added models.py

src/pythermalcomfort/__init__.py

@@ -1 +1,3 @@
 __version__ = '0.0.0'
+
+from pythermalcomfort.models import *

src/pythermalcomfort/models.py

@@ -0,0 +1,119 @@
+import math
+
+
+def pmv_ppd(ta, tr, vr, rh, met, clo, wme=0):
+    """
+    Returns Predicted Mean Vote (`PMV`_.) and Predicted Percentage of Dissatisfied (`PPD`_.) calculated in accordance with ASHRAE 55 2017 Standards.
+
+    Parameters
+    ----------
+    ta : float
+        dry bulb air temperature, [C]
+    tr : float
+        mean radiant temperature, [C]
+    vr : float
+        relative air velocity, [m/s]
+    rh : float
+        relative humidity, [%]
+    met : float
+        metabolic rate, [met]
+    clo : float
+        clothing insulation, [clo]
+    wme : float
+        external work, [met] default 0
+
+    Returns
+    -------
+    PMV : float
+        Predicted Mean Vote
+    PPD : float
+        Predicted Percentage of Dissatisfied occupants, [%]
+
+    Notes
+    -----
+    You can use this function to calculate the `PMV`_. and `PPD`_. in accordance with the ASHRAE 55 2017 Standard [1].
+    More information about the `PMV`_. model are available in the Wikipedia page.
+
+    .. _PMV: https://en.wikipedia.org/wiki/Thermal_comfort#PMV/PPD_method
+    .. _PPD: https://en.wikipedia.org/wiki/Thermal_comfort#PMV/PPD_method
+
+    References
+    --------
+    [1]  ANSI, & ASHRAE. (2017). Thermal Environmental Conditions for Human Occupancy. Atlanta.
+
+    Examples
+    --------
+    .. code-block:: python
+
+        >>> from pythermalcomfort import pmv_ppd
+        >>> results = pmv_ppd(25, 25, 0.1, 50, 1.2, .5, wme=0)
+        >>> print(results)
+        {'pmv': 0.08425176342008413, 'ppd': 5.146986265266861}
+
+        >>> print(results['pmv'])
+        0.08425176342008413
+    """
+
+    pa = rh * 10 * math.exp(16.6536 - 4030.183 / (ta + 235))
+
+    icl = 0.155 * clo  # thermal insulation of the clothing in M2K/W
+    m = met * 58.15  # metabolic rate in W/M2
+    w = wme * 58.15  # external work in W/M2
+    mw = m - w  # internal heat production in the human body
+    if icl <= 0.078:
+        fcl = 1 + (1.29 * icl)
+    else:
+        fcl = 1.05 + (0.645 * icl)
+
+    # heat transf. coeff. by forced convection
+    hcf = 12.1 * math.sqrt(vr)
+    taa = ta + 273
+    tra = tr + 273
+    tcla = taa + (35.5 - ta) / (3.5 * icl + 0.1)
+
+    p1 = icl * fcl
+    p2 = p1 * 3.96
+    p3 = p1 * 100
+    p4 = p1 * taa
+    p5 = (308.7 - 0.028 * mw) + (p2 * math.pow(tra / 100.0, 4))
+    xn = tcla / 100
+    xf = tcla / 50
+    eps = 0.00015
+
+    n = 0
+    while abs(xn - xf) > eps:
+        xf = (xf + xn) / 2
+        hcn = 2.38 * math.pow(abs(100.0 * xf - taa), 0.25)
+        if (hcf > hcn):
+            hc = hcf
+        else:
+            hc = hcn
+        xn = (p5 + p4 * hc - p2 * math.pow(xf, 4)) / (100 + p3 * hc)
+        n += 1
+        if n > 150:
+            print('Max iterations exceeded')
+            return 1
+
+    tcl = 100 * xn - 273
+
+    # heat loss diff. through skin
+    hl1 = 3.05 * 0.001 * (5733 - (6.99 * mw) - pa)
+    # heat loss by sweating
+    if mw > 58.15:
+        hl2 = 0.42 * (mw - 58.15)
+    else:
+        hl2 = 0
+    # latent respiration heat loss
+    hl3 = 1.7 * 0.00001 * m * (5867 - pa)
+    # dry respiration heat loss
+    hl4 = 0.0014 * m * (34 - ta)
+    # heat loss by radiation
+    hl5 = 3.96 * fcl * (math.pow(xn, 4) - math.pow(tra / 100.0, 4))
+    # heat loss by convection
+    hl6 = fcl * hc * (tcl - ta)
+
+    ts = 0.303 * math.exp(-0.036 * m) + 0.028
+    pmv = ts * (mw - hl1 - hl2 - hl3 - hl4 - hl5 - hl6)
+    ppd = 100.0 - 95.0 * math.exp(-0.03353 * pow(pmv, 4.0) - 0.2179 * pow(pmv, 2.0))
+
+    return {'pmv': pmv, 'ppd': ppd}

tox.ini

@@ -25,8 +25,8 @@ basepython =
     pypy3: {env:TOXPYTHON:pypy3}
     py27: {env:TOXPYTHON:python2.7}
     py35: {env:TOXPYTHON:python3.5}
-    {py36,docs}: {env:TOXPYTHON:python3.6}
-    py37: {env:TOXPYTHON:python3.7}
+    py36: {env:TOXPYTHON:python3.6}
+    {py37,docs}: {env:TOXPYTHON:python3.7}
     py38: {env:TOXPYTHON:python3.8}
     {bootstrap,clean,check,report,codecov}: {env:TOXPYTHON:python3}
 setenv =