Questions tagged [cooling]

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Non-physical result in very primitive laser cooling simulation in Mathematica [closed]

Basically I am trying to very very primitively simulate laser cooling of a 2 level atom in Mathematica. The code: ...
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1answer
44 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
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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 ...
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1answer
89 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
24 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
261 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.
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1answer
72 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
29 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
32 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
60 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 ...
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1answer
66 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 ...
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2answers
59 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 ...
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1answer
26 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 ...
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0answers
166 views

main difference between dry and wet dilution refrigerator

I always wondered what the main differences are between dry and wet fridges. To operate wet fridges, I noticed people had to continuously fill it with liquid helium whereas dry fridges don't seem to ...
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2answers
270 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
29 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. ...
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1answer
40 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
915 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
445 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 $T>T_a$, ...
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1answer
254 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 ...
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1answer
132 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 ...
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5answers
97 views

Is it more difficult to cool than heat?

While it seems there is a lot of ways to generate heat, using mechanical, chemical or electrical engineering solutions, it seems that generating cold is more difficult. Most cooling devices that exist ...
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2answers
211 views

Heat transfer in the isothermal expansion in the Carnot cycle

Problem In the Carnot cycle there are two adiabatic and two isothermal processes. This question focuses on the isothermal expansion. In the isothermal expansion books often writes that the system is ...
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1answer
212 views

Adiabatic expansion of ideal gas

I am considering a system with initial pressure $P_{A}$ and volume $V_{A}$. The internal energy $U_{A}$ should be zero. Then I have the following law for an ideal mono atomic gas $P^{3}V^{5}=const$. ...
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1answer
75 views

How does a heated object raise the air temperature around it?

When object is heated and the heat source is removed, how long does it take to cool down and how it does it change the air temperature around it. If We know the temperature of the heated object and ...
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1answer
82 views

Refrigerant vs water heatpipe [closed]

For a heatpipe that is connected to a 50 Celsius object on one side,and a heatsink at 23 Celsius air at other side, what fluid filling will give better heat conductivity? Plain water, or some kind of ...
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1answer
638 views

What is Excess Temperature?

I am reading about Newton's Law of Cooling and the following is an extract from my textbook on the experimental verification of this law. "Consider a spherical calorimeter of mass m whose outer ...
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1answer
102 views

Why must Debye cooling eventually slow down?

Masanes and Oppenheim derive a maximal cooling rate $T(t)\geq k/t^7$ in their paper on the third law of thermodynamics. This is not just a bound on passive cooling, but also active cooling using any ...
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2answers
137 views

Can I increase cooling efficiency with evaporative cooling?

I had an idea recently. But I don't have the physics knowledge to know if it makes sense or not. I've become a bit of a PC enthusiast lately and one thing that is big in the PC world lately is water ...
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0answers
84 views

What is the radiative cooling rate at extremely cold temperatures?

Consider a spherical object in empty space, in the far future where the CMB can be entirely neglected. What is the cooling rate as it approaches radiative equilibrium? Here is what I got so far: The ...
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1answer
130 views

How does the power consumption and cooling capacity of a Peltier refrigerator change when the interior is made reflective?

I've a small Peltier cooler which I used to store some chemical stuffs. So, I recently modded the design to make it more bigger and improve its cooling + insulation. I've added an aluminium piece ...
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1answer
299 views

Analyzing the rates of cooling points using the graph and data [closed]

how should i use this data to analyse the differences between the two materials. and what calculations could i use for it?
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1answer
58 views

Cooling a bottle to around -70°C the easy way

As the topic already tells, I want to cool a glass or aluminium bottle down to roughly -60 to -70 °C for the sake of science. Additionally this setup should be portable for showcasing it at school. I ...
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1answer
378 views

Time of death from Newton’s law of cooling – do I need the initial temperature? [closed]

Suppose that a corpse was discovered in a room and its temperature was 32°C at 12pm. The temperature of the room is kept constant at 20°C. Three hours later the temperature of the corpse dropped to 27°...
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2answers
3k views

Is frequent opening of the fridge really so significant for the power consumption?

I've read several popular articles telling that frequent opening of the fridge highly increases the power consumption. Is it really so significant? Isn't the heat in the room-temperature food which ...
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1answer
566 views

What is the role of the plug in Joule-Thomson expansion?

I've read a lot on J-T effect but it isn't still very clear... What is the role of the plug or valve ? It seems to me a very strange "non physical" requirement... It is often said that because of the ...
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3answers
231 views

Air cooling by forcing air through soda bottles

I saw this story on YouTube about a guy who made a panel of empty soda bottles to cool wind as it blew through them: https://www.youtube.com/watch?v=i2NWr6bRKWU I tried this with a box, filling it ...
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1answer
93 views

How does the Newton Law of Cooling should be modified in case of free convection?

According to "Mathematical Modeling: a Differential Equations approach" by Barnes and Fulford 2nd edition, it should be $ T' = k (T-T_0)^{5/4} $ where $T_0$ is the temperature of external gas or ...
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1answer
2k views

How do the pressurizers in a PWR nuclear reactor (Pressurized water reactor) work?

I did a bit of googling and wikipedia informed me that the pressurizer is just a vertical tank of sitting coolant water that directly connects to the reactor. Then electrical heaters in this vessel ...
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0answers
28 views

Gas energy dissipation causing collapse

Why is the dissipation of energy of gas causing it to undergo gravitational collapse? Is this a result of the virial theorem? Reduced pressure gradient?
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2answers
148 views

generate electricity from cooling tower

I am wondering while there is a reasonable continuous air flow inside the cooling towers from down upward due to the pressure difference between down and up, why we don't use a wind turbine and placed ...
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1answer
47 views

Does condensation on a cooling element indicate lost cooling efficiency?

I have a box with 80%ish humidity, temp ~80f, a strong fan, and a TEC (peltier) with coolsink mounted-- the coolsink does NOT have a fan attached. The TEC is ~68' normally and drips condensation from ...
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1answer
430 views

Newton's law of cooling

I learned in physics class that, according to Newton's Law of Cooling, "The rate of fall of temperature of a body is directly proportional to the excess of temperature over the surroundings, ...
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10answers
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Condensation of Water. Classroom Controversy

In our test there was a question that went like so: Question 4 You have a glass of iced water on an unshaded picnic table and went for a walk for 30 minutes. When you return you noticed the glass ...
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1answer
195 views

Does Newton's law of cooling work for forced convection?

Does Newton's law of cooling work for forced convection, what extra parameters do I have to consider in the law then?
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1answer
142 views

Q: Laser cooled hydrogen

Is it possible to cool down hydrogen some much (using lasers) to get a metalic form of the element? Or to try to produce it no such cooling is required?
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2answers
68 views

Self sustained cooling approach [closed]

I have a hot object (about 200 centigrade), and would like to cool it down. Is there a way to use its heat to operate a cooling system without exerting external energy; as heat is energy and can ...
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1answer
1k views

Venturi effect better for cooling through duct

I have a laptop which is overheating, and I would like to improve the cooling (without opening the laptop). The only option I can see (reasonably) is to increase the airflow moving through the laptop....
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1answer
26 views

Distributed Workload AS cooling?

To my understanding, many processes require cooling to achieve optimum use. Power stations, for example, require cooling for electricity production. Computer hardware systems, similarly require ...
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755 views

What are the physics behind a spin drink cooler?

I just came across this spin drink cooler project on Instructables, that purports to cool a drink in 60 seconds. You attach the can to some swiftly rotating device, like a drill or a motor, and ...