Free Refrigeration: Best Practice for data center energy-saving systems

Using energy-efficient systems to reduce energy costs with free cooling has been a hot topic in the data center. Any time, if you can turn off the air-conditioning unit or reduce the use of chillers, can reduce the heat generated by the server, which can not only reduce operating costs, but also extend the service life of cooling equipment, reduce wastage. North Anglo Access Technologies, a Business data center design and consulting company, Julius Neudorfer is its CTO, and will give us some information about best practices in data center energy-saving systems.

Question: What is the vision for an enterprise-class data Center for energy-efficient systems and "free cooling"?

Julius Neudorfer: We all like the word free, and cooling is a big part of the data center's energy costs. In traditional enterprise-class data centers, cooling is usually achieved by mechanical refrigeration, possibly by deploying a compressor unit (CRAC) or an Air processor (Crah) in a data center.

Free cooling is often considered an energy-saving system that reduces or reduces the operating overhead of mechanical refrigeration, but can provide direct or indirect cooling effects when the external temperature reaches or falls below a certain point.

Most free cooling schemes rely on systems based on air compression. You still need a complete mechanical cooling system to operate--even if only for a fraction of a day--to keep the data center cool for a hotter couple of days. At the same time, this does not reduce or reduce the energy cost of the fan, that is, the energy consumption of mechanical refrigeration.

Problem: Free cooling has a significant impact on data center design. is free cooling suitable for new data centers or can they be introduced into a data center that is already in production?

Neudorfer: Installing a free cooling system on an existing basis can be beneficial in some cases, but a more efficient approach is to introduce it into a new datacenter. There are two basic types: air cooling and water cooling. Direct air cooling systems are now getting more attention. The principle is to introduce a temperature in the cold channel of the data center by reaching an acceptable temperature and humidity range. It is very difficult to introduce an air energy-saving cooling system into existing data centers-which in many cases is almost impossible.

The use of water cooling energy-saving system is the current large-scale data centers commonly used methods, especially in the lower temperature of the season, but it can only in the ambient temperature is lower than the supply of water temperature effective, typical temperature of 45 degrees Fahrenheit. It is feasible to increase energy-saving system on the existing water cooling system, but the cost is extremely expensive, and the system can not operate, and the energy-saving effect is limited.

The green Grid provides a public map to assess the percentage of free cooling of air and water systems in the area. Still, there are many cooling air energy-saving devices, as they may provide 100% free cooling to 80 degrees Fahrenheit, some of which can reach the ambient temperature Fahrenheit 100 degrees.

It is important to analyze the number of days in which energy-efficient devices can operate effectively, in conjunction with data Centers for energy savings, to demonstrate that the new technologies introduced can generate benefits. This is especially important in calculating ROI.

Question: Are there other important complementary technologies that can be used with free cooling in the deployment of energy-saving devices?

Neudorfer: In any data center, it is important to prevent hot and cold air mixing. Even more meaningful than today's air or water-cooled energy-saving devices. Isolating the used hot air can enhance the operation dimension and prolong the cooling days. This approach is especially important for blade servers because they typically generate more heat and consume cooling resources than other small servers, and typically consume 15-20 degrees of heat from other servers.

The container-type data center provides near-perfect cold/hot air isolation, with some specially designed to achieve the highest free cooling effect. In other words, if you are considering creating a new datacenter, this is the best choice. There are a lot of things to consider before you start.

Question: What are the key considerations for evaluating a free cooling site?

Neudorfer: Besides the temperature, local humidity is also very important. In particular, a high humidity environment, the mechanical refrigeration efficiency can be reduced or completely ineffective, but also forced the system to wet treatment, even if the ambient temperature is within the allowable range. Too much humidity can also affect any energy-saving device based on evaporative water.

Keep in mind that direct air energy-efficient systems introduce external air, including possible smoke from adjacent sites, inhalable particulate matter or corrosive gases. May cause false smoke alarms or damage to it equipment, especially in the case of high ambient humidity. In fact, ASHRAE is currently studying the issue of corrosion damage.

Question: From the point of view of free cooling, what is the biggest negligence in data center design? Can these problems be avoided?

Neudorfer: Like new things, free refrigeration also has a learning curve. In this case, the water conservation system has been sorted out because of the relatively more experience of using it. The air energy-saving system is still in its infancy and there is no real "full" version. They are usually designed in structures and are unique. While some of the basic components are standard-electric vents and dampers-control system design, integration and optimization still need to be customized and in the early stages of commercial development.

In fact, Facebook's data center in Oregon State was cooled by fresh air and adiabatic systems, and a few months after its launch in early 2011, it experienced severe control-system bugs. The system responds incorrectly to rapidly changing external weather conditions, causing it to suddenly shut off all external air. Then redistribute the internal hot air while attempting to use adiabatic cooling to control the temperature rise. Redistribution of air forms a high humidity mist that condenses on the server, leading to a short-circuit, power and forced shutdown. Before the failure, the system has been functioning normally, but this also indicates that the system still has serious problems. While I believe that free cooling air energy-saving systems will become more common, they need to be treated with caution. Once this technology matures, it will be a huge opportunity to conserve energy.

About the Author: Julius Neudorfer Naat chief technology officer, is also the company since the founding of the main founder since 1987. He has designed and managed communications and data system projects for commercial and government clients.

(Responsible editor: The good of the Legacy)