Fig 4.12 The Rankine cycle process diagram superimposed on the EOS of water

Pump The efficiency of the pump in Fig. 4.11 is calculated using Eq (4.13a). For compressed liquid water, v ~ 0.001 m3/kg. The pump's inlet pressure is 15 kPa and the outlet pressure is 2 MPa. Using these values in Eq (4.13a) yields:

The actual work required for pump operation is 4 kJ/kg, so the pump efficiency is 50%.

Total entropy increase

The turbine and pump efficiency calculations indicate the presence of irreversibilities in the Rankine power cycle. The entropy increase of the cycle (the system) and the reservoirs (the surroundings) are expressed by:

AStot = ASfluid+ ASpump+ ASturbine+ ASthermal reservoirs (4.14)

Because the working fluid (water) cycles through four states but returns to the starting state,

ASfluid= 0

The component irreversibilities are obtained from Table 4.2:

ASturbine= 7.29 - 6.77 = 0.52 External irreversibilities due to heat exchange with the hot and cold reservoirs contribute:

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Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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