Author Topic: lesson learned  (Read 175 times)

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hudster

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lesson learned
« on: February 02, 2017, 12:02:27 pm »
After much trial and error , faffing about and investigation, I have discovered that Revit, when referring to temperatures, may report them in C, but in reality Revit works in Kelvin, so when you reference a temperature in a formula, remember to add in a correction factor to change temperature to kelvin, or else your formula doesn't work and you get false schedules, which you may have already issued to your client.

Cheers Revit.
Revit BDS 2017, 2016, 2015, 2014, AutoCAD 2017, 2016, Navisworks 2017, 2016, BIM360 Glue

Rob...

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Re: lesson learned
« Reply #1 on: February 02, 2017, 04:51:21 pm »
I haven't heard about that one, yet.
Senior Mechanical Designer/Model Manager
Building Systems

lamarn

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Re: lesson learned
« Reply #2 on: February 03, 2017, 05:24:04 am »
After much trial and error , faffing about and investigation, I have discovered that Revit, when referring to temperatures, may report them in C, but in reality Revit works in Kelvin..

Same for mm resp. inches..


Cheese Revit.
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hudster

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Re: lesson learned
« Reply #3 on: February 03, 2017, 10:40:44 am »
Its a lovely game when you try to automate sizing with Revit, I prefer excel where a number is a number end of story, not a number which is actually so very different to the one shown.

By the way the formula was for auto setting the flow rate on a radiant panel based on the M2 of the panel. Defaulting to a minimum of 0.013 L/s if its below that, any lower and you couldn't commission the system.
Quote
if(((Heating Load / 1000 kPa) / 4.18) / ((CT F Temp - 0 C) / (273.15 C / 546.3) - (CT R Temp - 0 C) / (273.15 C / 546.3)) > 0.013 L/s, ((Heating Load / 1000 kPa) / 4.18) / ((CT F Temp - 0 C) / (273.15 C / 546.3) - (CT R Temp - 0 C) / (273.15 C / 546.3)), 0.013 L/s)

The Heating Load can be set by using a standard rule of thumb of 0.43kW per m2
Quote
((Length / 1 m) * (Width / 1)) * 0.43 kW
Revit BDS 2017, 2016, 2015, 2014, AutoCAD 2017, 2016, Navisworks 2017, 2016, BIM360 Glue