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A modular data center is a data center assembled from standard factory-built modules: IT modules with racks, power modules, chiller plants and safety systems. The modules are built and tested at the factory while the site is being prepared, so a 1 MW site goes live in 8-12 months instead of 18-30 months for a conventional build. OS Power supplies modular data centers from a 20-foot container up to 5 MW prefabricated sites together with the power infrastructure: energy storage and gensets.
Modular data center in plain terms
A conventional data center is built as a permanent building: design and permits first, then construction, then the engineering systems. In a modular data center the building and the engineering are replaced by standard modules. The IT module with racks, the power distribution module and the chiller plant are assembled and tested at the factory; on site the work is limited to crane lifting, fixing and connection.
Factory readiness reaches 90 %: the module arrives with the equipment inside. For oversized modules and difficult logistics there is a mode of about 70 %, where the shell and engineering are factory-made and the equipment is installed on site. The third mode is the retrofit of an existing building with factory-built engineering blocks.
For owners and investors modularity has three practical benefits. Capacity is commissioned in phases that follow actual demand. Expansion means adding the next module without stopping the running ones. Quality is defined by factory testing rather than by the mix of contractors on site.
Three formats: containerized data center, micro-module and prefabricated data center
Modular data centers come in three main formats. The choice depends on capacity, rack density, whether a building is available, and the target launch date.
A containerized data center is a complete facility in one enclosure for outdoor installation: power, cooling, racks, fire suppression, access control and monitoring. Operating range is -40...+55 °C, enclosure protection is IP55 or higher, and on-site installation starts from 1 day. A micro-module is assembled row by row inside an existing hall, with general-purpose air-cooled racks and liquid-cooled GPU racks in the same module. A prefabricated data center is formed by IT modules 4.2-4.7 m wide, a chiller plant and a power block: this is the base option for 1-5 MW sites.
| Format | IT capacity | Racks | kW per rack | When to choose |
|---|---|---|---|---|
| Containerized data center, 20 ft | up to 100 kW | up to 8 | air 7-15 | telecom node, branch, pilot, site without a machine room |
| Containerized data center, 40 ft | 100-300 kW | up to 16 | air 7-15, liquid up to 40 | regional node, AI pilot, backup site |
| Micro-module in a building | 70-400 kW per row | 10-48 | air 7-15, liquid up to 40 | a hall with power and enough ceiling height is available |
| Prefabricated data center | 1-5 MW | 8-40 liquid plus network racks | liquid 40-140, air 7-40 | commercial or AI data center on a greenfield site or at a host partner |
What is inside a modular data center
A modular data center is more than racks in a box. A typical site has seven engineering layers, and each needs an owner. In many projects the bottleneck is not the module but power: grid connection takes years, while standard UPS units carry the load for 10-15 minutes.
That is why OS Power delivers the site together with its power infrastructure and takes single-point responsibility for every layer, from the 6-35 kV input to the rack. See power and cooling for details.
| Layer | What it includes |
|---|---|
| Power supply | 6-35 kV switchgear, dry-type transformers, main LV switchboard, automatic transfer in factory-built power modules |
| Uninterruptible power | modular UPS, OS Power LFP or sodium NFPP storage for 1-4 hours, supercapacitors for GPU load pulses |
| Generation | OS Power gensets in N+1 or 2N with fuel for 48-72 hours (from 24 hours depending on the design) |
| Distribution | high-power busways, switchboards, PDUs, independent feeds to every rack |
| Cooling | in-row air conditioners, chiller plant, CDU for liquid cooling, free cooling |
| IT modules | racks, cold aisle containment, cable trays, access control, video surveillance |
| Fire suppression and monitoring | quota-free perfluorohexanone gas suppression, aspirating detection, monitoring that can run fully offline |
Deployment timeline: modular data center vs conventional build
The main difference of a modular data center is time. While the modules are manufactured (from 5 months), the site gets foundations, power inputs and roads. A 1 MW site goes live in 8-12 months from contract to acceptance, or 4-6 months if power is ready at the host site; 2-5 MW sites take 9-14 months in phases. A conventional data center of the same capacity takes 18-30 months.
For an estimate at your capacity see modular vs conventional build, and for the sequence of work see stages and timelines. Timelines are guidance, not a commitment: they depend on site readiness and grid connection.
| Parameter | Modular data center | Conventional build |
|---|---|---|
| Timeline for 1 MW | 8-12 months, 4-6 with power ready | 18-30 months |
| Capital spending | in phases that follow actual demand | mostly upfront, for the target capacity |
| Quality | factory assembly and testing | depends on site contractors |
| Expansion | next module without downtime | new construction phase |
| Relocation | modules can be moved to another site | not possible |
| Service life | shell and engineering for 20-25 years | building for 50 years or more |
Modular data center cost: what drives the price
There is no single price for a modular data center: two sites with the same IT capacity can differ significantly in equipment scope. The cost is made up of several blocks, and each depends on project inputs. That is why we do not publish a price list and calculate each site at the concept stage.
What the cost of a site is made of:
- IT modules: shell, racks, aisles, cable trays
- Power: power module, switchboards, busways, UPS
- Cooling: air conditioners or a chiller plant with CDU
- Autonomy: energy storage and gensets with fuel reserve
- Safety: fire suppression, access control, monitoring
- Design, delivery, installation, commissioning and service
| Factor | How it affects the site scope |
|---|---|
| IT capacity now and in 3-5 years | sets the number of modules and the power and cooling capacity; growth is planned in phases |
| Rack density | air is enough at 7-15 kW per rack; from 40 kW direct-to-chip liquid, CDU and a chiller plant are needed |
| Cooling type | air, mixed hall or liquid: this defines the cooling scope and PUE |
| Redundancy | N+1 or 2N for power and cooling; 2N needs a second independent path, and reliability level requirements (for example Tier III) set the architecture |
| Site climate | for -40 °C: insulation, heating and winter kits; for heat: 20-25 % extra heat exchanger area and adiabatic cooling |
| Available grid capacity | when capacity is short, storage that reduces the declared connection capacity and gensets are added |
| Required autonomy | battery runtime and fuel reserve set the storage capacity and the number of gensets |
| Site and logistics | building, foundations and access roads define the format and the factory readiness mode |
Modular data center for AI and GPU
Model training clusters need high density and change consumption by tens of percent within fractions of a second. We design the site for the platform chosen by the customer: up to 40 kW per rack in a container or micro-module, up to 140 kW with direct-to-chip liquid cooling in a prefabricated data center.
Load pulses are absorbed by supercapacitors on the hall bus, while storage carries the load until gensets start and shaves peaks. The design reserves space and busbars for 800 V DC power and coolant supply up to 45 °C. OS Power does not supply servers or accelerators: the customer procures them. See AI and GPU for details.
| Rack class | kW per rack | Cooling | Format |
|---|---|---|---|
| Air-cooled GPU servers | 10-20 | air, contained aisle | micro-module, container, prefabricated data center |
| Mixed hall | 20-40 | air and rear-door heat exchangers | micro-module, prefabricated data center |
| High-density liquid racks | 40-80 | direct-to-chip liquid, CDU | prefabricated data center |
| Supernode racks | 120-142 | direct-to-chip liquid, supply 30-45 °C | prefabricated data center, power blocks with a permanent hall |
How to start a modular data center project
Five inputs are enough for a concept. Based on them, within a week we prepare the equipment list, site layout and schedule.
You can pre-select the format and scope in the site configurator; the full list of questions is in the data center questionnaire. The modules are made by a partner plant that has built data centers for China Mobile and China Telecom; OS Power runs design, supply, installation supervision, commissioning and service under single-point responsibility.
- IT capacity now and in 3-5 years, kW
- Rack type and kW per rack; GPU platform if known
- Redundancy: N+1 or 2N for power and cooling
- Required battery autonomy and genset fuel reserve
- Location and climate: minimum and maximum temperature
Questions and answers
What is a modular data center?
A data center built from standard factory-made modules: IT modules, power modules, chiller plants and safety systems. The modules are assembled and tested at the factory and then installed and connected on site.
How much does a modular data center cost?
Cost is calculated per project and depends on IT capacity, rack density, cooling type, redundancy, climate, available grid capacity and required autonomy. We prepare a concept with an equipment list within a week based on the questionnaire.
What is the difference between a containerized and a prefabricated data center?
A containerized data center is a single enclosure up to 300 kW for outdoor installation without a machine room. A prefabricated data center of 1-5 MW is assembled from IT modules, a chiller plant and a power block and forms the data center building.
How fast can a modular data center be deployed?
A 1 MW site takes 8-12 months from contract to acceptance, or 4-6 months with power ready; 2-5 MW sites take 9-14 months in phases. Module manufacturing takes from 5 months.
Does a modular data center work in extreme cold?
Yes. The containerized data center operates at -40...+55 °C with 100 mm insulation, heating when IT load is off and winter kits for air conditioners. The prefabricated data center is rated for -40...+45 °C with extra heat exchanger capacity for hot climates.