Thermal Engineering

Chapter 8

Steam Condensers

8.1 ❐ DEFINITION

A condenser is a closed vessel in which steam is condensed by abstracting the heat and where the pressure is maintained below atmospheric pressure.

8.2 ❐ FUNCTIONS OF A CONDENSER

There are two main functions of a condenser, which are explained below:

1. To reduce the back pressure considerably upon the prime mover, and thereby increasing the work output of steam during expansion.

   Consider the ideal p−v diagram of a non-condensing steam engine, as shown in Fig. 8.1(a), in which steam is supplied at pressure p₁ and the exhaust takes place at atmospheric pressure p₂. The work output is given by the area 1–2–3–4–5–1. If we reduce the back pressure p₂ to p′₂, which is below the atmospheric pressure, keeping ...