[Bldg-sim] wind speed in TMY

[Jeff Haberl]

Hello,



Unfortunately, historical wind speeds on TMY files that come from NOAA data are from peak 5 minute gusts, which can have little correlation to average hourly wind speeds. At some stations integrating sensors have been added, but it will take time to push these data through the average year data base.



In addition, previous work in England using ultrasonic sensors has shown that NOAA data also suffers from severe drop out at speeds less than 5 to 10 MPH, which means that most sites show "0" wind speed, whereas there is actually some wind, but not enough to move the cups on the anemometer. This can be a problem for simulation of natural ventilation.



ASHRAE's TC 4.2 continues to discussed these and other issues, which can be viewed on ASHRAE web page in their meeting minutes.



Jeff



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Jeff S. Haberl, Ph.D.,P.E., FASHRAE..............jhaberl at tamu.edu

Professor............................................................Office Ph: 979-845-6507

Department of Architecture.............................Lab Ph:979-845-6065

Energy Systems Laboratory.............................FAX: 979-862-2457

Texas A&M University.....................................77843-3581

College Station, Texas, USA, 77843..................URL:www.esl.tamu.edu

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________________________________
From: bldg-sim-bounces at lists.onebuilding.org [bldg-sim-bounces at lists.onebuilding.org] on behalf of Paul Carey [paul at zed-uk.com]
Sent: Saturday, June 11, 2011 4:16 PM
To: leen peeters; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] wind speed in TMY

Dear Leen

Most weather data quotes the reference wind speed which is that at 10m above the ground as measured at certain weather stations. Adjustment factors are then made for levels of surface roughness, I.e. urban, rural environments. I think the TMY follows the same convention.

Paul


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Dr Paul Carey
Director

Zero Energy Design Ltd
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Stalybridge
Cheshire
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SK15 3AD

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Email - paul at zed-uk.com



----- Reply message -----
From: "leen peeters" <l.f.r.peeters at gmail.com>
Date: Sat, Jun 11, 2011 20:34
Subject: [Bldg-sim] wind speed in TMY
To: <bldg-sim at lists.onebuilding.org>

Hi,

can anyone tell me what wind speed is exactly meant in the TMY. Is it the
free, undisturbed wind speed, the wind speed above the roof, the wind speed
at 10 metres above the ground ....

Thanks,

Leen


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