Review of STULZ ASD 231 A InRoom ventilation

Unit type: ASD 231 A

Cooling capacity (total): 25.2 kW

Cooling capacity (sensible): 25.2 kW

Net total cooling capacity: 23.4 kW

Net sensible cooling capacity: 23.4 kW

Condensing temperature: 53 °C

EER: 2.96 kW/kW

AER: 0.22 W/(m³/h)

Sound power level: 78.6 dB(A)

LpA (2m freefield): 58.5 dB(A)

Number of refrigerant circuits: 1

Number of compressors: 1

Total power consumption: 8.5 kW

Fan (Data per unit)

Fan type: R3G595

Number: 1

Max. revolutions: 1,400 rpm

Nominal power: 2.9 kW

Revolutions: 1,154 rpm

Condenser

Unit type: KSV045A21p

Ambient temperature: 43 °C

Sound pressure group: Standard

Required condenser capacity: 31.8 kW

Available condenser capacity: 34.2 kW

Difference: 7.5 %

Number of fans: 2

Number of condensers: 1

Airflow: 8,000 m³/h

Air velocity: 3.1 m/s

Return air temperature: 23 °C

Return air humidity: 40 rel.%

Supply air temperature: 14 °C

Altitude above sea level: 0 m

Height: 1,980 mm

Width: 950 mm

Depth: 890 mm

Weight: 376 kg 

Refrigerant: R407C

Power supply: 400V/50Hz/3Ph/N/PE

Power consumption:

1.8 kW

ESP external static pressure: 50 Pa

Total pressure drop: 484 Pa

Control voltage:

8.2 V

Electrical power consumption: 6.7 kW

Heat rejection: COP:

Number:

31.8 kW

3.78 kW/kW 

1

Evaporating temperature: 10.6 °C

Weight: 142 kg 

Current consumption (per fan): 2.30 A 

Power consumption (per fan): 0.53 kW

Height: 1,066 mm

Width: 1,860 mm

Depth: 920 mm

Airflow: 12,100 m³/h

LpA (5m freefield): 54.6 dB(A)

CyberAir 3PRO DX

Air conditioning data centers with maximum precision, reliability and energy efficiency

The complete range of air conditioning technology – from one source.

For over 50 years, the STULZ family-run company has been synonymous with precision air conditioning at the highest level.

Our solutions for the air conditioning of business- critical applications and sensitive systems have made us a leading company in our industry.

Whether for data centers, industry or communication technology, the STULZ portfolio has a tailor-made cooling solution to suit your requirements.

We guarantee adherence to our uncompromisingly high requirements and quality standards both at our factory in Hamburg and all our production sites around the globe. Moreover, we work hard not only to satisfy our customers’ individual wishes, but also to make sure our air conditioning solutions offer maximum energy efficiency and a minimal CO2 footprint.

Our portfolio extends from traditional room cooling and High Density Cooling to chillers, air handling units and container modules, all the way to micro data centers, service, and our self-developed monitoring software. An all-embracing quality assurance system monitors all the details in development, production, implementation, and service.

Today, STULZ has a presence in more than 140 countries. STULZ GmbH has 23 subsidiaries and eleven production sites in Europe, India, China, and North and South America. We also have partner agreements with numerous sales and service partners on every continent. Our network of highly qualified specialists is a reliable guarantee of the highest standards.

Maximum cooling capacity, minimal footprint

High-efficiency precision air conditioning units for optimum regulation of temperature and humidity

The CyberAir 3PRO DX is the result of more than three decades of experience with projects around the world, and is the logical next step in the development of the successful CyberAir 3 series.

To achieve maximum cooling capacity with a minimal footprint while promising you maximum potential savings, these units are more adaptable than any other precision air conditioning unit on the market. Size, cooling capacity, air conduction or control system – STULZ air conditioning solutions can be tailored precisely to your data center’s individual requirements.

Advantages at a glance

• Technological leader when it comes to cooling capacity with maximum efficiency

• Maximum cooling capacity with a minimal footprint

• Air conduction with maximum efficiency

• Further reduction in operating costs as supply air conditions conform to the ASHRAE recommendation

• Maximum potential savings thanks to Indirect Dynamic Free Cooling from STULZ

• Cools reliably, precisely, quietly and exceptionally economically

• Designed for a long service life

• Use of EC technology for maximum efficiency

• Compact design for easier transport and installation

• Option of having your unit tested in our Test Center

• Control based on supply air, return air or room air

Optimized unit design for maximum potential savings

The design of our units means that STULZ precision air conditioning units boast maximum EER values and the lowest AER (Airflow Efficiency Ratio) values, and therefore achieve air conduction with maximum efficiency. The AER describes the ratio of the fan power consumption to the airflow.

ASR air conduction (fans integrated in the raised floor), in particular, hugely reduces fan power consumption by ensuring minimal turbulence and changes in airflow direction, for energy savings that you will notice straight away.

Precise control

The air-side difference in temperature between the air inlet and outlet of your server cabinets or air conditioning systems is known as ∆T. To ensure optimum operation and the greatest possible savings on operating costs, it is vital

that the ∆T of the air conditioning units is adapted precisely and efficiently to the ∆T of your server cabinets.

Our dynamic control enables this adaptation to the changing requirements of your IT, ensuring maximum energy efficiency during operation

AT A GLANCE

• Cooling capacity: 20 kW to 150 kW

• Largest possible heat exchanger and filter surface areas for minimal pressure drops

• Available with R407C, R410A, R134a and R513A (on/off compressor) refrigerants

• STULZ controller manages all functions and components, even when several units are combined in one system

• Filter control manager

• All parts requiring maintenance can be accessed from the front

• Filter class ISO 16890:

ISO Coarse 80 % up to ePM10 70 %

• Simple transport – fits through any standard door

• Flexible installation in the data center

• 2 designs and 6 sizes

• 5 cooling systems

Optimum supply air conditions for reliability and maximum efficiency

To cool your data center as efficiently as possible without compromising on reliability, ASHRAE has published a recommendation for the air temperature at the server inlet. We have been developing air conditioning units for mission- critical applications – where even tiny malfunctions can have serious consequences – for decades now. Not only that, we have always focused on energy efficiency, and because of this, the supply air temperatures of our units lie within ASHRAE’s recommended range.

Two designs for individual installation options

The CyberAir 3PRO DX is a model of adaptability. Size, cooling capacity, air conduction or control: STULZ air conditioning solutions can be precisely adapted to your data center's individual requirements. With two designs and air conduction systems specifically optimized for each unit, the CyberAir 3PRO DX ensures maximum flexibility for integration in your system.

ASD and ASU versions

The design with integrated fans is available with standard ASD (Downflow) and ASU (Upflow) air conduction. Through further development and by optimizing the design, the units are now considerably more efficient than the previous version. This can be witnessed in the noticeably higher EER and lower AER.

ASR version

The ASR (Raised Floor) series promises even higher energy savings than units with fans on the raised floor. This model is equipped with an external fan box, and air conduction is specific to the unit. The fan

box is installed under the unit, in the raised floor. The resulting additional space in the air conditioning unit enables the use of larger heat exchangers, resulting in a noticeably higher cooling capacity per footprint. What’s more, positioning the fans in the raised floor means less turbulence and fewer changes

in airflow direction. The result is ideal air conduction and therefore massively reduced fan power consumption (AER).

Direct Free Cooling

Direct Free Cooling exploits the potential of low outside temperatures, to cool the data center with outside air.

With this method of cooling, outside air treated by filtration systems enters the room directly. Direct Free Cooling is suitable for applications with wider temperature and humidity tolerances.

The CyberAir 3PRO DX precision air conditioning unit with Direct Free Cooling air conditions data centers up to 90 % more economically than conventional compressor cooling systems.

Special solution for small to medium- sized data centers: Direct Free Cooling with FreeCool Plenum (FCP)

To exploit huge potential savings in smaller data centers, too, and when modernizing existing cooling systems, CyberAir 3PRO DX units with downflow air conduction can be equipped with the FreeCool Plenum. With this option, Free Cooling is automatically combined with compressor cooling in three variable stages to suit the outside temperature and cooling needs, ensuring that maximum savings are always exploited to the full:

1. Free Cooling

• The outside air damper opens

• Outside air is conveyed through the filter of the FreeCool Plenum directly into the unit, then into the data center

• The compressor remains off, completely saving the cooling energy normally required

• If the outside temperature is too cold, the outside air is mixed with return air

2. Mixed mode

• As 1, plus:

• The compressor is switched on for extra support

• When the outside air damper is open, the compressor runs in partial load mode

• The return air damper of the FreeCool Plenum opens proportionate to this

3. Compressor mode

• The CyberAir 3PRO DX cools solely using compressor cooling

• The outside air damper remains closed, and no outside air is used for cooling

• Return air damper open 100 %

Indirect Dynamic Free Cooling

With Indirect Free Cooling, no outside air gets into the sensitive interior of the building. Indirect Free Cooling is therefore not dependent on the quality of the outside air. Indirect Dynamic Free Cooling from STULZ is the only system in the world with automatic efficiency optimization. Dynamic control without a fixed Free Cooling start value and an additional operating mode guarantee maximum potential savings.

The dynamic controller regulates all active components based on the outside air temperature and current heat load, therefore reducing compressor cooling to a minimum. Moreover, the dynamic controller has an Extended Free Cooling mode. In this mode, variable-speed components keep cooling capacity constant by increasing the airflow. This has the side effect of lengthening Free Cooling periods, cutting operating costs to a minimum.