Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [heat-transfer]

Questions relating to the transfer of heat via the mechanism of convection, conduction, or radiation, in forms of systems (or your device) attempting to obtain thermodynamic equilibrium with another system (the environment or your other device)

1
vote
1answer
22 views

Vertical vs Horizontal Ground Loop Heating

I'm wondering how to compare the efficiencies of vertical and horizontal ground loops for heating. [Assumptions follow, please correct if any are wrong!] The biggest differences seem to be the higher ...
0
votes
1answer
17 views

How to control precisely the wall temperature of a tubular reactor?

I have modelled a multi-tubular reactor performing a Fischer-Tropsch synthesis of alkanes and I was wondering about the stability of such a reactor. Even a very tiny deviation of the wall temperature ...
-1
votes
0answers
21 views

Time-dependent boundary condition

I ve got a problem about heat conduction boundary condition. For a 1-D time dependent problem, i ve got only one initial condition and one boundary condition (b.c. is like periodic step function). To ...
1
vote
1answer
41 views

Modelling reactor jacket with or without insulation, how to proceed?

I am currently trying to derive a model to help estimate as precisely as possible how much time can be saved by insulating the jacket of a reactor used for eating and cooling. EDIT: I edited my post ...
1
vote
2answers
49 views

Cooling Down Fridge Encased in wooden box

I'm currently working on a project which involves a small fridge encased in a wooden box. It's designed for hotels and the boxes vary slightly, but one common trait is that the box has an open vent ...
1
vote
0answers
25 views

Heat Transfer in A Cylinder of an Internal Combustion Engine

I am new in engineering, could anyone explain the approach to calculate the max heat generation, the heat transfer from the cylinder to the atmosphere and from cylinder to the piston. I am also ...
0
votes
0answers
9 views

How do you calculate the temperature after methane combustion if liquid H2O is sprayed into the combustor?

Calculating adiabatic flame temperature is pretty clear in thermo books, but how would you determine the temperature if liquid H20 was sprayed into the combustion chamber simultaneously? Thanks
0
votes
0answers
28 views

Heat transfer in a cable placed flat on soil

I need to calculate the heat transfer of a cable placed flat on soil. I already determined the thermal convection coefficient (natural convection, external flow) with Nusselt equations for horizontal ...
0
votes
0answers
16 views

How to achieve successful Peltier cooling

I'm using a TEC12706 Peltier module for making a cooling setup. The hot side rejects heat to a Cooler Master Hyper 410R cooler and the cold side fin gets cold enough to form water condensate on itself....
0
votes
3answers
35 views

Thermal Non-Insulators?

I need a clear material that will allow sun in but won't insulate heat. Sun sun rays get in but doesn't trap heat. Any ideas?
0
votes
0answers
16 views

Sizing radiator

I'd like to do a DIY project to reuse my home AC heat output to heat my pool that is located very nearby the AC radiator. I planned on fitting a second radiator directly onto the heat output and hook ...
0
votes
0answers
23 views

Will a video projector submerged in mineral oil still work?

I’ve seen folks submerge computers in mineral oil to cool them- but would doing the same to a video projector profoundly throw off its internal optical aspects? I’m considering one of those small “...
0
votes
0answers
10 views

Help me Solve this Steady State 2-D Heat equation

So I tried to solve this PDE by separation of variables which was not applicable because of non-homogeneous nature of this PDE. Then I assumed ( after reading from a book ) : $$ T(x,y)=v(x,y) + \phi(...
0
votes
1answer
50 views

Calculating the Surface Temperature of a Cable with known heat flow

I have a cable which dissipates $\dot Q_{total}$ and I need to determine the surface temperature of the insulation $T_{ins}$ and the surface temperature of the conductor $T_{cond}$. There is an ...
0
votes
1answer
35 views

calculating the efficiency of a microwave oven

If I want to calculate the efficiency of a microwave oven, I have the input Energy (= power (watts) x time (s)) and the output which I measured using temperature difference (q=mct). So do I divide ...
0
votes
1answer
22 views

Determine Cp of an oil from density and temperature?

I suspect I know the answer to this, but hoping someone may know something I don't here. Is there a way I can determine the specific heat capacity at constant pressure (Cp) of an oil if I know the ...
0
votes
0answers
31 views

Characteristic length for the given problem of heat transfer

In the following problem of heat transfer, what does characteristic length actually mean? In this problem, they have found the heat transfer coefficient (h) separately for the vertical and horizontal ...
1
vote
0answers
33 views

Industrial scale heat pumps

I've read (1) that the efficiency (COP) of a heat pump does not change much with size. If that is true, why don't power companies employ them to produce yet more power from fossil fuels or renewables? ...
0
votes
0answers
37 views

Can radiant induction heat thermally decompose wood

Is it possible to thermally decompose an indicator like wood in a induction heating container made of stainless steel if the induction frequency is low enough to heat the container about 1000°c. ...
0
votes
1answer
25 views

Evaluating drag and convection for a flower heat budget model

I am currently in the process of creating a heat budget model to compute stigma surface temperature. Stigmas are part of the reproductive organ of a flower (which in my case are flowers of orchards). ...
1
vote
1answer
49 views

Calculating heath exchange for custom boiler

I am playing with the Idea that I should make a my own heath exchanger to generate warm water. But as a hobbyist I would like to calculate the potential of my design and here is the question for me, ...
0
votes
1answer
63 views

Boundary conditions in a heat transfer problem

One end of a small insulated rod is attached to a support which is maintained at a constant temperature of 473 K,and once the rod has reached a uniform temperature in its entire length the insulation ...
2
votes
2answers
47 views

Does a tank of liquid nitrogen increase in total internal energy after emptying?

Suppose there's a 10 liter perfectly-insulated sealed tank of saturated liquid nitrogen at 4 bar. Therefore the fluid has properties, $\rho=740 \,\frac{\text{kg}}{\text{m}^3}$, $m=7.4 \,\text{kg}$, $\...
0
votes
0answers
24 views

Developing a model of rate of cooling of steel tube in air

I am trying to develop an equation to determine the cooling rate of a steel tube in air. I'm using Fourier's Law, Stefan-Boltzman Law, Newton's Law as well as the specific heat capacity equation. The ...
0
votes
3answers
65 views

Does kettle shape affect the speed at which water boils?

Consider I have two type of cooking kettles, which the shape is just like a pure tube with the volume is 1000 cc (1 liter) with the radius and the height as below (volume=pi*r^2*h): The first kettle: ...
0
votes
1answer
38 views

Which is more important XY plane thermal conductivity or z direction thermal conductivity?

Im seeking an alternative to thermal grease/ pastes. I was researching graphite pads when I stumbled across the soft PGS line from Panasonic. I need to choose a suitable thermal interface material ...
1
vote
1answer
54 views

How to calculate the time to heat up a tank using recirculating liquid

My question is about a tank filled with some liquid (properties of the liquid are known and can be considered constant. Specific heat equals 1.5 kJ/(kg.K)). The initial temperature of the liquid in ...
0
votes
1answer
30 views

Calculating geothermal heat pump

So I need to calculate how big geothermal heat pumps I need for a building. Heat pump is used for heating and to heat used water. If I know how many kW's are needed for heating the building and the ...
0
votes
2answers
101 views

Save money with using a refrigerator correctly - blowing cold air to the back of it?

We are heating up our houses in winter to ex.: 21C to then have an insulated box inside the house, which we cold down to 5 and -15C, and we call it a refrigerator.. :) The situation: we would buy a ...
1
vote
1answer
29 views

Absorbing heat from a surface

I have a cold body of constant temperature A and a hot surface several times it's area. What is the best way I can absorb the heat from that surface using A. Will sheets of metal like alluminium or ...
3
votes
2answers
62 views

Why are home geothermal systems usable anywhere in the U.S. but industrial geothermal plants limited in geographical use?

Geothermal systems are used in regions across the U.S. for home use, but industrial geothermal plants are only used in areas where subteranian temperatures are very high. Why is this? https://en....
2
votes
0answers
20 views

DIY Thermal Solution [closed]

What would be the best way to design a sealed computer containing a gas or liquid circulated by a fan/pump to cool the components? ( With a metal case ) Then the computer would not be susceptible to ...
1
vote
1answer
44 views

Air Cools As It Expands

What is the degree of cooling caused by air flowing from smaller diameter into a large diameter? How much does air cool as it expands? If the air inlet was the biggest hole on the right and the ...
1
vote
0answers
22 views

Please help solve this problem! [closed]

Fluid with mdot = 0.025 kg/s and Tm,i = 25oC is flowing through a long metal cylindrical tube where the diameter is 0.032 m and the length is 2 m. The surface of the tube is heated with a heat flux of ...
0
votes
1answer
37 views

Peltier Element - Segregation of the Hot/Cold

Referring to this diagram: How does the height of the P and N components affect heat or cold generated on this thermoelectric element? The idea I keep having is that it seems like the hot and cold ...
2
votes
1answer
45 views

Connect heated copper tube in PVC tube

I have a copper tube that I'm heating (quite a lot) with a torch, I have to connect a PVC pipe in the entrance of the copper and one in the exit (so water can flow through the copper pipe). The only ...
0
votes
1answer
30 views

Temperature not changing in my code for 1-D heat equation: Explicit Scheme

I am trying to solve the following 1-D heat equation with provided boundary conditions using explicit scheme on Matlab. I have been trying to plot the results but I realized that my temperatures are ...
1
vote
2answers
68 views

Wouldn't it be most effective to insulate a house with just an air space?

It is my understanding that of all three states of matter, gases have the lowest thermal conductivity. If this is the case, why are solid materials, such as fiberglass and polyurethane, used for ...
5
votes
2answers
96 views

The concept of flux

I find it difficult to understand the concept of flux and field.I have searched the internet and refered a few books.From what I understand, generally flux can be defined as "some quantity per unit of ...
0
votes
1answer
40 views

Conductive Heat Transfer calculation over time

I am trying to heat the oil in a 1/2 inch thick rectangular steel box by using an Insulated heated blanket covered on all 6 faces of the box, the working conditions of the operation are at -50 Celsius,...
2
votes
1answer
47 views

What does stanton mean physically?

In heat transfer, we come across Stanton number which is the ratio of heat transferred into a fluid to the thermal capacity of the fluid. But what does this physically mean and its importance in ...
2
votes
0answers
40 views

hot wire anemometry

Hot wire anemometry can be used to measure the temperature of a wire in fluid flow. The voltage fluctuation across the wire is used in conjunction with an energy balance on the wire to obtain the ...
2
votes
0answers
58 views

Does a closed loop biomass-fired cogeneration/CHP make sense?

I'm working on a project concerning electricity production using biomass, and we have seen that making use of cogeneration is very attractive in order to increase the efficiency of the installation. ...
0
votes
1answer
47 views

Is there any practical way to partially absorb the heat from a refrigeration condenser

I have currently been experimenting with a phase change material to absorb the heat given off by the condenser in a small refrigeration system (about 1/5 hp compressor) and while it does absorb a ...
3
votes
1answer
81 views

What is the most common control method in Underfloor heating?

I am trying to research the common methods on an underfloor heating system that are available in the market. I know there are usually, On/Off control to control the flow of water into the pipe ...
1
vote
1answer
25 views

Operative Temperature in Underfloor Heating?

I am new to the Underfloor heating system, and a bit confused on the terminology for Operative Temperature. Is this the temperature that is measured by the sensor or is this the set-point temperature ...
2
votes
0answers
33 views

How much can a double Peltier stack cool to -30 C?

I need a -30 C freezer. Inside volume 5-30 l. I've seen videos of double Peltier stacks reaching -50 C with one Peltier running at 12V and the other at 5 or 7 V. How big a freezer could such a stack ...
1
vote
2answers
131 views

Adiabatic paths

Can two adiabatic process paths intersect on a plot? This question is for 2 cases- 1.) Can two irreversible adiabatic curves intersect. 2.) Can a reversible & an irreversible adiabatic curve ...
2
votes
3answers
83 views

Why not drive an air source heat pump domestic heating system with an auto engine?

Theses are my thoughts on the question. I can't find an answer to "why not?". It there something I am missing, or are auto manufacturers simply too focussed on cars only? The automotive industry has ...
0
votes
0answers
35 views

Tempreture distribution in a furnace

I am simulating a furnace as follows: Is it possible to capture temperature distribution in this furnace without designing intake fan? Which kind of boundary conditions can replace with intake fan? ...