temperature has to hold no matter how often the doors open.

Every unit uses a high-efficiency H-type finned coil — aluminium fins mechanically crimped onto copper tubes — inside a pre-painted galvanised steel casing that resists both corrosion and knocks from forklifts and pallet handling. External rotor fans in Ø630 mm or Ø800 mm sit outside the airstream for easy service, and the whole range ships in reinforced crates already in its mounting position, so it lands on site ready to hang.

With 75 model configurations, one to four fans and three fin spacings, the NKH range lets you match air throw and coil depth to the actual shape of the room instead of oversizing to the nearest catalogue box.

Why specifiers choose the NKH Series

• Compact heat exchangerThe H-type fin gives high capacity from a smaller coil, which also means a faster, cheaper defrost cycle.
• Serviceable by designGalvanised side panels and drain pan are hinge-mounted, and the fans mount externally — cleaning and inspection take minutes.
• Double drain protectionAn internal aluminium drain pan limits condensation dripping below the main pan during defrost.
• Optimised distributionCoils are supplied with diaphragm distributors optimised for R22 and R404A; other refrigerants can be circuited on request.
• Defrost to suit the roomElectric, hot gas, water and shell heaters are all available, with electric defrost standard on low temperature models.
• Wash-down readyStainless steel casing (SSC) versions are available for food processing and corrosive environments.

Typical applications

• Cold storage & frozen distribution — chilled and frozen warehousing, cross-dock chambers, 3PL cold rooms
• Food process industry — chilling halls, packing rooms, meat and seafood processing, bakery retarders
• Blast and holding freezers — down to -30 °C room temperature with 9 mm fin spacing
• Process industry — pharmaceutical and chemical storage, controlled-temperature production areas

How to read an NKH model number

Every digit in the code tells you something about the unit. Read it left to right.

NKH 3 x 6 D B2 R Y - HGT

1. NKHH-type high-efficiency fin
2. 3Number of fans, 1 to 4
3. 6Fan diameter — 6 = 630 mm, 8 = 800 mm
4. DMotor connection, Delta
5. B2Coil module (B1–B3 for Ø630, C1–C2 for Ø800)
6. RFin spacing — R = 4 mm, L and C = 6 mm, S = 9 mm
7. YRefrigerant — blank = R22, Y = R404A / R507
8. HGTOption code (see the options list below)

Series letters at a glance

Option code +ELU adds low-temperature coil and drain-tray electric defrost. Below +2 °C room temperature, electric or hot gas defrost must be used.

Full NKH model list and technical data

All 75 models, with capacity, airflow, air throw, heater load and shipping weight.

Fan data at 380 V / 3 Ph / 50 Hz in delta connection. Residual air speed 0.5 m/s in compliance with standard. For star (Y) connection instead of delta (D), apply the correction factors below. Heater load shown is the electric defrost kit at 380 V / 3 Ph / 50 Hz.

Defrost options

NKH…C and NKH…S — low temperature

Shielded electric heating elements sit in sleeves inside the finned coil, with two or three further elements under the intermediate drain pan. Heat is distributed evenly for a fast, clean defrost, and the heaters are factory-wired to a 380 V / 3 Ph terminal block in a junction box. Total hot gas defrost (HGT) is available as an option.

NKH…R and NKH…L — medium temperature

Low-temperature electric defrost (ELU) is available as an optional extra. Water defrost (DAE) can be used where room temperature is +4 °C or above; specifying it increases the unit cooler depth by 40 mm.

Maximum water flow rate: 5 m³/h for 1 fan, 10 m³/h for 2 fans, 15 m³/h for 3 fans, 20 m³/h for 4 fans.

Options and accessories

The VAP air pressure shell increases air throw significantly — from roughly 29–53 m on a standard unit to 44–68 m — which is worth specifying for deep racking runs. Configurations not listed here can usually be built; ask us.

Dimensions and connections

Ø630 mm fan units

Ø800 mm fan units

Connection sizes — Ø630 mm range

Connection sizes — Ø800 mm range

Stainless steel range connections

Liquid and suction dimensions are the product inlet and outlet sizes only. Calculate the actual connecting pipe diameter from your own system design.

Sound power level

Ø800 mm fans run at 1 000 rpm on 6 poles and are noticeably quieter than the 1 500 rpm 4-pole Ø630 mm fans — useful where the cold room adjoins occupied space.

Capacity correction factors

Actual capacity = catalogue capacity × correction factor × (actual TD ÷ rated TD).

Room temperature factors

Star (Y) motor connection factors

Capacities are rated to Eurovent standards. Refrigerant capacity factors are calculated from current refrigerant manufacturer thermodynamic data and the Beijer Ref coil rating program. For duties outside these limits, contact us — distributor, circuiting and defrost characteristics may need to change.

Common questions