LB Comfort Statistics

BestiaParda · December 26, 2020, 9:55pm

Hello,

I have compared the results from de LB Comfort Statistics component with the Statistics obtained by hand and show different results.
The image below shows the percentage of time that the first room is above and below the ±0.5 PMV by the two methods.

The LB PMV Comfort component has the PPD threshold set to 10.

Thank you

chris · December 26, 2020, 10:50pm

Everything looks good on my end:

Bear in mind that -0.5 and +0.5 correspond approximately with the 10 PPD threshold. The exact function between the two is given here:

github.com

ladybug-tools/ladybug-comfort/blob/master/ladybug_comfort/pmv.py#L431-L440


def ppd_from_pmv(pmv):
    """Calculate the Percentage of People Dissatisfied (PPD) from PMV.
    Args:
        pmv: The predicted mean vote (PMV) for which you want to know the PPD.
    Returns:
        ppd -- The percentage of people dissatisfied (PPD) for the input PMV.
    """
    return 100.0 - 95.0 * math.exp(-0.03353 * pow(pmv, 4.0) - 0.2179 * pow(pmv, 2.0))

BestiaParda · December 27, 2020, 10:28am

Hi @chris,
I thought that ±0.5 PMV was exactly the 10 PPD and I realize that is 10.22 PPD.
Thank you for your clarification