The Physical air flow In the server room, operational safety and power consumption are controlled. Without spatial sectoral separation The cooling air immediately mixes with the hot exhaust air. Server fans rotate at maximum speed, air conditioners operate against excessively high return air temperatures, and hotspots endanger the hardware. A structured arrangement solves this problem: the Cold passage leads the processed air volume to the rack fronts. The Warm-up takes up the thermal load on the back of the cabinet and channels it away in an orderly manner.
What are cold passage and warm passage?
The terms describe two opposing zones within a structured RZ air duct. A cold passage is created by the Comparison of rack front panels. Pre-treated cooling air flows directly into the intake openings of the IT hardware via a double floor or a duct network.
The warm-up session is on the Back sides of server racks. Here, the exhaust air heated by the components exits from the housings. This area collects the thermal load and returns it to the air conditioning units. The spatial separation This two zones prevents cold supply air and hot exhaust air from mixing together.
Operation of cold and hot air circulation: This is how the cooling air circulates in the server room
The principle uses physical laws of thermodynamics to keep cool incoming air and hot exhaust air strictly separated. The connection to the Server room air conditioning This is done through a closed air circuit.
- Compression of cooling energy in the double-floor through a central air conditioning unit (CRAC or CRAH)
- Flow of cold air from the double floor via perforated floor panels directly into the cold aisle
- Suctioning the prepared air volume through the server hardware at the rack front
- Exhaust air heated from outside on the back sides of the cabinets during the warm-up phase
- Reintroduction of the thermal load through the ceiling or separate ducts to the air conditioning unit
This physical separation protects the hardware from overheating and stabilizes the entire cooling process.
Reasons for the separation of cold aisle and warm aisle in the server room
Physical barriers between the zones prevent high operating costs and protect the hardware in the server room. The sector separation optimizes cooling directly at the rack for the following reasons:
- Blocking of air short circuits: The mixing of cool incoming air and hot exhaust air in front of the server fronts is eliminated.
- Avoid local hotspots: Uniform cold air supply prevents dangerous heat build-up on individual racks.
- Raising the cold water temperature: Air conditioning units work much more efficiently thanks to higher return air temperatures.
- Reducing electricity consumption: The cooling output can be precisely adjusted, which reduces operating costs.
Without these barriers, the servers suck in heated exhaust air. This requires a higher cooling capacity from the air conditioning units and drives up energy consumption.
Cold-run or warm-run containment: Which system is suitable for which situation?
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Cold aisle containment |
Hot Aisle Containment |
|
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Infected area |
Air intake corridor in front of the cabinet fronts |
Air exhaust corridor behind the back panels of the cabinets |
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Temperature in the rest area |
Warm (corresponds to the air outlet temperature) |
Pleasantly cool (corresponds to the air temperature) |
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Inventory retrofit |
Simple with modularly constructed racks |
Requires adjustments to the outflow channels and the ceiling |
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Personal comfort in the room |
Limited by high ambient temperatures |
High, maintenance work in areas without heat load |
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Case of use |
Classic RZ storage areas with double floor |
New buildings, rooms without a double floor and high thermal insulation |
Enclosure in the server room – differences between existing buildings and new construction projects
At the New construction The connection of a hot-air circulator to the building’s HVAC system can be planned directly. Racks, ceiling ducts and exhaust air shafts form a coordinated unit from the very beginning.
In Existing buildings Limited room heights, fixed double floors, or staggered rows of cabinets limit the building options. A cold aisle enclosure can usually be mounted more easily on already installed racks. Nevertheless, installing it in operation requires great care to ensure the cooling chain remains stable.
In narrow space structures ensures foresight Modernization of data centers the continued operation. A reliable approach to implementation in the current system provides a structured Retrofit.
Efficient cooling in the server room through coordinated cold and hot-running systems
Avoid heat loss and high energy costs by precisely separating the air flows. Daterra plans and installs cold and warm aisle enclosures that are precisely matched to your racks and climate control systems to protect the hardware during operation.
Errors in cold and hot mode: Causes of efficiency losses in the server room
Errors in the spatial separation of the cold aisle and the warm aisle reduce cooling performance and increase energy costs. Often, inconspicuous gaps in the ducting system prevent the desired effect.
- Missing blind plates: Open height units in the server rack cause hot exhaust air to flow directly back to the cabinet front.
- Leakage cable connections: Unsealed openings in the double bottom allow cool air to escape unused before reaching the hardware.
- Incorrectly positioned sensors: If sensors are placed in the warm air flow instead of in front of the intake fan, air conditioning units will operate with incorrect set temperatures.
- Missing gang endings: If the sliding doors or roof panels on the front sides are missing, the air currents mix laterally on the walkway.
Careful design of the air flow eliminates these weaknesses and ensures the efficiency of the entire cooling system.
DIN EN 50600 and ANSI/TIA-942-C as standards for cold and hot runs
Standards set clear framework conditions for air guidance. The European standard DIN EN 50600 regulates the infrastructure of Data center solutions and in Parts 2-3 calls for the targeted avoidance of air mixtures in order to measurably increase energy efficiency values.
Both regulations require the complete recording of the cabinet temperatures and define limits for the entry temperature of the rack. For compliance with these requirements during building permits and audits, a physical enclosure forms the technical basis.
Protection against cold and hot weather: How redundancy and USV prevent heat stress
The spatial separation into cold aisle and warm aisle only fully takes effect when combined with the rest of the IT infrastructure. If cooling is lost, temperatures in the data center rise. closed enclosures It is important to act quickly. Therefore, planners connect the air duct directly to redundant cooling systems.
One Fail-safe cooling requires an appropriate design of the power supply. In the event of a network failure, the uninterrupted power supply (USV) the time until the generators kick in. During this time window, the fans of the air conditioning units must also continue to run in order to maintain a Heat accumulation to prevent in the hallway. The principle of how such protection is technically implemented is shown in the figure below. N+1 redundancy.
Frequently asked questions about air handling in the server room
What are the differences between cold flow and warm flow?
In the cold aisle, the focus is on supplying cool air in front of the server front panels. The cold air is directed into this area, while the heated exhaust air escapes uncontrollably into the rest of the room. In the warm aisle, on the other hand, the hot exhaust air is isolated behind the racks and routed directly through channels or the ceiling to the air conditioning units. As a result, the remaining server room remains at a cool temperature.
When does a physical enclosure become worthwhile?
Insulating a room is worthwhile as soon as cooling capacity in the room needs to be increased or energy costs need to be reduced. As early as four to five racks, the spatial separation protects against mixed air flows. Higher return air temperatures at the air conditioner increase the efficiency of the system, so that the savings in electricity costs quickly compensate for the investment.
What mistakes are most commonly made in implementation?
Often, small leaks prevent the intended effect of air separation. Unefended cable entries in double-deck cabinets, missing blind plates in unoccupied height units of the racks, and defective door seals on the gang sides allow air to escape unused. Additionally, incorrectly placed temperature sensors that incorrectly transmit the cooling requirement to the control system also pose a critical issue.
Can a shot system be retrofitted during operation?
Retrofitting existing server rooms is easily possible. Modular systems allow the installation of roof and door elements directly on the existing cabinets without interrupting server operation. Careful planning ensures that the cooling chain remains intact throughout the installation process.
How do the failover system and N+1 redundancy interlock?
The physical air separation ensures that cool incoming air reaches the IT components without loss. A N+1 redundancy ensures this supply performance in the event of a cooling generator or fan failure. The remaining systems take over the load without interruption, while the containment system prevents a rapid heating of the rack fronts.