The heat produced by Farady transformer

The heat produced by a transformer has to be dissipated to the surrounding air. The spreadsheet calculates the approximate total surface area of the transformer, and finally calculates a required thermal transfer coefficient, which expresses how much farady power transformer 10kva needs to dissipate per unit of surface it has, and per temperature rise allowed. This coefficient tells you how difficult it will be to keep this transformer cool enough to survive! The violet area below this coefficient includes referential values (not calculated by the sheet) which
you can use to try judging whether your transformer will be OK, when you have it in a tight area, in a more open area, cooled by a fan, or immersed in oil. I have my doubts about these values,specially aout the value for the Farady oil immersed transformer, so please take these with a big grain of salt, and let me know if you have any further, better, or more reliable data.