Questions tagged [thermal-radiation]

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Blower door DIY test

Since in my area there is no way to do a blower door test for a house, I was thinking to do a DIY blower door test. Here is my test scenario: Preheat the house before testing to have 10 degree ...
Milos Radojevic's user avatar
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What are the design trade-offs between Parabolic Dish (Scheffler) and Parabolic Trough (Euro Trough) Solar Concentrators?

Two types of prevalent medium-to-large-scale concentrated solar thermal fields use: Parabolic trough or Parabolic dish Since 1986, hundreds of sites around the world have built arrays of Scheffler ...
Michael Altfield's user avatar
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Blackbody radiation profile inside a heated, spherical conatiner with energy loss

My question is rather specific and perhaps not of general interest. I'm working on a specific problem in physics. Let's suppose we have spherical vessel with a vacuum inside. The walls of the ...
MattEdwards's user avatar
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1 answer
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Thermal cameras - what is the practical significance of NEDT in relation to accuracy?

(Hi, I put this question on the elec eng. stack exchange and someone suggested I move it here. This question has also been edited to make the actual question clearer and fix an error). Using accuracy ...
Shara's user avatar
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How to calculate the thermal conductivity of a composite material

Very new to thermal conductivity calculations, so I'm aware there are already queries on here that may cover this, but I'm struggling to apply them to this instance. I'm trying to calculate the U-...
newuser2967's user avatar
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1 answer
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Can a steel plate reach -20°C due to radiative cooling when the ambient temperature is 2°C?

Conditions: there is a steel plate insulated at the bottom and facing the clear night sky, the ambient air temperature is 2°C, the cosmic microwave background radiation is 3K, and the convective heat ...
Miya's user avatar
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Analytical or approximate formula for temperature distribution in a greenhouse

Here is my problem: Imagine an hemicylindrical greenhouse, with length $L >> R$, its radius. So we consider it as a 2D problem. According to the schematic we have the flux of the sun at the $\...
Fefetltl's user avatar
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How much Energy is Radiated by a gray body?

How much energy is radiated by a gray body at an ambient temperature of T Degrees Kelvin, between the wavelengths of w1 and w2 micrometers , if the emissivity of this gray body is 0.6 ? (Note: ...
Derek's user avatar
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2 answers
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Removing air from voids plastic powder

A cylinder contains a powder made up two substances - spherical grains of metal and spherical grains of plastic. In between the grains are voids, so that the cylinder is made up of 75% powder grains ...
EddieP's user avatar
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2 votes
2 answers
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Do infrared heaters have a special blackbody radiation specturm?

There are many infrared heaters on the market, that I would put in 3 categories, filament in quartz tube, filament in ceramic, and carbon film (for flat panel heaters). They all claim to be "...
Manu de Hanoi's user avatar
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Why is infrared used in thermal imaging and not microwave or radio wave or ultraviolet?

In my company, we use IR Thermography. But I was thinking, why IR? Why not microwave or radio wave or ultraviolet even. Is it because of some unique property of infrared or the cost-effectiveness? Or ...
Prasoon Surendran's user avatar
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Why do we consider a wavelength range when defining spectral emissive power of a blackbody?

The spectral hemispherical emissive power of a blackbody is the amount of thermal energy emitted in the form of EMW lying in the wavelength range of $\lambda$ to $\lambda + d\lambda$ via thermal ...
Harshit Rajput's user avatar
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2 answers
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What are the factors I need to over/under estimate cost of heating in a box-like room? [closed]

For economic purposes, I am interested in studying the equilibrium of heat in a typical rectangular room from various sources, such as a classic radiator or vents. If I have a radiator sitting next to ...
PhiEarl's user avatar
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2 votes
1 answer
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Trapping sun heat the most - greenhouse

Greenhouse have recently caught my attention lately, which yesterday I posted in Why greenhouse's inside temperature never been infinitely hot? From what I understand recently, greenhouse gases traps ...
gijoe's user avatar
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Thermography - objects appear hotter than they are

recently I started working with IR thermal camera (Hikvision DS-2TD1217-3/V1) and I have a slight problem. The camera works fine when there are only people in the image, however if I place a hot ...
user29106's user avatar
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1 answer
587 views

How much time to melt marshmallow under heat lamp?

Using the Specific Heat Formula, I found that I need to apply 612J of heat to melt 18g of marshmallow. Marshmallow has a specific heat of 2 J/(g*C), melting point of 98.6°F, and a starting room ...
Wei Xun He's user avatar
2 votes
2 answers
378 views

Do the tubes of an automotive radiator flow in parallel or series?

The radiator in my car is damaged. One tube has a severe gash in it. I need to drive the car about 100 km before I can get a replacement radiator installed and coolant drains too fast to reasonably ...
Jacob Marciniec's user avatar
4 votes
2 answers
356 views

Effects of Solar Shield on Electronics Enclosure

I am designing a prototype of an electronics package that will sit out on a pole in the sun 24/7 with a max ambient temperature of 50˚C and at 30˚N latitude. It produces 50W of internal heat ...
Shea's user avatar
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1 answer
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Melt plastic powder bed with radiant heat?

I want to melt a bed of plastic powder so that the powder bed once melted and then cooled forms a solid sheet of plastic. In order to melt the powder I'm thinking of passing a nichrome (Ni80/Cr20) ...
Somanna's user avatar
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1 answer
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Calculate FTIR-system response functions from measurements of a calibrated black body

I need to find the response of my FTIR spectrometer. I do have a calibrated black-body source (area-emitter) which I measured at various temperatures. The system operates in inverse cm, cm-1. My ...
bebissig's user avatar
1 vote
3 answers
271 views

How to calculate the volume of air required to keep electrical box cool?

I have a steel electrical box that is 15 cm x 15 cm x 10 cm. The weight of the box is 1kg. Inside the box is a relay that loses 30 Watts of heat while in operation (it's attached to a heat sink that ...
Wise Shepherd's user avatar
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1 answer
2k views

calculating the efficiency of a microwave oven

If I want to calculate the efficiency of a microwave oven, I have the input Energy (= power (watts) x time (s)) and the output which I measured using temperature difference (q=mct). So do I divide ...
Shahad's user avatar
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Heat Resistance of Melamine Particle Board

I want to make a cheap thermoforming fixture out of melamine particle board so I can form some PETG plastic sheets. The forming temperature ( hence oven temp) for thermoforming PETG is around 300 deg. ...
Janet Fernie's user avatar
1 vote
1 answer
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Mount thermal imaging camera on ordinary optical microscope?

Anyone tried mounting thermal imaging camera on ordinary optical microscope? I know it is unlikely to work. Because of different refraction index and possible absorption of IR radiation by the lens.
somebody4's user avatar
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Flow of hot gasses around the pipe

I have the following problem: there is a copper pipe getting through a wooden wall. On one side of the wall (hot side), I have elevated temperature which is defined by radiation and convection. On the ...
blackarrow's user avatar
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1 answer
76 views

How cold for lack of heat?

I know that on the moon, while the daytime surface temperature can be above 270° F, in the shade but a few feet above the surface temperature can get quite low. Wondering whether a similar phenomenon ...
GGizmos's user avatar
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