Eleven things to note when using natural cooling technology in data centers

The Green Grid, a non-profit organization dedicated to improving data center energy efficiency, published some interesting findings about free cooling technology in data centers (most of the data centers surveyed were located in the United States).

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The survey results show that half of the respondents are using natural cooling technology to save energy and costs, and 25% of the respondents said they would consider using this technology in the future. Will natural cooling technology be more widely used and will the environment be further improved? However, this may not be the case. Some of the conclusions of this survey are somewhat surprising: the PUE value after using natural cooling technology is not much different from the PUE value without natural cooling technology.

If we analyze the data carefully, we will find that those who think that the use of free cooling technology will not significantly reduce PUE may not be too harsh: according to the survey results, the average PUE of data centers using free cooling technology is 1.56, while the PUE of data centers without free cooling technology is 1.83. This difference can also save these data centers millions of pounds in electricity and energy costs during their service life and reduce thousands of tons of carbon emissions.

The survey also showed that one of the main reasons for not adopting free cooling technology is the high cost of modifying existing data center systems. We recently replaced our old computer room air conditioning (CRAC) system with a Stulz free cooling system, which has brought us great benefits both in terms of free cooling system modification and in terms of saving as much energy as possible during its service life:

When using natural refrigeration technology, the following points should be noted:

1. Understand the climate, and moderate temperatures are best. While there is currently a lot of interest in new data centers in Scandinavia and Iceland, it is important to note that extremely cold weather may require heating of the air entering the data center from outside. We recently found that in extremely cold weather, free cooling systems increase rather than reduce energy consumption.

2. Understand the life of the equipment and continue to manage them effectively; understand the total cost of ownership of managing and maintaining existing systems. Although in the short term, "rebuilding" the existing system will not immediately pay off, in the long run, it will become more and more attractive, especially as the power density and power consumption of IT equipment continue to increase.

3. Do the basics in your data center: There is no point in spending a lot of money to replace the air conditioning system if there are major airflow leaks or improper placement of perforated tiles.

4. Consider deploying modular free cooling solutions in the data center to supplement existing cooling capabilities. If space is not an issue, it may be very practical to keep the existing CRAC system for summer use and add a free cooling solution next to it. Control of the old and new systems may be an issue; the simple approach is to set higher values ​​for the older units.

5. Understand the different IT loads and power densities of the data center now and in the future, especially the IT loads and power densities of different halls or suites in the data center, and configure cooling resources accordingly. This can reduce the risk of needing to revisit new systems at a higher cost in the future.

6. Purchase a cooling system with a variable speed drive. Our systems have variable speed electronically rectified fans that can be reduced to minimum speed when needed. Due to the fan law that power input is the cube of fan speed, any reduction in fan speed will significantly reduce the power input to the computer room air conditioning unit (CRAC). Cutting the fan speed in half will reduce the power input by a factor of eight.

7. Maximize the use of natural cooling methods, ensure that natural cooling methods are used as much as possible throughout the year under the conditions of external temperature permitting, and set goals for use; measure the use of natural cooling methods on a weekly or monthly basis, and motivate data center managers to strive to achieve these goals, and provide financial incentives for those who achieve the goals.

8. IT equipment suppliers have made great progress in improving the operating temperature range of equipment. When upgrading IT equipment, it is important to form a comprehensive view of data center energy consumption by ensuring that the operating temperature range of IT equipment is understood. To maximize data center energy efficiency, efforts need to be made to integrate the operating parameters of IT equipment with the free cooling system.

9. Manage and monitor airflow – deploy aisle encapsulation etc. This increases the return air temperature and allows the supply air temperature to be raised by a few degrees, which can help improve energy efficiency and extend the free cooling operation time.

10. Measurement, monitoring and maintenance: PUE values ​​and temperature setting values ​​need to be constantly tested to ensure that the various devices in the data center can operate at the required level. Don't wait until the electricity bill comes out to measure the PUE value.

11. In summary, natural cooling technology is becoming more and more widely adopted. It can greatly reduce costs and reduce environmental pollution. However, like other technologies, it needs to be implemented and used properly to save as much cost as possible.