scholarly journals Reverse Heat Flow with Peltier-Induced Thermoinductive Effect

2021 ◽  
Author(s):  
Kenjiro Okawa ◽  
Yasutaka Amagai ◽  
Hiroyuki Fujiki ◽  
Nobu-Hisa Kaneko
Keyword(s):  
Thermal Conductivity ◽  
Exact Solution ◽  
Solid State ◽  
Heat Flow ◽  
Negative Temperature ◽  
Peltier Effect ◽  
Local Cooling ◽  
Heating And Cooling ◽  
Inductive Component ◽  
Ac Current

Abstract The inductive component is the only missing components in thermal circuits unlike their electromagnetic counterparts. Herein, we report an electrically controllable reverse heat flow, which can be regarded as a proper equivalent of the “thermoinductive” effect. The underlying concept is the heating and cooling of the ends of the material by the Peltier effect under an applied ac current; this form a negative temperature gradient in the opposite direction in a controllable manner. We have derived the exact solution indicating that this reverse heat flow occurs universally in solid-state systems, even in conventional metallic Cu, and that it is considerably enhanced by thermoelectric properties (i.e., a large Seebeck coefficient and low thermal conductivity). A local cooling of 25 mK was demonstrated in (Bi,Sb)2Te3, which was explained by our exact solution. This electrically controlled reverse heat flow is directly applicable to the fabrication of a “thermoinductor” in thermal circuits.

scholarly journals Reverse heat flow with Peltier-induced thermoinductive effect

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kenjiro Okawa ◽  
Yasutaka Amagai ◽  
Hiroyuki Fujiki ◽  
Nobu-Hisa Kaneko
Keyword(s):  
Exact Solution ◽  
Heat Flow ◽  
Thermal Inertia ◽  
Peltier Effect ◽  
Local Cooling ◽  
High Temperature Side ◽  
Inductive Component ◽  
Ac Current ◽  
Single Material ◽  
Temperature Side

AbstractThe concept of “thermal inductance” expands the options of thermal circuits design. However, the inductive component is the only missing components in thermal circuits unlike their electromagnetic counterparts. Herein, we report an electrically controllable reverse heat flow, in which heat flows from a low-temperature side to a high-temperature side locally and temporarily in a single material by imposing thermal inertia and ac current. This effect can be regarded as an equivalent of the “thermoinductive” effect induced by the Peltier effect. We derive the exact solution indicating that this reverse heat flow occurs universally in solid-state systems, and that it is considerably enhanced by thermoelectric properties. A local cooling of 25 mK is demonstrated in (Bi,Sb)2Te3, which is explained by our exact solution. This effect can be directly applicable to the potential fabrication of “thermoinductor” in thermal circuits.

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

Downhole Measurements of Thermal Conductivity in Geothermal Reservoirs

1977 ◽  
Vol 99 (4) ◽  
pp. 607-611 ◽  
Author(s):  
H. D. Murphy ◽  
R. G. Lawton
Keyword(s):  
Thermal Conductivity ◽  
Exact Solution ◽  
Heat Flow ◽  
Thermal Contact ◽  
Approximate Solutions ◽  
Laboratory Measurements ◽  
Transient Effect ◽  
Transient Heat Flow ◽  
Geothermal Wells ◽  
Downhole Measurements

The line source method of determining thermal conductivity is extended to include the transient effect associated with the fluid in flowing geothermal wells. The general equations describing transient heat flow are utilized. Approximate solutions are derived and compared to the exact solution of the general equations. The proposed method is operationally simple since the heater, and the associated problems of obtaining adequate thermal contact between the heater and the sides of the borehole are eliminated. Using this method downhole measurements were obtained and favorably compared with laboratory measurements on characterized core specimens taken from wells in a hot dry rock geothermal reservoir.

Thermal Transport in Nanostructured Solid-State Cooling Devices

2005 ◽  
Vol 127 (1) ◽  
pp. 108-114 ◽  
Author(s):  
Deyu Li ◽  
Scott T. Huxtable ◽  
Alexis R. Abramson ◽  
Arun Majumdar
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Nanostructured Materials ◽  
Thermal Transport ◽  
Experimental Studies ◽  
Phonon Transport ◽  
Peltier Effect ◽  
Cooling Devices ◽  
Low Dimensional ◽  
Solid State Cooling

Low-dimensional nanostructured materials are promising candidates for high efficiency solid-state cooling devices based on the Peltier effect. Thermal transport in these low-dimensional materials is a key factor for device performance since the thermoelectric figure of merit is inversely proportional to thermal conductivity. Therefore, understanding thermal transport in nanostructured materials is crucial for engineering high performance devices. Thermal transport in semiconductors is dominated by lattice vibrations called phonons, and phonon transport is often markedly different in nanostructures than it is in bulk materials for a number of reasons. First, as the size of a structure decreases, its surface area to volume ratio increases, thereby increasing the importance of boundaries and interfaces. Additionally, at the nanoscale the characteristic length of the structure approaches the phonon wavelength, and other interesting phenomena such as dispersion relation modification and quantum confinement may arise and further alter the thermal transport. In this paper we discuss phonon transport in semiconductor superlattices and nanowires with regards to applications in solid-state cooling devices. Systematic studies on periodic multilayers called superlattices disclose the relative importance of acoustic impedance mismatch, alloy scattering, and crystalline imperfections at the interfaces. Thermal conductivity measurements of mono-crystalline silicon nanowires of different diameters reveal the strong effects of phonon-boundary scattering. Experimental results for Si/SiGe superlattice nanowires indicate that different phonon scattering mechanisms may disrupt phonon transport at different frequencies. These experimental studies provide insight regarding the dominant mechanisms for phonon transport in nanostructures. Finally, we also briefly discuss Peltier coolers made from nanostructured materials that have shown promising cooling performance.

AN INSTRUMENT FOR MEASURING HEAT FLOW, TEMPERATURE, AND THERMAL CONDUCTIVITY IN THE LUNAR SURFACE LAYER

1970 ◽  
Author(s):  
A. E. Wechsler ◽  
E. M. Drake ◽  
F. E. Ruccia ◽  
J. E. McCullough ◽  
P. Felsenthal ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Layer ◽  
Heat Flow ◽  
Lunar Surface ◽  
Flow Temperature

ON MEASUREMENT OF THERMAL CONDUCTIVITY AT HIGH TEMPERATURES

1961 ◽  
Vol 39 (7) ◽  
pp. 1029-1039 ◽  
Author(s):  
M. J. Laubitz
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
High Temperatures ◽  
Mathematical Analysis ◽  
Temperature Range ◽  
Linear Heat ◽  
Flow Systems

A method is given for exact mathematical analysis of linear heat flow systems used in measuring thermal conductivity at high temperatures. It is shown that a popular version of such a system is very sensitive to the alignment of its components, which seriously limits the temperature range of its satisfactory use.

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