My physical science class is currently doing a formal experimental assessment on "The Dynamics of Heating a Room", where we have to investigate the effectiveness of heating using a 12V, 21W light bulb in a cardboard house we have built.During this investigation we also have to change a variable...
How come heat pumps aren�t used more widely for heating buildings?Is it because they are expensive to install, the efficiency i.e. (energy pumped / input driving power) is not very high , they take up too much space for the heat they deliver or because the capacity to pump heat is limited?I...
The other day i needed some pure water to do an experiment (which i will post on PF as soon as i feel that i am done of it).So the only way i could think to get some pure water is to evaporate the water first, and then cold it down, i know i will not get 100% pure water, but i thought that i...
If gravity can stir up the inside of a planet, and heat it up, then isn't the same effect true for atoms? Imagine a hydrogen atom. The electron, however insignificant, must make the nucleus wobble at least a little. And the uneven gravity must cause frictional heating.Tribbobith
An electric heating coil will consume 6.0 X 10^2 W of power when it is connected to a 120 V outlet. A greenhouse operator has two such coils and she wants to construct a single heater using the two coils to keep her small greenhouse at a temperature of 50.0 degrees Celsius during the winter...
Could the power of lightning be harnessed as a source of energy for heating water in a power station?How many joules of energy are present in a lightning bolt and would it be worthwhile economically?
I would like to ask if any one can point me in the right direction regarding finding suitable equations for the following problem.I wish to heat a greenhouse and for arguments sake lets say it is 2 metres long by 3 metres wide. I wish to increase the ambient temperature by X degrees C. I will...
I figure this one is bound for theory development anyway, might as well just start it here.Where does energy go (infrared energy for instance, after it heats something up)? Doesn't conservation of energy mean it has to go somewhere as opposed to just disappearing?
hi allthe other day i heard a little problem, a good oneit says :"two persons, 1 and 2, made a experiment to heat water by an electrical resistance, they both heated the same mass of water from the same temperature to the same temperature (and the water was always liquid), they both used a 100V...
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...
My city has large district heating system, where the heat is generated at an incineration plant. I'm personally not a fan of district heating, and I would rather see the plant generate electricity through steam instead. I don't know if that was ever considered when the plant was built. Are there...
Hi, I need to heat up a flat surface in a controlled way from room temperature to approximately 950 C. The surface will be some square meters large. Is there any way doing this without combustion, that is using a electric heating blanket? Does anyone know if such blankets exist? (Have already...
Summary: In a heating by induction experiment performed, the idea was to determine the efficiency of heating up a small steel cylinder, an aluminum cylinder and then compare the two efficiencies. The cylinder was surrounded by a metall coil that alternating current was going through...
I want to surface heat internal splines with induction heating with an internal diameter coil. It is a cylinder, uniform shape, and the teeth are 1mm wide and 2mm deep. The inside diameter of the hollow section is 19mm and the length is 55cm.
I was wondering when calculating power/resistance...
One of the emission lines of iron is 404nm, would iron absorb the heat from a blue laser and not copper?
Not a student, just an old curious guy.
Thanks,
Philip
Hello,
I've done some background research on this, and answers seem to vary. I would like to calculate the amount of heating in a wire. Let's say I want to heat a wire up to 60 degrees. I have 1 W of power and 150 mA of current at my disposal to do so. How could I estimate the wire diameter...
Hi,
of all the main plasma heating techniques employed by multiple fusion reactor designs, namely
1) ohmic heating
2)RF
3)neutral beam
4)some other method?
Which of them is the most efficient in terms of how much of the input electricity gets converted to direct heat/kinetic energy of the...
Hi,
I understand mathematically why using low resistance results in a greater heating effect. Could someone give an intuitive and microscopic picture of why the current contributes more to a greater power dissipation by the resistor rather than the resistance contribution to the power...
I am interested in a water heater found in consumer market, however, it's made of kind of plastic, I often "feel" that there must be some problem heating up something like plastic.
I understand that it should be tested and safe before putting into the market, however, I still wish to know -...
Summary: Looking for input on either floating or sinking a large sheet of dark screen for solar absorption in a pool
Looking for input on either floating or sinking a large sheet of dark screen for solar heat absorption in a pool. My though its that screen would be very user friendly to roll...
Summary: is it possible to heat a coiled spring
If I had a spirally coiled spring like inserted pic, spiral coiled spring approx. 300mm dia and spring section +-12mm dia with +-1mm gauge wire, with a total length of spring approx. 4mtr-6mtr , is it possible to heat this with induction heating...
Many asteroids and planets have undergone enough heating so that they were at some point completely or partially melted. What physical mechanisms are in play here? I'm assuming a solar system such as our own.
Thanks!
hi everyone.
my uncle currently has a big "cylindrical rolling cooking pot" (imagine a cement mixer with burners at the bottom) that he uses to cook his stuff, ie sesame seeds.
this cooking pot currently runs on gas.
as he has been facing some issues with the gas supplier, he intends to...
I am having trouble wrapping my head around a particular problem I am thinking about.
Consider that I have a heating source that I can describe in terms of either degrees Celcius / second or Joules / second, but essentially I am able to determine a fixed heating rate.
Let's say:
dT/dt = 5...
I am not sure how to proceed. This is just something that i have been thinking about and would love a little help with.
Lets say I have a situation where i am increasing an object's heat energy at some specific rate - for arguments sake, it's 2 degrees every second. If you like we can also...
Given that:
When will fossil fuel reserves be diminished?
"The new formula is modified from the Klass model and thus assumes a continuous compound rate and computes fossil fuel reserve depletion times for oil, coal and gas of approximately 35, 107 and 37 years, respectively."
[bolding mine]
36...
I am working on used device works on low not the three higher levels. I drew out circuit so I could see how it works.
The ground goes to three of the four wires to the pad fourth wire is ac positive which goes thru some thing like scr comes in on a1 and goes out on a2 and controlled by gate...
I have a little heating pad 12" X 15" runs on AC 120 volt has around 220 ohms resistance on low final got to hot burned up wire. What to replace it with using junk box parts light bulb wastes 10% for light would need metal cage to keep bulb from breaking seems like not good way. Have 300...
so far I have found the velocity 1 and 2 by dividing the volume flow rate over the area which I got from pi x dia squared/4 my v1 = 1.01859m/s and v2= 2.82942m/s i have then figured out a pressure for the 15mm pipe which i got an answer of 2.71 bar however i am stuck on the rest of the question...
I will make some assertions and then phrase a question , please correct me if necessary.
So the tokamak works like a transformer where the primary is a coil winding while the secondary is a torus which contains plasma which being electrically conductive forms the secondary winding?
The toroidal...
Hi guys, I am currently exploring dissertation ideas and have been looking into the heat recovery potential from domestic gas boilers and ovens. More specifically, I am seeing if it is viable to collect heat from these appliances during or after their use, and then pump this heat into the attic...
Homework Statement
Solid sodium bicarbonate decompose when it's heated above 50 celsius. However, when it is dissolved in water interactions of components changes. So what happens when sodium hydrogen carbonate solution is heated? Does it release carbon dioxide when temperature is above 50...
This may be a ridiculous question but I wanted to find out whether it would be possible to heat a 10x10x5 mm sheet of inconel 718 alloy (weighs around 500 g) to 1000 degrees C using a bunsen burner. The burner I have in mind is the Integra Fireboy safety bunsen burner (link below). It has a max...
Good day everybody!
As we have already known the structure and operation of the cloud chamber, can someone explain to me why the cooling is done at the bottom of the chamber and the heating at the top, but not vise versa?? How this affect the function of the cloud chamber?
Homework Statement
Why is it inefficient to use low voltage when transmitting electricity?
Homework Equations
P∝i2
P=Vi
H=Vit
P=Ri2
E/ti2=V/i
These are all basically the same few formulas, but I wrote down all iterations of them.
Anything from Joule's Law/Joule Heating
The Attempt at a...
In this task of mine, I need to develop a tool/software to carry out (dynamic) hydraulic analysis of a central heating network, formed with supply and return pipes so forming a multi-parallel loops in a closed circuit, as can be seen in the below picture.
Can anyone suggest me some references...
I’m using an inductive heater to try to melt some 99.85% polycrystalline silicon, as would occur in the Czochralski process, but the silicon workpiece is not melting let alone even getting hot. The silicon workpiece is about the size of a playing dice. It becomes conductive at 200 F and becomes...
I've moved to a "new" house - built about 350-400 years ago. Firewood in a stove kind of works for heating a few rooms, but not the full house. So far it seems like the grid power tends to die about twice a month. Temperatures is expected to reach -25C (-13F) for the coldest couple of weeks...
Here is a fun question for you heat transfer experts.
I have a high pressure waterjet firing into a open tank of water. The hydraulic power of the jet entering the tank is known, along with the flow rate of the jet entering into the tank. All of the energy of the jet is dissipated into the...
Homework Statement
Instead of pumping heat into the cabaret air from the outside air, you could simply put an electric space heater inside the cabaret. A space heater turns electrical energy directly into thermal energy. Why would operating a space heater consume more electric power than...
Homework Statement
During the winter, your climate control system must begin warming the cabaret air so that the cabaret air is hotter than outdoor air. Amazingly enough, it can do this relatively efficiently by transferring heat from the outside air into the cabaret. However, your system must...
Homework Statement
Having chilled the air until it contains only the perfect amount of moisture, you want to reheat it to the ideal cabaret temperature. You could use an electric space heater or wood fire, but you already have another source of heat: the same system that chilled the air in the...
I found a simulation tool on wolfram alpha where the pressure of a constant volume is calculated. The pressure is affected by the heating of a mixture of water and air inside the container. There is an explanation to how the pressure is calculated which seems pretty straight forward. But there...
I am planning some low power heating devices in the 10 - 20 watt range and have been considering the usual high resistance alloys: nichrome, kanthal, and stainless steels (304, 316, 630). I have noticed that all of these materials are expensive. Is there some reason I could not just use steel...
Homework Statement
Calculate the power needed to heat a 1360 gram chunk of ice in a 600 gram copper pan from 0 ◦C to the system’s final temperature of 35◦C in a time of 10 minutes.
Homework Equations
Q=mcchange in temp
Q=mLf
P= energy/time
The Attempt at a Solution
I thought that adding the...
Today, I turned on an electric kettle for heating up some water, then I going to did something else. Since the cover of the kettle was lost, it didn't automatically stop when boils, and I forgot to turn off the kettle when boiled, then all the water vaporized at last and the kettle stopped...
I'm a high schooler involved in a research in which we aim to grow perovskite crystals in microgravity. I've recently come across this article (https://scitechdaily.com/researchers-develop-a-better-method-for-making-perovskite-solar-cells/) in which they explain how to grow better perovskite...