Alessio Sapienza

Adsorption Heat Storage: State of the Art and Future Perspectives

Thermal energy storage (TES) is a key technology to enhance the efficiency of energy systems as well as to increase the share of renewable energies. In this context, the present paper reports a literature review of the recent advancement in the field of adsorption TES systems. After an initial introduction concerning different heat storage technologies, the working principle of the adsorption TES is explained and compared to other technologies. Subsequently, promising features and critical issues at a material, component and system level are deeply analyzed and the ongoing activities to make this technology ready for marketing are introduced.

Experimental Findings: Main Factors Affecting the Adsorptive Temperature-Driven Cycle Dynamics

In Chap. 2, the two main methods to study the sorption dynamics for AHT cycles were widely described: (i) the Large Pressure Jump (LPJ) method, in which adsorption is initiated by a jump of pressure over the sample, is the most adequate for pressure-driven AHT cycles; (ii) the Large Temperature Jump (LTJ) method, in which adsorption is enabled by a temperature swing of a heat exchanger wall that is in contact with the adsorbent under an almost isobaric ad/desorption stage, is the proper choice for temperature-driven AHT cycles (see Chaps. 1 and 2). In this chapter, the main factors affecting the sorption dynamics will be highlighted for temperature-driven AHT cycles by the analysis of results achieved by the two versions (namely V-LTJ and G-LTJ) of the LTJ method.

Optimization of an “Adsorbent/Heat Exchanger” Unit

Despite significant progress, the AHT technology as yet remains unfinished and expensive, so that there is still a big room for its improvement [1, 2]. This concerns, first of all, enhancement of the AHT dynamics, like the ad/desorption rate and finally the specific power that is the main figure of merit of the AHT dynamic performance. Therefore, further R&D activity is necessary to realize the potential economic and ecological advantages of the AHT technology [3]. The optimization of the AHT dynamic performance is a multi-purpose task that includes, first of all, the improvement of the “adsorbent–heat exchanger” unit.

Adsorptive Heat Transformation and Storage: Thermodynamic and Kinetic Aspects

At present, the majority of thermodynamic cycles of heat engines are high-temperature cycles that are realized by internal combustion engines, steam and gas turbines, etc. (Cengel, Boles in Thermodynamics: an engineering approach, 4th edn. McGray-Hill Inc., New York, 2002). Traditional heat engine cycles are mainly based on burning of organic fuel that may result in dramatic increase of CO2 emissions and global warming. The world community has realized the gravity of these problems and taken initiatives to alleviate or reverse this situation. Fulfilment of these initiatives requires, first of all, the replacement of fossil fuels with renewable energy sources (e.g. the sun, wind, ambient heat, natural water basins, soil, air). These new heat sources have significantly lower temperature potential than that achieved by burning of fossil fuels which opens a niche for applying adsorption technologies for heat transformation and storage (Pons et al in Int J Refrig 22:5–17, 1999).

Measurement of Adsorption Dynamics: An Overview

Analysis of the Ad-HEx dynamic behaviour is of pivotal importance in development of advanced adsorber concepts, enabling reduction of weight and volume of the real adsorption heat pump/chiller unit, as well as its energy density enhancement.