Data centre air handling is dominated by cooling load, and the most effective way to reduce it is to precondition outdoor air with heat recovery before it reaches the cooling plant — a total heat recovery unit transfers both temperature and moisture from the exhaust air to the incoming outdoor air, so the chiller handles a pre-conditioned airstream instead of raw outdoor air. ROTER's range covers 1,000–15,000 m³/h of total heat recovery capacity at 68–76% efficiency, with modular building-block AHUs available to 80,000 m³/h for hyperscale projects.

 

 

 

 

 

Why the outdoor-air load dominates the data centre

 

 

A data centre's cooling plant serves two very different loads. The first is the IT load — servers, storage and network gear — which is entirely internal and constant. The second is the outdoor-air load, which arrives hot and humid and must be conditioned to the cold aisle temperature before it can be delivered at all.

 

 

 

Because the outdoor airstream enters the building once and is then recycled many times, the cooling plant must remove its latent load again and again. The efficient strategy is to reduce the load on the way in. Heat recovery does exactly that: the exhaust air, which is already at or near room temperature, gives up its heat to the incoming outdoor air before the mixing point.

 

 

 

ROTER's documented measurement on a 200 m² room in Beijing quantifies the effect of total heat recovery: with the outdoor temperature at 33°C, supply air arrived at about 28°C rather than the roughly 7°C that plain ventilation would have delivered, saving approximately 1,112 kWh in winter and about 1,427 kWh in summer — roughly 42.3% annual saving at ¥0.48/kWh.

 

 

 

 

 

Choosing the core for a data centre duty

 

 

Core selection for data centre outdoor-air handling

 

Duty Recommended product Reason

Medium outdoor airflow, clean exhaust Medium ceiling-mounted total heat recovery unit 68–72% total heat recovery, 1,000–15,000 m³/h, no moving parts

Large outdoor airflow, high duct pressure Combined rotary AHU Rotary core handles large airflow and duct pressure efficiently

Very large project, staged delivery Commercial air conditioning unit series Modular building-block configuration, 2,000–80,000 m³/h

Cooling required alongside heat recovery Direct expansion air conditioning unit Integrated DX cooling for the conditioned side

Condensing exhaust heat recovery Condensing exhaust-air heat recovery unit Recovers heat from the condensing compressor discharge

Strict humidity control required Rotary desiccant dehumidifier −70°C dew point capability for controlled spaces

 

 

 

 

Published performance for data centre sizing

 

 

CXH series — medium ceiling-mounted total heat recovery unit

 

Model Airflow m³/h Static pressure Pa Motor power kW Efficiency % Noise dB(A) Weight kg

CXH-25DA 2500 200 1.10 68 59 210

CXH-50DA 5000 270 2.74 70 63 350

CXH-80DA 8000 330 5.60 72 71 570

CXH-100DA 10000 400 7.00 71 72 670

CXH-150DA 15000 400 11.0 70 75 780

 

 

Full 14-model range on the medium ceiling-mounted total heat recovery unit page. Test conditions (GB/T 21087): summer — outdoor dry bulb 33°C, RH 80%; indoor dry bulb 26°C, RH 50%. For reference only.

 

 

 

 

 

High-efficiency and low-noise options

 

 

For plant rooms where the noise limit is tight, the DC inverter total heat recovery ventilators publish 40 dB(A) at 100 Pa with 70% total heat recovery efficiency, 220 V / 50 Hz single-phase supply, and a PM2.5 removal rate of 99.9% — see the DC inverter range. A standard haze variant covers the same envelope at 40–45 dB(A) across 200–1,000 m³/h.

 

 

 

 

 

Project reference in a high-performance building

 

 

ROTER's project record includes Phase II of the Training Center of the National Cybersecurity Talent and Innovation Base — a high-performance building project with demanding air handling requirements. Related infrastructure and building references are published on the case study page.

 

 

 

 

 

Frequently asked questions

 

 

Can heat recovery be used in a data centre?

 

Yes, and it is one of the standard measures for reducing the outdoor-air cooling load. The important distinction is that in a data centre the supply air is normally delivered cold rather than at room temperature, so the benefit comes from reducing the load on the chiller rather than from avoiding reheat. It is worth modelling alongside free cooling, which typically takes priority in a temperate climate, and alongside the refrigeration efficiency of the installed plant.

 

 

 

What airflow is needed for a data centre?

 

That depends on the containment design and the IT load. ROTER's published range covers 1,000 m³/h per unit up to 15,000 m³/h, with modular building-block air handling units available from 2,000 to 80,000 m³/h for larger halls. The correct figure comes from the room cooling load, not a rule of thumb, so send us the IT load and the design outdoor conditions and the sizing comes back with the calculation.

 

 

 

Do you have data centre or high-performance building references?

 

ROTER's named projects include Phase II of the Training Center of the National Cybersecurity Talent and Innovation Base, a high-performance building project. It has also supplied large ventilation quantities for institutional projects, including 880 ventilation units to Wuhan Huoshenshan Hospital. Full references are published on the case study page.

 

 

 

Which is better for a data centre, a plate or a rotary heat exchanger?

 

For large outdoor airflow with high duct static pressure, the rotary core is usually the more economical choice because it handles both without splitting into multiple units. Plate cores remain the right answer where the exhaust is clean and moisture-laden, because they have no moving parts and do not foul with condensate. The full comparison is on the ERV comparison page.

 

 

 

How do you reduce the outdoor-air load in a hot climate?

 

Three measures are typically combined: heat recovery to precondition the outdoor air, free cooling for as many hours per year as the climate allows, and demand-controlled ventilation so that fresh air is supplied in proportion to occupancy rather than continuously. ROTER's equipment addresses the first of these directly; the second and third are control strategy decisions, and ROTER units can be supplied with CO₂ demand control and BMS or BACnet integration.

 

 

 

Can the units be integrated with our building management system?

 

Yes. The terminal and combined units can be supplied with on/off control, differential pressure sensing, CO₂ demand-controlled ventilation, and BMS BACnet integration. Specify the controls requirement in the inquiry so it is included in the quotation and the drawings rather than added later.