A central heating system provides warmth to the number of spaces within a building and optionally also able to heat domestic hot water from one main source of heat unlike heating, ventilation, and air conditioning system which can both cool and warm interior spaces.
Hello guys,
I am currently running an experiment in my hobby room: I want to heat a cube in a microwave and then measure the surface temperature. Unfortunately, it takes about 20 seconds, so the cube cools down during this time which means I don't measure the actual temperature after heating...
According to the Joule experiment, work can increase the temperature of a liquid. Is it possible to boil water simply by stirring it? How much energy would be required?
This is my first post of a homework problem, and I am just trying to make sure I am not missing anything as I help a child who is taking a college class on this stuff this summer. And to be clear, just trying to help her understand stuff, not help her with the homework problem. So I won't go...
Suppose I have a current carrying wire that is 20 AWG copper. There is insulation on the copper wire that is rated for 200 degrees C. I have 500 meters of the wire wound into a coil. The coil takes up a total volume of 0.0001157 meters cubed (roughly 1000 turns). Suppose I run 3 amps of current...
There's a recent article about cooling hydrogen in an industrial scale with the magnetocaloric effect.
Read the article here
But where does the heat go there? Can it be used for heating liquids? Could it be used for an ecologically and economically viable source of energy like a heat pump...
Hi,
This is my first post on PF. I am engaged in a project seeking to find a simple way to reduce ethanol content in wine for those wishing to minimize alcohol intake for health or personal reasons. The alcohol-reduced wine will be used for cooking. Seems heating would do the trick however, the...
Yet no-one has been able to provide any formulae etc to expand the topic further. A lot is said about house construction (high mass vs low mass) but that doesn't take the discussion any further.
I think the key question is if your house is badly insulated then it's losing heat all the time...
Dear all,
First of all I would like to thank everyone for this great forum. I've been reading the forum for years, but I hadn't registered until today.
My registration on this forum obviously has a reason. I have an issue that I can't quite figure out.
I am trying to calculate how much power I...
I have searched online for this and found that it's due to friction. But for a rolling tyre there is only static friction acting and static friction produces no heat. For heat to be produced the two surfaces in contact must slide over each other i.e. there needs to be kinetic friction.
Perhaps...
As a transformer freq bet higher, inside induction get more efficient i.e. less loss:
1. Hysteresis loss = η * Bmax^n * f * V.
2. Eddy current loss( proportional to B2mf2Bm2f2 )Now it seems that losses increases with increase in efficiency...
But the above equations are valid when max flux...
I was taking notes from a lecture on Quantum Physics and during the introduction, they gave an example of what led to the discovery of Quantum Physics: The electric bulb example where the brightness and colour of light depended on the temperature of the filament(see...
High School Physics Lab: Take 200mL of water (Room temp) and place it in a microwave on high for 60 seconds. Calculate the Energy transferred to the water by the microwave.
Pretty easy:
Step 1: Heat of Temp Change : Q= mC∆T where m=200mL
Step 2: Add Heat due to phase change: Q=mL where m=...
Hello,
I am stuck how to proceed with the equations below.
The problem:
A tank containing ##m_0## mass, with a temperature of ##T_0##, is to be filled with a total mass of ##m_1##, with the constant mass flow rate ##G## and temperature ##T_1## during ##t_p## seconds. ##T_0>T_1##. Other than the...
I've found this question online and don't agree with the explanation given.
Explanation
I disagree. If you heat the jar, the diameter of the top opening increases more than the diameter of the wooden lid, making it looser. The opposite happen if you cool the jar and the lid.
Can you please...
I was thinking the other day about green houses and how they would act in space or on another planet without an atmosphere. I know that green houses work on Earth by stopping convection but could they theoretically trap heat in a non atmospheric environment? I am imagining a material that allows...
Hello there, Physics forum. I live in Alamo, California and I'm planning to install pool solar. All of the installers have completely different POVs on which face of the roof I should put them, and hoping to get some physics-based advice. Here's the home with the 3 face options (front already...
Hello, everyone!
I am calculating the time of substrates' heating in the vacuum chamber.
It is a simple mathematical model to calculate roughly how much time does it take to heat polycor substrates in the vacuum chamber.
At least all the tube heater`s power heats the substrates (this is...
Quick question 1st, is there a Magnetics forum here on PF?
I am working on a project that is inductive heating using two coils and some simplified current control circuitry that can drive coils 10-100kHz.
I have some questions around the magnetic fields and localized eddy currents.
Let me set...
It has to be going somewhere!
The boiler pressure drops by about 0.5Bar every few weeks. I've looked at the radiators for signs of small leaks but I haven't been inside the boiler as yet because I only recently terminated a maintenance contract with British Gas. BG were not interested in a leak...
Summary:: This is a question about resistive heating at low power in a thermally sealed chamber.
Suppose one has a resistive wire inside a small very well insulated chamber that can stand very high temperatures such as 1500C. For applications such as a kiln, the heating element is powered at...
In winter I heat my workshop with a radiant heater and an oil heater. Easy to know how much heat is entering the room.
But in spring and summer I don't use those; I blow hot air from the ceiling cavity into the room, and I was wondering how I would estimate the heating power and the formula to...
Hi group,
I heated a steel spring until red hot then plunged in water quenching it.
My understanding is that quenching so quickly would have an effect of the grain size such that I would expect it to be much more brittle as with small grain there is much less plastic deformation possible (as...
I've been thinking and can't come up with a satisfying answer. Would there be a difference in the amount of heat generated in a given time in a metal rod if it was heated by
a) induction
b) current passing through the same length of rod
Given that the current is the same amperage and...
Hello, everyone :).
I try to resolve this common problem. But, when i got in the interpolation of state 2, the values not make the sense.
I have 25 psia and 75 F, but, in the superheated water table, there are not values with 25 psia (only 20 psia and 40 psia). And, the temperature values...
Summary:: Gibbs and Helmholtz energies calculations for heating an ideal gas at constant volume
I am solving a problem involving an ideal gas that undergoes several chained changes of state. One of the steps asks to calculate the change in Gibbs Energy (DeltaG) and Helmholtz energy (Delta A)...
Plz forgive. Old man fingers on young whippersnapper phone kb.
This stove takes an hour to boil a pot of water. I'm looking at replacing the burners right now. They look brand new (top) but who knows?
I bought this one (bottom) which is not exactly the same one. The prongs will fit but the new...
I thought about this for some time but I can't seem to really understand the cause.
Now I remember some time ago using a transformer for my self made soldering iron, I wound it to have the right temperature at about 45 VAC input but I guess I missed a bit , so that when I connected it to the 45...
Several apartments have under floor heating (water) with a common boiler room and a central pump. There is no pump in the apartments. Each pipe run on each apartment's manifold has its own flow-indicator. The owner of one apartment is worried that if the neighbor turns off its heating, then more...
I found this interesting thermodynamics problem on another site. I thought PF members might find it challenging to attack. I'm not asking for help since I've already solved it. So pease feel free to present your entire solution if you desire.
Chet
Could directed energy fundamentals be used in active confinement by hybridizing the heating system with directed energy. I'm sure I'm wrong in this because I only have my high school diploma.
I am looking for a reference that will give me some physical intuition into radiative heating and cooling. I am not afraid of math, but I am not interested in performing detailed calculations.
hi i have a 646 se from quickie powerwheel chair pride company.i bought it used
it always have had a pull on the right side as if the right side motor was weaker so to go strait i had to aim a bit at the left with the joystick.This summer the right motor or close to it started making a...
I am trying to determine the coldest temperature my campervan can be in, so that the heater is still able to keep the van at 21C, while still being able to blow 15CFM air into and out of the van.
Here is an earlier post figuring out the need for ~15cfm per person of fresh air to maintain less...
I just found this piece in an article:
Terahertz waves (THz), which are submillimeter waves sitting between microwave and infrared light on the electromagnetic spectrum, have been used to achieve data rates greater than 100 Gbps. Unfortunately, THz waves share an Achilles’ Heel with the...
I thought about using Black principle to solve this question but I am confused about the final temperature of system
Q released by vapor = Q absorbed by water
mvapor . cvapor . ΔTvapor + mvapor.Lv + mvapor . cwater . ΔT2 = mwater . cwater . ΔTwater
But what is the final temperature of the...
Hi guys, girls, and non-binaries. I'm a private high school teacher and I'm preparing myself to prepare others for polish physics olimpiad. So I delved into books which have a lot of tricky questions and from time to time I stumble upon one I have trouble with. And that's exactly what happened...
1)$$R=\frac{\Delta t(\Delta V)^2}{Q}=\frac{\Delta t(\Delta V)^2}{mc\Delta T}=8.33\,\Omega$$2)$$\Delta t'=\frac{mcR\Delta T'}{(\Delta V)^2}=\frac{\Delta T'}{\Delta T}\Delta t=59.4\text{ min}$$3) I surfed the net a bit and have found a post on physics.stackexchange in which it is mentioned that...
In class, we briefly discussed those experiments where a paper cup is filled with water and heated, and the cup does not end up burning while the water is able to boil.
From what I remember of what was said, although I am not sure I understood correctly, the water has a much higher specific...
Hello everyone!
I'm new to the forum, and I've been trying to solve a problem that seems farily but I can't still convince myself of having the right (or wrong) answer.
Imagine you warm up one mol of for example potassium hydride from standard temperature 298.15K to 673.15K (400 deg C). It is...
Apparently the answer is to have the jumper over the bucket. Am I wrong in thinking that the jumper transfers heat to the ice cream, why does it not do so?
A similar question elsewhere was "Colin claims to have built a refrigerator alternative which works without any power supply. It is a box...
In previous manifestations explaining the Coronal Heating Problem, scientists pointed out the discontinuity between a very hot Solar interior, the 'cool' Photosphere and a Hot Corona.
According to the newly modified entry in Wikipedia, they now explain the discontinuity only between a cool...
I've had a question bugging me lately and no matter how much I google, I can't seem to find an answer. I'm sure this probably isn't possible, and my logic is probably flawed (Earth sciences isn't my forte), so I figured I'd ask you fine folks here.
First, my understanding of wind, it's caused...
A thermal flask with water of temperature 90c is placed out in room temperature 20c, sealed. How long before it reaches 55c?
outer radius and height: 5cm, 25cm
volume of water is 1litre.
R = 0.5 Km2/W
using this equation to solve it combining these two and integrating with respect to T...
A)W goes downward because before AB gets heat up the system was in equilibrium hen after getting heat up the Force that AB produce makes the roller moves to the right and that makes the whole system go down
B)I don't know what it means I know that this can mean the forces that the member Ab is...
Through the research that I conducted is that I wasn't able to find actual supporting answer to this question. I struggle with Physics and math and because of Coronavirus my school has shut down meaning I don't have access to my teachers or tutor. The main line that i am thinking is that if it...
I know typically the hot cathode of an electron gun or vacuum tube is heated either directly or indirectly by electric resistance heating. What if the tungsten (cathode) were heated by another means, say focused sunlight? Electrons would still boil off through thermionic emission. If a small...
I'm having quite a bit of a problem with this one. I've managed to figure out that ##T_0 = 0##. However, not knowing what ##q(t)## is bothers me, although it seems that I could theoretically solve the problem without knowing it. For ##t>t_1##, integration by parts gives me ##T = Ce^{-t/10}##...
Homework Statement:: I'm working with solar heating systems, and my teacher added this picture to his PowerPoint. But I don't understand the picture. Could someone help me?
Homework Equations:: The only thing I understand is that ##I_0## is the energy from the sun. But the other arrows confuse...