Evaluating the performance of the EnergyNest thermal energy storage (TES) poses a number of technical challenges. How does one determine the performance for a given storage system? How much energy is stored? How much energy can be extracted? And how fast?
There are two ways to answer these questions. The first is to build a physical TES, run and test the facility, and measure the performance. The second is by simulation – that is, by using advanced computer models to calculate and predict the TES performance.
For commercial projects, EnergyNest always performs detailed simulations. This is required to ensure that the customer receives a TES operating at high temperatures with optimum performance.
The company’s in-house modelling tool has been verified against a physical pilot model at a small scale, which EnergyNest has been operating at the Masdar Institute Solar Platform. Comparing measured and simulated performance ensures that the model is correct, and that it captures the right thermal processes. Relying on a tested and proven computer model is an essential first step for designing, running and maintaining a large-scale TES system.
EnergyNest’s computer model simulates how a heat transfer fluid (HTF) exchanges heat with the storage medium (HEATCRETE®). The fundamental thermal processes in the TES are accurately captured in this computer model, thereby allowing it to calculate the energy transferred between the HTF and solid-state storage medium. The outcome of the computer model is the temperature in the TES, the power flow, and the energy stored and extracted.
Data recorded from EnergyNest’s TES pilot facility at Masdar, in the United Arab Emirates, is used to validate the simulation software. The pilot has been operated for more than 6,000 hours, providing an extensive amount of high quality temperature measurements.
The measured data are compared to simulation results at all times, and the results are spot on. In fact, the computer models can predict temperatures that are only within a few degrees of the values measured at the TES pilot.
EnergyNest’s proprietary simulation software has become vital for achieving an optimal design and a reliable performance evaluation for customers. The sophistication and specialisation of the software, achieved over many years of technological development, is indispensable to determine the storage design that maximises customer value.