Heating Definition and 616 Threads

I was wondering if anyone knows of an equation that will properly calculate the rate of heating on any material, at any altitude, at any speed, and with air hitting that surface at any angle. The equation will be somewhere similar to (DT/dt)t=0=(Tr-Tinitial)h/(cρz) Where: T=temperature...

Why heating water at 90C takes longer than heating water at lower temperatures such as 70C?

Hi, I'm having a problem building a sort of pool heater for my backyard. I've assembled some black tubing into 9 spirals, making 3 groups of 3, and then attaching the groups of spirals to a manifold, to supply equal pressure to each group, see pic below. The water is pumped up to my...

I am currently constructing a supersonic rocket and am trying to empirically calculate the heat transferred onto all different parts of the missile body to know what materials to buy. However, I do not know how to calculate the heat transferred onto the fins of the rocket as it travels (the fins...

When some certain object (asteroid, aircraft, spaceship and etc.) moves at great velocities into Earth’s atmosphere it heats. The faster its moves and the denser is the atmosphere the heater this certain object becomes. This is simple is clear. Now, is it possible somehow to predict or calculate...

Hello everyone, I think this is very simple. I have very little knowledge about electricity and would like to understand a bit more about a simple experiment I was recently shown: Basically a steel nail was connected to an electrical circuit at both ends. The two electrical contacts to...

question For a plane wave of the form E(z,t)=Ee^i(kz-wt) and B(z,t)=Ee^(-kz)*e^i(kz-wt) write down the time-averaged ohmic heating loss per unit volume for any z. Homework Equations J=\sigmaE Maxwell's equations for linear media The Attempt at a Solution not sure where to start, i...

sorry re posted in homework...

Hi, I'm a heating engineer. part 1: I typically install 300 litre to 100litres stores of hot water (to be extracted at 40deg c for low temp heating). I understand that the specific heat capacity of paraffin wax is something like ten times that of water. So can I play around with a...

Homework Statement i am trying to make an air flow meter using an heating element which i got from an iron..basically i have thought of inserting the element into a duct through which i will pass air using a blower,to connect the element with a 12v supply in series with a ammeter...thn i...

Homework Statement in verifying joule's law of heating namely the first law that is law of CURRENT " HEAT IS PROPORTIONAL TO SQUARE OF CURRENT" MY TEXTBOOK MENTIONS THE FOLLOWING LINE the initial temperature of water is measured as THETA1. let W be the heat capacity of the calorimeter and...

Design of heating element: Supply Voltage: 220V/3Ph/60HZ, Power: 9KW Resistance= VXV/P= 220X220/9000= 5.4 Ohms, But when physically when measure the resistance of wire using multimeter it is showing 17 ohms. Can you explain why there is differnece in practical and theortical value...

Why is it that when you heat an object, it takes longer compared to cooling it?

Homework Statement I have two identical volumes of gas, and I heat them both to 100 C, one under constant pressure, one under constant volume. Which has more internal energy after the process? The attempt at a solution I believe that they both have the same as the extra heat you have...

So this is my current problem: I have block of solid material that separates two bodies of gas. The temperature of all three is known (and presumably all different). The solid material is also being heated, equally throughout its volume. I want to know the instantaneous heat transfer...

When going through topics on melting and freezing, i came across 2 graphs of slightly different curvature for both the heating and cooling of naphthalene. The ending part of the graphs are the ones that confuse me, whether slope upwards or downwards. Most graphs in the internet just show...

If we somehow could apply a significant amount of heat to the black hole, what would happen? Photons get redshifted near the event horizon, so how energy transfer towards black hole goes?

Homework Statement Hey Everyone, I am working on a physics project in which we need to look at a basic physics model. I have a couple of quick questions regarding conduction and heat generated through a resistor. So I basically have a wire acting as a resistor that I want to run current...

Hi guys, is this right? Homework Statement A mole of nitrogen is heated at constant external pressure of 1 atm from 25° C to 100° C. The heat capacity of nitrogen is 29.1 J/mol·K. Calculate ΔSsurr 2. The attempt at a solution delta_S=Q/T = -1*29.1*75/373=-5.85 J/K (heat...

Is it possible to approximate the amount of heating in tissue (and other materials) due to electromagnetic radiation?

Hello new to the site and i usually don't post questions but after a few days searching I answered a few and found many more I'm hoping someone here can help. Background for project: Looking to preheat my RC (remote control) nitro motors to 200-220'F prior to starting the break-in process.i...

Can anyone please size a heater battery for me? On a supply and extract heat recovery air handling unit. (50% efficient for heat recovery) Outside temperature -2 degrees C Room temp/Return air - 21 degrees C Air voume - 1.3 m3/sec Boiler flow and return - 80-60 degrees C. I have been...

Needed some guidance for my circuit: Have a circuit consisting of a microcontroller + SSR relay + load (heaters)...issue is when the temperature reaches cutoff the heaters are not getting stopped and temp. keeps on increasing... I have a connection of outputs from microcontroller into...

So, I'm a student working on a M.S. Environmental Science. I just took a test, the course is Mechanisms in the Environment, and got a question marked wrong that I believe is a correct answer. The question was, paraphrased, Can ozone formation in the mid to upper stratosphere heat up the...

HI there, I have a thought question. Normally when we wish to warm up food in a microwave oven, common sense tells us that the lid of the plastic containter (or container of whatever material) should be off, so that the microwave can reach the food. Just wondering...if the lid is on, ie...

1. A cylinder with thermally insulated walls contains a movable frictionless thermally insulated piston. On each side of the piston are n moles of an ideal gas. The initial pressure (P_0), volume (V_0), and temperature (T_0) are the same on both sides of the piston. The value for (gamma) is 1.5...

I'm wondering about what's going on in an effect I've noticed with heating pads (as well as electric mattress pads). Try this experiment: take an ordinary heating pad (one of those flat rectangular things about 1 foot by 1.3 feet with an electric plug), plug it in, and have a friend sit...

Homework Statement If the following substances were heated what gas would be given off and what solid would remain? strontium carbonate, zinc carbonate, and iron carbonate. Homework Equations N/A The Attempt at a Solution So I presume carbon dioxide would be given off and the 3...

Hi there, I have been doing research on a lil private project of my own, and am looking for some help. Would it make sense to use nichrome wire to build a heating element that will heat to 80-100 degrees? It seems that nichrome is great for heating way way past that temperature. I want to...

Homework Statement If the specific heat capacity of water from an experiment is smaller than its actual value, does it mean more heat is lost to the surroundings? If the heat is emitted by a wire into a cup of water and the change in temperature is measured, does it mean that the change in...

I have heard about this term called radiant flooring, i don't know exactly what it is can anyone here explain me about radiant flooring.

I have problem in calculating heating time of Lube Oil ( SAE 40 ). There is a tank of Lube Oil ( SAE 40) of 19000 liters at 20° C. this oil has to be heated up from 20° C to 40° C with help of a heater of 85 kW through which oil flows at 4800 liter/hour and back to tank. How much time it...

Hi I need a heating element, 5 cm x 5 cm, to heat up a chip. Temperature range 293 - 373 Kelvin Anyone know what to go for?

Hello, I am new to this forum, I thought you guys could send me in the right direction. what I am trying to do is heat water with a wind turbine. the turbine produces 3 phase wild AC with voltage of 0 to 270V. related to wind speed. I am aware of the general practices with wind turbines-...

Just out of curiosity, has anyone ever heard of using sodium thiosulfate pentahydrate (liquid crystals) as a viable method of heating a house? I'm doing a project on this now and it seems hugely inefficient due to the massive amounts of crystals that would be needed to produce enough energy to...

Regarding a 12v source, is there a way to calculate how much energy is required to maintain a certain temperature through an element? Meaning if you want to maintain an element temperature of 35 F how much energy will it consume using 12v? How will the ambient temperature affect this equation...

In regard to (tile) radiant floor heating, a professional is needed to come and install a heat-conducting plastic mat with wire lattice-work, hook it up to the home’s electrical system, and then do the standard grout and tile work etc. I was wondering what the possibility would be to produce...

Homework Statement An oil-filled radiator is used to maintain the temperature of a room at 21C when the outside temperature is 10C. The radiator has a surface area of 1.5 m2, and a surface temperature of 70C. Given that the radiator is made of a metal with a thermal conductivity 80...

Homework Statement A 750-MW power plant sends its power out on a 475,000 V high-voltage line. If the total resistance of the line is 0.65 Ω, what percentage of the power is lost due to resistive heating? Homework Equations i have NO idea but maybe... P(loss)=I²R P(loss)=^v²/R...

I want to find the increase in the temperature of a resistor due to joule heating. I mean that if we apply some electrical power to a resistor then the electrical energy is converted to heat energy due to joule heating. The heat energy will increase the temperature of the resistor. Is it...

Homework Statement I have two problems. What is Delta U, Delta H, q, and w for the Reversible heating of an ideal gas at constant P. Also, what are these values for the Reversible cooling of an ideal gas at constant V. Homework Equations The Attempt at a Solution For the...

Homework Statement A toaster with a Nichrome heating element has a resistance of 70 ohms at 20oC and an initial current of 1.6 A. When the heating element reaches its final temperature, the current is 1.39 A. What is the final temperature of the heating element? Homework Equations V=IR...

if we heat semiconductors, so that the energy provided is more than threshold energy will they generate a current?

When I heat up, for example, a sweet potato in the microwave, how is the heating process affecting the nutritional aspects of the sweet potato? Heat affects enzymes, proteins, vitamins and whatever else. Does the heat render them useless? I heard vitamin C is destroyed in the pasteurization...

Say I want to put a bottle of water in the microwave and heat it up. How do I determine the pressure in the bottle as a relation to the temperature of the water? Assuming that there is a headspace of air between the liquid and the bottle cap. Is it dependant on the volume of the air space? ie...

hi all I am trying to use a circuit of NiCr wire to heat a surface. I have setup my circuit using parallel 'branches' of NiCr connected to a bus so that voltage is equal across each branch. I am an undergrad EE so I get electrical aspect, but have little knowledge of the thermo. My...

We are testing an Air Handling Unit, we need to raise the internal temperature by 30 degrees to pass the test, but cannot exceed an energy input of 500W. It is a completely sealed unit. We have four fans constantly running, consuming 384W. Firstly, how can I work out what temperature they...

Hi, I want to electrically heat a uniform block of a known material to a high temperature (about 2000 K). I want to get a rough idea of how much electrical energy I need to supply to raise the material to this temperature so as to gauge what apparatus I will need. How would I go about this...

This is an oversimplification of a practical problem I am currently trying to design for. Suppose, we have a very long cylinder closed at both ends which contains water at a given pressure P1 and temperature T1. P1 and T1 are such that water is in a compressed state (subcooled). One end of...

I have experimented the converse of Newton's law of cooling, i.e. the rate of heating of a cold body is directly proportional to the deficient temperature when the difference in temperatures is small and the states of the system remain the same.