<I took a look at the example for TYPE 703 - Slab on grade and I saw that the weather file is for Wisconsin-Madison. Parameter 10 in Type 703 - Day of minimum surface temperature is set to 36. But I imported the weather file in Excel and checked if that is correct and I found that the day of minimum ambient surface is 28. Is there a mistake in the example or the way I checked isn't correct?>
The day of the minimum ambient temperature in the weather data file is likely 28 as you suggest. But that data file is based on a real month's worth of data from a given year that best matches the average month over a 30-year period. Historically, I believe the day of minimum surface temperature for Madison is near day 36. Use whatever value you're more comfortable with. I would also point out that Type 703 is no longer part of the standard package and has been replaced by newer and better models. You should strongly consider upgrading to the new models.
<I also need to find the amplitude of surface temperature, which is the difference between the maximum average monthly temperature and the minimum average monthly temperature.>
Not so fast. The amplitude actually has multiple definitions unfortunately and the one that is used in TRNSYS for this model is the peak deviation from the mean - not the crest to trough value. For example the simple function for surface temperature in the model is:
T = X * Sin (Time + Y) + Z
In this case, X is the amplitude of the function and the crest is at Z + X and the trough is at Z - X.
<Do I have to average the hourly temperature in the imported weather file in Excel for every month to find the two average temperatures? Or is there an easier way? >
That's the approach but I've already done that for quite a few locations - so let me know if you'd like the parameters for a particular city. I'd laos like to point out that Type 15 calculates the monthly average temperatures and outputs them.
<The defined value in TYPE 703 is 13.32 and I have a question about this value too. From the weather file I imported in Excel I found that the average temperature in january for Wisconsin-Madison is approximately -8 degC. I didnt't checked for the rest of the months, but assuming that this temperature is the minimum average temperature and that the maximum average temperature is a positive value (for example 20 degC in july), then the amplitude would be A=20-(-8)=28 degC. This value is much greater than 13.32. Is there a mistake in the way I determined the amplitude?>
Yes - see above. You would need to divide by two in your approach to get the amplitude for the model.
Jeff
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Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
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