Heating Definition and 616 Threads

I have to build a small green house and to calculate if one heating wire is enough (or even too much...) Just for my curiosity I would like to understand the physics implied in this. The starting point is the desired dimensions: two modules of greenhouse with the following dimensions: 60 cm...

Hey guys, I have been scouring the internet to find an answer but I can not. The problem is: I want to heat water to boiling point with the least amount of energy required. I found out that if you apply vacuum into an chamber with water (room temp), the boiling point can be as low as room...

I'm into watching snooker. The tables have slabs of slate under the cloth. They also have heating elements underneath in order to heat the surface to 21°C which apparently is perfect. What I don't get is that the arena is probably around 21°C in the first place as people are sitting there...

Consider an underfloor heating system in an apartment building. Each apartment has its own distribution box with a number of loops and a thermostatic mixing valve set to 35°C. The loops are intended to work with a ΔT of 5°C (35-30), and the riser pipe supply temperature is 75°C. Say there are...

hi, I met a problem about heat transfer in cylinder, if you can help, I will appreciate it. The question is simple. I want to know the transient heat distribution in a cylinder with internal heating(constant temperature not constant flux). The boundary conditions comprises two constant...

Hi all, A happy 2018 for all PF members. I have a question. I am trying to understand some basic principle of thermodynamics. My book tells me tge following: "Heating of a gas at a constant pressure uses more heat as when heating the same gas a constant volume" How do i interpret this? I...

I was told recently that in a central heating system, the pressure on the suction side of the circulation pump should be at least equal to the static height of the system. I've never heard this stated before, and I don't intuitively get why this should be the case. If there is actually something...

Hello every one I’m a newbie to electrical stuff (I do have basic knowledge) so please be patient with me, please help me! :frown: So, coming to the details of my diy project I’m trying to vibrate a metal string with an electromagnet. so, after an ample amount of research I’ve made the...

I'm reading up on the use of the valve seen in the link below. On page page 5-6 there is the mentioning of available differential pressure. I struggle with understanding what that means exactly. Say I have a set of main supply/return pipes along a building, with some branches along the way...

I'm trying to guess when my hot tub will be ready for use. If an ideal body of water is insulated and has a constant source of heating applied to it, can its temperature be expected to rise linearly? (No. Even as I write this I see it can't be true. As the water temp rises, it will approach...

Let's assume you have a perfectly insulated closed liquid loop with a pump who's motor is cooled by the liquid its pumping. Assume steady state operation, so the pump is operating at some pressure difference and flow rate based on intersection of pump curve and back pressure curve. Does this...

Hello . I am trying to make power supply using LM317T. As i need Variable output voltage from 14 V to 27.6 V. I made a power supply of 29V/1A using Power Integration IC LNK6775E. At the output of 29V i am using LM317T to vary voltage. But after 5 minutes IC is going in protection mode if apply a...

<mod: moved from intro> Hello all! This is my first post in this forum. I am struggling with the following question regarding a hair dryer. The hairdryer can be seen as a cilinder with a fan inside blowing air at speeds from the table below and 1 nichrome wire which heats up consuming different...

Hi everyone, I'm currently working on a research project about dielectric heating of some materials and I'm trying to understand the physics of this phenomenon before going any further. I'm especially trying to understand the concept of complex dielectric constant and loss factor. I'm...

Air is flowing through a pipe, through a heater matrix. Flow, Inlet temperature and heater power vary. Is it possible to calculate the heat capacity of the matrix by using the Inlet & outlet temperatures, power & flow? I'm assuming no heat loss to the pipe walls to make it easier, but I'm not...

Homework Statement 2. Homework Equations [/B] Consider the following circuit where: $$R_A=330 k\Omega$$ $$R_B=220 k\Omega$$ $$C= 2.2 nF $$ $$v_1(t)=6u(t) V$$ $$ i_2(t)=-10u(t-t_2) \mu A$$ $$t_2 = 12 ms $$ All the currents go clockwise (with the obvious exception of the current source)...

Hi there, I'm a material chemist, currently working on ceramics. I know the very basics of physics, but I have many doubts about electromagnetism. How does induction heating exactly work? I understand that you use a hollow coil of copper with a cooling fluid circulating inside, through which...

I am building a house and would like to understand how to perform an energy balance/efficiency calculation on various electrical heating systems

I am proposing a collision between Earth and the Centaur 10199 Chariklo (a.k.a. 1997 CU26). For the actual collision information I used the "Impact Earth" website from Purdue University. This is the data I used: 10199 Chariklo (a.k.a. 1997 CU26) Diameter: 248 ± 18 km (334 x 266 x 172 km)...

Homework Statement Household water heaters use a 240 V rather than a 120 V source. What is the resistance of a water heater's heating element if it heats 40 gallons (151 kg) of water from 15 C to 60 C in 15 min Homework Equations P = IV P = I^2R I = dq/dt The Attempt at a Solution Honestly no...

Suppose I have two light bulbs, an LED and a halogen, but both have the same power P. Their radiation spectra are different, the LED radiating much less IR. Putting them in identical closets from which no heat may escape, will the walls and air in each come to some temperature T which, although...

Homework Statement [/B] Q- Hydrated barium nitrate, Ba(NO3)2.4H2O, is strongly heated in a boiling tube and the following changes occur. Stage 1: The white solid forms a clear colourless solution. Stage 2: Condensation forms around the mouth of the boiling tube and a white solid starts to form...

I have a relatively simple design problem but my memories of thermodynamics are very rusty and I can't figure it out on my own. To make it short, I want to put a mix of solid, water and air in a 500mL pressure vessel and heat it all up to 250'C for several weeks. T and P are at room conditions...

I'm considering making a plastic melter / extruder for making my own 3D printer filament as opposed to buying the spools of it. The basics of the project are simple, but the hard part (for me at least) is making a heating element that has a control on it so that I can turn the heat up or down...

When a heating experiment for example when measuring the specific heat capacity of an aluminum block, why is it practical to turn the heater off and wait for the highest temperature reading on the thermometer and take that reading. Why does the reading even rise when the heater is turned off...

After taking a course on Solid State electronics, (and doing a bit of my own research into the matter) I've gained a little bit of knowledge in the area of band structures, and phonons/photons. My question is as follows: I know that photons with an energy greater than the band gap can cause...

Hi everyone, I'm conducting an experiment where I place a ferrous material rod inside a solenoid to measure it's temperature due to induction heating, as shown in the video below: The aim of my experiment is to calculate the magnetic field from the temperature of the ferrous material rod. Is...

This question is purely theoretical, so don't worry about safety or doability. Is there a way of calculating how many watts it takes to heat different metals? To be specific, how many amps and bolts it would take to get lead to its melting point. Thanks in advance.

Homework Statement The thermistor is heated so that its resistance decreases. State and explain the effect this has on the voltmeter reading in the following positions. A–C Homework Equations V=IR[/B] The Attempt at a Solution :[/B] I will say that the voltage will increase because if the...

Homework Statement In the open cylindrical chamber is the piston of the total mass m. The initial air pressure inside the container is pa, the initial temperature T0. The initial height of the piston above the bottom h0. Now we start the gas supply heat to the moment when the piston reaches the...

Hi I am planning on building an immersion heater to heat oil when it is -20 C degrees outside. I need some help calculating the heat transfer. I want to find out how long it would take to heat around 10 litres of oil from -20 degrees to 10 degrees using an immersion heater with a constant...

Hello, I have a question for you guys and gals. I am working on a Desalination project and am ironing out questions about efficiency. What would be the most efficient temperature to evaporate water? 50, 100, 110 degrees? Does it make a difference, or is the energy required to evaporate a fixed...

Homework Statement The box's measurements are 277*120*195mm. The lamp's power is 15W. Trying to figure out how long it will take to heat the box so that it reaches a given temperature. According to Wikipedia ρair=1,2kg/m3 and cp air=1004J*K-1*kg-1 Homework Equations ΔU=m*cp*ΔTemperature E=p*Δt...

I recently came across a paper where there was a term ''stochastic heating of very small grains". I went through some papers on this area but I am still confused about it. What is the vibrational temperature associated with very small grains? Does temperature has got a meaning if it's a highly...

Homework Statement Excel Table gives Temperature of Month & Avg NOAAtemp for bill Homework Equations y = mx + b (Assuming) The Attempt at a Solution 1) if we take temp of month as temp, linear model y=-0.1481*temp+124.8. 2) If we take temp for days of bill as temp, y=-0.1466*temp+124.74

Homework Statement We wish to heat water from 10 °C to 50 °C using vapor at 180 °C and 1.5 bar of pressure. How much cold water do we need to mix with every Kg of vapor to obtain the result? Homework Equations I am not sure. I think the problem is related with exergy and energy balance The...

Homework Statement An office worker uses an immersion heater to warm 250 g of water in a light, covered, insulated cup from 20 degrees C to 100 degrees C in 4 minutes. The heater is Nichrome resistance wire connected to 120V power supply. Assume wire is at 100 degree C during 4 minute time...

In my labs we use hot plates with a 0-10 temperature knob. The hot plates don't have a temperature monitor, so i have no idea how hot each number can increase it or how hot it is at the time. Sometimes i have labs where i have to heat something to more specific temperatures or else the reaction...

Fuel for a paraffin/kerosene inverter heater is sold typically in 20L containers (in Europe). They all claim to be highly filtered to remove odour, and burn cleaner. Customers are also given the opportunity to pay more for different brands, but they all seem to meet the same standards. The...

Hi , How can I calculate the resistive heating occurring in the internal resistances of a solar cell ? Are ohm's law or the power dissipation relation P=RI2 applicable in this case ? if not the case how can we calculate the resistive heating there? Thank you in advance for your help

I put a tumble dryer that had been used only a few times back in operation after a decade being completely out of service. Heating failed shortly after switching on. Checked the heating element and noticed that it is broken at a dozen locations. The spiral is very brittle and breaks easily when...

Hello community. I have a question about electrical heating. I am familiar with the fact that textbooks explain how power losses are reduced by transmitting at high V and low I since P = I^2 X R (equation from Ohm's law and P=I X V) But if you use a different sub for P = I V then you get P =...

hi everyone, i need some help with my project that is DC rice cooker. i have the same problem for my calculation and logic cause my rice cooker use 12V and 100Watt. is that mean i need to use 8.3333Amp for the current? or i need to design a circuit that can reduce the amount of current needed...

If this is not ok to post then let me know, but I have a question that I feel can only be answered here. Question: Would it be possible to heat a 50' semi trailer frame to roughly 400F through electrical resistance, I know it would require a lot of power but the reason I ask is because I am...

Goodmornig everybody, I'm working on the design of a power converter for high frequency induction heating. The induction coil should be a flat spiral (pancake) with a rectangular shape, but my customer would like to design it as shown in the following picture. I think it will not work because...

I would like to get a clue of how to arrive at the power and frequency for an Induction heater. I am planning to heat a graphite rod upto 1200 degC and also to provide a heat flux of 1 MW/m2. The graphite rod dimension will be for one case Dia 5 and length 100 mm and in the second case will be...

I have a question in regards to a specific situation and really don't know which elements are significant. The example is high pressure AIR (a real gas/ not ideal ;-) of relatively unlimited volume, released via a rupture diaphragm into an enclosed tubulation. (dead ended) Relative dimensions...

if I heat a resistor, it will reach a specific temperature and keep it. because as temperature increases the resistance decreases, so reducing the power absorbed. is that true? and how to calculate how much current and voltage I have to deliver to reach a specific temperature?

Hi everyone, I'm struggling to understand what I think is a very basic concept: Joule's law of heating. Allow me to explain my confusion: We know that voltage can be expressed as: V = I · R And power can be expressed as: P = I · V Making power equivalent to: P = I2 · R According to my...

Homework Statement An electrical heating element is to be designed so that the power dissipated will be 750 W when connected to the 240 V mains supply. (a) Calculate the resistance of the wire needed. (b) The element is to be made from nichrome ribbon 1.0 mm wide and 0.050 mm thick. The...