Related Concept Videos
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:14Mechanisms of Heat Transfer
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
01:14Mechanisms of Heat Transfer I
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
01:19Mechanism of heat transfer
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...
01:22Mechanical Systems
Mechanical systems are analogous to to electrical networks where springs and masses play similar roles to inductors and capacitors, respectively. A viscous damper in mechanical systems functions similarly to a resistor in electrical networks, dissipating energy. The forces acting on a mass in such systems include an applied force in the direction of motion, counteracted by forces from the spring, a viscous damper, and the mass's acceleration. This interplay of forces is mathematically described...
01:07Refrigerators and Heat Pumps
Refrigerators or heat pumps are heat engines operating in a reverse direction. For a refrigerator, the focus is on removing heat from a specific area, whereas, for a heat pump, the focus is on dumping heat into one particular area. A refrigerator (or heat pump) absorbs heat Qc from the cold reservoir at Kelvin temperature Tc and discards heat Qh to the hot reservoir at Kelvin temperature Th, while work W is done on the engine’s working substance.
A household refrigerator removes heat from the...
A household refrigerator removes heat from the...
You might also read
Related Articles
Articles linked to this work by shared authors, journal, and citation graph.
Sort by
Same author
Green's function methods for computing supercurrents in Josephson junctions.
Reports on progress in physics. Physical Society (Great Britain)·2026
Same author
Surface Energy Modulation of NiO<sub><i>x</i></sub> through In Situ Click-Cross-Linked Networks for Air-Processed Flexible Blue Perovskite Light-Emitting Diodes.
The journal of physical chemistry. A·2026
Related Experiment Video
Updated: Jun 2, 2026
10:52
Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System
Published on: August 7, 2018
Heat pumping in nanomechanical systems.
Claudio Chamon1, Eduardo R Mucciolo, Liliana Arrachea
1Department of Physics, Boston University, Boston, Massachusetts 02215, USA.
Physical Review Letters
|April 27, 2011
Summary
We propose a novel phonon pump to transfer heat from cold to hot objects, enabling cooling of nanomechanical systems without active feedback. This method achieves significant temperature reduction using modulated medium propagation.
Area of Science:
- Thermodynamics
- Solid-state physics
- Nanotechnology
Background:
- Active feedback cooling methods for nanomechanical systems are complex and resource-intensive.
- Understanding heat transfer mechanisms at the nanoscale is crucial for developing advanced cooling technologies.
Purpose of the Study:
- To introduce a phonon pumping mechanism for passive heat transfer from a cold to a hot body.
- To demonstrate the potential of this mechanism for cooling nanomechanical systems without active feedback.
Main Methods:
- Utilizing a propagating modulation within the connecting medium to drive heat transfer.
- Calculating the minimum achievable temperature using theoretical models of phonon transport.
Main Results:
- The proposed phonon pump effectively transfers heat against the natural temperature gradient.
- The theoretical lowest temperature achievable by this passive cooling method was computed.
Conclusions:
- Phonon pumping offers a viable alternative to active feedback for cooling nanomechanical systems.
- This mechanism presents a new pathway for nanoscale thermal management and refrigeration.