Energy Storage
There are various categories of energy storage systems that feature different components and characteristics to enhance or impact the availability of data centers during utility outages. The history and duration of utility outages in a specific location can help evaluate the potential effectiveness of incorporating energy storage systems for data center power backup applications.
1. What utility power issue is most likely to cause the backup generator to start?
A. Power glitch – under 1 second
B. Sustained interruption of 60 seconds or longer
C. 3 cloudy days
D. Low levels of harmonic distortion
2. What is the most common form of energy storage used in data centers?
A. Compressed air
B. Fuel cell
C. Battery connected to a UPS for the IT load
D. Flywheel
3. What characteristic is the most important factor when considering the expected backup time for an energy storage system?
A. Power to weight ratio
B. The KVA and kW rating of the of the generator
C. The fuel consumption rate of the generator at its full rated load
D. The kWh capacity at the expected power draw
4. What characteristic is the most important factor when analyzing IT power requirements?
A. The KVA and kW rating of the of the generator
B. The maximum KVA and kW demand expected to be transferred to the ESS
C. The fuel consumption rate of the generator at a rated load
D. How long it takes for the generator to reach the correct rpm
5. What characteristics are the most important factors when analyzing battery-based energy storage requirements?
A. The ampere hours at the manufacturers C/10 and C/20 discharge rate
B. The maximum recommended discharge rate amperes and the ampere hour capacity available at the desired backup time
C. How long it takes for the generator to reach the correct operating frequency
D. The battery terminal type and form factor
6. Other than electrochemical battery energy storage, what other storage technology is used in data centers?
A. High-speed flywheel connected to DC bus of electronic UPS
B. Rotary UPS (AC motor-generator)
C. Diesel rotary UPS (AC motor-generator)
D. All of the above
7. What type of cooling system offers the best match for thermal energy storage?
A. Air-cooled DX CRAC
B. Water-cooled DX CRAC
C. Water-cooled chiller
D. All of the above
8. Which of the following is a benefit of a thermal energy storage?
A. The primary added cost is the size of the TES chilled water tank and piping
B. Increases thermal stability to the IT equipment
C. Decreases the chiller compressor cycling
D. All of the above
9. What is a possible return on investment factor when considering energy storage for peak shaving applications?
A. The peak power demand rate
B. The peak energy rate
C. The capital cost of the energy storage system
D. All of the above
10. What is a significant factor when considering the potential benefits of energy storage for data center applications?
A. History of the frequency of outages in your area
B. The power rating of the generator
C. History of the duration and frequency of outages in your area
D. How fast the generator reaches the correct voltage and frequency and can accept load
