We are all trying to fix the unfixable in the Data Centre. How do we get more cooling capacity from sites we built a decade ago for low power density applications?
One of the biggest problems is that everyone is trying to work against a basic law of physics; hot air rises, and cold air falls. Here’s the problem, a conventional data centre is designed to support servers that pull air in from the front and blow it out the back of the cabinet. (Except for the odd aberration from Cisco that blows the air side to side). So common sense tells us that computers at the top of the cabinet don’t get as much cold air as computers at the bottom.
Emerson Network Power supply cold aisle containment solutions, IBM offers water-cooled doors on the back of their racks (what a dumb idea that is) and data centre operators lay out their sites in hot and cold aisles. It is all about getting cold air onto the hotter and hotter processors in higher and higher density packages.
Keeping the hot air and cold air separate is important as Data Centre Air Conditioning (CRAC) units run at peak efficiency only when the return airflow is as hot as possible and high volumes of this hot of air passes the cooling coils. Trying to maintain hot and cold air in separate vertical aisles between racks is hard to achieve and requires a great deal of attention to detail.
So why not turn the whole thing through 90 degrees and maintain horizontal separation between hot and cold air, put the hot on top and cold on the bottom? This aligns with the laws of physics and does not require any special procedures like cold aisle containment or maintenance of blanking panels.
Verari get it, their patented Vertical Cooling Technology draws air from the bottom of the cabinet and exhausts it through the top. Using a series of large and efficient cabinet level (not server level) fans cold air is pumped from the plenum through the cabinet at high velocity and exhausted at high temperature out of the top.
There is no opportunity for cold and hot air to mix. CRAC units are then able to operate at peak efficiency providing maximum capacity to the data centre.
Turning the hot and cold aisles into a horizontal configuration has a number of significant efficiency benefits:
- Better CRAC unit efficiency
- Lower air handling energy (larger more efficient fan units)
- Significantly better Power Usage Efficiency
- More cores per KW of electricity
- The front and back of the servers (blades) are unencumbered by the need for cooling fans and slots freeing space for connectors and indicators
- There is no front and back so servers (blades) can be fitted into both doubling the number of cores per U of rack space.