Custom Indoor AHU

New cooling concept. Customized. Efficient. Reliable.

STULZ is breaking new ground with its Indoor Air Handling Unit. The purpose-built solution meets users unique requirements for mission-critical environments by using proven STULZ technology.

Thanks to the new cooling concept the unit not only saves white space in large and hyperscale data centers but also makes highly efficient, reliable and performance-oriented operation possible without the need of a raised floor.


  • Large and hyperscale data centers

  • Free Cooling

  • Indoor installation

  • IT sector

  • Without raised floor

In collaboration with the customer, we develop the design concept, manufacture and deliver the optimal solution.

Modular Design

Customized Modular Design for Maximum Cooling Density

From extensive range of cooling capacities and systems to different unit configurations STULZ offers the optimum solution for your individual requirements. With the STULZ Custom Indoor AHU, our customers receive a purpose-built solution that has been ideally configured for their application.

Explore Custom AHU Examples


Customized Modularity – Maximizing cooling density

STULZ Custom Indoor AHU is customizable to project-specific sizing and to various site conditions. The design concept with zero side access results in an increased cooling capacity per wall length. Furthermore the modularity increases the operational reliability through redundancy.



  • Low pPUE values

  • Best price-performance ratio

  • Taller racks and higher heat loads possible because no raised floor is needed

  • Supply air temperature within the range recommended by ASHRAE TC 9.9 guidelines

  • Lowest AER (Airflow Efficiency Ratio) values and therefore conduction with maximum efficiency

  • Use of EC technology for maximum efficiency


  • Compact footprint yet maximized cooling capacity

  • Higher efficiency and lower noise level

  • Robust, extruded aluminum construction with various panel thicknesses, including a thermal break option

  • Zero side clearance, space-efficient, modular design

  • Operational reliability and redundancy through modularity

  • Provides uniform cooling along the entire length of the aisle due to the larger area of supply air

Effective Airflow
Efficient and reliable

CFD analysis to ensure the optimal operation

To avoid pressure losses and ensure uniform temperature distribution, it is important to generate CFD analyses. STULZ aims to develop the most energy-efficient solutions and analyses the design and components of all STULZ units to guarantee the most efficient and reliable operation.

The CFD analysis of the fan section shows an even temperature distribution across supply air side.

The CFD analysis shows an airflow example of a data center cooled with STULZ Custom Indoor AHUs. The unit provides uniform cooling along the entire length of the aisle because of the larger area of supply air.

STULZ E² Control and Monitoring

  • Designed specifically for precision control of mission-critical environments
  • Different operating modes for maximum efficiency and reliability
  • Multiple I/O capabilities for all major components to optimize control for energy savings
  • Controller UPS available
  • Suitable for connection to all common BMS systems


  • Easy replacement of fans and filters through front access

  • Quick installation

  • Factory trained and experienced sales and service partners in over 140 countries

  • Lowest total cost of ownership (TCO)

EC fans

  • Speed-controlled fan
  • Nominal airflow rate at a fan speed optimized for partial load
  • UPS available for continuous fan operation
  • Multiple fan sizes available
  • Increased airflow in each size

Various valves available

PICV/Energy Valve

  • Dynamic load balance across all operating conditions

  • Eliminates problems associated with low delta T syndrome

  • Precisely matches design requirements for capacity and delta T

  • Maximizes energy savings of variable flow systems while addressing unique control challenges


Options for customization

Tailor-made solutions for data centers are achieved by numerous options and equipment versions:

  • Backdraft and control dampers

  • Door interlocking

  • Aluminum frame construction

  • Steam canister humidification

  • Built-in UPS for unit control

  • Dual power with auto transfer switch

  • Horizontal and vertical orientation

  • Various voltages available in 50/60 Hz designs

  • STULZ E2 microprocessor with a range of BMS interface

  • Different filter options available; MERV-8, 11, 14

  • Stainless steel dual sloped construction drain pan

Download Custom Indoor AHU brochure

    • File: STULZ_Custom_Indoor_AHU_brochure_1810_EN.pdf

    • Type: application/pdf

    • Size: 2,58 MB

    • Language:

    • Date: 09.10.18

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