R-Gaïa Free-Cooling and Meteorological conditions Jean-Yves Clément December 2012 Copyright International Business Machines Corporation 2012. All rights reserved. IBM and its logo are trademarks of IBM Corporation. This document may not be reproduced in whole or in part without the prior written permission of IBM. Please consider the environment before printing this document
Agenda Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 2
Agenda Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 3
Light structure Real Estate and Site Operations 4
Heavy structure Real Estate and Site Operations 5
Heavy structure principal 6
Light structure principal 7
Cold air aisle is more efficient: Heat exchange is better shared with all CRAC s Less expensive (non return air plenum) Heat exchange with building structure are optimized T ext = 15 C and below Delta T Cold aisle = 15 C Delta T Hot aisle = 5 C Favorable to Cold aisle T ext = 25 C Delta T Cold aisle = 5 C Delta T Hot aisle = - 5 C Favorable to Cold aisle T ext = 35 C and above Delta T Cold aisle = - 5 C Delta T Hot aisle = - 15 C Favorable to Cold aisle Cold aisle Hot aisle 8
Humidification: steam time is over! 9
Humidification: steam time is over! Cold vapor generation High pressure Centrifugation Compressed air Piezo 10
Humidification: steam time is over! 11
Agenda Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 12
Montpellier Airport Temperatures 2008 DATE C Mean 00h-06h C Mean 07h-18h C Mean 19h-23h 35 30 25 20 15 10 5 0 janv.-00 févr.-00 avr.-00 mai-00 juil.-00 sept.-00 oct.-00 déc.-00 févr.-01-5 13
Grenoble Temperatures 2007 14
Agenda Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 15
Air specification to apply to IT : ASHRAE 2008 was an improvement for air containment efficiency: Temperature of cold air (25 C) blown under the raised floor is a limiting factor during summer. 5,5 C dew point is too strict compared with IT specification Proposed solution Extent humidity working range to IT specifications Control hygrometry in DC and adjust blowing temperature with AMU 16
ASHRAE IT 2008 ASHRAE 2008 Allowable (Class 1) ASHRAE 2008 Recommended 17
Weather example 18
Weather example: too hot during 2h30 19
Weather example: too dry during 23h30! 20
12,5 C and 60% RH is too dry for ASHRAE! 21
Agenda Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 22
IT Requirements X3550 Supported environment: Air temperature: Server on: 10 to 35 C (50.0 to 95.0 F); altitude: 0 to 914.4 m (3,000 ft). Humidity: Server on: 20 to 80%, maximum dew point 21 C, maximum rate of change 5 C/h 23
IT Requirements ZSeries S/390 z196 24
IT Requirements Environmental and shipping specifications for tape cartridges 25
IT Requirements: worst case hygrometry 26
Weather limit for air blowing at T=21 c and Hr=20% in DC 27
Water weight evolution during October 8 th 28
November 6 th to 11 th humid period outside air 29
ASHRAE Real Estate and Site Operations Free-cooling design choices Weather analysis Operation example IT specifications ASHRAE 2011 30
ASHRAE 2011 Real Estate and Site Operations 31
ASHRAE 2011 Real Estate and Site Operations 32
ASHRAE 2011 Real Estate and Site Operations 33
ASHRAE IT Equipment Environment Corrosion Data corruption Reduced life Cycle Electrostatic discharge 34
ASHRAE humidity limit vs IT specification la spécification de l'air soufflé dans les data centres doit être conforme au cadre pointillé vert de la page 29 de la présentation jointe, c'est à dire t=18 C à 27 C et hr= 80% à 20%. Ceci implique que l'air extérieur présentant des températures même très inférieurs à 15 C doit être utilisé du moment que son poids d eau permet d être en spécification une fois réchauffé dans le data center. Plus largement l efficacité du FreeCooling sera améliorée si l AMU (Air Mixing Unit) permettre de balayer toute la plage de température autorisée de manière à utiliser au mieux les caractéristiques de l air extérieur. De ce fait les jours ou l air extérieur est froid et sec, une température de soufflage de 15 C donnera le meilleur résultat. La température extérieure remonte en cour de journée de 8 C à 10 C en 8heurs. Ceci respecte les 5 C/h de variation demandées dans les spécifications des équipements IT. 35
ASHRAE humidity limit vs IT specification Only solution to use Free-Cooling in winter No risk for IT No energy lost with humidification system Reduce condensation risk 36