Modeling and Simulation methods, tools and techniques aim at supporting the different phases of the lifecycle of modern systems, going from requirements analysis to system design and operation. However, their effective application requires investigating several aspects such as the formal modeling of system requirements and the binding and automated composition between heterogeneous models (e.g. requirements models, architectural models, behavioral models). In this context, the paper presents a new formal requirement modeling language based on temporal logic, called FORM-L, and a software library, based on the Modelica language, that implements the constructs provided by FORM-L so as to enable the visual modeling of system properties as well as their verification through simulation. The effectiveness of the proposal is shown on a real case study concerning an Intermediate Cooling System.