In-Rack technology can be considered the best technology from the point of view of creating an accurate temperature inside the rack, because the rack and its cooling system are directly connected with each other from a temperature point of view during operation. The cool air produced from the Inrack unit has no choice but to pass through the corresponding rack server, and on the other hand, all the hot air produced from the server must also pass through the Inrack cooling system. In comparison with these products, because the length of the produced air passage is much shorter, therefore, fans with less power are needed in this product. On the other hand, hot air is trapped in a certain range and this creates the biggest temperature difference with the cold side, which itself leads to maximum thermal efficiency compared to other technologies. From the perspective of performance, this technology is very similar to separate hot and cold aisles, with the difference that the space of the hot and cold aisles in this technology is very limited and both spaces are created inside the rack itself. From the point of view of placement, these systems can be divided into two categories: rack-mount and side cooling.