Specialty grand challenge: Thermal energy storage and conversion

The world is experiencing rapid technological advancement on a multidimensional scale but at the expense of its environmental sustainability. In this ever-developing world, the hunger for energy is increasing day by day. Natural resources for energy production, such as fossil fuels, are on the brink of extinction due to their extensive use to meet this ever-growing demand for energy. Most of the fossil fuel-burned energy in today’s world is spent on the continuous production of drinkable water, heating, cooling applications, and power generation (Rupam et al., 2022a). Along with irreversible resource exhaustion, burning fossil fuels causes excessive emissions of greenhouse gases and other pollutants responsible for global warming. Keeping in mind the catastrophic effects of the rising temperature, in recent times, there has been a global urge for the development of energy-saving, eco-friendly systems for water production, HVAC applications, power generation, etc. Although renewables are advancing at a fast pace, it has not yet reached a satisfactory level where all the energy-intensive systems can be operated with that. Apart from that, renewables are overly dependent on environmental constraints. For example, at night time or on gloomy days, solar energy cannot be harvested, or the energy conversion rate of photovoltaics drastically decreases. On the other hand, when there is plenty of sunshine, solar photovoltaics produce more energy than the required amount at that time. Most often, this surplus energy ends up being wasted due to the lack of proper energy storage or conversion systems. In this regard, thermal energy conversion and storage systems can offer reasonably realistic alternatives due to their multifaceted features. Thermal energy storage systems can store surplus energy in favorable conditions and provide clean and affordable energy in adverse situations in various forms such as heating, cooling, drinking water, or even power generation. Contrarily, thermal energy conversion systems can pave the way to further increase the share of renewables in the energy mix and play a significant role in the future decarbonized society. Globally, there are a variety of thermal energy storage and conversion (TESC) technologies currently being extensively researched. Figure 1 illustrates some of the most prominent technologies associated with the vast research field of TESC. Although the TESC technologies hold enormous potential, their utilization is subjected to various challenges associated with them. Depending on the applications and working conditions, certain obstacles can come forward, and to overcome those, efforts from both science and engineering fields are required. This speciality grand challenge aims to address the major drawbacks and discuss future research directions for overcoming these challenges associated with current TESC technologies. OPEN ACCESS