Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models

One cause for the substantial amount of energy used for data center cooling is poor airflow effects such as hot-aisle to cold-aisle air recirculation. To correct these and to investigate innovative designs that will notably increase efficiency requires a robust, well-verified computational fluid dyn...

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Main Authors: Lloyd, Michael, Glicksman, Leon R.
Other Authors: Massachusetts Institute of Technology. Building Technology Group
Format: Article
Language:en_US
Published: American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 2014
Online Access:http://hdl.handle.net/1721.1/90482
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author Lloyd, Michael
Glicksman, Leon R.
author2 Massachusetts Institute of Technology. Building Technology Group
author_facet Massachusetts Institute of Technology. Building Technology Group
Lloyd, Michael
Glicksman, Leon R.
author_sort Lloyd, Michael
collection MIT
description One cause for the substantial amount of energy used for data center cooling is poor airflow effects such as hot-aisle to cold-aisle air recirculation. To correct these and to investigate innovative designs that will notably increase efficiency requires a robust, well-verified computational fluid dynamics (CFD) model. Most above-plenum data center CFD models are only validated using temperature data. Although a temperature-only validation method can be useful, it does not confirm that the airflow patterns predicted by the CFD model are accurate. Since the airflow patterns above a raised-floor plenum should be confidently understood before they can be optimized, it is necessary to adopt a validation method that offers more than just a comparison of temperature data. This paper summarizes the unique validation process of a CFD model for a small data center test cell located in Cambridge, Massachusetts. The validation method features point velocity and temperature measurements and the use of small neutrally-buoyant bubbles to visualize the airflow patterns above a raised-floor plenum. The data center test cell was designed to emulate a standard hot-aisle and cold-aisle airflow configuration. The airflow visualization revealed that each perforated tile had a substantial non-uniform air velocity distribution leading to an unexpected three-dimensional flow pattern above the racks. When this surprising reality was properly accounted for in the CFD boundary conditions, good agreement was found with the observed airflow patterns. It is the purpose of this paper to show the difficulties and value of utilizing more robust validation techniques for data center CFD models.
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spelling mit-1721.1/904822022-10-01T00:57:54Z Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models Lloyd, Michael Glicksman, Leon R. Massachusetts Institute of Technology. Building Technology Group Massachusetts Institute of Technology. Department of Architecture Massachusetts Institute of Technology. Department of Mechanical Engineering Lloyd, Michael Glicksman, Leon R. One cause for the substantial amount of energy used for data center cooling is poor airflow effects such as hot-aisle to cold-aisle air recirculation. To correct these and to investigate innovative designs that will notably increase efficiency requires a robust, well-verified computational fluid dynamics (CFD) model. Most above-plenum data center CFD models are only validated using temperature data. Although a temperature-only validation method can be useful, it does not confirm that the airflow patterns predicted by the CFD model are accurate. Since the airflow patterns above a raised-floor plenum should be confidently understood before they can be optimized, it is necessary to adopt a validation method that offers more than just a comparison of temperature data. This paper summarizes the unique validation process of a CFD model for a small data center test cell located in Cambridge, Massachusetts. The validation method features point velocity and temperature measurements and the use of small neutrally-buoyant bubbles to visualize the airflow patterns above a raised-floor plenum. The data center test cell was designed to emulate a standard hot-aisle and cold-aisle airflow configuration. The airflow visualization revealed that each perforated tile had a substantial non-uniform air velocity distribution leading to an unexpected three-dimensional flow pattern above the racks. When this surprising reality was properly accounted for in the CFD boundary conditions, good agreement was found with the observed airflow patterns. It is the purpose of this paper to show the difficulties and value of utilizing more robust validation techniques for data center CFD models. 2014-09-30T16:31:41Z 2014-09-30T16:31:41Z 2011-05 Article http://purl.org/eprint/type/JournalArticle 0001-2505 http://hdl.handle.net/1721.1/90482 Lloyd, Michael, and Leon Glicksman. "Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models." ASHRAE Transactions, Vol. 117, Issue 1 (2011). © American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. en_US http://connection.ebscohost.com/c/articles/67359312/unique-airflow-visualization-techniques-design-validation-above-plenum-data-center-cfd-models ASHRAE Transactions Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Ebsco
spellingShingle Lloyd, Michael
Glicksman, Leon R.
Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title_full Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title_fullStr Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title_full_unstemmed Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title_short Unique Airflow Visualization Techniques for the Design and Validation of Above-Plenum Data Center CFD Models
title_sort unique airflow visualization techniques for the design and validation of above plenum data center cfd models
url http://hdl.handle.net/1721.1/90482
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