How to Accurately Size UPS and Cooling for Data Center Power Efficiency

1. Data Center Area Calculation

Typical power distribution in a data‑center: IT equipment consumes about 44% of total power, cooling accounts for over 38% (sometimes up to 50%), and the remaining 18% is used by power supplies and lighting.

Room area formula: A = 4.5 ㎡/rack × N. For 30 racks, the main hall area is 4.5 × 30 = 135 ㎡.

2. UPS Selection

Equipment load: 30 racks × 3 kW per rack = 90 kW. Additional devices (fire safety, monitoring, emergency lighting) consume roughly 8 kW, giving a total load P = 98 kW.

Basic UPS capacity must satisfy E ≥ 1.2 P, so E ≥ 1.2 × 98 kW = 110.4 kVA. Considering optimal UPS utilization (60‑70%), the required capacity is 110.4 kVA ÷ 0.7 ≈ 184 kVA. A 200 kVA UPS is therefore selected, and for reliability a 1+1 redundant configuration (two 200 kVA units) is recommended.

3. Air‑Conditioning Selection

Using the “power‑and‑area method” for cooling load:

Indoor equipment load: Q₁ = UPS power × 0.8 = 200 kVA × 0.8 = 160 kW Environmental load: Q₂ = 0.15 kW/㎡ × 251 ㎡ = 37.5 kW Total cooling requirement: Qₜ = Q₁ + Q₂ = 197.5 kW. Adding a 40% redundancy leads to a design cooling capacity of about 320 kW, which can be provided by four 80 kW precision air‑conditioners.

4. Total Power Consumption

Estimated power consumption:

UPS: 200 kW

Cooling (assuming 2.5 kW per kW of cooling capacity): 320 kW ÷ 2.5 = 128 kW Lighting: 20 W/㎡ × 251 ㎡ = 5 kW

Other loads: 10 kW

Overall consumption ≈ 343 kW. Adding a typical 25% safety margin results in a design power of roughly 450 kW.

5. Space Requirements

Workstations & storage area: 135 ㎡.

UPS, distribution, and battery area (including maintenance space): about 70 ㎡.

Air‑conditioning units: 4 units × 2.1 ㎡ each ≈ 16 ㎡.

Fire protection area: 30 ㎡.

Total data‑center footprint ≈ 251 ㎡.

Accurate power monitoring—using dedicated measurement devices or management software such as UPS and PDU systems—is essential for energy savings and reliable operation.