**2. Literature review**



#### **Table 1.**

*Seven major features of offset parabolic dish design in foregoing research.* 

dependent factors in her comparative analysis were: (a) the geometry of the reflectors having a diameter of 1.5 m and (b) the radiation of the sun. For better reflectivity in both receiver and concentrator, stainless steel was used. She utilized Matlab Simulink software to compare the Scheffler dish concentrating ratio to that of a parabolic dish collector. The results showed an 8% better efficiency of the Scheffler reflector when compared to the parabolic collector.

#### **2.1 Major features affecting the design of the offset parabolic dish concentrator**

**Table 1** summarizes seven key features that make a significant difference to the design of the offset solar parabolic dish concentrator.

 The diameter of the dish determines the power or heat flux generated by the parabolic dish. This value is usually decided so that minimum solar radiation of 600–1000 W/m<sup>2</sup> is collected [13]. Concentration ratio greater than 10 is advisable in any solar dish design. Researchers in Ref. [13] reported that rim angle values near 45° lead to the highest concentration ratio and better thermal performance of CSP systems.

#### **3. Conclusions**

This feasibility study brings forward the various factors that affect the solar offset parabolic dish when using it as an independent single desalination unit. We can establish certain design parameters that are responsible for obtaining optimal performance from the offset parabolic dish systems. These features are rim angle, the reflective material used for the concentrator, shape of the dish concentrator, and the concentration ratio.

#### *Water Desalination Using Offset Solar Parabolic Dish Concentrator: A Review DOI: http://dx.doi.org/10.5772/intechopen.81083*

Using a solar offset parabolic dish as a reflector improves temperature concentration at the focal point (point focus) with minimum cosine losses when compared to prime focus parabolic dish systems. There is a low yield problem when making use of solar energy for production of potable water in the form of a stand-alone distillation unit.

 Researchers have worked on designs based on the offset type of dish geometry. Although this technology can be made available on a smaller scale, there seems to be a shortage of exploration. As of today, scarcely any reported research works on concentrating solar power for desalination process with smaller aperture area of 1–2 m2 range are available.
