Mindblown: a blog about philosophy.

In the Rankine cycle, the heat rejected is considered to be of no value. However, this heat can be supplied by steam, for the heating of buildings, and heating required by many industrial processes. Thus, the functions of power generation and heating can often be combined effectively. This combination is often called cogeneration. In such a…

In a binary vapour cycle, two working substances are used—one with good characteristics at high temperature and the other with good at low temperature characteristics. Figures 4.23(a) and (b) show two Rankine cycles in a combined arrangement. The heat is rejected from the high temperature cycle (mercury cycle) as energy supplied to the low temperature cycle (steam cycle). This…

An ideal working fluid should have the following favourable properties:

Reheating is mainly adopted to gain advantage of drier steam in the low pressure stages, and regeneration is adopted for increasing the thermal efficiency of the cycle. Therefore, it is advisable to execute cycle adopting both reheat and regeneration. Figure 4.22(a) shows the schematic diagram of such a cycle with two-stage regeneration and one-stage reheating at first…

In the Rankine cycle and reheat, the condensate which is at a fairly low temperature is pumped to the boiler. Thus, there is an irreversible mixing of the cold condensate with hot boiler water. This results in loss of cycle efficiency. Regeneration is a method to heat the feed water from the hot well of…

The efficiency of the Rankine cycle can be improved by the following methods: 1 Reheat Cycle Figure 4.8(a) shows the schematic diagram for the reheat cycle. The corresponding h–s and T–s diagrams are shown in Fig. 4.8(b) and Fig. 4.8(c), respectively. The steam is extracted at a suitable point and is reheated with the help of flue gases in the boiler furnace. This…

The schematic of Rankine cycle is shown in Fig. 4.3(a). It consists of a turbine, boiler, condenser, and pump. The p-v diagram is shown in Fig. 4.3(b) and the T-s diagram in Fig. 4.3(c). The delivery of steam from the boiler takes place at state 1 when assumed dry saturated or 1′ when assumed superheated. The steam expands isentropically in the prime mover…

The elements of steam power plants are as follows: The schematic diagram of a steam power plant is shown in Fig. 4.1. The p-v and T-s diagrams for the Carnot vapour power cycle are shown in Fig. 4.2(a) and (b). Dry and saturated steam at temperature TH = T1 enters the steam turbine and is expanded isentropically to sink temperature TL = T2 to do work. The exhaust steam from the…

In steam power plants and refrigeration cycles, the working fluid changes from liquid to vapour and back to liquid state. This succession of processes is called vapour cycle. In steam power plants, water is the working fluid in the form of steam and vapour. In refrigeration cycles gasses such as Freon, CO2, and ammonia (aqua-ammonia)…