def c_min(mass_flow_rate_hot, spec_heat_hot, mass_flow_rate_cold, spec_heat_cold):
    """Computes the minimum C value for NTU calculations
    
    Args:
        mass_flow_rate_hot (int, float): Hot side mass flow rate.
        spec_heat_hot (int, float): Hot side fluid specific heat.
        mass_flow_rate_cold (int, float): Cold side mass_flow_rate_cold.
        spec_heat_cold (int, float): Cold side fluid specific heat.
        
    Returns:
        int, float: The value of the minimum c value 
    """
    
    c_hot = mass_flow_rate_hot*spec_heat_hot
    c_cold = mass_flow_rate_cold*spec_heat_cold
    
    if c_hot == 0 or c_cold == 0:
        raise ValueError("A non-zero c_min value should be specified")
    
    return min(c_hot,c_cold)