Industrial Heat Pumps: Appropriate Placement and Sizing Using the Grand Composite

Abstract

Correct thermodynamic placement of heat pumps is a necessary condition for optimality. The most sophisticated equipment designs can do very little to improve the cost-effectiveness of inappropriately placed heat pumps. The practice of designing heat pumps to fit particular unit operations without regard to the thermodynamic characteristics of the total process may result in inefficient designs and is detrimental to the "image" of industrial heat pumps. In this paper the heat pump placement is discussed in the context of the total process. The process grand composite curve is introduced as a tool for appropriate placement and sizing of heat pumps. An example is presented to show that evaluation of heat pumps in a "stand-alone" sense can give misleading results. A procedure for quick preliminary screening of industrial processes to determine their suitability for cost-effective heat pump placement is presented. This procedure can be used to identify heat pump markets as well as development needs for advanced heat pumps. As Phase I of a USDOE funded project, this procedure was applied to several diverse industrial processes. Some key findings of Phase I of the project are also reported.