Online transactions, mp3 downloads and video chats – day in and day out, hundreds of thousands of terabytes of data cause the wires of data centres worldwide to glow. To keep that from being more than a figure of speech, powerful air-conditioning units provide a remedy. That often happens at the expense of energy efficiency: A study of the German Energy Agency (dena) shows that cooling equipment alone constitutes 25 percent of a data centre’s total power consumption. That is a condition that one of Menerga’s innovations now plans to change. In addition to the common mechanical cooling, the “Adcoolair” air-conditioning unit also uses free cooling and “adiabatic” evaporation cooling, and saves a considerable amount of energy doing so. Even with regard to air conduction, maximum efficiency is the objective: so far up to eight GreenTech EC fans can operate in parallel in the air intake and exhaust of the device cube, thereby achieving combined output.
Since air-conditioning units do not run all year round with the same output, the continuous controllability of GreenTech EC fans is a decisive advantage. Unlike other solutions, they feature high efficiency even at low output levels. The energy balance speaks for this solution: The cube already outperforms EU requirement 640/2009 for central air conditioners, which will not fully come into force until 2017.
Strength in numbers
When development began, however, there was a critical limitation to GreenTech EC technology: An individual fan works with a maximum air flow volume of 10,000 cubic metres per hour, while a data centre requires many times that. But if one fan is not enough, why not have more fans do the job? Menerga had corresponding tests carried out in ebm-papst’s test chamber – with positive results: “With an optimum arrangement, the air flows add up without any loss in output,” confirms Project Engineer Ralf Mühleck, who supervised the development for ebm-papst. The tests also dealt with the topic of operating reliability, which plays a large role precisely for data centres. In addition to the redundancy provided by combining several systems, each system has built-in redundancy for air flow. Even if one fan unit fails, most of the required air flow can be maintained by the remaining devices. despite its many advantages, the fan unit is no larger than comparable solutions; in contrast, “The compact EC motors are directly integrated in the centrifugal impeller, meaning the total design turns out substantially shorter.” Maintenance is also very user-friendly, as Mühleck describes, “Each fan has a service life of at least 40,000 hours. And if one ever does fail, it can be replaced without much effort.”