Chapter 6 - Advanced geothermal energy systems

Abstract

Renewable energy sources have become especially important due to the prolonged utilization of fossil fuels and their unavoidable environmental problems. Burning fossil fuels to obtain electrical power is still widely used in many areas, such as heating and cooling buildings. Therefore, inevitably we need to switch to renewable energy–driven systems for a sustainable future. Renewable energy–supported systems can meet many needs of a building, such as electricity, heating, and cooling, in a clean and sustainable way. It is a known fact that the main energy source of many cooling systems is electricity, and this electrical energy is obtained from fossil fuels. Therefore, it is a fact that cooling systems also contribute to environmental problems such as global warming. So it is indispensable to use renewable energy–supported systems in all areas to combat such environmental problems. At this point, it is possible to design renewable energy–supported multiple production systems as completely environmentally friendly systems. Renewable energy systems, such as geothermal energy, are an important factor for a sustainable future and can produce many useful outputs such as power, heating, cooling, hydrogen, etc. Depending on temperature, geothermal energy output is used in many areas and is an environmentally friendly energy source. Nowadays, the design of advanced geothermal energy systems to generate electricity, hydrogen, hot water, cold water, and freshwater plays a significant role in developed and underdeveloped countries. In this chapter, step ahead of basic systems and proceed with advanced geothermal energy systems, such as multistaged direct systems, multiflashing systems, multistaged binary systems, multiflashing binary systems, and combined/integrated systems. We discuss these systems from various perspectives and introduce their thermodynamic analyses through energy and exergy approaches. Furthermore, there are several examples and parametric studies to investigate the effects of working conditions and environmental variables on the advanced geothermal energy systems and their efficiencies in terms of energy and exergy parameters.