Which of the following is a common technique used to optimize cooling efficiency in a data center?

Regularly cleaning and maintaining cooling equipment, such as Computer Room Air Conditioners (CRACs) and Computer Room Air Handlers (CRAHs), is a fundamental technique for optimizing cooling efficiency. Maintenance tasks like cleaning filters, coils, and fans prevent airflow blockages and ensure the system operates at its designed performance level. Obstructed or dirty components force the cooling system to consume more energy to achieve the desired temperature, thereby reducing its overall efficiency. This proactive approach is a low-cost, high-impact method for energy savings and maintaining a stable data center environment.

A. Increasing the number of servers in the room increases the thermal load, making cooling less efficient, not more, as more heat must be removed.
B. Setting the temperature higher than recommended operating envelopes (e.g., ASHRAE guidelines) can lead to equipment overheating, performance throttling, and permanent damage.
D. Disabling cooling systems during peak hours would cause a rapid and dangerous rise in temperature, leading to automated server shutdowns and potential hardware failure.

1. HPE White Paper: "Ten steps to reducing data center cooling costs." Step 8, "Maintain the cooling system," states: "Regular maintenance of the cooling system is essential to ensure that it is operating at peak efficiency. This includes cleaning or replacing filters, checking refrigerant levels, and ensuring that fans and compressors are working properly." (HPE, Document ID: 4AA4-7125ENW, Page 8).

2. Lawrence Berkeley National Laboratory (LBNL) - U.S. Department of Energy: In the publication "Best Practices Guide for Energy-Efficient Data Center Design," the importance of maintenance is highlighted. Section 4.2 discusses how regular maintenance, including filter changes in CRAC units, is critical to maintaining airflow and the efficiency of the cooling system. (LBNL, Report No. LBNL-55262, Section 4.2, Page 21).

3. ASHRAE TC 9.9: The "2021 Thermal Guidelines for Data Processing Environments, 5th Edition" establishes the recommended and allowable operating envelopes for IT equipment. While the guidelines have expanded the recommended temperature range to allow for energy savings, operating above this range (as suggested in option B) is explicitly warned against due to reliability risks. The entire standard is predicated on systems being properly maintained to achieve these conditions efficiently. (ASHRAE TC 9.9, 2021).