Low velocity PMV results calculation error in Python

[mrh335]

Using the python code provided, the comfPMV results have an error at the low velocities. The error results in a different PMV value compared to the javascript local calculator or online calculator. This error originates from a float / integer division issue within that function. In two places, a value is divided by 100. By changing this divisor to 100.0, the number returned is a float and follow on calculations are correct and match the javascript implementation and online tool results.

These two lines need to be modified adding the .0 as shown in the corrected lines below: p5 = (308.7 - 0.028 mw) + (p2 math.pow(tra / 100.0, 4)) hl5 = 3.96 fcl (math.pow(xn, 4) - math.pow(tra / 100.0, 4))

[FedericoTartarini]

Thank you for letting us know. I have edited the source code, and planning to update the tool in less than a month.

[chriswmackey]

@mrh335 ,

Thanks for reporting this and I support adding the .0 because of all the places this code might get copy/pasted. However, I just wanted to point out that the issue you experience is only with Python 2 and not Python 3 (integer division in Python 2 was fairly odd).

Another way to easily address the Python 2 limitation is to just add from __future__ import division at the top of the file as the PEP8 style guides suggest.

[chriswmackey]

When I get the chance, I can put together a better PR that follows all of the PEP8 conventions as you see in my most recent code for the PMV model here.

[FedericoTartarini]

That would be great but please do that only after I upload the new version of the tool online. You can have a look at the latest version of the CBE comfort tool here