Sequential optimization of cooler and pump networks with different types of cooling

Abstract

A cooler network plays an important role in a heat exchanger network (HEN) in aspects of energy and water conservation, and economic performance of the whole process. However, most studies focus on the circulating cooling water system (CWS), paying less attention to the extensive used various air coolers in industrial practice, including the dry type air cooler (DAC) and wet type air cooler (spray type air cooler (SAC) is a typical example). In addition, the usage of auxiliary pumps in CWS can effectively reduce energy consumption. In this paper, the objective system is a cooler network coupled with the main-auxiliary pump network. In the cooler network, cooling types are considered among CWS, DAC and SAC. Superstructure-based mathematical models are proposed with the minimum total annual cost of the whole system as the objective function. A case study is used to demonstrate the effectiveness of the proposed model, which can obtain the expense reduction with 13% of the cooler network and 32% of the pump network.