Atlas Copco ZR 50 VSD⁺ (FF) Oil-free Tooth Air Compressor

The Atlas Copco ZR 50 VSD⁺ is the water-cooled 50 kW member of the ZR/ZT 30-50 VSD⁺ oil-free tooth compressor family, and it is the step where water cooling stops being a plumbing detail and becomes an energy asset. The machine compresses through two oil-free tooth elements driven by two direct-coupled IE5 permanent magnet motors — one per stage, each with its own NEOS Next converter — and published data covers 8.6 and 10 bar(e) classes with three measured points per class. Water takes the compression heat out of the frame, the work-station level is listed at 69 dB(A), and the Energy Recovery control unit turns that heat into process hot water at temperatures up to 90°C, which is the capability no air-cooled frame in this family can offer.

Energy Recovery Turns Compression Heat into 90°C Water

Every kilowatt the 50 kW motor draws ends up as heat, and a water-cooled frame hands that heat to the cooling circuit in a usable form. With the Energy Recovery control unit, the ZR 50 VSD⁺ feeds hot water up to 90°C into plant systems — cleaning-in-place loops, wash-down stations and space heating are the classic consumers — and the heat that would otherwise go to a cooling tower returns as a second energy stream. The water-cooled layout also decouples the compressor from the room it stands in: the machine does not push 50 kW of rejected heat into the building air, so the ventilation budget of the compressor bay shrinks along with the acoustic load, which the sheet lists at 69 dB(A) for both pressure classes.

Six Published Points Across the Two ZR 50 VSD⁺ Classes

The specification sheet prints each class as a Minimum row at 4 bar(e), an Effective row at 7 bar(e) on the lower class and 9 bar(e) on the higher class, and a Maximum row at rated pressure. One 50 kW (67 hp) power rating drives all six rows, and the flow bands stay narrow from floor to ceiling.

Inside the 8.6 bar(e) class the band travels from 37.5–147.7 l/s at Minimum to 36.8–143.5 l/s at Maximum, and the printed m³/min ceiling gives up only 0.2 units across the whole pressure travel — from 2.2–8.8 down to 2.2–8.6. The 10 bar(e) class closes at 35.8–129.3 l/s and 2.1–7.7 m³/min, so a header regulated near 10 bar(e) still commands 129.3 l/s at rated pressure. The psig columns read 58 / 102 / 125 on the lower class and 58 / 130 / 145 on the higher, and buyers working in imperial flow will find the Maximum bands printed at 77.9–304.07 cfm and 75.9–274.09 cfm respectively. Plants whose night demand drops far below the day profile should hold the Minimum rows in view: the drive range reaches down to 28% of maximum capacity across the family, but the printed flow floor stays where the sheet puts it.

Where the ZR 50 VSD⁺ Sits in the Water-Cooled 30-50 VSD⁺ Ladder

The water-cooled half of the family runs from the ZR30VSD⁺-8.6 at 93.2 l/s to the ZR 50 VSD⁺ at 147.7 l/s, and the ZR line stays inside a 3 dB(A) acoustic window across the whole ladder. The table below reproduces the published 8.6 bar(e) bands for the water-cooled models, and it shows the ZR 50 VSD⁺ opening its flow floor at 37.5 l/s — a step lower than the 37.8 l/s printed for the three models below it.

Two Stages, an Intercooler and 40% Regeneration Air

The air path inside the ZR 50 VSD⁺ explains the efficiency figures above. Air enters through the inlet filter, passes the blow-off valve that handles load and unload regulation, and reaches the first stage, which raises it to an intermediate pressure. The intercooler then cools the air and a moisture separation system drains condensate before the second stage lifts the flow to final pressure; from there the air crosses a pulsation damper with an integrated check valve into the aftercooler. Downstream, the cooled wet air is mixed with 40% of cooled regeneration air and enters the integrated dryer, where the guaranteed dew point is produced. The oil that cools the motors and gears runs in its own closed path and never contacts the air stream — the physical basis of the Class 0 oil-free rating this family certifies under ISO 8573-1.

Weights, Dimensions and Dryer Builds of the ZR 50 VSD⁺

The family weight table groups the 45 and 50 kW frames together, so the ZR 50 VSD⁺ shares its build weights across both pressure classes: 1373 kg as the Pack build, 1646 kg as the Full Feature build with the integrated MD dryer (iMD), and 1531 kg as the Full Feature build with the integrated refrigerant dryer (iD). The standard frame measures 2005 × 1022 × 1909 mm and the Full Feature build stretches to 2440 × 1022 × 1909 mm, so the machine swaps into a bay sized for the 45 kW step without widening or raising the footprint. Both classes list ID / IMD dryer availability, and the Elektronikon Touch controller plus a SMARTLINK connection handle regulation, energy reporting and early-warning diagnostics.

Questions Buyers Ask About the ZR 50 VSD⁺

What does the plant need to connect the Energy Recovery unit? The water-cooled frame ties into your cooling-water loop, and the recovery control unit exports the captured heat as hot water up to 90°C. A plant already running a tower or a closed loop can route that water to CIP systems, wash-down stations or heating circuits, and the heat recovered scales with the hours the 50 kW motor runs.

Which class fits a header near 7 bar(e)? Read the Effective row of the 8.6 bar(e) class at 146.1 l/s and 2.2–8.7 m³/min. The 10 bar(e) class keeps its own headroom for a line regulated near 9-10 bar(e) and closes at 129.3 l/s at Maximum, so the class decision follows the pressure your header actually holds, not the larger number on the label.

How narrow is the acoustic footprint? The sheet lists 69 dB(A) at the work station for both classes — one step below the 70 dB(A) printed for the air-cooled ZT 50 VSD⁺ — and the soundproof canopy removes the need for a dedicated compressor room, measured under the ISO 2151:2004 work-station method.

Stepping Up from the ZR 50 VSD⁺

When the plant outgrows the 147.7 l/s top edge of the ZR 50 VSD⁺, the next water-cooled point of the oil-free tooth line is the Atlas Copco ZR 55 VSD, which closes its single 8.6 bar(e) class at 134.6 l/s on a 55 kW motor at 70 dB(A). Send the measured demand profile together with your cooling-water data, and the quotation will match the class and build to what the plant actually runs.