What is a CO2 unit cooler?

A CO2 unit cooler is the evaporator inside a cold room or freezer on a system running R744 refrigerant. The coil, circuiting and connections are built for the higher operating pressures of CO2, and the fans blow the cooled air across the stored product.

What is the difference between the MT and LT models?

MT models start with MM and are rated for medium temperature chill rooms at -8C saturated suction with 0C air on. LT models start with ML and are rated for low temperature freezer rooms at -25C saturated suction with -18C air on. LT models also use wider fin spacing so they hold capacity longer between defrosts.

How do I select the right model?

Start from the room heat load in kW, then match a model with capacity at your operating condition plus a margin for defrost time. Check that the air throw reaches the far wall of the room and that the length and service clearance fit the ceiling space.

Are Muller CO2 unit coolers available in Malaysia?

Yes. RNA Engineering and Trading Sdn. Bhd., a Beijer Ref company, supplies Muller CO2 unit coolers in Malaysia with selection support, spare parts and after sales service.

Muller CO2 Transcritical Unit Cooler Kuala Lumpur (KL), Selangor, Malaysia Wholesaler, Supplier

Name: Muller CO2 Transcritical Unit Cooler
Brand: Muller
Availability: InStock

What this cooler does

The unit cooler is the part of a CO₂ system that sits inside the room. Liquid refrigerant boils in the coil, the fans push room air across the fins, and the product sees a steady temperature instead of a swing between defrosts.

Because R744 runs at far higher pressure than R404A or R448A, the coil, headers and connections are built specifically for CO₂ duty. The same body serves booster racks, transcritical packs and cascade low-stage circuits.

Two temperature families cover most food and cold-chain work. MM models are rated for chill rooms, ML models for freezers, with wider fin spacing so frost takes longer to close the coil.

Why buyers choose it

A refrigerant with no phase-out dateCO₂ has a GWP of 1 and zero ozone depletion, so a system built today will not be re-gassed out of existence by the next regulation.
Sized in small stepsThirty-nine models across four fan platforms, so you match the room load instead of rounding up to the next big box.
Electric defrost as standard dutyHeater ratings from 1.0 kW to 15.24 kW are published for every model, which makes defrost design and switchboard sizing straightforward.
Backed locallySelection, delivery, commissioning support and spares handled in Malaysia rather than through an overseas help desk.

Where these coolers are used

Typical applications for the medium and low temperature ranges.

Supermarket cold rooms

Back-of-house chillers and freezers running off a CO₂ booster pack.

Food processing

Chilling, holding and blast-adjacent rooms in meat, poultry and seafood plants.

Cold storage and 3PL

High-bay freezer stores where a five-fan cooler throws air up to 26 m.

Distribution and logistics

Dock chillers and staging areas with frequent door openings.

Bakery and dairy

Ingredient stores, proofing support rooms and finished-goods chillers.

Ice cream and frozen goods

Low temperature rooms held near -25°C saturated suction.

Muller MMSCE five-fan industrial CO2 unit cooler with 500 mm fans and stainless casing for a cold storage freezer — Five-fan industrial model, up to 52.7 kW at medium temperature and 39.9 kW at low temperature.

All models, capacities and dimensions

Four ranges, thirty-nine models. Type a model number, a capacity or a fan size to filter every table at once.

Showing all 39 models

Medium temperature, 300 and 350 mm fans

Rated at SC2: -8°C SST, 0°C air on. Japan condition: -10°C SST, 0°C air on.

Model	Capacity, kW SC2 cond.	Capacity, kW Japan cond.	Fin spacing FPI	Surface m²	Rows	Fans no. x mm	Air flow m³/h	Air throw m	Fan power W, 50/60Hz	Fan current A, 50/60Hz	Power supply	Defrost W	Weight kg	Dimensions L x W x H mm
MMSCA1022	1.77	2.21	6	7.9	4	1 x 300	1,310	7.1	120 / 170	0.54 / 0.76	1~230V ±10%, 50/60Hz	1,000	15	750 x 470 x 494
MMSCA1026	2.11	2.64	6	11.9	6	1 x 300	1,159	6.4	120 / 170	0.54 / 0.76	1~230V ±10%, 50/60Hz	1,000	17	750 x 470 x 494
MMSCA2039	3.12	3.89	6	11.9	3	2 x 300	2,801	10.6	240 / 340	1.08 / 1.52	1~230V ±10%, 50/60Hz	2,000	23	1155 x 470 x 494
MMSCA2050	3.96	4.96	6	19.9	5	2 x 300	2,459	9.6	240 / 340	1.08 / 1.52	1~230V ±10%, 50/60Hz	2,000	26	1155 x 470 x 494
MMSCA3069	5.48	6.85	6	23.8	4	3 x 300	3,928	12.5	360 / 510	1.62 / 2.28	3~400V ±10%, 50/60Hz	3,000	34	1560 x 470 x 494
MMSCA4091	7.30	9.12	6	31.8	4	4 x 300	5,238	14.0	480 / 680	2.16 / 3.04	3~400V ±10%, 50/60Hz	4,000	44	1970 x 470 x 494
MMSCB1031	2.46	3.08	6	8.7	3	1 x 350	2,610	8.9	230 / 340	1.05 / 1.50	1~230V ±10%, 50/60Hz	1,750	18	850 x 470 x 545
MMSCB2069	5.49	6.86	6	19.5	3	2 x 350	5,220	13.0	460 / 680	2.10 / 3.00	3~400V ±10%, 50/60Hz	3,500	32	1485 x 470 x 545
MMSCB2095	7.59	9.48	6	39.1	6	2 x 350	4,280	11.7	460 / 680	2.10 / 3.00	3~400V ±10%, 50/60Hz	3,500	42	1485 x 470 x 545
MMSCB3120	9.61	12.01	6	39.1	4	3 x 350	7,261	14.8	690 / 1020	3.15 / 4.50	3~400V ±10%, 50/60Hz	5,250	49	2060 x 470 x 545
MMSCB4162	12.96	16.20	6	52.1	4	4 x 350	9,680	16.5	920 / 1360	4.20 / 6.00	3~400V ±10%, 50/60Hz	7,000	65	2630 x 470 x 545
MMSCB4191	15.26	19.07	6	78.1	6	4 x 350	8,561	15.7	920 / 1360	4.20 / 6.00	3~400V ±10%, 50/60Hz	7,000	78	2630 x 470 x 545

Low temperature, 300 and 350 mm fans

Rated at SC3: -25°C SST, -18°C air on. Japan condition: -35°C SST, -25°C air on.

Model	Capacity, kW SC3 cond.	Capacity, kW Japan cond.	Fin spacing FPI	Surface m²	Rows	Fans no. x mm	Air flow m³/h	Air throw m	Fan power W, 50/60Hz	Fan current A, 50/60Hz	Power supply	Defrost W	Weight kg	Dimensions L x W x H mm
MLUCA1019	1.48	1.87	4.5	5.5	4	1 x 300	1,390	6.1	120 / 170	0.54 / 0.76	1~230V ±10%, 50/60Hz	1,000	15	750 x 470 x 494
MLUCA2036	2.88	3.63	4.5	11.0	4	2 x 300	2,779	9.5	240 / 340	1.08 / 1.52	1~230V ±10%, 50/60Hz	2,000	24	1155 x 470 x 494
MLUCA3049	3.86	4.87	4.5	12.4	3	3 x 300	4,439	11.2	360 / 510	1.62 / 2.28	3~400V ±10%, 50/60Hz	3,000	32	1560 x 470 x 494
MLUCB1026	2.07	2.61	4.5	6.0	3	1 x 350	2,761	8.3	230 / 340	1.05 / 1.50	1~230V ±10%, 50/60Hz	1,750	18	850 x 470 x 545
MLUCB2058	4.56	5.75	4.5	13.5	3	2 x 350	5,519	12.1	460 / 680	2.10 / 3.00	3~400V ±10%, 50/60Hz	3,500	32	1485 x 470 x 545
MLUCB2074	5.89	7.42	4.5	22.5	5	2 x 350	4,860	11.0	460 / 680	2.10 / 3.00	3~400V ±10%, 50/60Hz	3,500	38	1485 x 470 x 545
MLUCB3101	7.97	10.06	4.5	27.0	4	3 x 350	7,769	14.3	690 / 1020	3.15 / 4.50	3~400V ±10%, 50/60Hz	5,250	49	2060 x 470 x 545
MLUCB4133	10.55	13.30	4.5	36.1	4	4 x 350	10,361	15.6	920 / 1360	4.20 / 6.00	3~400V ±10%, 50/60Hz	7,000	65	2630 x 470 x 545
MLUCB4148	11.71	14.77	4.5	45.1	5	4 x 350	9,720	15.3	920 / 1360	4.20 / 6.00	3~400V ±10%, 50/60Hz	7,000	73	2630 x 470 x 545

Medium temperature industrial, 500 mm fans

Rated at SC2: -8°C SST, 0°C air on. Supplied with full electrical wiring.

Model	Capacity, kW SC2 cond.	Fin spacing FPI	Surface m²	Rows	Fans no. x mm	Air flow m³/h	Air throw m	Fan power W, 50/60Hz	Fan current A, 50/60Hz	Power supply	Defrost W	Weight kg	Dimensions L x W x H mm
MMSCE1105	10.55	5.0	27.6	6	1 x 500	7,190	20	770 / 1100	2.95 / 3.3	3~400V ±10%, 50/60Hz	3,700	84	1265 x 520 x 890
MMSCE2165	16.48	5.0	37.0	4	2 x 500	15,120	22	1540 / 2200	5.90 / 6.6	3~400V ±10%, 50/60Hz	6,150	135	2215 x 520 x 890
MMSCE2209	20.93	5.0	55.5	6	2 x 500	14,380	22	1540 / 2200	5.90 / 6.6	3~400V ±10%, 50/60Hz	6,150	163	2215 x 520 x 890
MMSCE3248	24.81	5.0	69.4	4	3 x 500	22,170	24	2310 / 3300	8.85 / 9.9	3~400V ±10%, 50/60Hz	10,120	198	3165 x 520 x 890
MMSCE3320	31.98	5.0	83.2	6	3 x 500	21,570	24	2310 / 3300	8.85 / 9.9	3~400V ±10%, 50/60Hz	10,120	237	3165 x 520 x 890
MMSCE4362	36.25	5.0	85.2	5	4 x 500	28,800	25	3080 / 4400	11.8 / 13.2	3~400V ±10%, 50/60Hz	12,610	277	3315 x 520 x 1015
MMSCE4405	40.51	5.0	102.2	6	4 x 500	28,040	25	3080 / 4400	11.8 / 13.2	3~400V ±10%, 50/60Hz	12,610	299	3315 x 520 x 1015
MMSCE5476	47.58	5.0	106.5	5	5 x 500	36,000	26	3850 / 5500	14.75 / 16.5	3~400V ±10%, 50/60Hz	15,240	348	4065 x 520 x 1015
MMSCE5527	52.69	5.0	127.8	6	5 x 500	35,050	26	3850 / 5500	14.75 / 16.5	3~400V ±10%, 50/60Hz	15,240	363	4065 x 520 x 1015

Low temperature industrial, 500 mm fans

Rated at SC3: -25°C SST, -18°C air on. Supplied with full electrical wiring.

Model	Capacity, kW SC3 cond.	Fin spacing FPI	Surface m²	Rows	Fans no. x mm	Air flow m³/h	Air throw m	Fan power W, 50/60Hz	Fan current A, 50/60Hz	Power supply	Defrost W	Weight kg	Dimensions L x W x H mm
MLSCE1088	8.82	4.5	27.6	6	1 x 500	7,190	18	770 / 1100	2.95 / 3.3	3~400V ±10%, 50/60Hz	3,700	89	1265 x 520 x 890
MLSCE2136	13.56	4.5	37.0	4	2 x 500	15,120	20	1540 / 2200	5.90 / 6.6	3~400V ±10%, 50/60Hz	6,150	142	2215 x 520 x 890
MLSCE2174	17.44	4.5	55.5	6	2 x 500	14,380	20	1540 / 2200	5.90 / 6.6	3~400V ±10%, 50/60Hz	6,150	173	2215 x 520 x 890
MLSCE3238	23.84	4.5	69.4	5	3 x 500	22,170	22	2310 / 3300	8.85 / 9.9	3~400V ±10%, 50/60Hz	10,120	228	3165 x 520 x 890
MLSCE3262	26.24	4.5	83.2	6	3 x 500	21,570	22	2310 / 3300	8.85 / 9.9	3~400V ±10%, 50/60Hz	10,120	240	3165 x 520 x 890
MLSCE4293	29.35	4.5	85.2	5	4 x 500	28,800	23	3080 / 4400	11.8 / 13.2	3~400V ±10%, 50/60Hz	12,610	281	3315 x 520 x 1015
MLSCE4322	32.16	4.5	102.2	6	4 x 500	28,040	23	3080 / 4400	11.8 / 13.2	3~400V ±10%, 50/60Hz	12,610	304	3315 x 520 x 1015
MLSCE5359	35.92	4.5	106.5	5	5 x 500	36,000	24	3850 / 5500	14.75 / 16.5	3~400V ±10%, 50/60Hz	15,240	353	4065 x 520 x 1015
MLSCE5399	39.94	4.5	127.8	6	5 x 500	35,050	24	3850 / 5500	14.75 / 16.5	3~400V ±10%, 50/60Hz	15,240	368	4065 x 520 x 1015

Capacities are catalogue ratings at the stated conditions. Capacity at your own suction temperature, air-on temperature and defrost regime will differ, so ask us for a selection before ordering.

Reading the model number

Every model number states the application, the fan size, the fan count and the nominal capacity, so you can identify a unit on site without opening the manual.

Compact ranges, for example MMSCA2039-E

MMuller

MSMS medium temp
LU low temp

CCO₂ / R744

AA 300 mm fan
B 350 mm fan

2Number of fans

039Nominal capacity

-EElectric heaters
(MS models)

Industrial ranges, for example MMSCE1105J

MMuller

MSMS medium temp
LS low temp

CCO₂ / R744

EElectrical full wiring

1Number of fans, 1 to 5

105Nominal capacity
SC2 for MT, SC3 for LT

JSpecial zone code
(Japan)

Installation and clearances

Plan 350 mm of service space at each end and 300 mm behind the unit for return air. Drain connection is 32 mm; suction and liquid connection sizes shown on the drawing are the product inlet and outlet, so line sizing must still be calculated for the actual run.

Compact models are 470 mm deep at 494 mm or 545 mm high. Industrial models are 520 mm deep at 890 mm or 1015 mm high and run from 1265 mm to 4065 mm long, so check the beam and racking layout before you fix the hanging points.

Dimension drawing of a Muller CO2 unit cooler showing fan spacing, 32 mm drain connection, suction connection and minimum service clearances — General arrangement and minimum service clearances. Certified drawings are issued per model on request.

CO₂ compared with the refrigerants it replaces

Refrigerant	GWP	Flammable	Safety class
CO₂ / R744	1	No	A1
R404A	3922	No	A1
R507	3985	No	A1
R448A / R449A	1387 / 1397	No	A1

A CO₂ charge carries roughly one four-thousandth of the warming impact of the same mass of R404A, which is why new cold-chain projects across the region are specifying R744 from the start.

Questions we get asked

What is a CO₂ unit cooler?

It is the evaporator inside the cold room on a system running R744. The coil, circuiting and connections are built for CO₂ operating pressures, and the fans move the cooled air over the stored product.

What is the difference between the MM and ML models?

MM models are medium temperature, rated at -8°C saturated suction with 0°C air on, and use 5 to 6 fins per inch. ML models are low temperature, rated at -25°C saturated suction with -18°C air on, and use 4.5 fins per inch so frost takes longer to block the coil.

How do I pick the right size?

Work out the room heat load in kW, add a margin for defrost off-time, then choose a model whose capacity at your suction temperature covers it. Check two more things: that the air throw reaches the far end of the room, and that the length plus 350 mm service clearance at each end fits the ceiling.

Can these replace an existing R404A cooler?

Not directly. A CO₂ cooler belongs to a CO₂ system, so the pack, pipework, valves and controls all change with it. Talk to us early if you are planning a conversion, since the room load and defrost strategy usually get revisited at the same time.

What defrost is used?

Electric defrost, with heater ratings published for every model from 1.0 kW on the smallest compact unit to 15.24 kW on the largest five-fan industrial cooler.

Do you supply outside the Klang Valley?

Yes. We deliver nationwide across Peninsular Malaysia, Sabah and Sarawak, and support contractors on site through the commissioning stage.

Send us the room, we will send back a selection

Give us the room size, product, entering temperature, target room temperature and the pack you are running. We will come back with a model, the capacity at your condition and a delivery date.

Muller CO2 Transcritical Unit Cooler