Abstract Numerical models allow the solving of dynamic and complex problems such as industrial processes. Reliable numerical models representing the unit operations and energy systems within plants can greatly increase the competitiveness of industries. Industrial plants besides the primary circuits related to the manufacturing processes, also include secondary circuits related to water circuits and commonly neglected as not being directly involved in the processes. Typical industrial water circuits (IWC) include: water cooling, gas washing circuits, water treatment, water transportation and quenching circuits. The OpenModelica environment allows users to perform modelling and simulation of processes in an accessible and open source way. There is however a lack of dedicated open source library including the variety of equipment and processes of typical IWC. Hence, this paper presents a library based on typical IWC and validated with real case studies from different industrial sectors. The validation has shown good agreements between the modelling and the real data and therefore applicable for a variety of applications such as: energy efficiency improvement, circuits design, equipment dimensioning, operational and maintenance conformity.