Large-value data types cannot be converted to the sql_variant data type. For information about how to convert Microsoft .NET Framework common language runtime (CLR) user-defined types, see Performing Operations on User-defined Types.
Heat of Vaporization-the amount of heat required to convert unit mass of a liquid into the vapor without a change in temperature. For water at its normal boiling point of 100 C, the heat of vaporization is 2260 J g-1. 2260 J of heat must be absorbed by the water. Conversely, when 1 g of steam at 100 C condenses to give 1 g of water at 100 C, 2260 J of heat will be released to the surroundings.
The average energy of molecules will increase when the liquid is heated. Some molecules, with energy above average are able to break away from the attraction of other molecules and enter the vapour phase. to sum it all up heat must be supplied to convert liquid water into water vapour. Therefore vaporisation is endothermic.