Types and Modes of Heat Effects

When heat is supplied into (or remove heat from) a fluid, this heat might be used (in whole or in part) to contribute some work towards surroundings, even change the fluids temperature, to change the phase of the fluid or to provide the energy required to carry out a chemical reaction. These concepts are termed into  sensible heat effects, and latent  heat effects  caused during transfer of heat energy into fluid system.

Sensible Heat Effect:

Which involve 'heating' that changes the temperature of the system.Consider a closed system where there is (1) No chance of changing state of the material which could be identified as, solid is converted into liquid or liquid is changed into vapor or gas form, 
(2) No chemical change in chemical structure or chemical identity which the substance is made of, and 
(3) No possibility of altering the composition of the substance in the system, 


Then by adding heat to or removing heat from the system will change its temperature and/or cause it contribute some work on the surroundings. The aim here is to relate the temperature change and work done by which the amount of heat added. For a homogeneous substance having constant composition, Well used phase rule shows us about two intensive properties should be made maintained  constant value to find out the state of the fluid.

Internal energy or 
Enthalpy are function of two intensive variables, pressure, temperature. Thus, using T and V as the independent variables for U, we write U = U (T, V