## 1 Introduction  
Central solar receiver system technology presents a promising solution for the advancement of concentrated solar power (CSP). These systems can reach higher operating temperatures, which improves efficiency and reduces costs compared to other CSP technologies [1]. Currently, commercial central receiver power plants operate with receiver outlet temperatures below 565 \({}^{\circ}\)C, using a steam Rankine cycle as the power generation method [2]. Supercritical carbon dioxide (S-CO\({}_{2}\)) cycles have emerged as a promising alternative to steam Rankine cycles in solar tower power plants, primarily due to their higher efficiency. This efficiency arises from the relatively high density of S-CO\({}_{2}\), which decreases the specific work needed during compression. S-CO\({}_{2}\) cycles also reduce heat rejection to the environment, thanks to S-CO\({}_{2}\)'s specific heat properties. The relatively high density leadsto lower volumetric flow, allowing for more compact turbomachinery. Additionally, CO2 is cost-effective, abundant, non-explosive, chemically stable, and less corrosive than other working fluids [3]. The S-CO2 Brayton cycle can operate with central solar receiver systems in direct or indirect mode. The direct method circulates CO2 through both the power cycle and the solar receiver. The indirect method uses a different heat transfer fluid (HTF) and requires an intermediate heat exchanger to connect the two systems. This indirect method is preferred because it prevents the direct heating of S-CO2[4]. Choosing the right HTF is crucial, as its maximum temperature determines the efficiency of the power cycle. Solar salt, a mix of 60% NaNO3 and 40% KNO3, is often used, reaching a maximum of 565 \({}^{\circ}\)C, which limits performance. Researchers are exploring chloride salts, a mix of MgCl2 and KCl, because they can be obtained easily and economically through mining or desalination [5; 6]. Several authors have compared different HTFs using S-CO2 power cycles driven by central solar receiver systems. [PERSON] et al. [4] investigated six S-CO2 Brayton cycles powered by a solar tower with thermal energy storage. The intercooling cycle had the highest efficiency, while the partial-cooling cycle yielded the greatest specific work. The straightforward recuperation, partial cooling, and precompression cycles presented the largest temperature difference. In the study referenced [7], the authors examined three solar tower power cycles: Rankine recompression and partial cooling S-CO2. They used three molten salts: NaNO3-KNO3, MgCl2-KCl, and Li2 CO3-Na2 CO3-K2 CO3. Conducted in Seville and Dubai, the study aimed to determine annual electricity production efficiency. The results showed that the partial cooling S-CO2 cycle was the most efficient at both locations, with the best performance in Dubai using Li2 CO3-Na2 CO3-K2 CO3. Regarding reference [6], this study compares solar salts and a MgCl2-KCl mixture as heat transfer fluids in a solar tower recompression S-CO2 Brayton cycle. It evaluates thermal efficiency, specific work, and thermal storage capacity. The MgCl2-KCl system shows the highest thermal efficiency and specific work due to its ability to operate at higher temperatures, but it has limitations from its low specific heat capacity and higher viscosity. [PERSON] et al. [1] compared two heat transfer fluids: liquid sodium and MgCl2-KCl. They examined four S-CO2 cycle configurations: a simple cycle, a recompression cycle, a partial cooling cycle, and a recompression main compressor intercooling cycle. They calculated the solar electricity efficiency in Seville, Spain, and Las Vegas, USA, under design and yearly conditions. The results showed that liquid sodium provided higher efficiency in both conditions. [PERSON] et al.