**1. Introduction**

Among different energy resources, sun's energy is introduced as a versatile source of energy which may be used for number of purposes like heating, cooling and brightening of houses and businesses. Sunlight is environment friendly source of energy that is converted into other useful form of energies for multiple purposes from different

ways. The primitive solar designs for space heating, solar water heating and cooling are the most common solar applications for domestic and commercial use in present time. For solar designers and installers, it is important and critical to generate energy-efficient, environment friendly and cost-effective systems for both domestic and industry sectors. Due to these reasons, solar simulation software is important for researchers, engineers, solar cell designers, planners and dealers in market to create realistic offers for reliable attractive potential solar customers for sustainable future. Hence, let us get insight for some vital and novel information with respect to solar simulation software and informative knowledge about what are their use, how to choose one along with main phases in PV system design and its application in numerous fields.

Now days, for theoretical evaluation and investigations of solar cell working before final solar cell fabrication through different fabrication and deposition techniques, it is necessary for researchers to work on computer-based simulation programs or simulators that are becoming increasingly famous for their reliable theoretical assessment. The development of different solar simulators for photovoltaic applications was introduced in the mid-1980s when the technology was at its peak [1, 2]. With the passage of time, the increase in speed, performance and capacity of computers also enhanced the performance, speed and other features of the solar simulators. Despite the fact that fundamental objective for the invention of these simulating programs was to aid the researchers to reveal the well device performance to the academians but after some time it has grown into an essential tool in lab as well as for domestic and industrial applications. Up to now, several solver packages designed for simulating and modeling of solar cells are commercially available [3].

In the family of modern solar technology, photovoltaic community is familiar with various one-dimensional modeling tools that are mainly used like PC-1D, SCAPS-1D, AMPS-1D along with multi-dimensional modeling tools that are mainly used like Silvaco ATLAS, COMSOL multiphysics, Sentaurus ASPIN3 [4]. Generally, the basic modules of many simulators have similarities but they differ by features like speed, effectiveness, graphical interface and user access. PV simulators are usually designed and generated for various areas such as optics, semiconductor physics and electrical circuits along with characterization, production, costs analysis and photovoltaic operations. To produce ever-better materials and techniques for solar PV cells, there are numbers of parameters that may be accommodated for the improvement and enhancement of device performance along with multiple factors such as material type, geometric arrangement and thickness. The development of new solar technology is a challenging process that involves making small changes to various parameters. However, computational modeling simulators have made it easier and more accessible to evaluate and examine these advances, thereby eliminating the need to physically build every new change for evaluation. In this chapter, there are number of scientific publications on solar simulators [5, 6] and researchers mainly focused on modeling softwares of PV system and along with analysis and vice versa. In our work we have studied frequently used well-established solar simulators in details. We also reviewed the benefits and drawbacks of these tools, as well as comparisons with our prepared list of free simulation programmes.
