High-temperature solar receiver integrated with a short-term storage system

Abstract

Small-Scale Concentrated Solar Power Plants could have a potential market for off-grid applications in rural contexts with limited access to the electrical grid and favorable environmental characteristics. Some Small-Scale plants have already been developed, like the 25-30 kWe Dish-Stirling engine. Other ones are under development as, for example, plants based on Parabolic Trough Collectors coupled with Organic Rankine Cycles. Furthermore, the technological progress achieved in the development of new small high-temperature solar receiver, makes possible the development of interesting systems based on Micro Gas Turbines coupled with Dish collectors. Such systems could have several advantages in terms of costs, reliability and availability if compared with Dish-Stirling plants. In addition, Dish-Micro Gas Turbine systems are expected to have higher performance than Solar Organic Rankine Cycle plants. The present work focuses the attention on some challenging aspects related to the design of small high-temperature solar receivers for Dish-Micro Gas Turbine systems. Natural fluctuations in the solar radiation can reduce system performance and damage seriously the Micro Gas Turbine. To stabilize the system operation, the solar receiver has to assure a proper thermal inertia. Therefore, a solar receiver integrated with a short-term storage system based on high-temperature phase-change materials is proposed in this paper. Steady-state and transient analyses (for thermal storage charge and discharge phases) have been carried out using the commercial CFD code Ansys-Fluent. Results are presented and discussed

Design optimization of the phase change material integrated solar receiver: A numerical parametric study

“…The receiver consists of a cylindrical container filled with PCM and having a cone-shaped cavity on its front face. A previous preliminary design was not shaped with a cavity [41] and was abandoned because such configuration could not provide a sufficient surface for the solar flux absorption. In this modified configuration, the conical cavity walls have an angle of 8˚with the horizontal.…”

Recuperated solar-dish Brayton cycle using turbocharger and short-term thermal storage

“…A compact high-temperature high-conductivity phase-change thermal storage material, as suggested by Giovannelli et al (2017) and Bashir et al (2019), is housed inside the solar receiver structure and around the open-cavity coiled tubular solar receiver (see Fig. 3) which was optimised for a recuperated solar-dish Brayton cycle using a turbocharger (Le Roux et al, 2014a) (see Fig.…”

“…Most Brayton cycles require a minimum temperature of 753 K to sustain itself (Stine and Harrigan, 1985). Thermal storage systems can allow the system to operate when the sun has set (which is also when there is a peak in electricity demand) or to balance out sudden fluctuations in the solar radiation due to clouds (Giovannelli et al, 2017). Storage such as lithium fluoride (Cameron et al, 1972;Asselman, 1976), packed rock beds (Allen, 2010;Ozturk et al, 2019), and encapsulated sodium sulphate (Klein, 2016) have been investigated.…”

Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver

“…The PCM is an intermediate medium which can store sensible and latent heat and transfers part of the heat to the compressed air inside the U-tubes. On the basis of previous analyses carried out by the authors [37,38], the receiver front surface was shaped with a conical cavity. Such geometry increases the radiation absorption capacity of the receiver reducing the hot wall temperature and, consequently, the re-radiation effects.…”