A Chinese language analysis staff has developed a brand new idea for extracting thermal vitality from low-temperature waste warmth sources and reusing it on demand just by controlling the strain.
Warmth manufacturing accounts for greater than 50% of the world’s last vitality consumption and evaluation of waste warmth potential exhibits that 72% of the world’s major vitality consumption is misplaced after conversion, primarily within the type of warmth. It’s also answerable for greater than 30% of world greenhouse fuel emissions.
Towards this background, researchers led by Prof. LI Bing from the Institute of Metallic Analysis of the Chinese language Academy of Sciences have proposed and realized a brand new idea—barocaloric thermal batteries based mostly on the distinctive inverse barocaloric impact.
The research might be revealed as we speak (February 17, 2023) within the journal Science Advances.
An inverse barocaloric effect is characterized by a pressure-induced endothermic response, in sharp contrast to a normal barocaloric effect where pressurization leads to an exothermic response. “A barocaloric thermal battery cycle consists of three steps, including thermal charging upon pressurization, storage with pressure, and thermal discharging upon depressurization,” said Prof. LI, corresponding author of the study.
The barocaloric thermal battery was materialized in ammonium thiocyanate (NH4SCN). Discharge was manifested as the heat of 43 J g-1 or a temperature rise of about 15 K. The heat released was 11 times greater than the mechanical energy input.
To understand the physical origin of the unique inverse barocaloric effect, the working material NH4SCN has been well characterized using synchrotron X-ray and neutron scattering techniques. It undergoes a crystal structural phase transition from a monoclinic to an orthorhombic phase at 363 K, accompanied by a volumetric negative thermal expansion of ~5% and entropy changes of about 128 J kg-1 K-1.
This transition is easily driven by pressure as low as 40 MPa, and it is the first inverse barocaloric system with entropy changes greater than 100 J kg-1K-1. Pressure-dependent neutron scattering and molecular dynamics simulations showed that the transverse vibrations of SCN¯ anions are enhanced by pressure and the hydrogen bonds that form the long-range order are then weakened.
As a result, the system becomes disordered in response to external pressure and thus the material absorbs heat from the environment.
As an emerging solution for manipulating heat, barocaloric thermal batteries are expected to play an active role in a variety of applications such as low-temperature industrial waste heat harvesting and reuse, solid-state refrigeration heat transfer systems, smart grids, and residential heat management.
Reference: “Thermal batteries based on inverse barocaloric effects” 17 February 2023, Science Advances.
This study was supported by CAS, the Ministry of Science and Technology of China, and the National Natural Science Foundation of China.