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3
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1answer
33 views

What are the effects of compositional changes in a thermocouple's junction?

We use thermocouples (type B) to measure the temperature of metals (Fe, Ag, Pd, etc) in a furnace under pressure. We weld two thermocouple wires together using an arc welder. This junction then comes ...
0
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0answers
13 views

Thermoelectric generator

I am building an underground solar greenhouse using the principles of passive annual heat storage. I have designed the greenhouse using old rig mats. This means that I will have about 100 000lbs of ...
0
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0answers
14 views

About the energy requirement in a TEG

When a TEG ( ThermoElectric Generator) is rated 12V, 138.6Watts, does it mean that it requires 138.6 watts of energy to produce 12V of electricity? Also, what will happen if the energy level is more ...
2
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0answers
22 views

Can seebeck chips be used to extract Peltier chip waste heat?

I understand that a problem with employing the Peltier effect for the purpose of cooling is that it produces a significant amount of heat on the hot plate. But why don't we use seebeck optimised chips ...
-2
votes
1answer
64 views

Liquid conductors and conservation [closed]

Would gas or liquid conductors cost less than metal and are they more efficient conductor? Is there a material that would contain a magnetic field and would it increase conductivity? If so, This ...
1
vote
1answer
37 views

what is the lowest temperature that a thermocouple can respond to?

I am trying to find out if a thermocouple could detect low temperatures like 40 or 37 degrees centigrade, it's been really difficult for me to find it, for I'm just an O'level graduate.
0
votes
1answer
46 views

Equation for heat dissipation from flat surface (ignoring convection)

As part of a school project, I would like to calculate whether the efficiency of the Peltier effect is greater, less or equal at higher voltages. In other words, I'm testing if the temperature ...
2
votes
1answer
66 views

Cause of negative Thomson's effect?

Why the metals like iron, cobalt, nickel show negative Thomson's effect? What is the reason for other metals like copper and zinc to show positive Thomson's effect? Is there any reasonable idea ...
1
vote
2answers
31 views

Using Thermoelectric generator to power another Peltier cooler

i have a feeling that this isnt possible but wanted to double check. Could you use a Peltier plate on a heat source to generate electricity and then use that electricity to power a Peltier plate as ...
0
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0answers
12 views

Is it possible that the current due to the photothermoelectric effect at a interface lessens after prolonged laser illumination?

I have performed some measurements photocurrent measurements at the interface of a material with a high thermopower (Bi2Te2Se) and gold where the current has decreased at measurements performed around ...
1
vote
3answers
110 views

why do coiled wire create so much heat?

I am wondering how coiled wire creates so much heat when a current is passed through it. Is it just a larger surface area of heated substance is available or are interacting forces at work eg ...
0
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0answers
15 views

Range of thermocouples

Why do thermocouples have a restricted range of temperature that can measure, say for example some go from –200 °C to +268 °C, what makes them to be useless below or above?, I know above may become ...
1
vote
3answers
99 views

The thermal expansion of material

The question is that: they drill a hole in the middle of a metal. Then when this metal is heated, will the hole become larger or smaller? The hole will get bigger, by experiment, but I think that when ...
0
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0answers
16 views

Adding thin films to a Peltier Device

I am using a peltier device maintaining a constant gradient by applying a voltage/current. My current setup is: Cold Side Peltier Device Hot Side CPU fan Was just wondering forgetting time ...
25
votes
5answers
3k views

Is it possible to build a thermoelectric nuclear power plant?

Current nuclear power plants are essentially an enhanced version of a kettle, which seems like a stupidity caused by a lack of other options. We heat the water which turns to steam which rotates the ...
0
votes
2answers
43 views

Is the screen in CRT connected with a positive pole?

I don't understand this passage would you clarify it? "These electrons are then freed (liberated) from the metal and are then picked up by the screen, which is connected to a positive pole called the ...
1
vote
0answers
87 views

LOCAL Temperature Gradient and Stress

I'm investigating the thermo-migration failure mechanism in nanoscale ICs interconnects. Typically, a nano wire under thermal stress suffers from material/mass migration or void nucleation if it ...
2
votes
3answers
2k views

Why does a thermoelectric generator need both p and n elements?

A thermoelectric (peltier) generator turns heat flow into DC electrical power. Here is a typical schematic: (image from here). Notice that there are two thermoelectric materials required: p-type (...
2
votes
1answer
162 views

Water behaviour under theoretical near-infinite pressure conditions

I've asked a similar question here but the answer given shows the behaviour of water under general conditions. I'd like to know what the behaviour of water is like as pressures increase towards ...
2
votes
2answers
69 views

Does the conductivity of a wire in a vacuum decrease over time?

Does the conductivity of a wire in a vacuum decrease over time, say over the period of years or decades? In other words: Does current degrade a wire, making it less conductive? If so, by how much, and ...
1
vote
1answer
53 views

Does Peltier effect decrease temperature?

Does Peltier effect decrease temperature? Such as infamous flashlight from your hand temperature. It use Peltier effect to generate light while your hand has more heat than air. So, whenever ...
3
votes
4answers
159 views

The conduction electrons in metals is a thermal phenomenon?

When applying an external electric field in a metal at absolute zero, there is electrical current? There must be thermal fluctuations in the electron's band to be occurs current?
0
votes
1answer
473 views

How is voltage generated due to difference in temperature in a thermocouple? [duplicate]

How is voltage generated due to difference in temperature between the two junctions of a thermocouple? What happens to the electrons at the junctions of the two materials and how do they behave when ...
2
votes
1answer
634 views

Calculate TEC efficiency

I am currently doing a small experiment using a Peltier to cool 250ml of water. My aim is to achieve the cooling of 250ml from 23degC to 8degC in under 20minuets which I have done by strapping the ...
1
vote
0answers
33 views

Why do ferromagnetic thermocouples change their behaviour near the Curie point?

Having read Wikipedia's current explanation that certain types of thermocouple (specifically Type K thermocouples) experience a step-change in their potential when they reach the Curie point of the ...
1
vote
2answers
2k views

Thermo-Emf variation with temperature

In the following experiment for seebeck effect After a certain temperature, the thermo-emf begins to fall. Why does this happen? What is happening microscopically at this level to cause such an ...
1
vote
2answers
361 views

Why does hydrogen give up its electron to a platinum catalyst?

All descriptions of a Hydrogen fueled fuel cell (such as this one) Start with $H_2$ giving up its electrons to a platinum coated anode. Then the $H^+$ ions (protons really) travel through the ...
1
vote
2answers
5k views

How much electricity can be produced by my thermoelectric generator?

I am using a thermoelectric cooler from a pc's heatsink to produce electricity. Its size is 30mm by 30mm. I will cool it on one side at -10 degree Celsius and the other at 24 degree Celsius. Can ...
1
vote
2answers
204 views

Which thermoelectric effect is better?

I am doing an experiment which requires the thermoelectric effect. I know about the Seebeck and the Peltier effects. Well, from what I have found till now on these topics is that they both can produce ...
0
votes
0answers
48 views

Heat Sink considerations for thermionic generators

I recently read an article describing thermionic generation. I am considering building a TG for a science fair experiment. I was thinking about surrounding my heat source with a spherical emitter and ...
0
votes
1answer
1k views

What is the maximum theoretical efficiency of heat to electricity conversion?

I know that heat engines (heat to kinetic) are limited by Carnot cycle and that kinetic energy to electric energy conversion via standard generator reaches over 90%. However I would like to know ...
5
votes
3answers
2k views

How do charge carriers move thermal energy? (Peltier effect)

I am having hard time understanding how the charge carriers (electrons and holes) are able to move thermal energy. I am on a high school physics level, so I will probably have a hard time ...
2
votes
2answers
352 views

Continuously feeding an evaporating micro-black hole?

What would happen if you created a micro-black hole and could continuously feed it as quickly as it evaporates? Is it possible that it would remain relatively stable? If so, how might such a thing ...
0
votes
2answers
130 views

Will the heat flow of Joule heat be different, if the Joule heat is dissipated in a material that has a temperature gradient beforehand?

Let us assume one dimensional heat transfer, for example a finite length wire starting at point $0$ and ending at point $\ell$. If the current passes the wire, the Joule heat $I^{2}R$ will be ...
0
votes
3answers
525 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. ...
0
votes
2answers
1k 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 ...
2
votes
1answer
168 views

Clarification on the Seebeck Effect

Alright, I've been interested in the Seebeck effect lately, so I've been trying to learn it. From what I understand, this is measured with the Seebeck Coefficient, which gives you the $\mu\textrm{V}$ (...
3
votes
2answers
193 views

What are the largest thermal gradients achievable in a lab environment?

I am looking for a system capable of creating a gradient of $100\, \mathrm{K}/\mathrm{\mu \textrm{m}}$ on a $30\, \mathrm{\mu}\textrm{m}$ spacing of a system mounted on a Si-N membrane. My so-called ...
3
votes
3answers
5k views

When drift velocity equals thermal velocity?

In some papers, I can see the drift velocity of electrons equaling thermal velocity. Can anyone tell me when both almost equal each other?
1
vote
2answers
653 views

Starting vehicle on hot days

Why it is easy to start the vehicle on hot day than on cold days? Since on winter days it is diffcult to start than on hot days I thought it is due to the low temperature which in turn affects the ...
0
votes
1answer
124 views

What are the resulting forms of energy after thermal equalization

When two bodies of matter are placed together, one hotter than the other, where does the energy go when the two temperatures equalize? Is there any energy in thermal difference at all? If not, how ...
0
votes
0answers
171 views

direct conversion of heat to electric potential / current - are there theories that contradict the 'Kelvin Statement'?

In particular, William Thomson (Kelvin) appeared to be wrong about key things in physics (initially X-rays, aether, even aviation feasibility). en.wikipedia.org/wiki/William_Thomson,_1st_Baron_Kelvin#...
0
votes
1answer
202 views

Is a low-current electrical arc harmful to humans?

I've heard that electrical flux non-destructive particle testing machines are considered safe because they use less than 2 amps. I have seen an arc created between two objects do considerable damage, ...
0
votes
2answers
155 views

static shock=thermocouple?

I used to live in Boston. Near my complex, there was an apartment complex with lots of our friends. Anyways, that place had faulty heating most of the time; mainly in the corridors. They were pretty ...
2
votes
1answer
2k views

Understanding the Seebeck effect

Thermoelectricity is, as I understand it, the difference in voltage between the hot and cold ends of two dissimilar materials. If two materials are connected at two different junctions, the hot ...