Heat Transfer Design Using Peltier Heat Pumps

I have a challenge to design a bit of test kit for our production guys to calibrate temperature tranducers. In effect it will consist of a flat bed, the temperture sensor of the tranducer unit is a flat metal surface to be bolted to oil filled National Grid cables, transformers etc. and these will be connected to the flat bed for calibration. The question is simple, I want to use Peltier effect heat pumps to heat/cool the plate; a series of thermistors embedded in the plate and some electronics will regulate it's temperature from -10 degrees to +55 degrees Celcius. How do I calculate the power required for the heat pump for any given heat sink? I know there's a degree per watt spec for bespoke manufactured heatsinks and I may need to know the specific heat capacity of the material for the flat bed, size etc all comes into play. Is there a simple formula I could utilise? Any ideas or suggestions would be greatly appreciated.