def convective_and_conductive_heat_fluxes(HEC, T1, T2) -> float:
    """Convective and conductive heat fluxes
    Equation 8.40

    :param float HEC: the heat exchange coefficient between object 1 and 2
    :param float T1: the temperature of object 1
    :param float T2: the temperature of object 2
    :return: The heat flow from object 1 to object 2 [W m^-2]
    """
    return HEC * (T1 - T2)