# Questions tagged [thermodynamics]

Questions relating to the various laws of thermodynamics, transformation or movement of a form of energy to another form, primarily but not limited to heating or cooling of a fluid.

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### What cars had this cooling system?

As emission standards tigthened, water-cooled engines far surpassed air-cooled engines due to the relatively cold start, so to speak, of an air cooled engine. I wonder, though, if a system that first ...
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### How to calculate temperature increase in a step motor?

The background is, I'm working in quality, and I just need to be able to tell if someone can burn themselves on the motors built into the product. I have the datasheet for the motor, and the ...
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### Understanding sensible enthalpy for steady-flow system

I am reading a book (Thermodynamics an Engineering approach), I am reading over the section of steady-flow systems with chemical reactions. The book just introduced the following formula for the ...
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### Building a Peltier module mini-cooler

I am just a noobie in engineering stuff. Should the DC Fan 1 suck the air out of the Al heat sink OR push air into it for more efficient heat dissipation? For the small heat sink placed on the colder ...
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### Geothermal: Energy output calculations for a very large heat exchanger

Using deep wells as heat exchangers to extract geothermal energy has recently emerged as a concept. It can be visualized as a long (2000 m) vertical tube with an inner diameter of 162 mm (the outer ...
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### Determine downstream temperature of (upstream) saturated liquid -- problem underspecified?

I was given the following problem as a pop quiz: You have liquid nitrogen in a container, in a saturated liquid state, at known pressure P1. It flows through an orifice to known pressure P2. How ...
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### Between black and white plastic bag, which one is better to conserve hot and cold respectively?

I want to sell online fresh food and drink, something like in the picture. The food is newly cooked, so it is hot. While the drink is iced, so it is cold. The food mostly will be eaten during lunch ...
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### Reactor with mixing and a cooling jacket

Suppose we have a reactor with mixing that contains a known quantity of water at $121^{\circ}C$ (due to the pressure, the water is liquid). We want to cool the water to $37^{\circ} C$ by using cooling ...
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### The Heat Generation and heat flux both in General Heat Conduction Equation

How would I incorporate both heat generated within and element and heat flux from external to the element in GHCE. For example, Let there be a thick wall of thickness 'L', with internal heat ...
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### Finding Static Conditions from Total conditions

I am trying to create a code which determines the static properties of a flow given the total (stagnation) conditions, plus an area and mass flow rate. Since the velocity and as an extension, the mach ...
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### How powerful would a laser need to be to melt through an iron girder from a distance of ~260m?

Merely a curious fool contemplating how plausible it would be to cut the Eiffel Tower in half with a massive laser (you know, for fun). What kind of laser would it take to cut an iron girder from ...
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### Help Needed: Looking for Sample Phase Change Material (PCM) Calculations

I am working on implementing a Phase Change Material (PCM) system for a cold storage facility. While I'm familiar with traditional refrigeration systems, I'm relatively new to PCM technology and would ...
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### Parameters to characterize heat dispersion

I'm working in a team to model some production machinery in a factory. They ask me to find a way to describe and quantify the heat loss to be able to make an initial and approximate comparison between ...
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### How to derive the relation of a and b according to critical points (including compressibility factor) from Peng Robinson EoS

I've been trying to prove the relation of a and b according to critical points of PR EoS: prove that a and b are: a = 0.457 (R^2T_c^2)/p_c , b=0.0778(RT_c)/p_c I tried to prove it by doing the partial ...
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