RE: [EnergyPlus_Support] weather file for park merced (south san francisco)

A philosophical consideration:

Putting too much emphasis on a specific "typical" meteorological year may distract the analyst from the fact that in 99% of all analyses, you're modeling a very hypothetical condition.

Even though you have very specific data about the materials of construction and lighting and HVAC ..... you have no clue about how the building will actually be operated, whether sensors will be calibrated, equipment operating at optimum, pressure drops of real systems will be as calculated, and no end of other impacts / influences of a real system.

Couple that with the fact that this year's weather is different (sometimes greatly) from last year's and next year... and it all gets a bit hazy. Although I appreciate using data that's as close as possible to "real", the accumulation of errors makes even the best model predictions plus/minus 20% on a good day!

That said, I should assure you that I DO appreciate the modeling tools which are available, including all the weather data, and wish that there were more and better tools. Currently, my #1 hope in the energy analysis arena is for better tools with which to analyze existing buildings, including the use of the actual weather (including temps, humidity, solar, shading, wind) for the most recent billing periods.

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Emanuele Naboni
Sent: Wednesday, March 11, 2009 7:59 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx; EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] weather file for park merced (south san francisco)

Thank you Joe,

Yes, seems like micro climate conditions are quite determinant for energy performances.
Thanks anyway for your extended answer!

Emanuele Naboni

PhD Building Science, LEED AP, EU licensed architect

+1.510.395.7241

Please consider the environment before printing this email.

On Wed, Mar 11, 2009 at 5:41 PM, Joe Huang <joe@drawbdl.com> wrote:

Emanuele,

Yes, there are many microclimates in San Francisco, but unfortunately only
two active weather stations - one at SFO and the other at the Civic Center.
This reminds me of some work I did about 15 years trying to simulate a
building
at the San Francisco Presidio, and looking around for a better weather
file.
There used to be a station at the Presidio, but that's been defunct for
30+ years.
The other possibilities are to go up and down the coast, and find some
station
with data, such as Arena Point, etc., but then you're trading off
geographical
distance and sparseness of data against closeness to the coast. You
could also
cull local sources of weather data, such as PG&E or CMIS. Or, you might
be able to get sparse data, i.e., max/min temperatures, etc. (I have a
set from
EarthInfo that I haven't looked at yet), for a closer stations and then
run that against
the detailed hourly data from a first-order station to "learn" the
pertubations and
get a hourly data set, but that's a research project (ASHRAE Weather
Committee
is actually working on a Work Statement (RFP) in this area).

Joe Huang
White Box Technologies

Emanuele Naboni wrote:
>
> Dear All,
>
> Is there anyone that could suggest a weather file for Park Merced
> (close to lake Merced - south San Francisco)?
> The weather is very particular over there and San Francisco airport
> data seems to be not appropriate.
>
> Thanks you so much.
> Regards,
>
> Emanuele Naboni
>
> PhD Building Science, LEED AP, EU licensed architect
>
> +1.510.395.7241
>
> Please consider the environment before printing this email.
>
>

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