3 votes
Accepted

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

All (car) radiators are parallel, it is the only way to get the flow rate and reduce the fluid velocity in each tube sufficiently to allow the time for heat transfer. However, some radiators are ...
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2 votes

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

If I get you right, there is a box having a small device that dissipates 30 Watts of heat continuously into the air. The air is blocked into a box, no way in or out. There are no fans/blowers trying ...
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2 votes

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

This question can only be answered after many tests as to the convective properties of the box, it's geometry with respect to the geometry of the void, ignoring radiation. Because convection which is ...
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2 votes

Melt plastic powder bed with radiant heat?

Any diameter wire, multiple parallel heated elements describes a toaster, an electric oven, any number of radiant heaters already in existence. Your problem is not whether you can do it with such a ...
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  • 6,092
2 votes

Effects of Solar Shield on Electronics Enclosure

If you are worried about the solar radiation (which is understandable), a much more affordable solution might be to put the whole thing in a shade if its possible, with enough clearance from the ...
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2 votes

How much time to melt marshmallow under heat lamp?

You are missing several things. You need to know the emissivity of marshmallow. That will tell you how much of the 150W of radiation is absorbed, and how much is reflected. You need to know the ...
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1 vote

Why do we consider a wavelength range when defining spectral emissive power of a blackbody?

Thermally radiated photons are emitted in whole piece of material, but only those photons which were born near the surface have a substantial possibility to avoid getting caught inside the piece. So ...
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1 vote

What are the factors I need to over/under estimate cost of heating in a box-like room?

Thermal equilibrium will be reached when heat in = heat lost. Find the U-value for each surface and calculate the heat loss rate in W/K (watts/kelvin) for each surface. Add them up and you've got the ...
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  • 7,509
1 vote

Trapping sun heat the most - greenhouse

Greenhouses generally work by trapping radiation (infrared to be more specific). More specifically what they do is allow most of the sun radiation to come through and then trap the infrared radiation ...
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1 vote

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

Parallel, each tube just opens into the end-cap or top/bottom chamber ( On those I have seen, which is a bunch ,but they were all old copper/brass types).
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1 vote

Effects of Solar Shield on Electronics Enclosure

Briefest start. Written from a hosp[ital bed just post operation :-) - better could follow if useful. Solar loading will be peak in hours around noon. Angles shift across year. Find your site 0n ...
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1 vote
Accepted

Calculate FTIR-system response functions from measurements of a calibrated black body

For anyone coming later: I ended up using a procedure described here: Kevin C. Gross, Phenomenological model for IR emission from high explosive detonation fireballs In one sentence: I ended up ...
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1 vote

calculating the efficiency of a microwave oven

The equation for efficiency in thermodynamics is as follows: $$\eta = W_{out}/W_{in}$$ and to get this as a percentage you just multiply $\eta \;\mathrm{x}100=\%$ See the link below! https://en....
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1 vote
Accepted

How cold for lack of heat?

Imagine the system below at equilibrium. The energy balances are as follows: At the ball ... $$\epsilon_b T_b^4 =\epsilon_w T_w^4$$ At the wall ... $$\epsilon_w A_w \sigma T_w^4 = h_a A_w (T_a - ...
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