**3.1 Identification of the optimum geometric arrangement of the components of a solar furnace for heating metallic materials**

The photovoltaic system will be composed of (see **Figure 17**):


◦ tension regulator;

**Figure 17.** *The photovoltaic system necessary for supplying the solar furnace with resistors.* *Assessment of Solar Energy Potential Limits within Solids on Heating-Melting Interval DOI: http://dx.doi.org/10.5772/intechopen.104847*

#### **Figure 18.** *Assembly images of the solar furnace.*


The temperature control in resistor furnaces has a special influence on the quality of the final products and on the specific energetic consumptions. With respect to the specific conditions of the technological process, especially the allowed temperature variations in the furnace and in the material, adjustment systems are used with intermittent action or a continuous one. The assembly image of the built solar furnace is given in **Figure 18**.

A PID control algorithm will be used for temperature control using PtRh-18 class thermocouple as a sensor. The maximum working temperature of these thermocouples is 1820°C [1, 2].

The PID algorithm is implemented using LabVIEW graphic programming language. **Figure 19** presents the panel, program interface, and PID application, and **Figure 20** presents the diagram and the proper program.

### **3.2 Interpretation of the achieved results**

The solar furnace works by using electric energy produced by a photovoltaic system, which converts solar energy, solar radiation, into electric energy.

For a feasibility study for the solar radiation in the Brasov area, an SPN1 pyranometer is purchased. Global and diffuse solar radiation is measured using this device, and direct solar radiation can also be calculated using this device. Solar radiation monitoring starts from February. Global and diffuse solar radiation monitoring is noticed at every 5 minutes.

The conclusions that can be drawn after monitoring the solar radiation, according to **Figures 21**–**23**, are as follows:

**Figure 19.** *The interface of the PID application.*

**Figure 20.** *Diagram of PID application.*


*Assessment of Solar Energy Potential Limits within Solids on Heating-Melting Interval DOI: http://dx.doi.org/10.5772/intechopen.104847*

**Figure 21.**

*Distribution of global and diffuse solar radiation during a sunny day (14 June).*

**Figure 22.** *Distribution of global and diffuse solar radiation during a cloudy day (12 June).*


**Figure 23.** *Distribution of horizontal global radiation during the interval 12–17 June.*

• For example, for the weakest days energetically speaking, 12 June, the energy quantity a system can generate is under 800 W.
