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The Rankine Cycle

Rankine cycle is a heat engine with vapor power cycle. The common working fluid is water. The cycle consists of four processes:

• 1 to 2: Isentropic expansion (Steam turbine)
• 2 to 3: Isobaric heat rejection (Condenser)
• 3 to 4: Isentropic compression (Pump)
• 4 to 1: Isobaric heat supply (Boiler)

Work output of the cycle (Steam turbine), W1 and work input to the cycle (Pump), W2 are:
 

	W1 = m (h1-h2)  
	W2 = m (h4-h3)  

where m is the mass flow of the cycle. Heat supplied to the cycle (boiler), Q1 and heat rejected from the cycle (condenser), Q2 are:
 

	Q1 = m (h1-h4)  
	Q2 = m (h2-h3)  

The net work output of the cycle is:
 

	W = W1 - W2 

The thermal efficiency of a Rankine cycle is:

The efficiency of the Rankine cycle is not as high as Carnot cycle but the cycle has less practical difficulties and more economic.