5 - Utilities, heat and power systems

Abstract

This chapter analyzes the interaction of heating and cooling utilities with power requirements and discusses the combined heat and power (CHP) systems that generate power while simultaneously providing hot utility and heat pumps. A heat engine is a device for converting heat into power. Nuclear reactions and burning coal, oil, natural gas, or other fossil fuels or combustible materials provide high-temperature heat. Three types of machines are used in the generation of industrial CHP. They include steam turbines, gas turbines, and reciprocating engines. Economic aspects as well as case studies are discussed. CHP economics depend strongly on the cost of heat, the cost of power, and the ratio between them—all of which have substantially fluctuated since the 1970s. Normally there is only a significant cost difference for CHP systems and refrigeration levels. Heat pumps are used either as a refrigeration system or as a heat recovery system. Closed-cycle heat pumps, mechanical vapor recompression (MVR), thermal vapor recompression (TVR), absorption refrigeration cycles, and heat transformers are the main types of heat pumps. Total site analysis provides information about the quantity of steam used at each steam level, cost of steam, and maximization of power generation from letdown to the various levels.