What is hot spot/cold spot?

A hot spot/cold spot is an undesirable, tightly focused local temperature variation that often occurs when data center equipment is improperly cooled.

Hot spots are a serious issue that can result in equipment damage. Consider a typical blade server, which might individually include several processors and a large quantity of memory. These components can demand a significant amount of power -- much of that power is dissipated as heat. When many blade servers are installed into a tight, highly integrated chassis, the available cooling resources might dissipate the cumulative heat adequately. This results in one or more areas of excess temperature within the blade chassis. In extreme cases, the excess heating might cause processors, memory modules or other blade server components to fail.

Proper cooling design is critical in addressing the hot spots encountered with modern, dense IT equipment. When a hot spot is discovered, it might be necessary to reconfigure or relocate the affected equipment or provide supplemental local cooling (point cooling) to address the condition.

A cold spot might develop on or around equipment that receives excess cooling -- perhaps the equipment is located too close to a floor grate or inlet. When a cold spot is discovered, it's important to review the airflow and rectify any disruptions. When a surface becomes unusually cold, it often means that the cooling airflow is being obstructed. Cold spots might also pose a moisture danger. If a surface temperature falls below the surrounding air's dew point, condensation may form and allow liquid water to accumulate in a location that might damage equipment.