def pvsyst_cell(poa_global, temp_air, wind_speed=1.0, u_c=29.0, u_v=0.0,
    eta_m=0.1, alpha_absorption=0.9):
    """
    Calculate cell temperature using an empirical heat loss factor model
    as implemented in PVsyst.

    Parameters
    ----------
    poa_global : numeric
        Total incident irradiance [W/m^2].

    temp_air : numeric
        Ambient dry bulb temperature [C].

    wind_speed : numeric, default 1.0
        Wind speed in m/s measured at the same height for which the wind loss
        factor was determined.  The default value 1.0 m/2 is the wind
        speed at module height used to determine NOCT. [m/s]

    u_c : float, default 29.0
        Combined heat loss factor coefficient. The default value is
        representative of freestanding modules with the rear surfaces exposed
        to open air (e.g., rack mounted). Parameter :math:`U_{c}` in
        :eq:`pvsyst` [W/(m^2 C)].

    u_v : float, default 0.0
        Combined heat loss factor influenced by wind. Parameter :math:`U_{v}`
        in :eq:`pvsyst` [(W/m^2 C)(m/s)].

    eta_m : numeric, default 0.1
        Module external efficiency as a fraction, i.e., DC power / poa_global.
        Parameter :math:`\\eta_{m}` in :eq:`pvsyst`.

    alpha_absorption : numeric, default 0.9
        Absorption coefficient. Parameter :math:`\\alpha` in :eq:`pvsyst`.

    Returns
    -------
    numeric, values in degrees Celsius

    Notes
    -----
    The Pvsyst model for cell temperature :math:`T_{C}` is given by

    .. math::
       :label: pvsyst

        T_{C} = T_{a} + \\frac{\\alpha E (1 - \\eta_{m})}{U_{c} + U_{v} \\times WS}

    Inputs to the model are plane-of-array irradiance :math:`E` (W/m2), ambient
    air temperature :math:`T_{a}` (C) and wind speed :math:`WS` (m/s). Model
    output is cell temperature :math:`T_{C}`. Model parameters depend both on
    the module construction and its mounting. Parameters are provided in
    [1]_ for open (freestanding) and close (insulated) mounting configurations,
    , and are coded for convenience in
    ``temperature.TEMPERATURE_MODEL_PARAMETERS``. The heat loss factors
    provided represent the combined effect of convection, radiation and
    conduction, and their values are experimentally determined.

    +--------------+---------------+---------------+
    | Mounting     | :math:`U_{c}` | :math:`U_{v}` |
    +==============+===============+===============+
    | freestanding | 29.0          | 0.0           |
    +--------------+---------------+---------------+
    | insulated    | 15.0          | 0.0           |
    +--------------+---------------+---------------+

    References
    ----------
    .. [1] "PVsyst 6 Help", Files.pvsyst.com, 2018. [Online]. Available:
       http://files.pvsyst.com/help/index.html. [Accessed: 10- Dec- 2018].

    .. [2] Faiman, D. (2008). "Assessing the outdoor operating temperature of
       photovoltaic modules." Progress in Photovoltaics 16(4): 307-315.

    Examples
    --------
    >>> from pvlib.temperature import pvsyst_cell, TEMPERATURE_MODEL_PARAMETERS
    >>> params = TEMPERATURE_MODEL_PARAMETERS['pvsyst']['freestanding']
    >>> pvsyst_cell(1000, 10, **params)
    37.93103448275862
    """
    total_loss_factor = u_c + u_v * wind_speed
    heat_input = poa_global * alpha_absorption * (1 - eta_m)
    temp_difference = heat_input / total_loss_factor
    return temp_air + temp_difference
