1U, 2U, 3U Server Fan Requirements
SANYO DENKI continues to develop air cooling fans for data center applications to meet the rising demand of High Power Computing (HPC) and Artificial Intelligence (AI). This guide to selecting fans serves to outline the key parameters between SANYO DENKI’s Counter Rotating and High Static Pressure fans in sizes suitable for 1U, 1.5U, 2U, and 3U server racks.
Since server racks are built to high densities, the cooling demand is equally high. Therefore, the use of fans with greater depth and having multiple rotors help counter the back pressure needed to push the air through the components such as CPU chips, heatsinks, GPU chips, and switches.
An advantage of Counter Rotating fans is that the two impellers with opposite rotation directions help concentrate the airflow into a straight column versus a more diffuse spread from stacking two fans in tandem. This helps with spot cooling and ensures that the cool air being pushed in can spread further into the server rack. In addition, the Counter Rotating fans can handle higher static pressure environments while maintaining high airflow.
1U Sizes: 40mm Fans
For the 1U (44.45mm / 1.75”) height, a good fan frame size is 40mm. SANYO DENKI has a rich Counter Rotating product lineup for the 40x40x56mm size, seen in the table below.
- 40x40x56mm Options for 1U Server Racks:
In situations where space is constrained in the 1U rack, there are also single axial high-performance fans. The single axial fan options are available in frame sizes 40mm, 38mm, and 36mm, providing a variety of options if spacing is tight.
- Single Axial Fan Options for 1U Server Racks:
The following graph visually represents the static pressure (P) and airflow (Q) behavior of each 1U Server Rack fan option, highlighting their power consumption and sound pressure level (SPL) at free air. If power is no constraint and cooling performance is the main objective, then the 9CRJ0412P5J001 offers the maximum performance for a 1U server rack.
1.5U Sizes: 60mm Fans
For applications where more performance is needed, there is a half size up in the 1.5U configuration. There are also thermal benefits to using a larger fan, and the 60mm frame size fits the need. The list is below with links to each product page.
- 60x60x56mm Options for 1.5U Server Racks:
- 60x60x76mm Options for 1.5U Server Racks:
For comparing the PQ chart along with the power and sound, the graph below shows the discussed models and their depths.
2U Sizes: 80mm Fans
The 2U (88.9mm / 3.5”) size is one of the more common server sizes. Therefore, the variation in fans that meet this demand is well represented in SANYO DENKI’s rich product lineup. In addition to the high performance options, there is also a Long Life model with triple the L10 life at 60ºC of a standard fan. 80x80x80mm fans are suitable for this 2U size, and often times the system infrastructure requires a 48V or 54V operating condition. The following list exhibits fans rated at 12V and 48V for this size.
- 80x80x80mm Options for 2U Server Racks:
The following PQ graph shows all models overlayed on the same chart with their power and SPL at free air. It’s important to note that while 9CRHA0848P8K001 has the same listed power of 135W as 9CRHA0848P8J001, the K-speed model has higher performance across the rest of the PQ chart, and with it, higher power consumption and sound levels.
3U Sizes: 120mm Fans
For the 3U (133.35mm / 5.25”) size, 120mm fans can help maximize the cooling performance while staying comfortable within the rack.
SANYO DENKI’s 120mm size lineup includes the option to stack two single-rotor high performance fans together, as well as a Counter Rotating option.
- 120x120x76mm Options for 3U Server Racks:
- 120x120x38mm Options for 3U Server Racks:
The below PQ graph shows a single unit of each fan, where the Counter Rotating 9CR1212P0G03 has 76mm depth. The 9HV1248P1G001 and 9HV1248P1H001 both have 38mm depth, and if stacked in tandem, the static pressure would double and provide even greater cooling power for a 3U server rack.
Summary
In summary, SANYO DENKI offers a wide range of products to meet the demands of HPC, AI, and data centers. Based on the system’s power budget, noise constraints, and performance requirements, design engineers can choose from multiple SANYO DENKI products. There are a lot of competing system constraints to consider when choosing a cooling fan, and it can start with the server rack sizes of 1U, 1.5U, 2U, and 3U. SANYO DENKI’s staff can help narrow down the options in a given size while providing engineering support throughout a system’s design and prototype phases, mass production, and beyond.
Written by Jerry Wu
This article is part of SANYO DENKI AMERICA’s San Ace cooling engineering knowledge base, sharing practical guidance engineers use when working with DC fans in electronic cooling designs.
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