Approach of Dynamic Modelling of a Hydraulic System

Abstract

In response to environmental degradation, particularly due to greenhouse gas emissions, renewable energy is increasing significantly today. Their development is also a major concern with regard to the depletion of non-renewable energies. However, their use is limited due to the instability induced in the electrical grid. Energy storage aims to regulate these fluctuations and thus smooth electricity production. Compressed air energy storage (CAES) is a type of high-capacity, low-cost energy storage on the market. REMORA, the storage system studied here is an underwater isothermal CAES system. This innovative system consists of compressing and relaxing the air in a quasi-isothermal way using liquid pistons. This method minimizes overall energy loss by maximizing heat transfer during air compressions and expansions. Compressed air is stored in underwater tanks and takes advantage of the hydrostatic pressure associated with the depthof the water. The architecture and operation of the hydraulic system are specific in order to maximize performance. During the energy storage and restitution processes, the exchange flow become transient due to several valve commutations. It occurs frequently during REMORA hydraulic system operation. Modeling the system become complex. A simple example of a hydroelectric plant, similar to the case study, is modeled using two different software. The results show the most appropriate tool, to model the hydraulic system, with an integrated approach based on dynamic modeling.