For analysis of Thermodynamic Cycle, we draw T-s or P-h diagram. Why don’t we draw T-h or P-t diagram? Solution For analysis of thermodynamics cycle we draw various diagrams, In all these diagram T-s,P-h,T- h and P-T diagram are some of them. Every diagram give some specific informations about system working like T-s diagram give information about Heat transfer, P-h diagram use in air conditioning because air is mixture so pressure affect more and enthalphy is measure of energy. like these two diagram we use P-t diagram use in pure substance to see the transformation at triple point. and T-h diagram use for visualise how energy change with temprature..