How is calorimetry used in the industry?
To measure the temperature change associated with a reaction, and use it to work out the enthalpy change associated with the reaction, just like in the laboratory,
Reasons for doing this would include:
The look at how much energy a fuel releases when it is burned, and to compare the energy released when it is burned completely or incompletely in insufficient oxygen.
To measure the energy released when foods are consumed and digested, I.e. The calorie content (calories are just an old set of units for Energy - we use Joules now.)