**3. Operating Principle**

In order to achieve and optimize the proposed installation, the Stirling solar conversion unit was studied and two main circuits were identified, depending on the working fluid, functionality, and destination:


Figure 4 shows the main components of the Sunflower 35 solar concentrator, Figure 5 presents the Stirling solar conversion unit, and Figure 6 describes the test stand.

**Figure 4.** Sunflower 35 solar concentrator components [27].

The test stand presented in Figure 6 contains the following components:


The use of the stand was justified by the numerous interactions, adjustments, modifications, and tests that would have been much more difficult and would not have allowed a fast reaction if the solar concentrator had been used as the heat source.

**Figure 5.** Solar conversion unit.

**Figure 6.** Test Stand.
