Mathematical modeling of a PCM storage tank in a solar cooling plant

•Solar energy use has increased considerably in the last decade.•The intermittent character of solar radiation requires storage systems to fulfill the demand.•Storage systems based on phase change materials (PCMs) are becoming very popular.•The solar cooling plant of the ESI of Seville has a PCM storage tank.•The mathematical model of the PCM storage tank is presented. Solar cooling plants can work in multiple operation modes. A numerical model of the whole plant can be used to choose the adequate operation mode and optimizing the energy production by using hierarchical control strategies. Simplified models are required for solving the control problem in a suitable time-window using systems such as Programmable Logic Controllers (PLCs) or microcontrollers. The storage system is an important component of a solar cooling plant. They are useful in solar systems for helping to satisfy the energy demand when solar energy is not available. Those based on phase change materials (PCMs) have the advantage of high storage density at a small temperature range. This paper presents a simplified model of a PCM storage tank placed at the solar cooling plant of the Escuela Superior de Ingenieros (ESI) in Seville, focusing on the parameter estimation algorithm.