DC Cooling Load Calculator — Data Center
Calculate the cooling capacity required by your data center based on IT load and target PUE. Understand what fraction of total facility power goes to cooling.
Cooling Load (kW) = IT Power × (PUE − 1)
How PUE drives cooling load
| PUE | Overhead % | Cooling for 1 MW IT |
|---|---|---|
| 1.2 | 17% | 200 kW |
| 1.5 | 33% | 500 kW |
| 2.0 | 50% | 1,000 kW |
| 3.0 | 67% | 2,000 kW |
Published: April 2026 | Author: TriVolt Editorial Team
Cooling Load and PUE
The relationship between PUE and cooling load is direct: every decimal point of PUE represents a fraction of IT power that the cooling system must remove. At PUE 1.5, 33% of total facility power goes to cooling and other overhead. At PUE 2.0, it's 50%.
This calculator answers a practical design question: given a target IT load and PUE, how many kW of cooling capacity do you need to procure?
The Formula Explained
PUE = Total Facility Power / IT Power
Total Facility Power = IT Power × PUE
Overhead (Cooling + Other) = Total − IT = IT × (PUE − 1)
Note: "cooling load" here includes all non-IT overhead — cooling, lighting, security, switchgear losses. Cooling typically dominates (60–80% of overhead).
Converting to Tons of Refrigeration
Cooling equipment is often specified in Tons of Refrigeration (TR) or BTU/hr, not kilowatts.
- 1 Ton of Refrigeration = 3.517 kW
- 1 kW = 3,412 BTU/hr
A 1 MW IT load at PUE 1.5 requires 500 kW of cooling capacity = 142 TR. Size CRAH/CRAC or chiller capacity with 20–30% headroom for redundancy and peak conditions.
Cooling Load vs. Actual Cooling Design
This calculation gives you the total overhead to reject, not the cooling system capacity. In practice, you need to size cooling for peak load, including safety factors:
- Peak load allowance: Size for 110–120% of calculated load to handle peak IT load and worst-case conditions
- Redundancy: N+1 or 2N for chiller and CRAH units in Tier II/III+ facilities
- Climate: Free cooling potential depends on wet-bulb temperature — warmer climates require more mechanical cooling hours
- Partial load efficiency: Chillers and CRAHs operate more efficiently at partial load — size appropriately, don't massively oversize
Related Calculators
- → PUE Calculator — Calculate PUE from measured power
- → Rack Density Calculator — Cooling strategy by rack density
- → UPS Sizing Calculator — Power backup capacity
- → Cooling Load Calculator — General building cooling load
Disclaimer
This calculator derives cooling load from PUE — a useful planning estimate, not a substitute for detailed mechanical engineering design. Engage a licensed mechanical engineer for cooling system design and equipment selection.