A target‐oriented solid‐gas thermochemical sorption heat transformer for integrated energy storage and energy upgrade

Abstract

An innovative target-oriented solid-gas thermochemical sorption heat transformer is developed for the integrated energy storage and energy upgrade of low-grade thermal energy. The operating principle of the proposed energy storage system is based on the reversible solid-gas chemical reaction whereby thermal energy is stored in form of chemical bonds with thermochemical sorption process. A novel thermochemical sorption cycle is proposed to upgrade the stored thermal energy by using a pressure-reducing desorption method during energy storage process and a temperature-lift adsorption technique during energy release process. Theoretical analysis showed that the proposed target-oriented thermochemical sorption heat transformer is effective for the integrated energy storage and energy upgrade, and the low-grade thermal energy can be upgraded from 87 to 171 C using a group of sorption working pair MnCl 2 -CaCl 2 -NH 3 . Moreover, it can give the flexibility of deciding the temperature magnitude of energy upgrade by choosing appropriate sorption working pairs.

A review of promising candidate reactions for chemical heat storage

“…Li et al [82] proposed target-oriented chemical sorption heat transformer. The novel heat transformer realized energy storage as well as energy upgrade.…”

“…Fig. 12 illustrated the schematic diagram of the novel solid-gas chemical sorption heat transformer combining energy storage with energy upgrade of low-grade thermal energy [82]. During the energy storage phase, the application of the resorption technology gives rise to the decrease of input temperature of the exterior heat source.…”

A novel solid–gas thermochemical multilevel sorption thermal battery for cascaded solar thermal energy storage

“…Especially, the proposed thermochemical multilevel sorption thermal battery can also works as a heat transformer when the evaporation temperature of refrigerant during the discharging phase is higher than its condensation temperature during the charging phase. In this case, it would have the capacity of integrated energy storage and energy upgrade of solar thermal energy, making heat output temperature higher than heat input temperature [17,19,21]. Tables 1-3.…”

“…It has been proved that composite sorbent is a promising material for sorption thermal energy storage, and it can improve sorption capacity significantly. Solid-gas thermochemical sorption energy storage can be used for space heating and cooling of building [16], long-term seasonal energy storage [17,18], industrial waste heat recovery [19], and solar power plants [20]. Moreover, it has the capacity of multifunctional energy application for integrated energy storage and energy upgrade, combined cooling and heating supply, and waste heat recovery [21].…”

Experimental investigation on a dual-mode thermochemical sorption energy storage system

“…Thus, it is inappropriate for the long-term solar heat storage in most cases. 5 Thermochemical sorption energy storage has the advantages of higher energy storage density, stable heat output temperature, combined heat and cold storage, integrated energy storage and energy upgrade [11][12]. Besides these advantages, the most remarkable merit is that the thermal energy can be transformed and stored in the form of chemical bonds, which rarely depends on the value of temperature.…”