CDCP Energy Efficiency and Sustainability 4 — Questions and Answers
Question 1: Which metric specifically measures the ratio of IT equipment energy consumption to total facility energy consumption?
- Power Usage Effectiveness (PUE)
- Data Centre Infrastructure Efficiency (DCiE) (Correct answer)
- Carbon Usage Effectiveness (CUE)
- Water Usage Effectiveness (WUE)
Correct answer: Data Centre Infrastructure Efficiency (DCiE)
DCiE (Data Centre Infrastructure Efficiency) is the reciprocal of PUE and expresses IT load as a percentage of total facility power, directly measuring the proportion of energy reaching IT equipment.
Question 2: A data centre is located near a cold climate region and uses outside air for cooling. What is this technique called?
- Geothermal cooling
- Economizer mode (free cooling) (Correct answer)
- Adiabatic cooling
- Absorption chilling
Correct answer: Economizer mode (free cooling)
Economizer mode, also called free cooling, uses ambient outside air when temperatures are low enough to cool the data centre without mechanical refrigeration, significantly reducing cooling energy.
Question 3: What does the term 'stranded power' refer to in data centre capacity planning?
- Power lost during electrical transmission from the utility
- Reserved power capacity not associated with active IT load (Correct answer)
- Energy wasted by legacy UPS systems
- Power drawn by decommissioned servers still plugged in
Correct answer: Reserved power capacity not associated with active IT load
Stranded power is reserved but unused power capacity—typically allocated to racks or zones but not consumed by IT equipment—reducing overall data centre efficiency.
Question 4: Which international standard provides a framework specifically for energy management systems applicable to data centres?
- ISO/IEC 27001
- ISO 50001 (Correct answer)
- TIA-942
- ASHRAE 90.4
Correct answer: ISO 50001
ISO 50001 defines requirements for establishing, implementing, and maintaining an energy management system (EnMS), and is applicable to data centres seeking certified energy governance.
Question 5: A data centre operator wants to reduce PUE by optimizing airflow. Which of the following actions would be MOST effective?
- Installing higher-wattage PDUs
- Implementing hot aisle/cold aisle containment (Correct answer)
- Increasing UPS battery capacity
- Upgrading to higher-density power strips
Correct answer: Implementing hot aisle/cold aisle containment
Hot aisle/cold aisle containment prevents mixing of supply and return air, allowing cooling systems to operate more efficiently and directly lowering PUE.
Question 6: What is the primary purpose of a DCIM (Data Centre Infrastructure Management) tool in relation to energy efficiency?
- To automate server provisioning and deprovisioning
- To provide real-time visibility into power and cooling consumption (Correct answer)
- To manage software license compliance
- To configure network switches remotely
Correct answer: To provide real-time visibility into power and cooling consumption
DCIM tools monitor power draw, thermal conditions, and capacity in real time, enabling operators to identify inefficiencies and optimize energy use across the facility.
Question 7: Which cooling strategy delivers cooled air directly to the server inlet within or adjacent to the rack, minimizing distribution losses?
- Raised floor plenum cooling
- In-row cooling (Correct answer)
- Precision air conditioning (CRAC units)
- Chilled water perimeter units
Correct answer: In-row cooling
In-row cooling units are placed within server rows, delivering conditioned air directly to equipment inlets and reducing the distance cold air must travel, improving efficiency.
CDCP Energy Efficiency and Sustainability 4
Which metric specifically measures the ratio of IT equipment energy consumption to total facility energy consumption?