Study On Energy-saving Design Of Air-conditioning System In High Heat Density Container Data Centers

In the information age with technology ever-changing, technological changecan be achieved brought about by the soon to open the era of cloud computing thatwill rely on the data center.Most global IT companies pay more and more attentionto data centers which is one of the core elements to affect their development.Container data centers have the advantage of modular rapid deployment,smoothexpansion and energy saving to meet the development strategy of IT companies.Known as the "electric tiger", data centers bring about a huge initial investment andoperating cost pressure, air-conditioning systems account for the data centers powerconsumption30%to45%, has a huge potential for energy saving. With theincreasingly high degree of integration of electronic devices, data centers heatdensity continue to rise, single rack power as high as20~30kW. High heat density isa great challenge to both to protect the data center all-day safe operation but also thegreen energy-saving air-conditioning system design. Therefore, the energy-savingdesign research of the high heat density container data centers air conditioningsystems is imperative.The main contents include the requirements of the air-conditioning systemdesign, numerical simulation of room thermal environment, and analysis ofenergy-saving economizers and heat exchangers.Firstly, the room air-conditioning system design requirements for temperature,humidity, cleanliness and minimum fresh air to ensure that the room environment tomeet the provisions of the existing standards.Secondly, using of software to simulate the thermal environment of20feetstandard container room, discoveries as follows:(1)the lateral airflow organizationis better to improve the effect of the uniform rack inlet air temperature and windspeed than the top airflow organization;(2)changing the air speed to improve theroom working environment than to change the effective air temperature;(3)settingcabinet backplane fans to strengthen the ability of local cooling, which can satisfythe single rack power15kW cooling requirements, but difficult to meet single rackpower above20kW.Thirdly, air-side economizer and wet-buld economizer are suitable for mildclimate area, such as Kunming; open water-side economizer suitable for low outdoorair wet bulb temperature and no pipeline freeze danger hot summer and cold winterzone, the mild region and cold region; closed water-side economizer should be usedin the servere cold region to deploy free cooling through ethylene glycol drycoolers. Finally, the two-stage sensible heat exchangers can achieve an optimalenergy-saving rate that is far higher than the total heat+sensible heat exchangers,which are respectively74.8%~83.2%and-26.6%~-57.4%. In the hot summer andcold winter zone, the mild region and the subtropical region, the single-stage heatexchanger can avoid core body frosting in winter.Using rack cooling index(RCI) and return temperater index(RTI) to evaluateroom airflow and cooling capacity utilization effect in different airparameters.Combined with the operational features of the economizer and heatrecovery, and each typical urban meteorological parameter in five different climaticzones, to analysis the energy-saving effect of different economizers or heatexchangers.This study provides reasonable solution ideas for designing the high heatdensity container data centers air-conditioning system, and makes energy-savingmentoring programs to reduce the initial investment on the air-conditioning systemand its operating cost.