TABLE OF CONTENTS Chapter Nine addressed heat integration and the selection of heating and cooling utilities. In heat integration, thermal energy is the focus. Energy integration is a more general concept which provides a holistic view to the generation, allocation, transformation, and exchange of all forms of energy including heat and work (or heat rate and power when the system is studied on a per unit-time basis). This chapter discusses key issues in integrating heat and power which is commonly referred to as combined heat and power (CHP).
A heat engine is a device which uses energy in the form of heat to provide work. Because of the second law of thermodynamics, it is impossible to convert all the input heat into useful work. Consequently, a heat engine discharges heat. A heat engine has three elements:
A heat source (or hot reservoir) which provides the heat input to the engine. The temperature of the heat source is referred to as T H.
A heat sink (or cold reservoir) which receives the discharged heat from the engine. The temperature of the heat sink is referred to as T L.
An object on which work is done.
The concept of a heat engine is widely used in many applications such as the automobile engine (internal combustion engine) where heat is generated during one part of the cycle and is used in another part of the cycle to produce useful work. Another application of heat engines is in...
