Questions tagged [cooling]

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31 views

What is the Festina Lente Regime?

I am studying BEC formation without evaporative cooling, so realized only thrpugh optical means. One of the problems to face is "photon reabsorption": an atom absorbs a photon of the laser ...
1
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1answer
54 views

Air conditioner on rainy day [closed]

I got a new LG 1.5 ton AC(Air conditioner) . It's summer time here and the temperature reaches approx 40 degree Celsius at peak time. And it's working quite satisfactorily. But in the last two weeks ...
0
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1answer
53 views

Can a fan in a room cool down objects?

Does a fan cool objects? I have a ceiling fan in my office which really helps to keeps the room cool. Does it also cool down vitamins in a plastic bottle with a screw on top? My office can get very ...
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0answers
13 views

Initial and final pressures for the Joule-Kelvin expansion?

The Joule-Kelvin (or Joule-Thomson) expansion is an isenthalpic expansion in which the reduction of a gas' pressure from $ P_{i} $ to $ P_{f} $ results in a change in Temperature. It results in ...
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0answers
29 views

Temperature drop along silicone tube

I would like to ask your help to calculate the temperature drop of a fluid (at a specific conductivity) that flows in a silicone tube at different rates. This is a real case and I expect to perform ...
2
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2answers
160 views

Open window in hot room, how fast will temperature equalize? [closed]

I am currently sitting in a warm room. I just opened a window to the outdoors, where it is cooler. Middle school science says the warm air should move toward the cool air, which should (in theory) ...
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0answers
16 views

Random walks and the Doppler limit in laser cooling

I have a question about some conflicting definitions I have encountered regarding the diffusion coefficient in random walks of laser cooled atoms. I was wondering if someone here may be able to clear ...
0
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1answer
18 views

Will a consumer freezer survive air travel with a pressurization/depressurization cycle?

Is it possible to ship a consumer freezer by air cargo (such as this one: https://www.danby.com/products/freezers/dcf072a2wp/ )? Or will the refrigerant gas expand too much and break the freezer? We ...
1
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1answer
67 views

Cooling something by applying a decreasing temperature

I've recently come across Fourier's Heat Equation: $k \cdot \nabla^2 \; T = \rho c \cdot \dot{T}$ and the solution to Newton's Law of Cooling: $T(t)=\left(T_\text{initial} - T_\text{cool}\right) \cdot ...
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1answer
45 views

Is it possible that an instant coffee 3 in 1 (or any other type of coffee) is cooling faster than tea?

I have observed a strange phenomenon. I my mouth is very sensitive to very hot liquids (like, freshly made tea, or just freshly boiled water), so when I make my tea, I usually wait around 20 minutes ...
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1answer
33 views

Artificial sun Sculpture [closed]

I am designing a dynamic sculpture of the solar system, about 6,500 feet long from the sun to Neptune. At this scale the sun will be 24 inches in diameter, Earth a quarter of an inch. Every hour the ...
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0answers
44 views

Coldest temperatures achievable in DIY enthusiast/hobbyist setting

Assume I, as a physics DIY enthusiast, would like to cool a little piece of material down to coldest possible temperatures, for my own entertainment or my private curiosity/research ambitions. We all ...
0
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1answer
43 views

Using an electric/magnetic field to cool particles

I was just thinking that temperature and the motion of atoms are connected. Hence, I was wondering why we can’t just use a magnetic or electric field to hold atoms more or less in place, lowering ...
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1answer
33 views

Cooling of compressed air

If we compress air from $p_1=1bar$ with starting temperature $T_1=20°C$, the pipes behind the compressor become usually "very" hot. However, if we start at $T_1=20°C$ and $p_1=10bar$ and we decompress ...
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4answers
311 views

Intuitive explanation why rate of energy transfer depends on difference in energy between two materials?

The temperature of an object will decrease faster if the difference in temperature between the object and it's surroundings is greater. What is the intuitive explanation for this?
1
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1answer
48 views

Cooling down room with just a water

As I know, heat capacity of normal air is ~1kJ/kg and heat capacity of water is ~4.1kJ/kg. I am trying to cool down room (around 6m³) from 30C to 20C just by cold water. Let's say I have water with ...
0
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1answer
69 views

Passive dissipator block between two peltier cells seemingly raising overall temperature differential

I am experimenting with stacked Peltier cells trying to build a simple diffusion cloud chamber. I noticed that when simply stacking two peltier cells the upper side reaches a temperature (around -15 C)...
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0answers
11 views

How to calculate CFM of cooling fan using anemometer and duct?

I have quite a few 4010 (40x40x10mm) fans and would like to measure the air flow of each one. I have designed this 3D Printed duct that fits on a handheld anemometer, and the fan mounts on the other ...
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0answers
16 views

Choosing Molecular Beam Carrier Gas

What is the specific criteria for picking the carrier gas for a molecular beam? If you are studying a large neutral species, does it make sense to choose argon over helium for better collisional ...
0
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2answers
29 views

Calculate the rate of cooling of huge amount of water to room temperature

Is it possible to calculate the rate of cooling of huge amount of water to room temperature given the following parameters: The surface of water in contact with air the surface of water in contact ...
0
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1answer
41 views

What was the original statement of Newton's Law of Cooling?

In our courses of differential equations we usually find Newton's Law of Cooling stated and written as The rate of change of temperature of a body is directly proportional to the difference in ...
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3answers
183 views

Why don't people just put a water sprinkler on their roof for cooling? [closed]

Some air conditioners work with evaporative processes. So I'm not sure why people wouldn't just use a sprinkler that turns on for a minute every hour or half hour or whatever in order to wet the roof. ...
1
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1answer
62 views

What is the obtainable work from cooling water? [closed]

In Callen's thermostatistics textbook, problem 4.5-14 says If the temperature of the atmosphere is 5°C on a winter day and if 1 kg of water at 90°C is available, how much work can be obtained as ...
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2answers
45 views

Cooling of objects Thermodynamically unfavourable?

As I've learnt, systems in the Universe always tend to increase their entropy since it provides a larger number of availiable microstates for energy to be distributed and is hence statisticaly ...
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0answers
31 views

Can radiators cool down using only back body radiation?

If you could produce a very thin tube, say less than the thickness of a human hair, designed to carry a hot liquid inside, the diameter is small so that the liquid would have a high surface area to ...
0
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1answer
42 views

Laser beam versus activly cooled armor. Who will win?

I'm interested in space warfare from a hard sci-fi perspective. Usually I ask these kind of questions on Worldbuilding SE, but I felt that this one fits this SE better. Recently read this post on the ...
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0answers
32 views

Modeling the cooling rate of a nuclear fireball in space

I am interested in modelling the cooling and luminosity curves for a nuclear detonation in space (after the release of the prompt radiation). How do I get the timing of the second hump right? I tried ...
40
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4answers
9k views

Is this cheap “air conditioner” able to cool a room?

My parents bought this "air conditioner", but I am very skeptical that this can cool a room, or even cool anything. I doubt that it even has a cooling element, I suspect that it is just a fan + ...
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0answers
26 views

Cooling just one mode?

In the context of Brillouin scattering and Stokes/anti-Stokes scattering in a silicon waveguide, a speaker mentioned optical cooling, but apparently only cooling a single "mode" was cooled. I had ...
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0answers
61 views

calculate CFM of a ceiling fan

I'm trying to calculate, or even understand what data do i need to calculate the CFM of a ceiling fan. in many countries this is a given data in the product details but not where I'm from. I have the ...
0
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1answer
44 views

How do we cool gases to the $mK$ range?

When we set new records for coldest temperature in the universe, we usually do it with gases (see: https://physicsworld.com/a/millikelvin-cooling-of-large-molecules-is-no-myth/) How do we pull this ...
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1answer
440 views

How does an ultrasonic humidifier / atomizer affect temperature?

Evaporative cooling is a technique used to cool air by using the evaporation of a liquid. My google research on evaporative cooling shows a ubiquitous concept of forcing air through a pad/membrane/...
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3answers
1k views

Does tea made with boiling water cool faster than tea made with boiled (but still hot) water?

I always make tea with boiling water - not water that is almost boiling, not water that has boiled and stopped boiling a few seconds earlier - in my opinion, for the best tea flavour the water must be ...
4
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1answer
143 views

Cooling effect caused by evaporation

Evaporation is said to cause cooling effect because it absorbs energy from surroundings to change its phase from that of a liquid to gas. I am in doubt as to why would the surroundings be ready to ...
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1answer
34 views

How does evaporator coil absorb heat when a cool liquid is passed inside it?

My question is how does evaporator coil inside a refrigerator cools the inside atmosphere by absorbing heat? I am fully confused, how the heat absorption happens? This technically sounds confusing.
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2answers
2k views

What are some factors affecting the rate of cooling of a liquid?

What are possible factors affecting the rate of cooling of a liquid, aside from the volume of water, surface area of the water, or type of container.
3
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1answer
199 views

Cause of change of tea volume during cooling

At work I often drink tea, and i usually fill my cup to the brim with boiling water. When I let it cool though, until it's ready to drink, the liquids surface has sunken by about a fingers width. To ...
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2answers
33 views

New black Van in South Florida - To insulate or Not? Radiative Cooling effect?

I'm not homeless, I'm just frugal and trying to drive a lot less.. maybe I'm adventurous. :) Anyways, I've been working , eating and sleeping out of my new Black van. The van is brutally hot during ...
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2answers
105 views

Can cooling airflow be too fast for efficiency?

If using pressurized air flow to cool a hot metal tube (by blowing the air through the tube, not blowing it over the exterior), would high volume fast airflow cool better than low volume slower air ...
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2answers
139 views

Momentum Change from Spontaneous Emission

In page 188 of Christopher Foot's book on atomic physics, he talks about the Doppler cooling limit, and how it comes from a random walk caused by spontaneous emission. He claims that each spontaneous ...
0
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1answer
247 views

How to develop a model for cooling rate of steel tube in air?

I am trying to develop an equation to determine the cooling rate of a steel tube in air. I'm using Fourier's Law, Stefan-Boltzman Law, Newton's Law as well as the specific heat capacity equation. The ...
0
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2answers
96 views

which give higher cooling rate , strong circulated water or thick copper plate? [duplicate]

imagine if I have hot metal piece I want to cool it as fast as possiple, should I put it in strong circulated water bath or just stick it between 2 thick copper plates ? the calculated heat ...
-1
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1answer
30 views

which is more effective chilling for metal casting, thick copper die or water-cooled thin copper mold? [closed]

It is will known that increasing cooling of a metal casting will lead to finer micro-structure which mean higher mechanical properties. If I have 2 molds one is thick copper die ,& second is just ...
0
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2answers
1k views

Effectiveness of cooling oneself by a hand fan

I recently had a discussion with a friend of mine regarding the effectiveness of handheld fans. My friend argued that you would always get warmer. I’m sure that this needn’t be the case, as the system ...
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0answers
41 views

Cool a room with a fan, what sens orientation? [duplicate]

It is really hot these days, and at night, I try to cool my room before going to sleep but I'm wondering in which sens I should orient my Fan Answer A : Push the hotter air with my fan outside. ...
-1
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1answer
53 views

Name of this type of cooling system?

If you pump around air in a cyclic tube at a high speed, and one part of the tube is narrower than the rest of the tube, the air flow will have to increase in speed when it enters the narrow part in ...
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3answers
2k views

Why does evaporation cause cooling?

I am aware that the evaporation process causes cooling in the remaining liquid, but why? If anyone can give me the maths and or equations to prove / show this I would be most appreciative.
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1answer
732 views

Newton's law of cooling for negative Kelvin temperatures

Newton's law of cooling says that $$\frac{dT}{dt}=-k(T-T_a)$$where $T$ is the temperature of the substance, $T_a$ is the ambient temperature, and $t$ is the time. Usually, we say that if $T>T_a$, ...
23
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1answer
295 views

Melted chocolate forming fractal branches

Tree-like structure in chocolate Today I let some melted chocolate solidify in a smooth bowl in my fridge. When it had settled, I gently heated the outside of the bowl with warm water to unstick the ...
4
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1answer
189 views

Radiation cooling in space [closed]

Would the droplet cooling system from Mass Effect be actually possible in our universe? I'm interested in expanding the space industry and promote manufacturing in space. One of the biggest problems ...