**1. Introduction**

Many of the photovoltaic systems function independent of the wiring system (off-grid). These systems are made of solar panels matrixes, control systems, storage systems, and DC or AC consumption devices. The scheme of a PV system is shown in **Figure 1**.

**Figure 1.** *Scheme of an off-grid PV system.*

Panel matrixes are made of modules that consist of serially or parallelly connected panels depending on requirements. The panels are generally made of 36 serially connected cells (the number of cells commonly used are 32, 36, 48, 60, 72, and 96). For example, a solar panel comprising 32 cells typically can produce 14.72 volts output. Specific batteries are used for PV systems for storage and to stabilize tension. Control systems have charging regulators and converters/inverters which can be either DC-DC or DC-AC and blocking diodes. Control systems assure the interface between all the components of the PV system for protecting and controlling the system [1–6].

A solar furnace will use solar energy in the processes for technological purposes. This installation belongs to the thermal installations category. The advantages of thermal installations based on solar energy are as follows:


As a result of these electrothermal installations advantages, installations that rely on solar energy sources can be used in different industrial processes [7–17] such as:


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


The documentary research visits made at Instituto de Soldadura e Qualidade, Lisabona, and at Ecole Européenne d'Ingénieurs en Génie des Matériaux, Nancy, opened new collaboration perspectives with renowned teams from abroad for achieving new results due to their experience in the domain. Another documentary research visit is made at the Dipartimento di Ingegneria Aerospaziale e Meccanica, Secunda Universitadegli Napoli, Italia.

To achieve the necessary elevated temperatures, an important condition is to use quality materials. The best option is the use of electric resistor furnaces.

### **2. Materials and methods**

### **2.1 Documentary study regarding solar furnaces and the importance of climatic conditions**

In order to design a PV system, we start from the consuming requisite power (load resistance) which in this case is an electric furnace with a capacity of 1 liter and a 0.55-kWh power, a lab furnace, the working time and climatic conditions of the zone where the system is installed (**Figure 2**).


