# Estimation of Direct Normal Irradiance at Antarctica for Concentrated Solar Technology
## 3 Results
### Effective Case Study Analysis  
We propose a parabolic dish as a CS technology to generate electricity at Mario Zucchelli base. CS technology uses only the direct solar component. Parabolic dish technology is composed of the following units: a parabolic dish, a receiver compressor, a turbine and a recuperator (Figure 12). The electric power generators integrated into the dish-MGT (Micro Gas Turbine) systems are mostly based on the simple recuperated Joule-Brayton cycle.  
The parabolic dish unit (Figure 12a) is made from a high efficiency mirror created to concentrate the direct Sun's beam onto a receiver unit mounted on its focal point, where the solar energy is converted into heat. The heat is used to create pressurized steam inside the compressor unit from the ambient air. The air exiting the receiver flows into the turbine unit where it is expanded and then sent to the hot end of the recuperator unit. Inside the recuperator the hot air is cooled down by the compressor delivery air before being released into the atmosphere. When the available solar radiation exceeds the maximum turbine value, a fraction of the total mass flow through the engine bypasses both sides of the recuperator, in order to reduce the inlet temperature to the solar receiver and avoid overheating of the system [14]. The conceptual scheme and flow diagram of the MGT process is presented in Figure 12a. The parabolic dish external diameter is considered to be 11.7 m, with an effective aperture area of 96.1 m\({}^{2}\) and a focus quote of 7 m, while the receiver window diameter is 190 mm.  
Figure 11: Annual evolution of the daily average monthly DNI values and mean annual evolution (in red) at Eneide (MZS) station.  
In Antarctica, the direct solar radiative potential consistent in estimated DNI annual average from 2000 until 2013 year is 2014 kWh-m\({}^{-2}\) per year (Table 4). In order to make a comparison to the DNI values in other parts of the world, for example, in the southern part of Italy, the potential annual average in DNI is 1850 kWh-m\({}^{-2}\) per year. The daily DNI value in Antarctica is 16 kWh-m\({}^{-2}\), while in Italy the DNI daily value reaches 10 kWh-m\({}^{-2}\)[4; 5].  
The parabolic dish design specifications, such as the reflective efficiencies of the collector factor (90%) and the global efficiency in produced electricity (21%) are taken from Reference [15]. Further on, when we evaluated the DNI potential at the desired location and we know the specific parabolic dish characteristics we are able to evaluate the annual and summer electricity production (\(E_{\rm el}\)) of our system. The available solar energy input (\(E_{\rm sol}\)) depends on the effective aperture area of the parabolic dish and the DNI while the solar energy actually harvested by the system (\(Q_{\rm sol}\)) depends on the reflective efficiencies of the parabolic dish collector factor.  
The values in Table 4 give us a theoretical ratio that the electricity produced only in the summer is 89% of the electricity produced throughout the entire year. Based on these values, it seems convenient to envisage a CS power plant for the supply of energy needs for the Mario Zucchelli base.