1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Series L TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 12 (12/2014) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT ITU-T L.1300 Supplement on experimental stud
2、ies on plates and ducts installed at equipment inlets and outlets ITU-T L-series Recommendations Supplement 12 L series Supplement 12 (12/2014) i Supplement 12 to ITU-T L-series Recommendations ITU-T L.1300 Supplement on experimental studies on plates and ducts installed at equipment inlets and outl
3、ets Summary Supplement 12 to ITU-T L-series Recommendations describes experimental studies on plates and ducts installed at equipment inlets and outlets based on Recommendation ITU-T L.1300. More precisely, this Supplement provides a problem description of practical solutions for correcting airflow
4、direction for equipment, highlighting, at the same time, examples of practical solutions as well as experimental results. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L Suppl. 12 2014-12-19 5 11.1002/1000/12440 Keywords Best practice, data centre, energy efficient, inform
5、ation and communication technology and climate change (ICT examples of practical solutions; and experimental results. 2 Definitions None. 3 Abbreviations and acronyms This Supplement uses the following abbreviations and acronyms: BT Bottom-to-Top CRAC Computer Room Air Conditioner PDU Power Distribu
6、tion Unit RL Right-to-Left VAV Variable Air Volume 4 Problem description of practical solutions for correcting airflow direction for equipment This clause describes examples of practical solutions for airflow correction. It will enable the recognition of the practical solutions to be taken for equip
7、ment in which airflow correction is necessary. 5 Examples of practical solutions The installation of a plate or duct at the inlet and outlet of the equipment is a practical solution to correct the airflow direction of the equipment. An example of ducts installed in equipment with bottom-to-top (BT)
8、airflow direction is shown in Figure 1. Installation of such ducts corrects the airflow direction to front-to-rear and separates the intake air and the exhaust air. Such separation prevents the equipment from sucking in the exhaust air of adjacent equipment and prevents increases in its temperature.
9、 Experimental studies on plates and ducts installed at the inlets and outlets of equipment with bottom-to-top airflow direction and with right-to-left (RL) airflow direction are shown below. 2 L series Supplement 12 (12/2014) Figure 1 Examples of types of rack mount equipment in which airflow correc
10、tion is necessary An example of a duct installed at the inlet of equipment that is small in depth is shown in Figures 2 and 3. Such a duct directs the cold air in front of the rack to the inlet of the equipment and enables cold air to be supplied to the equipment sufficiently. Figure 2 Example of du
11、ct installation in equipment with bottom-to-top airflow direction L series Supplement 12 (12/2014) 3 Figure 3 Example of duct installation in equipment that is small in depth An example of the description given in an installation manual is shown in Figure 4. 4 L series Supplement 12 (12/2014) Figure
12、 4 Example of a description given in an installation manual 6 Experimental results The purpose of the experimental studies was to evaluate the effectiveness of the plates and ducts installed at the inlets and outlets of equipment with different airflow direction from the data centre airflow design.
13、L series Supplement 12 (12/2014) 5 6.1 Outline of experiment The layout of the experiment room, and equipment used for the experiment are illustrated in Figures 5 and 6 respectively. Four types of equipment and power distribution units (PDUs) were mounted on two open racks. A plate or a duct was ins
14、talled at the inlet and the outlet of two types of rack mount equipment, whose airflow direction was bottom-to-top (Type BT) and right-to-left (Type RL). The temperature was measured at 100, 500, 1000, 1500, and 2100 mm above floor level, at the front and the rear of the rack. It was also measured i
15、nside the raised floor, at the inlet and the outlet of the adjacent equipment. The room temperature setting and the outlet temperature setting of the computer room air conditioning (CRAC) were 24C and 19C, respectively. The CRAC was set to keep the air supply temperature constant and to operate in v
16、ariable air volume (VAV) mode. The left side of Figure 7 depicts the airflow in Rack 1. Equipment Type RL, mounted in Rack 1, sucks in the exhaust air from equipment Type BT, mounted under equipment Type RL, and from equipment Type RL, mounted in Rack 2. This causes an increase in the temperature of
17、 the intake air of equipment Type RL in Rack 1. As a measure to avoid this phenomenon, the following three cases were investigated, as shown on the right side of Figure 7. (1) Installing a duct at the outlet of equipment Type BT mounted in Rack 1. (2) Installing a duct at the inlet of equipment Type
18、 BT mounted in Rack 1, in addition to (1). (3) Installing a plate at the inlet and the outlet of equipment Type RL mounted in Racks 1 and 2, in addition to (1) and (2). Figure 5 Layout of experiment room 6 L series Supplement 12 (12/2014) Figure 6 Experiment environment Figure 7 Cases investigated 6
19、.2 Results (1) Figure 8 reports the results obtained by installing a duct at the outlet of equipment Type BT mounted on Rack 1. L series Supplement 12 (12/2014) 7 Figure 8 Results of Rack 1 after installing a duct at the outlet Temperature decrease was observed at 1500 mm above floor level at the fr
20、ont of the rack (26.2C23.8C). This shows that the duct prevented the exhaust air from circulating to the front of the rack. Temperature increase was observed at 1500 mm above floor level at the rear of the rack (31.2C32.5C). This shows that the duct led the exhaust air to the rear of the rack. (2) F
21、igure 9 reports the result obtained by installing a duct at the inlet of the equipment Type BT mounted in Rack 1, in addition to (1). Figure 9 Results of Rack 1 after installing a duct at the outlet and at the inlet A marked difference in the inlet and the outlet temperature of equipment Type BT was
22、 not observed, but the difference from the temperature inside the raised floor became slightly smaller. A marked temperature difference was not observed at other measurement points. (3) Figure 10 reports the result obtained by installing a plate at the inlet and the outlet of equipment Type RL mount
23、ed in Racks 1 and 2, in addition to (1) and (2). 8 L series Supplement 12 (12/2014) Figure 10 Results of Rack 1 after installing a plate at the outlet and at the inlet Inlet and outlet temperatures of equipment Type RL mounted in Rack 1 were in the same temperature range as those of the adjacent equ
24、ipment mounted in Rack 2. The plate prevented the equipment from sucking in the exhaust air from the adjoining equipment, and the outlet temperature became stable. 6.3 Conclusions For equipment whose airflow direction is bottom-to-top, the following results were obtained: The duct installed at the o
25、utlet prevents the exhaust air from circulating to the front of the rack. The duct installed at the inlet is likely to prevent exhaust air being sucked in, as with the blanking plate. For equipment whose airflow direction is right-to-left, the following result was obtained: Installation of the plate
26、 separates the intake air and the exhaust air, and prevents the equipment from sucking in the exhaust air from the adjoining equipment. L series Supplement 12 (12/2014) 9 Bibliography b-ITU-T L.1300 Recommendation ITU-T L.1300 (2011), Best practices for green data centres. Printed in Switzerland Gen
27、eva, 2015 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media
28、, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation an
29、d protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subje
30、ctive and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
