CDCP Energy Efficiency and Sustainability 2 — Questions and Answers
Question 1: According to ASHRAE A2 thermal guidelines, what is the maximum recommended server inlet temperature?
- 27°C (80.6°F)
- 35°C (95°F) (Correct answer)
- 40°C (104°F)
- 45°C (113°F)
Correct answer: 35°C (95°F)
ASHRAE A2 class (the most commonly used server classification) allows inlet temperatures up to 35°C (95°F) to enable more free cooling hours and reduce mechanical cooling energy.
Question 2: What does 'free cooling' in data centers primarily refer to?
- Cooling systems that operate without any electricity
- Using outdoor ambient air or water to reject heat without mechanical refrigeration (Correct answer)
- Cooling capacity provided at no cost by the utility company
- Recycling server waste heat to cool adjacent equipment
Correct answer: Using outdoor ambient air or water to reject heat without mechanical refrigeration
Free cooling uses outdoor ambient air or water at temperatures naturally lower than the data center to reject heat without running energy-intensive mechanical refrigeration compressors.
Question 3: What does ERE (Energy Reuse Effectiveness) measure in a data center?
- Net energy consumed minus reused energy, divided by IT equipment energy (Correct answer)
- The efficiency of UPS battery energy storage systems
- The percentage of renewable energy used by the facility
- The ratio of energy produced on-site to energy purchased from the grid
Correct answer: Net energy consumed minus reused energy, divided by IT equipment energy
ERE measures net energy use (total facility energy minus any energy reused externally, such as waste heat exported to nearby buildings) divided by IT equipment energy.
Question 4: What is the primary efficiency benefit of implementing hot aisle/cold aisle containment?
- Reducing the total number of servers required
- Preventing hot exhaust and cold supply air from mixing, improving cooling efficiency (Correct answer)
- Increasing rack density beyond standard configurations
- Eliminating the need for raised floor plenum systems entirely
Correct answer: Preventing hot exhaust and cold supply air from mixing, improving cooling efficiency
Hot aisle/cold aisle containment physically separates server exhaust from supply air, eliminating recirculation and bypassing airflow that wastes cooling capacity.
Question 5: What is Carbon Usage Effectiveness (CUE) primarily used to measure in data centers?
- Total CO2 emissions caused by a data center divided by IT equipment energy consumed (Correct answer)
- The efficiency of carbon filter systems in air handling units
- Carbon credits earned through renewable energy certificate purchases
- The frequency of carbon-based UPS brush replacement
Correct answer: Total CO2 emissions caused by a data center divided by IT equipment energy consumed
CUE measures total greenhouse gas emissions (in kg CO2 equivalent) produced by data center energy consumption divided by IT equipment energy, quantifying the facility's carbon footprint.
Question 6: LEED certification for green data center buildings is issued by which organization?
- The Green Grid
- ASHRAE
- U.S. Green Building Council (USGBC) (Correct answer)
- Uptime Institute
Correct answer: U.S. Green Building Council (USGBC)
LEED (Leadership in Energy and Environmental Design) certification is issued by the U.S. Green Building Council (USGBC) and provides a globally recognized framework for green building design.
Question 7: Which renewable energy procurement method allows a data center to claim renewable energy use without generating power on-site?
- Installing solar photovoltaic panels on the facility roof
- Purchasing Renewable Energy Certificates (RECs) (Correct answer)
- Deploying on-site wind turbines
- Using grid power exclusively during off-peak hours
Correct answer: Purchasing Renewable Energy Certificates (RECs)
Renewable Energy Certificates (RECs) represent proof that one megawatt-hour of electricity was generated from a renewable source, allowing buyers to claim renewable energy use without on-site generation.
CDCP Energy Efficiency and Sustainability 2
According to ASHRAE A2 thermal guidelines, what is the maximum recommended server inlet temperature?