[Equest-users] Calibration with Real Weather Data Extreme Year

[Glenn Haynes]

Niko,

 

This may be a dumb question by now, but how do you know that your heating loads are too high?  Do you have hourly measured heating loads?

 

If you are talking about excessive hourly heating loads at certain times, you might also check your wind speed at the time of the extreme heating load if you are modeling infiltration with an algorithm that responds to wind speed.  Actual weather data (including TMY) sometimes records excessive wind speeds for short times throughout a year, but if you want typical weather you have to adjust those wind speed to something more typical, or just ignore the heating loads during those times.  If your actual weather data includes actual coincident wind speed, then the overall infiltration rate specified in your model may be higher than the actual.

 

If you have been referring all along to monthly or seasonal heating loads, just ignore everything I said, and please forgive me for being presumptuous.

 

Glenn

________________________________

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of John Aulbach
Sent: Wednesday, April 08, 2009 2:37 AM
To: equest-users at lists.onebuilding.org; Niko Michael Kalinic
Subject: Re: [Equest-users] Calibration with Real Weather Data Extreme Year

 

Niko:

 

If you have actual weather to use for calibration and you are over predicting heating energy, then I would look at the model itself...

 

1) Are you turning off the system at night, or at least setting it back? Nighttime is when most heating occurs.

 

2) Are you setting the thermostat profiles to correct temperatures. Is the heating T-Stat actually 68°F vs. 72°F?

 

3) Are you modeling the correct HVAC system?

 

4) Are your wall, window, and roof U-Values correct?

 

5) Are you infiltrating too much air, especially at night?

 

6) How does your electric usage (I am assuming your heating is gas) match up with utility bills?

 

7) Is there large thermal loads like kitchen cooking, laundry hot water, or other thermal usage that should be increased in the simulation?

Just a few things you may wish to check?

 

John Aulbach, PE

Los Angeles, CA

 

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