What is Cooling: Definition and 638 Discussions

Hello all, quick question: When Plasma cools what state does it return to? Is it a liquid or the state it was in before at room temperature? Do the atoms rearrange into what it was like before i.e. the same element or something completely different? Thank you

Homework Statement A 0.2 m^3 steel container that has a mass of 30 kg is filled with liquid water. Initially both the steel tank and the water are at 50°C. Now heat is transferred, and the entire system (i.e., steel and water) cools to the surrounding air temperature of 25°C. Determine the...

Hey, so I was thinking how the atmosphere is held close to Earth due to gravity and realized that if certain molecules have a certain amount of kinetic energy, they are bound to leave the atmosphere correct? I mean there is an escape velocity that these molecules must need and I'm sure molecules...

Dear All, Referring to the subject above, I have found the calculation of heat load based on [Lawrence,K.W., Norman, C. P. & Yung, T. H. (2005). Advanced Air and Noise Pollution Control. Totowa: Humana Press.] My cooling pond system: 1. Purpose: cooling POME temperature from 70 to 40 degree C...

Homework Statement A boll of iron with the volume ##V=\frac{4 \pi 0.01^3}{3}## heats up to 1073 K in a chamber with vacuum, how long will it take until the iron is at 1063 K? The given data is this: ##\rho_{iron} = 7870 kg/m^3## specific heat.. ##c_i = 0.5 \cdot 10^3 J/(kg \cdot K)##Homework...

Not a physics student -- but was thinking about how the A/C system works in a vehicle. First surprise was that pressure drops when a tube narrows. Seemed counter-intuitive as I was picturing taking a balloon and squeezing it -- would the pressure in the middle be lower than the ends? Then again...

Dear Everyone, I need some help figuring part b in this problem. In the book states, "According to Newton's Law of Cooling, if an object at temperature T is immersed in a medium having a constant temperature M, then the rate of change of T is proportional to the difference of temperature...

Hi, just curious: Is there a nice rule-of-thumb to apply Newton's cooling to ACs? Specifically, if I know the AC temperature is , say 60 deg. , how long will it take, after I turn off the AC, before thetemperature rises to an unacceptable level of 85 degrees? Thanks.

Hi guys, I have a question on cooling the house. So at night, I usually open windows to let all of the cold air come in and open the 2nd floor windows to let the hot air out. The 2nd floor is a large open area and has windows in the front and windows in the back. Now, I normally open all the...

Hi everyone! I need some guidelines on how to calculate and design an external oil cooling system (the oil cooler is located outside of the oil tub) for a thrust bearing. Could you please give me some links to standards, handbooks, manuals etc to start with? Thank you.

I am wondering if someone can please advice on how to improve the effectiveness of a cooling system I am using. I am trying to cool a substance using an 8m long conveyor belt with 3 air conditioning units with two outlets on each unit blowing down on the material. The current set up I have...

Homework Statement Hi all, I have a question about using peltier cells for both cooling and reading temperature in the same moment. I need to cool down a couple of Integrated Circuits so I'll put put a 20mmx20mm peltier cell over them but I cannot read the cold side of the cell because it's...

So say I have a tank of water of about 2000mls which is at around 80 degrees celsius and is pumped around a copper system which is 3/8th inch thick pipe. how many meters would the water have to travel through copper pipe to return to ambient room temperature of about 20 degrees celsius. any help...

Homework Statement Mathematically prove how Newton's Law of Cooling is derived. Homework Equations Newton’s Law of Cooling states that the rate of change of a temperature of an object is directly proportional to the difference between its own temperature and the temperature of its...

Hello I am designing the cooling system for cabinet with all the electronic components inside. I am using 2 axial fan with louvers at one end and other end has exhaust louvers. Currently i want to optimize the air flow/cfm inside the cabinet so that i can maintain overall temperature under...

Hi all, I am not sure if the is the right place to post the question being new to the forum, but I am looking for some help with a heat transfer experiment that I ran for my honours thesis. Essentially the aim is to determine if warmed saline fluid bags taped to 3 different types of tree barks...

Homework Statement I have to study laser cooling. I'm actually trying to understand the Doppler limit on temperature. On the net I have found "at a certain point the cooling mechanism is foiled by heating due to the random absorption and reemission of photons...

I have a condenser with a mass flow rate of 60kg/s, an initial point 1: P=50kPa, Quality = 95% and a final point 2: P = 50kPa that is saturated liquid. cooling water flows through the condenser with a mass flow rate of m(dot) and has a delta temperature of 15 degrees Celsius. how do i...

Im working on a project for fun using a peltier cooler. A tec1-12706. If i am operating the peltier at 9v, 6.4 amps of current and dt =45ºC (from datasheet) and bring its cold side in contact with a body at 33ºC for 10 seconds. Keeping hot side at 27ºC(cold side =-18) using sink, what will be...

Hi, I just need help getting started with this problem. I am given the Newton's cooling law which is T'= -k[T-Ta] and I'm also given that Ta is a function also and it is Ta(t)=65-10cos(t) I'm asking to solve for T when k=2 and T(0) = 75. Do I just plug in 2 for...

Homework Statement A pocket of air rises 1000 meters. Estimate how much it cools. Use the atmospheric law to determine pressure at 1000 meters. Homework Equations P = P0 * e-Mgz/RT PVγ = constant TVγ-1 = constant The Attempt at a Solution Using the atmospheric law, I found the pressure at...

The inlet temperature of a baghouse under negative pressure is 400 F and the outlet temperature is 210 F. The volume of air is 10,500 acfm. (baghouse is in poor condition). How do I determine the actual volume given this information?

Hi, I'll describe my problem more specific. I have a continuous flow of this polymer thread (polystyrene) at 465 °K (190°C sorry I'm metric) that needs cooling down. It passes trough a water bath which is kept at 310°K (35°C). Now i try to calculate the heat exchange into the water, to...

I am modeling the injection of hot magma sills into the Earth's crust at varying rates (and varying sill heights for each rate). For instance, for a total of 16 km of magma ... 1a-n. 40, 400m high sills emplaced at rate of 5e-3 ma-1, 5e-4 ma-1, 1e-2 ma-1, , 2e-2 ma-1, 3e-2 ma-1, and 4e-2...

Hello everyone! I am new here. I have used this forum on and off through google searches in the past and learned a fair bit from the posts. This is the first time asking anything. The question is probably extremely simple but has been overrun in my head for a week! It is in regards to...

Newton's law of cooling is: dQ/dt = KA(θ - θo). Then where does the equation dQ/dt = KA(dT/dx) come from?

Hello all, I am solving a heat transfer problem for cooling of laminate plate in a cooling press and I intend to use a Robin boundary condition on one of the sides to evaporate heat away from the plate. The Robin boundary equation is specified thus: k∂T(t)/∂n + hT(t) = g(t) where k is the...

A detective finds a murder victim at 9 AM. The temperature of the body is measured at 90.3-degrees Fahrenheit. One hour later the temperature of the body is 89.0-degrees Fahrenheit. The temperature of the room has been maintained at a constant temperature of 68-degrees Fahrenheit. Estimate the...

Could anyone venture a guess or offer comments on the following... Jill is very P.O.ed at something Jack did. Jill decides to retaliate. Jill's blood is boiling the day after the incident with Jack and is most likely to retaliate that day. On Day 2, Jill has cooled down just a little but has...

One aspect of glasses that has confused me was the fact that the transition temperature Tg drops as you slow the rate of cooling. This has confused me because if the glass is slowly becoming more crystalline, then I would of thought that the Tg would start climbing up towards the crystal melt...

How much power do the different engine systems require to operate? For example - HVAC System - 3kW Engine Cooling System - xxkW Transmission cooling system - xxkW Heated/Cooled seats - xxkW

If the temperature of an object with temperature T(t) is place in a room with the ambient temperature Ta, Newtons Law of Cooling is defined as dT / dt = k (T(t) - Ta), correct? This implies we would need a negative k-value. Wouldn't the equation therefore be described better if T(t) and Ta...

I just need someone to confirm my answer so I can be certain that my book has a typo and I am not making a some minuscule mistake that is leading me to the wrong answer. A piece of metal is heated to 300 degrees Celsius and then placed in a cooling liquid at 50 degrees Celsius. After 4...

Hi there, i am currently working in an airline industry but unfortunately do not have enough facilities to carry out my research on the HPT Blades and its cooling holes of an Engine. Would anybody help me on this matter? Thanks

I am currently working on a prototype for a new product. Whithout exposing the product to much it is simply put a cooling box run by solar panels with a battery backup. Due to the fact that the surface area available for solar panels is limited the cooling module needs to be quite small and...

I'm currently studying ion trap experiments, many papers suggest the cooling of trapped ions, and other papers say its a heating process. I know there's a difference as to what each refers but am unclear of the difference. I'll quote...

Hallo, Working on building a cloud chamber based on thermoelectric coolers rather than dry ice or other "consumable" cooling methods, and having some difficulty working out some of the numbers. Say I have a volume of air at room temperature, for arguments sake 1600cm³, and I want to cool this...

Homework Statement Suppose we have a cylinder of radius R, in an environment with temperature Tenv, and heat is generated in the wire at a rate P per unit volume (for example due to a current - the exact nature is irrelevant). The heat flux from the surface of the wire is A(T(R)-Tenv) for...

I just began reading Feynman lectures and it turns out that during evaporation, water molecules that move faster than average (higher temp) break away from the attraction of their neighbors leaving behind molecules that move slower than average (lower temp) and result in a cooler liquid. When a...

Homework Statement Hi people, I am just having a little play with some physics because basically I went to drink my tea this morning and its always too hot. Then I wait and its always too cold. So therefore I fancy to try and workout how long should I leave it until it is cool. I found a study...

Hi, I'm a mechatronics student and I am currently working on a project on the effectiveness of a vortex tube to cool a cabinet. The cabinet has a thermostat inside and if the temperature exceeds a threshold, an air compressor is turned on, causing the vortex tube to cool the cabinet. The cabinet...

hI'm hoping someone here is well versed at using thermoelectric cooling modules. I'm not able achieve anywhere near the cooling capacity shown in the datasheets and I'm pretty sure I've covered all possible things that could be going wrong. All I'm trying to do is maintain chilled water...

Say there is a cup of coffee at 80ºC and you allow it to cool down. Eventually the cup of coffee will become at room temperature (if anyone knows the equation for this fluctuations of temperatures I'd love to see it) what is causing it to go from these temperatures? What are the principles are...

For dealing with different types of loss of coolant accident (LOCA), pressurized water reactors (PWR) have emergency core cooling system (ECCS). ECCS are simply redundant pumps to inject water into core to cool fuel, thus preventing fuel melting in case of an accident (hypothetical) that involve...

Homework Statement A hot solid sphere of initial radius ##a## with a uniform initial temperature ##T_{0}## is allowed to cool under stagnant air at ambient temperature, ##T_{\infty}## . Assume the temperature within the sphere is uniform throughout the cooling process. Show that under...

Homework Statement One method for cooling a gas is adiabatic throttling (Joule-Thomson Experiment). Another method is a reversible adiabatic expansion. Show that if the initial and final pressures are the same, the difference in temperature obtained by the second method is always higher. Hint...

If electric current passes from relatively good conductor to a much worse conductor (resistance), electrons start to loose energy and dissipate it as heat. Does opposite effect take place? I mean, when electrons pass from some poor conductor to a much better conductor, will they absorb energy...

What happens if a metal is heated and cooled at the same point at the same time?? will it expand or contract??

Homework Statement On a clear night, the loss of infrared radiation to space causes the loses 10 m of the atmosphere to cool by 5 K over 10 Hrs. Assuming a density of 1.25 kg^-3 for the air, what is the net rate of heat loss by radiational cooling, in Wm^-2 (Answer: 1.74 W m^-2)Homework...

As I understand it, a virus like HIV for example cannot survive more than a few degrees below normal body temperature. Is it possible, therefore, to reduce the whole body core temperature, under controlled conditions, to well below the virus survival threshold temperature, thereby killing the virus?