# 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)

397 questions
Filter by
Sorted by
Tagged with
1answer
109 views

### How do I determine the temperature inside a transformer vault?

I am trying to determine the temperature of an underground concrete vault buried 10m underground. The vault has the following dimensions: 2640mm x 5995mm x 2640mm with a wall thickness of 250mm. The ...
3answers
122 views

### Steam cycle for a boiler / radiator system vs Rankine cycle

Everything I've read on the Rankine cycle indicates that the feedwater pump is necessary for the cycle to work. However the steam cycle used in traditional household boiler / radiator systems seems to ...
1answer
101 views

### Wire heating and heat transfer in a cylindrical pattern

I have a series of copper coils with ¼” cooling plates between each coil. The cooling plates will be manufactured from aluminum and cooled using copper tubing. There are seven in series, and a plate ...
1answer
165 views

### Heat Transfer in Different Wire Configurations

I am trying to create a program which estimates the final temperature of a magnet made of copper wire. I have different configurations in mind, but I will start off with a straight square wire with a ...
1answer
39 views

### Heat Exchanger- the calculation of q

What is the heat transfer difference between parallel flow and counter-flow heat exchanger? Are different equations used to calculate q?
0answers
50 views

### Search for comprehensive term for plants with heat generation with heat storage and operating states

My master thesis deals with systems with several operating states that generate heat and store it in a heat storage. Thereby I analyze combined heat and power plants with combustion engines, but also ...
2answers
116 views

### Heat exchanger efficienccy

I'm thinking about a system that would replace water in a swimming pool with clean water from an Artesian well. The water in the well is about 1C and the swimming pool is around 20C. Reheating the ...
1answer
27 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 ...
1answer
60 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 ...
1answer
177 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 ...
2answers
70 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 ...
0answers
56 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 ...
0answers
30 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....
3answers
39 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?
0answers
19 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 ...
0answers
47 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 “...
1answer
339 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 ...
1answer
1k 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 ...
1answer
41 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 ...
0answers
197 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 ...
0answers
45 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? ...
0answers
39 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. ...
2answers
54 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). ...
1answer
63 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, ...
1answer
166 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 ...
2answers
64 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, $\rho=740 \,\frac{\text{kg}}{\text{m}^3}$, $m=7.4 \,\text{kg}$, \$\...
0answers
32 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 ...
3answers
423 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: ...
1answer
399 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 ...
1answer
700 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 ...
2answers
180 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 ...
2answers
138 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 ...
1answer
75 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 ...
2answers
71 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....
0answers
21 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 ...
1answer
126 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 ...
0answers
24 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 ...
1answer
64 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 ...
1answer
85 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 ...
1answer
36 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 ...
2answers
86 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 ...
2answers
185 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 ...
1answer
64 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,...
1answer
320 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 ...
0answers
52 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 ...
0answers
66 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. ...
1answer
54 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 ...
1answer
132 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 ...
1answer
30 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 ...
0answers
60 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 ...