Hi tall one. You can apply basic principals here. Do you know how to determine frictional force between the seal and shaft? Frictional force times distance is work. Work per unit time is power (ie: heat which must be disipated). Once you have heat load, you need to figure out how that heat is being rejected. Either through simple conduction or convection or perhaps there's a fluid that's flowing past the seal that can carry that heat away. Hope that helps.