This seems to be the same question as your post:
https://forum.ansys.com/forums/topic/act-mechanical-coordinates-units/#post-298285
You need to get the current units and convert:
import units
#toUnit = ExtAPI.DataModel.CurrentUnitFromQuantityName("Temperature")
toUnit = result.Properties["MyProperty"].GetCurrentUnit() # assuming unit="Temperature" in property in XML
fromUnit = 'C'
result.Properties["MyProperty"].Value = units.ConvertUnit(2.54, fromUnit, toUnit)