Techno-economic feasibility of pipeline and mobile thermal energy storage for liquid desiccant transport

Abstract

The use of desiccant solutions for heat recovery, transport and use offers an alternative to conventional district heating and cooling networks, providing heating, cooling, moisture control and drying in one multi-service system. Desiccant solutions are appealing to various industrial, residential and commercial applications and allow the utilisation of low-grade heat from industrial processes and low-temperature renewable energy. This manuscript presents a techno-economic assessment of liquid desiccant systems applied to district networks via pipelines and mobile thermal energy storage (M-TES). By using aqueous solutions of calcium chloride (CaCl₂), lithium chloride (LiCl) and potassium formate (HCO₂K), this study evaluates their potential to efficiently connect heat sources with end users requiring humidity control, removal, or drying. Evaluations of three use cases (a cleanroom, an indoor swimming pool and an industrial drying process) and comparisons to conventional operation demonstrated the feasibility of liquid desiccant technology for recovering low-temperature heat and reducing energy consumption for temperature and humidity control. While pipeline transport of desiccants, particularly aqueous CaCl₂, is suitable for shorter distances and large-scale applications, M-TES offers flexibility for long-distance transport without extensive infrastructure. Favourable conditions, such as reduced transportation schedule, extended operating hours and high electricity prices, could enable M-TES over distances exceeding 10 km. This study offers critical insights into optimising liquid desiccant systems for sustainable energy networks, highlighting their scalability, adaptability and economic viability in stationary and mobile applications.