6. Higher operating temperature
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) first issued recommendations regarding higher-temperature data centers in 2008, but these were largely ignored. Servers do not require refrigeration. Even with inlet air temperatures reaching 75 to 80°F (25 to 27°C), these devices can still function well. Server manufacturers have actually expanded the operating temperature range of their products, and older equipment can operate within this extended temperature range just as well as newer equipment. Increasing operating temperatures can significantly save energy consumption, but first, people need to accept this approach and agree to make hot aisles even hotter—imagine 100°F (38°C)? This would spur the application and widespread adoption of back-door coolers.
7. Chimney-style cabinets and ceiling-mounted air ducts
Using the space above the ceiling to create air ducts to deliver air to the server room air conditioning system ensures that return air returns to the cooling coils at optimal temperatures, significantly increasing the cooling capacity of the precision air conditioning system. The final equipment form combining ceiling-mounted air ducts and hot aisle measures is the chimney-style server rack, which achieves superior cooling efficiency. High-temperature exhaust gases from the server cluster are discharged from the chimney at the rear of the rack and then directly return to the air conditioning equipment through the air ducts above the ceiling. Throughout the process, hot and cold air remain separated, thus maintaining a high energy efficiency ratio.
While the effects are noticeable, chimney-style server racks haven’t seen widespread adoption or promotion. This is likely because the fully enclosed design offers greater flexibility, allowing for the use of more racks to achieve the same effect. However, chimney-style racks can maintain a cold aisle temperature throughout the room, making the working environment more comfortable.
Direct and indirect natural cooling
Data center cooling solutions utilizing natural cold sources mainly fall into two categories: indirect natural cooling and direct natural cooling. Data center air conditioning requires cooling year-round. During transitional seasons when outdoor temperatures are lower than indoor temperatures, abundant natural cold sources exist. Therefore, utilizing these natural cold sources for cooling is a key issue for energy conservation and emission reduction in data center air conditioning systems.