Chapter 10 - Central plants

Abstract

In various air-conditioning systems, heating and cooling can be provided from a central plant by means of hot water, steam, and chilled water. The chapter starts with some general considerations about what the central parts produce, their advantages and disadvantages. It identifies the main types of boiler and sketches a twin boiler circuit and describes the operation of chillers, and provides a sketch of a dual chiller installation with primary only, and primary-secondary chilled water circuits. In a central plant, the boilers and chillers are located in a single space in the building, and their output is piped to all the various air-conditioning units and systems in the building. Central plants generally require less maintenance than numerous smaller package systems and the equipment usually has a longer life. The chapter considers the main items of equipment found in central plants. These are boilers that produce steam or hot water, chillers that produce chilled water, and cooling towers that cool the chillers.