CRAC units, or computer room air conditioning systems, are specialized to regulate temperature in massive commercial data centers. Unlike typical air-conditioning, which provides broader comfort, CRAC units offer precision cooling and close control. From my experience working in IT, the precision with which these units maintain conditions has been critical during scenarios where high heat is generated by computer equipment and how it later leads to system failures.
But how does it work?
These units are part of a broader network within server rooms, including air distribution. The cooled air rises through perforated floor sections strategically positioned to create cold aisles where racks are cooled frontally. The warm exit air from these is then channeled into hot aisles, which are picked up by intakes of the CRAC units, thus forming a continuous loop that manages the climate.
Why The Need for CRAC Arose 🏢?
But you may ask why we need to cool down the data centers.
Let me explain if you haven’t heard of a historical event.
Back in March 2013, the heat built in Microsoft’s servers caused offline services, including Hotmail and Outlook.com, to go offline for the next 16 hours straight. After this incident, the technology & IT companies realized the importance of monitoring the temperature inside the data centers to keep running their operations smoothly. Other than this event, below are the 10 different events of overheating:
No. | Event | Date | Location | Cause | Impact |
---|---|---|---|---|---|
1 | OVH Data Center Fire | March 2021 | Strasbourg, France | Electrical failure leading to overheating | Total loss of 4 data centers, downtime for millions of websites |
2 | Google Data Center Fire | August 2022 | Council Bluffs, Iowa, USA | Heat-induced electrical malfunction | Downtime for Google services, damage to equipment |
3 | Samsung Data Center Fire | April 2014 | Gwacheon, South Korea | Power surge caused by overheating | Internet outage affecting South Korea for hours |
4 | Azure Data Center Incident | 2012 | Dublin, Ireland | Overheating due to electrical fault | Major downtime for Microsoft services |
5 | Bloomberg Data Center Fire | October 2003 | New York, USA | The fire was caused by an electrical overload due to inadequate cooling | Disruption to financial data services |
6 | Pixar Data Center Fire | 2000 | California, USA | Overheating due to lack of sufficient cooling | Production delay of a major animation project |
7 | Telehouse North Fire | September 2019 | London, UK | Overheating and electrical fire | Internet services outage across Europe |
7 Components of a CRAC Unit
These are some of the standard components of a CRAC unit:
1. Air Filter
First of all, just like a regular HVAC, a CRAC system also have HEPA air filters. It captures dust particles and debris to provide a clean airflow throughout the centers. Besides fresh air, it also prevents computer equipment from getting damaged due to dust buildup or any other reason.
2. Cooling Coil
Secondly, the cooling coil allows the magic to happen regarding heat absorption. Utilizing chilled water from a chiller system or compressed refrigerant, these coils allow cool air to circulate through the room. The choice between a chilled water type and a direct expansion system depends mainly on the specific cooling needs and the scale of the installation. These coils maintain an optimal temperature by managing the cooling cycle.
3. Compressor
Acting as the heart of the refrigeration cycle, the compressor pumps the refrigerant through the system. It increases the refrigerant’s pressure, propelling it through the cooling coils where it captures room heat before cycling it back as cooler air. This compression process is integral to the cooling performance of systems.
4. Condenser Coil
The condenser coil plays a vital role in heat release, typically outside the air conditioning system. After the compressor does its job, the condenser coil releases the absorbed heat into the outside air. Without this component, the CRAC Unit can’t throw the inside heat of servers to the outside.
5. EC Fan
The EC fan, or electronically commutated fan, adjusts the fan’s speed based on actual demand. Since it increases or decreases the speed, it reduces the electricity consumption. Since it uses magnetic fields to run, which were part of old belt-driven blowers, that’s how it functions, leading to lower heat generation and much quieter operation.
6. Humidifier & Dehumidifier
Most of the CRAC systems have multi-in humidification mode. It can balance the humidity and adjust the moisture levels. For instance, the mixture levels rise more on rainy days than usual. The dehumidifier setting removes excess water vapor from the air. So that it helps protect against static electric discharge, which can be a significant threat to electronic components.
7. Electric Heaters
Managers can utilize electric heaters in colder months to maintain the air temperature. These heaters ensure that the temperature control remains precise, avoiding the dangers that low temperatures pose to the system’s efficiency, mostly in Canadian or Atlantic regions where winters are too extreme for individuals and machinery.
CRAC vs. CRAH Units
There are two significant systems when we talk about data center cooling systems. The first is the Computer Room Air Conditioning (CRAC) units, and the other is Computer Room Air Handling (CRAH).
Let’s explore how they differ from each other:
Feature | CRAC Units | CRAH Units |
---|---|---|
Cooling Method | Use refrigerants to directly cool air through a refrigeration cycle involving compressors and valves. | Use chilled water in cooling coils, cooling air indirectly through a water loop. |
Air Flow Design | Employ a single-pass airflow design where cooled air is immediately returned. | May use a dual or multi-pass airflow design, recirculating air for additional cooling. |
Maintenance | Tend to be more costly and time-consuming to maintain due to complex refrigeration cycles. | Generally simpler and more reliable, requiring less maintenance due to their reliance on water systems. |
Energy Efficiency | Lower energy efficiency due to the energy-intensive refrigeration cycle. | Higher energy efficiency, as water conducts and transfers heat more effectively. |
Space Requirements | Require more space for components like refrigerants, compressors, and ductwork. | Require less space, lacking a refrigerant system and easier to integrate into existing structures. |
5 Benefits of Installing CRAC Units
- Protected Equipment: It helps to prevent overheating and humidity damage to sensitive computer components. This can extend the life of the equipment and reduce maintenance costs.
- Improves Efficiency: Overheated equipment can slow down and perform poorly, so good cooling helps maintain optimal performance.
- Reduces Downtime: Since CRAC units are reliable and keep the equipment in good working condition, they reduce the chances of system failures and downtime.
- Energy Efficient: Modern CRAC units are designed to use energy efficiently, which is good for cost-cutting.
- Flexible and Scalable: As your needs grow, you can scale up your cooling system with more or larger CRAC units in the existing setup.
How to Install CRAC Units?
Step # 1: Preparation and Space Requirements
When installing CRAC units, the first step is Preparation. You need to ensure the room where the unit will be placed has sufficient clearance and proper ventilation. Check the dimensions of the space and the CRAC unit’s dimensions to ensure it fits.
Step # 2: Electrical Setup and Safety
Next, focus on the electrical setup. CRAC units require dedicated circuits to prevent overloading. Ensure that the voltage and current levels are suitable for your unit as specified by the manufacturer. Proper electrical hazards management is necessary to safeguard the equipment and the personnel involved in the installation.
Step # 3: Physical Installation and Positioning
The third step involves the actual installation. Place the unit with careful attention to access for future maintenance. Positioning of the air intake and external ventilation should align with local regulations and manufacturer’s guidelines to optimize performance and air exchange.
Step # 4: Calibration and Initial Testing
Calibration and testing come next. Conduct a test run to identify any deviations or gaps in the system, such as air leaks or unusual noises and vibrations. Make necessary adjustments to settings and levels to achieve optimal functioning.
Step # 5: Maintenance & Management
Once it’s installed you have to maintain it for peak efficiency. A regular maintenance schedule includes filter cleaning, coil inspection, refrigerant checks, and water damage inspection.
Conclusion
At Ventiluxes, we understand the importance of keeping your CRAC units in optimal condition. Our expert team is here to provide top-notch repair and service to ensure your system operates efficiently. Whether you need routine maintenance, emergency repairs, or a thorough inspection, we’ve got you covered.
Don’t wait for issues to arise—contact Ventiluxes today to schedule your service and experience peace of mind knowing your HVAC needs are in capable hands!
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