Thermosensitive crystallization–boosted liquid thermocells for low-grade heat harvesting

Science ◽  
2020 ◽  
Vol 370 (6514) ◽  
pp. 342-346 ◽  
Author(s):  
Boyang Yu ◽  
Jiangjiang Duan ◽  
Hengjiang Cong ◽  
Wenke Xie ◽  
Rong Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Concentration Gradient ◽  
Relative Efficiency ◽  
Room Temperature ◽  
Cost Effective ◽  
Heat Energy ◽  
Thermoelectric Device ◽  
Low Grade ◽  
Low Grade Heat

Low-grade heat (below 373 kelvin) is abundant and ubiquitous but is mostly wasted because present recovery technologies are not cost-effective. The liquid-state thermocell (LTC), an inexpensive and scalable thermoelectric device, may be commercially viable for harvesting low-grade heat energy if its Carnot-relative efficiency (ηr) reaches ~5%, which is a challenging metric to achieve experimentally. We used a thermosensitive crystallization and dissolution process to induce a persistent concentration gradient of redox ions, a highly enhanced Seebeck coefficient (~3.73 millivolts per kelvin), and suppressed thermal conductivity in LTCs. As a result, we achieved a high ηr of 11.1% for LTCs near room temperature. Our device demonstration offers promise for cost-effective low-grade heat harvesting.

Growth of halide perovskites thin films for thermoelectric applications

MRS Advances ◽  
2019 ◽  
Vol 4 (30) ◽  
pp. 1719-1725 ◽  
Author(s):  
Shrikant Saini ◽  
Ajay Kumar Baranwal ◽  
Tomohide Yabuki ◽  
Shuzi Hayase ◽  
Koji Miyazaki
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Cost Effective ◽  
Thermoelectric Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Halide Perovskites

ABSTRACTThermoelectric materials can play an important role to develop a sustainable energy source for internet of things devices near room temperature. In this direction, it is important to have a thermoelectric material with high thermoelectric performance. Cesium tin triiodide (CsSnI3) single crystal perovskite has shown high value of Seebeck coefficient and ultra low thermal conductivity which are necessary conditions for high thermoelectric performance. Here, we report the thermoelectric response of CsSnI3 thin films. These films are prepared by cost effective wet spin coating process at different baking temperature. Films were characterized using X-ray diffraction and scanning electron microscopy. In our case, films baked at 130°C for 5 min have shown the best thermoelectric performance at room temperature with: Seebeck coefficient 115 μV/K and electrical conductivity 124 S/cm, thermal conductivity 0.36 W/m·K and figure of merit ZT of 0.137.

scholarly journals Enhanced Thermoelectric Performance of n-Type Bi2Se3 Nanosheets through Sn Doping

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1827
Author(s):  
Mengyao Li ◽  
Yu Zhang ◽  
Ting Zhang ◽  
Yong Zuo ◽  
Ke Xiao ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Cost Effective ◽  
Low Grade ◽  
Hot Press ◽  
Processing Technologies ◽  
Sn Doping ◽  
Practical Applications ◽  
Alternative Materials ◽  
The Cost ◽  
Low Grade Heat

The cost-effective conversion of low-grade heat into electricity using thermoelectric devices requires developing alternative materials and material processing technologies able to reduce the currently high device manufacturing costs. In this direction, thermoelectric materials that do not rely on rare or toxic elements such as tellurium or lead need to be produced using high-throughput technologies not involving high temperatures and long processes. Bi2Se3 is an obvious possible Te-free alternative to Bi2Te3 for ambient temperature thermoelectric applications, but its performance is still low for practical applications, and additional efforts toward finding proper dopants are required. Here, we report a scalable method to produce Bi2Se3 nanosheets at low synthesis temperatures. We studied the influence of different dopants on the thermoelectric properties of this material. Among the elements tested, we demonstrated that Sn doping resulted in the best performance. Sn incorporation resulted in a significant improvement to the Bi2Se3 Seebeck coefficient and a reduction in the thermal conductivity in the direction of the hot-press axis, resulting in an overall 60% improvement in the thermoelectric figure of merit of Bi2Se3.

scholarly journals Rolling membrane powered by low-temperature steam as a new approach to generate mechanical energy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chongshan Yin ◽  
Qicheng Liu ◽  
Qing Liu
Keyword(s):  
Water Vapor ◽  
Low Temperature ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Heat Energy ◽  
Steam Engine ◽  
Low Grade ◽  
Human Society ◽  
New Approach ◽  
Low Grade Heat

Abstract How to convert heat energy into other forms of usable energy more efficiently is always crucial for our human society. In traditional heat engines, such as the steam engine and the internal combustion engine, high-grade heat energy can be easily converted into mechanical energy, while a large amount of low-grade heat energy is usually wasted owing to its disadvantage in the temperature level. In this work, for the first time, the generation of mechanical energy from both high- and low-temperature steam is implemented by a hydrophilic polymer membrane. When exposed to water vapor with a temperature ranging from 50 to 100 °C, the membrane repeats rolling from one side to another. In nature, this continuously rolling of membrane is powered by the steam, like a miniaturized “steam engine”. The differential concentration of water vapor (steam) on the two sides of the membrane generates the asymmetric swelling, the curve, and the rolling of the membrane. In particular, results suggest that this membrane based “steam engine” can be powered by the steam with a relatively very low temperature of 50 °C, which indicates a new approach to make use of both the high- and low-temperature heat energy.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

Thermoelectric Properties of Binary-Phased Nanocomposites

2014 ◽  
Vol 809-810 ◽  
pp. 3-8
Author(s):  
Peng Xian Lu
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Hot Press ◽  
Point Temperature ◽  
Disordered Structure ◽  
Maximum Value ◽  
Hot Press Process

In order to increase the electrical conductivity greatly but maintain a large Seebeck coefficient and a low thermal conductivity simultaneously, the binary-phased LaCeFe3CoSb12-Sb nanocomposites composed of LaCeFe3CoSb12skutterudite nanospheres and semimetal Sb microsized ribbons were fabricated via a hydro/solvo thermal route. The results suggest that the Sb powders result in a disordered structure during a hot-press process at its melting-point temperature and the disordered structure has been partly preserved into the room-temperature materials successfully. The Sb microsized ribbons enhance the electrical conductivity of the binary-phased materials largely, meanwhile the disordered structure increases the Seebeck coefficient obviously even though the thermal conductivity is also increased slightly. Consequently, the figure of merit of the binary-phased materials is improved significantly and the maximum value of 1.54 at 773 K has been realized for the LaCeFe3CoSb15material.

scholarly journals ENVIRONMENTALLY SAFE USAGE OF HYDROPOWER POTENTIAL BY HYDROTHERMAL POWER SUPPLY SYSTEMS

2019 ◽  
pp. 67-75
Author(s):  
S. Goshovskyi ◽  
O. Zurian
Keyword(s):  
Heat Pump ◽  
Energy Systems ◽  
Hydrothermal Systems ◽  
Heat Energy ◽  
Operating Conditions ◽  
Small Rivers ◽  
Low Grade ◽  
Hydropower Potential ◽  
Environmentally Safe ◽  
Low Grade Heat

The article contains the results of scientific research and design work related to environmentally safe usage of hydropower potential of the small rivers of the Dnieper basin. The innovative design solutions for extraction of low-grade heat energy of water and systems for its transformation into energy convenient for consumption were offered. It was established that use of renewable low-grade energy of soil is widely used in environmentally safe and economically sound power systems. At the same time hydropower potential is not widely used in hydrothermal heat pump systems. It was proved that existing hydrothermal systems are not always adjusted to actual operating conditions and object location. The evidence was provided that the scientific approach to development of appropriate configuration of hydrothermal collector, to methodology of their optimal mounting and to efficiency determination depending on operating conditions is quite topical issue. The scientific novelty of the new process approach is use of special design of water collector that has modular configuration and consists of several functionally related water sondes. The efficiency of hydrothermal system was scientifically proved. The paper describes the results of experimental research of efficiency of hydrothermal heat pump system where the low-grade heat energy of water is used as a renewable primary heating energy source for functioning of the heat pump. The authors have developed experimental hydrothermal and geothermal heat pump systems to conduct the research. Both collector and ground section of the system have mounted sensors of temperature, pressure and coolant flow velocity. The software for archiving and visualization of obtained data was developed. The research procedure was developed. As part of study, observation data were received and performance efficiency of geothermal and hydrothermal systems was calculated. The comparative analysis of energy systems depending on used renewable energy source was carried out. The conclusion was made that use of hydrothermal heat pump systems is environmentally safe. The data obtained as part of study have great scientific and applied significance for engineering of heat pump energy systems using hydropower potential of the small rivers.

Joining Techniques for Novel Metal Polymer Hybrid Heat Exchangers

2019 ◽  
Author(s):  
Gowtham Kuntumalla ◽  
Yuquan Meng ◽  
Manjunath Rajagopal ◽  
Ricardo Toro ◽  
Hanyang Zhao ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Waste Heat ◽  
Cost Effective ◽  
The United States ◽  
Thermomechanical Properties ◽  
Low Grade ◽  
Ongoing Work ◽  
Metal Metal ◽  
Low Grade Heat ◽  
Metal Polymer

Abstract In the United States, over 50% of the unrecovered energy from industrial processes is in the form of low-grade heat (&lt; 220°C). Materials and maintenance costs of common heat exchangers are typically too high to justify their usage. Polymers, though more affordable, are usually unsuitable for HX applications due to their low thermal conductivity (∼0.2 W/mK). Here, we show that metal-polymer hybrids may be attractive from both performance and cost perspectives. The use of polymers further increases the resistance to corrosion by sulfuric and carbonic acids often present in flue gases. An ongoing work explores different configurations of layered polyimide-copper macroscale hybrids for heat exchanger applications using numerical simulations. This paper explores a manufacturing pathway for producing such layered hybrid tubes that involves directly rolling and bonding tapes made of polymer and copper foil into tubes. A critical problem in the fabrication process is the bonding of metal and polymers. We explore approaches involving adhesives (epoxy, acrylic and silicone) for metal/polymer interfaces and direct welding (ultrasonic) for metal/metal interfaces that can be integrated into the manufacturing process. We report characterizations of the thermomechanical properties of these joining processes. This work paves the way for realizing cost-effective manufacturing of heat exchangers for low grade waste heat recovery.

Thermogalvanic Hydrogel for Synchronous Evaporative Cooling and Low-Grade Heat Energy Harvesting

Nano Letters ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 3791-3797 ◽  
Author(s):  
Shirui Pu ◽  
Yutian Liao ◽  
Kyle Chen ◽  
Jia Fu ◽  
Songlin Zhang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Evaporative Cooling ◽  
Heat Energy ◽  
Low Grade ◽  
Low Grade Heat
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