Cooling water sources diagram

Highlights: • Cooling Water Sources Diagram enables a holistic view of the cooling water system. • Accuracy of the algebraic methods with the perceptions of the graphical methods. • Combined analysis of water and energy in cooling water systems. • Synthesis of multiple networks satisfying the lowest cooling water flow rate. • Goal and network structure simultaneous attainment. Recirculating cooling water systems are used to absorb heat in the heat exchanger network, usually operating in a parallel configuration and returning water to the cooling tower with a higher temperature. This configuration receives the fresh cooling water directly without any previous reuse. While this configuration is simple to operate, it leads to inefficient use of the cooling water. On the other hand, a series configuration can reduce the cooling water flow rate, but the complex arrangement and sometimes thermodynamic restrictions lead to higher operational costs. This paper proposes simplifying the network structure through a series-parallel configuration and determines the minimum water flow rate in the cooling system without affecting the heat load removal from the process heat exchangers, using the Cooling Water Sources Diagram (CWSD). Minimizing water consumption and increasing the water return temperature lead to an improvement in the cooling tower's efficiency, which reduces its operational cost. One case study with different scenarios is presented to cover several cooling system characteristics to demonstrate the proposed new tool's applicability and efficiency. The results are compatible with those observed in the literature, being superior in some cases, either in terms of cost values or generating different possible networks.