Computer Room Air Conditioning - How do CRAC units work?
video description
We use OptiCool which delivers refrigerant cooling directly to the racks via small overhead piping (typically hung off the overhead cable trays) to radiators located on the back of the cabinets (1-3 per cabinet, 5-15KW cooling) easily added/removed as load dictates. It is adjustable/expandable for changes in load as the cabinet contents change over time. It has some of the best PUE ratings in the industry. A side benefit is is makes its own redundancy. cool air is exhausted from the cabinet/radiators and helps keep the entire room cool, providing cool air to the fronts of nearby cabinets.
Date: 2023-11-17
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Comments and reviews: 12
Eddie
Great video! In the data center engineering industry we reserve CRAC designations for units with a direct expansion inside the CRAC and closed loop refrigerant such as R-410 is the only heat transfer media. This is similar to a mini split air conditioner or other AC unit.
If the heat transfer media is chilled water, the industry term is CRAH or Computer Room Air Handler.
Your content is top notch as always and I sometimes send new engineers your videos. Keep up the great work!
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Great video! In the data center engineering industry we reserve CRAC designations for units with a direct expansion inside the CRAC and closed loop refrigerant such as R-410 is the only heat transfer media. This is similar to a mini split air conditioner or other AC unit.
If the heat transfer media is chilled water, the industry term is CRAH or Computer Room Air Handler.
Your content is top notch as always and I sometimes send new engineers your videos. Keep up the great work!
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Ressy6
suspended floor? I think you mean raised floor: )
Your last method is close to the best, cold room but its better to send exhaust into plenum from each rack via boot systems, where its extracted in part, and recycled in another part, in such systems it is also code in many countries to inject external fresh air into the mix, rather than just recycling the same hot air over and over, but all in all a good explanation
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suspended floor? I think you mean raised floor: )
Your last method is close to the best, cold room but its better to send exhaust into plenum from each rack via boot systems, where its extracted in part, and recycled in another part, in such systems it is also code in many countries to inject external fresh air into the mix, rather than just recycling the same hot air over and over, but all in all a good explanation
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Richard
QUESTION: We have several Liebert crac units with water cooled condensers. Currently we use approx 70deg water flowing through the condensers. However, we need to know if we used 55 degree water would it drastically effect the units efficiency. There is a condenser water control valve in each unit. I ask because there are no parameters recommended in the owners manual. Any help here would be greatly appreciated.
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QUESTION: We have several Liebert crac units with water cooled condensers. Currently we use approx 70deg water flowing through the condensers. However, we need to know if we used 55 degree water would it drastically effect the units efficiency. There is a condenser water control valve in each unit. I ask because there are no parameters recommended in the owners manual. Any help here would be greatly appreciated.
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Rob
Our CRAC units have the compressors inside the units along with a water cooled condenser. Then the water pipes go outside to coolers. They also have a refrigerant coil and water coil, so In the colder months it uses water chilled by the outside air
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Our CRAC units have the compressors inside the units along with a water cooled condenser. Then the water pipes go outside to coolers. They also have a refrigerant coil and water coil, so In the colder months it uses water chilled by the outside air
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Sam
Funnily enough, I'm installing CRAC units this week in a hospital - but not for server rack cooling, they're being used for CT Imager cooling. Also, they're configured to supply conditioned air out the top and draw return air through the bottom.
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Funnily enough, I'm installing CRAC units this week in a hospital - but not for server rack cooling, they're being used for CT Imager cooling. Also, they're configured to supply conditioned air out the top and draw return air through the bottom.
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Travis
Have you made a video of making electrical schematics. Like how your choosing wire numbers locations of devices in a panel and how you would find it. I think that would help alot of people.
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Have you made a video of making electrical schematics. Like how your choosing wire numbers locations of devices in a panel and how you would find it. I think that would help alot of people.
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Raffaa
Great info regarding this video
Q? , do crack system had a cooling capacity ( BTU or tons ) like chiller & home ac air-conditioning.
Thanks and good luck
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Great info regarding this video
Q? , do crack system had a cooling capacity ( BTU or tons ) like chiller & home ac air-conditioning.
Thanks and good luck
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Das
Instead of a floating floor design, I wonder if this could be used as a geothermal system and just do away with all the cooling system components?
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Instead of a floating floor design, I wonder if this could be used as a geothermal system and just do away with all the cooling system components?
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education
That's the proper and sensible way to do it, but I have seen so many companies just use standard ceiling mounted air conditioning units.
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That's the proper and sensible way to do it, but I have seen so many companies just use standard ceiling mounted air conditioning units.
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billy
used to help design off-site data storage centres when i worked in london. doesn't look like it has changed much over the years.
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used to help design off-site data storage centres when i worked in london. doesn't look like it has changed much over the years.
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Mike
Very interesting how these systems function. I do like the cover on top to force the hot air up and over to the CRAC unit.
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Very interesting how these systems function. I do like the cover on top to force the hot air up and over to the CRAC unit.
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Brian
I was just given a project on CRAC units lol. Now I have a better understanding of their purpose. Thanks!
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I was just given a project on CRAC units lol. Now I have a better understanding of their purpose. Thanks!
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