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1answer
231 views

Does a Peltier Thermoelectric layer make a good regulator for LN2 heat-sink interfacing

I understand that when cooling water with LN2 directly (through pipes for example), that it can be too effective, freezing the water (and blocking the pipe). From what I read, regulation of the heat ...
0
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1answer
236 views

Ideal gas temperature and pressure gradients?

Consider an ideal gas in a $d\times d\times L$ box with the $L$ dimension in the $x$-direction. Suppose that the opposite $d\times d$ sides of the box are held at temperatures $T_1$ and $T_2$ with ...
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2answers
63 views

What is the distinction between thermal and electrical conductivities?

Aren't they both caused by electron motion?
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2answers
607 views

How can I measure the conductivity of a copper rod?

I would like to perform an experiment to measure the conductivity of a copper rod. What device can I use to perform to experiment? is there such a thing as a conductivity meter? All i found was an ...
0
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1answer
198 views

Is this a simple system in which no heat transfer is possible?

Let's say that a hot gas is trapped in a metal box. This metal box is magnetically suspended in another structure with a low temperature. The inner box does not touch anything. And there is a void in ...
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2answers
759 views

Is there a heat transfer equation that takes conduction, convection, radiation and dT/dt into account?

I see equations that take 2 or 3 of the listed parameters into account but I haven't been able to find one that is that complete. I'm seeking to solve this equation using matlab for a simulation ...
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1answer
45 views

What thermal conductivity coefficient should I be using when modeling a heatsink?

Using the finite difference model for heat transfer, I am trying to model the heat flow into a heatsink. However, I am unsure of what k value or coefficient of thermal conductivity to use. Should I be ...
0
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1answer
25 views

Thermal Dynamics Conduction Comparison

I didn't have to take much physics for my advanced college degree, so I apologize if my question is painful. From reading and experience it seems that water is a better thermal conductor than air. I ...
0
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1answer
54 views

Air insulation cavity depth: rule of thumb to avoid convection

I want to know more about optimising an air gap between two surfaces, such as window panes or a building's walls. I was taught that as a general rule, a 6cm air gap is the optimum. Any larger and ...
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2answers
97 views

Is it possible to “add cold” or to “add heat” to systems?

Amanda just poured herself a cup of hot coffee to get her day started. She took her first sip and nearly burned her tongue. Since she didn't have much time to sit and wait for it to cool down, ...
0
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1answer
956 views

Calculating (Glass) thermal conductivity

I read that glass has a thermal coefficient of 0.8-1 W/mK. Given that my window window thickness is around $5\ mm$, then I would calculate my heat loss per area being $160-200\ Wm^{-2}K^{-1}$. Yet ...
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1answer
293 views

Energy loss in pipe/hose with hot water (how its affected by pipe/hose size, temperature)?

I'm working on low budget small solar power project. I want to transport heat (peak heat power about 1kW) over ~10 meter (~30ft) long pipe or hose. I was thinking about thin hose (6-8mm / about 1/4 ...
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0answers
21 views

Thermography time evolution

I have an imaging problem. I essentially have a metallic plate with a number of holes through it. I am looking at the number of holes with a thermal camera. While looking at the plate I have two ...
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1answer
27 views

Can I apply symmetry to this boundary value problem (BVP)?

Let's say I have a hollow cylindrical shell with inner radius $a$ and outer radius $b$ and length $L$. The temperature at at z=L is $T_{2}$ and the temperature at z=0 is $T_{1}$. There is also an ...
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0answers
59 views

Is the thermal time constant simply the heat capacity divided by thermal conductivity?

My professor gave me this temperature decay data to make an exponential fit and told me that the time constant tau should be heat capacity over thermal conductivity. I'm looking at the wikipedia page ...
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0answers
60 views

Calculate thermal conductance of thick walls of a cuboid, given material conductivity and cube size

Note 1: This is probably as much a maths question as physics. Note 2: I am not sure if my use of the the term conductance is correct. I want to make a kiln. The walls will be thick. I can come to ...
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1answer
508 views

Stress due to the mismatch of thermal expansion coefficients of two different attached materials

I'm simulating the thermo-electro-mechanical behavior of a copper wire which is surrounded by silicon dioxide. In other words, the wire segments is under mechanical and thermal loads and at the same ...
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0answers
43 views

Can we make any substance that will produce ions at low temprature

I am talking about thermal ionization, Is to possible to make any material or is there any element that can be ionized at let say 20 degree centigrade Temperature? I am a computer engineer and into ...
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0answers
238 views

What is an accurate equation for joule heating?

I know two different equations that provides the joule heating effect. The first one only depends on the potential ($\varphi$) and the electrical conductivity ($\gamma$) and can de modeled based on ...
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0answers
1k views

What is the insulative value of water?

I am having a hard to finding what the R value of water is. I am trying to compare it to styrofoam (which has an R-Value of 5). EDIT Based on the assumption that water has an insulative property, ...
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3answers
152 views

Peltier heating/cooling of small surface area [closed]

I am looking at peltier heaters/coolers, and all of them are thin wafers like the one pictured below. This works fine for some things (ie. a microchip or a beer coaster) but not for others (ie. ...
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2answers
435 views

At the atomic level, is heat conduction simply radiation?

Radiation and conduction are two ways that heat is transferred. Convection isn't really a mode of transfer as the actual heat transfer really occurs through radiation/conduction and not by some other ...
-1
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1answer
94 views

Heat Sink Design-Choice of Material [closed]

I am currently designing a heat sink for OPA 549. Among the many considerations, for example, the choice of material, the geometry of heat sink, the design of fins and all the parameters that come ...
-1
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1answer
92 views

Heat preserving performance of container relative to content

This question has been addressed in the case of a thermos bottle: Performance of a thermos bottle relative to contents I am asking the question again without the hypothesis that it is a thermos ...
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1answer
342 views

Time constant of ice melt

I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
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1answer
454 views

Why do phonons cause excellent heat conduction in diamonds?

Phonons are the quantum of lattice vibrations in crystals and are not to be confused with photons, the gauge bosons of the electromagnetic force. Apparently, they contribute to heat conduction, but I ...