Materials and Technologies for a Green Environment

A recent survey of energy consumption indicates that there has been exponential growth in the need for renewable energy and also for curbing the growth of fossil fuel reserves. To meet this future need, renewable energy sources are being explored. In this paper, we have proposed a Recuperative Organic Rankine Cycle that operates in conjunction with air-cooled condensers. Solar energy is said to be an energy source that varies periodically, unlike geothermal energy which is available round the clock, to generate electricity continuously. Hence it is a highly recommended source to meet the growing demands for electricity globally. A major contribution to geothermal power development is the progress in Organic Rankine Cycles. These plants are best known for their ability to curb harmful gas emissions, especially that of noncondensable gases. There is a significant growth in geothermal power owing to the ORC (Organic Ranking Cycle) power units that are implemented. In this methodology, the working fluid of ORC is made to go through an evaporator where a hot turbine is used to heat the liquid. In this process, the temperature of the preheated liquid is further increased with the aid of solar energy. This heat generated thus is further converted into electricity when the turbine unit causes the expansion of the fluid. Finally, an aircooled condenser is used to condense the final exhaust of the turbine. Combining the two powerful forms of renewable energy (solar and geothermal), it is possible to generate power in such a way that the need for power begins to drop from its peak that it has achieved already. The simulated results define the decline in energy consumption of condensers based on the minimum heat transfer area of the condenser as well as the minimum power consumption of the fans.

Thermoelectric generator (TEG) converts waste heat energy from automobiles into valuable electrical power and has no moving parts compared to conventional thermoelectric motors. The functioning of TEG is dependent on the design and the material used. TEGs are classified as small and medium power outputs. Small power outputs are in the range between 5 μW to 1W, and high power outputs are higher than 1W in a TEG. Thermoelectric power generators offer fast, economical storage methods for wearable and mobile applications. Macro heat waste application is recovered through in-house, industrial and solid waste. Moreover, an immense amount of waste fuel, such as recycling and power plants, is emitted from the industry; this can be utilized in a useful manner by TEGs. This chapter discusses the TEG study of the fundamental operating principles, TEG products, micro applications and energy generation techniques. 

Electric mobility is one of the key technologies for the replacement of nonrenewable energy sources in the long term; creating new markets, opportunities, and new technologies, as the old energy order comes to an end with the evolution of new ones. With the passing of around two centuries, electric vehicle technology has developed to different levels across the globe. Norway has the highest percentage of electric vehicles, while China has the highest number of electric vehicles sold per year in the world. India is catching up with electric vehicle penetration. As per 2018 data, 49% of the total vehicles sold in Norway were electric. In 2019, China registered the maximum number of electric vehicles sold – 1.15 million vehicles. The key advantages of e-mobility are a reduction in GHG emissions, a reduction in the dependency on fossil fuels, higher efficiency compared to ICE vehicles, fewer noise emissions, and the flexibility of EVs becoming a platform for collaborative development of autonomous cars and shared mobility and MaaS. The key challenges are the total cost of ownership, charging infrastructure, reliance on the imported content and parts, customer acceptance of EVs, vehicle range anxiety and battery manufacturing, and availability of raw materials. This research investigates in detail the opportunities created by technologies such as solar-powered vehicle charging, the second life of traction battery, smart grid integration, connected and autonomous CAVE and vehicle light-weighting to enable e-mobility as a more commercial means of transportation.

Scramjet technology is one of the revolutionary technologies of the hypersonic industry. The scramjet engine uses air-breathing propulsion technology, which has been proven to be the most promising technology for high Mach number flights. The paper focuses on the status, key challenges and future scope of the scramjet engines. This paper presents an extensive literature review of the experimental and computational studies carried out by various researchers around the globe. In this paper, the current developments in scramjet technology and its future scope are precisely stated. It is concluded from the review that the flow inside the scramjet combustor is very complex and sensitive. The understanding of the turbulence, boundary layer formation and separation, physics of the flow, and the physiochemical processes involved in combustion still require extensive dedication of researchers in the near future to address the stated problems.

The current scenario in the field of aviation is focused on hypersonic-speed vehicles. To achieve the required performance, engines have to be designed in such a way that their outcome should be maximum. Nowadays high-speed performance engines have utilized a type of air-breathing engine amongst which, the scramjet is found appropriate. However, the engine can only perform under atmospheric area because the supersonic combustion ramjet engine utilizes the atmospheric air as an oxidizer. Nonetheless, engines do not comprise any rotating or moving parts. So, to complete the mixing and chemical kinetics, engine geometry has special dimensions. The present chapter is focused on a rigorous review of the geometrical modification of the combustor and fuel injector. The impact of mixed fuel, different types of working fuels, and variable inflow conditions have been explored to uncover the beneficial effects on scramjet combustion performance. Since numerous authors have explored different aspects of the ongoing challenges in scramjet hence a summary has been drawn to acquire a suitable model for future work.