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For power production, the emerging technologies of supercritical carbon dioxide (S-CO 2) cycles show potential advantages if compared to conventional plants. The current bottleneck in exploiting such cycles is the development of novel components such as turbomachines and heat-exchangers. This paper focuses on the layout arrangement and machinery design of a novel powerblock for a 10 to 15 MW supercritical carbon dioxide plant. The applied design procedure involves 0D and 1D models implemented using an in-house Fortran code, and 3D computational fluid dynamics (CFD) analyses using ANSYS-CFX. Novel configurations of the power block were designed, starting with the same primary thermal source. At nominal conditions, expected overall output powers from 13.2 to 16.2 MW were found. Finally, some qualitative considerations were included in the discussion to compare the analysed arrangements.

Refrigeration systems consume a relevant amount of electrical power worldwide. For this reason, in the last decades, several energy saving techniques have been proposed to reduce the power demand of such plants. The present paper deals with the development of an innovative internal power recovery system for industrial cryogenic cooling plants. Such an innovative system consists in a Compressor-Expander Group (CEG) for internal power recovery. In particular, the paper is focused on the development of the CEG compressor, which has to pre-compress the refrigerant main flow before the fluid enters the main compressor. The machine has been re-designed, modifying a centrifugal compressor for automotive turbocharging. To verify the performance and suggest improvements, a numerical fluid dynamic model has been set up and the commercial Ansys-CFX software has been utilized to perform steady-state 3D simulations. Expected performance of the secondary compressor are presented and discussed in this paper

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