Simpel Heat Transfer Calculation from an enclusure

Please create an excel sheet which takes the following input Height, Witdh and Dept of an enclosure in Meters By using standard formulas for overall heat transfer throug material such as steel plate or aluminum plate calculate the heat transfer by convection and conductiontion in simpel condiitions. Simpel conditions means that you can assume a constant high temperature inside the enclosure and constant temperature outside the enclosure. Also assume standard free air both inside and outside the enclusure. The main output is the heat transfer measured in Watt for the entire enclosure. After calculating the convection and conduction of a closed cabinet. Please add the additional cooling by adding holes or ducts in the top and in the bottom of the cabinet. I need to be able to type in the area of the hole (duct) and most likely the vertical distance between the lower and upper hole. Please use a stadard formula for Stack Effect for this part. Formulas used and constants used must be documented with references to source.