2nd LAW OF THERMODYNAMICS

The Second Law of Thermodynamics

Although the net heat supplied in a cycle equal to the net work done, the gross heat supplied must be greater than the work done; some heat must always be rejected by the system.

        In symbols, 

Q1 - Q2 = W

↓

Qin < Qout

Heat Engine


                            QH - QL = W 
                                     ↓
                                QH  > W

The work producing device that best fits into the definition of a heat engine are:

• The close cycle gas turbine
• The steam power plant

Thermal efficiency

Example

Heat is transferred to heat engine from a furnace at a rate of 252 GJ/hr. If rate of waste heat rejection to a nearby river is 162 GJ/hr, determine the net work done and the thermal efficiency for this heat engine. 

Solution :

                        Thankyou 😊


By : Nurul Faessza Binti Misbah
     (13DEM18F1028)