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)

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4
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2answers
524 views

Can a Peltier's device (i.e.Thermoelectric cooler) achieve cryogenic temperature efficiently?

Does the stacking of peltiers device shows promising results in achieving the cryogenic temperature? I have tried doing the experiment, the overall temperature of the system increased around 80ºC and ...
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2answers
235 views

Having three heaters on single PCB

I posted this question on electronics SE, but was suggested that I post it here. I basically having three heaters (serpentine pattern) on a PCB (fiberglass board), as the following image shows: The ...
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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, ...
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1answer
52 views

What's the setpoint of the temperature on the primary side of a heat exchanger?

I have a heat exchanger with known flows on priamry and secondary sides - $\dot m_p$, $\dot m_s$, known temperature in $t_{si}$ and a desired temperature out on the secondary side $t_{so}$. How to ...
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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 ...
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1answer
2k views

How to design a house to be cooled passively? [duplicate]

I live in Louisiana these days, in an area that is known for its numerous antebellum plantation homes (circa early 1800s). While touring one of these homes it was clear that almost everything about ...
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3answers
2k views

Can an isothermal process also be adiabatic?

I came across this question of "can an isothermal process also be adiabatic?", and at first thought that yes, why not? If the temperature is constant and there is no heat loss to the environment it ...
7
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1answer
715 views

Are smaller heat-pumps more efficient?

I was a doing a placement at a company, and they were designing a new heat pump. I was told the more compact you can make a heat-pump, the better it is for efficiency, and they mentioned something ...
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1answer
2k views

Modeling Transient Heat Transfer between two 1-D materials

I have been working on creating a 1-D model of a material with a layer of heat resistant material stuck to it. For this I have been trying to use the implicit finite-differential method. The equations ...
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5answers
396 views

what's the best shape for inducing condensation?

What would be the best ceiling shape for inducing condensation? I'm guessing it would a curve ︶ or V shape, but those are just guesses. (I don't have any background on thermal physics)
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1answer
159 views

Multiphase Flow - Energy Coupling Parameter

I have a general question regarding energy coupling in multi phase flow. My question comes is based on the text from this book: https://books.google.co.uk/books?id=CioXotlGMiYC&pg=PA33&lpg=...
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4answers
503 views

Difference between temperature and heat

It is becoming very difficult for me to understand the difference between temperature and heat. About heat all I have read : Heat exchange is related to as exchange of matter + energy. Heat is ...
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2answers
219 views

Solving heat loss equation associated with solar trough concentrators

My project is about finding the efficiency of solar trough (cylindrical parabola) concentrator that will boil water in a pipe located at the focus (check picture please). In the process of doing so (...
4
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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 ...
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1answer
503 views

Calculate thermal flow for air flowing through a tube, with fins

I have the same problem as described in this question: How to calculate the resulting temperature for a stream of air through a hot tube?, but I want to increase the transferred heat by adding fins ...
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1answer
118 views

Relationship between thermal conductivity and reaching the steady temperature?

The diagram is for three materials with different thermal conductivities. I think number 1 is the material with higher thermal conductivity because it transfers the heat faster so it gets to the ...
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1answer
2k views

How to calculate the resulting temperature for a stream of air through a hot tube?

Given the temperature $T_1$ and volume flow rate $\dot{V}$ at the start of the tube, which has a temperature of $T_0$ and an inner surface of $A_0$, what is the resulting temperature of the stream ...
3
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1answer
1k views

How to calculate required air mass flow to keep CPU below certain temperature?

I have been assigned to work out how much air flow is needed through each partition of our servers in order to keep our processors at (or below) 60C (333K). I have worked out the current mass flow ...
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1answer
139 views

How to determine heat exchanger equation?

What is the equation to determine the inside surface temperature along the length of the counter flow heat exchanger?
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2answers
90 views

Does a house heating system affect perceived and true indoor air humidity?

Does a house heating system affect indoor air humidity? Or to be more precise, does it affect your perception of how dry the air in the house feels (for instance dry is your mouth waking up)? (I ...
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2answers
79 views

How to calculate heat and mass transfer rates from an enclosed box?

I'd like to know if it's possible to calculate the heat and mass transfer rates from a small volume to the environment. Let's assume there is a box with a small opening at the top. The air inside the ...
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1answer
2k views

How do I calculate the temperature change inside a box with a heat source? What if I ventilate the box?

I have a box (as shown below). I know the temperature outside of the box (for example you could use 293K) and I would assume the temperature inside the box is initially the same as outside of the box. ...
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2answers
342 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 ...
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1answer
90 views

how would one calculate the % of heat not absorbed by a heat sink?

I'm planning on building a plant growth chamber inside a sealed/insulated 55 g rain barrel, and I'm trying to figure out how much of the heat from my lights will enter the chamber, and how much ...
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2answers
48 views

Difficulty in understanding the scenario for this Q

Q:If a closed rigid wall container filled with 20 gm of He moving at a constant speed of 10 m/sec is stopped abruptly to stand still, find the increment in temperature of this He sample. My question ...
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0answers
150 views

Using a Copper Waterblock or Aluminum Heatsink to Cool Water via Thermo Electric Cooler [closed]

I am attempting to create a ThermoElectric Cooler to Chill Water. I have thought of two options as to how I can cool the water: Some limitations of the design: The water is still, not moving. No "...
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2answers
2k views

Problem with Energy Transfer Rate Conversion

Given the question: Calculate the energy transfer rate across a 6 in wall of firebrick with a temperature difference across the wall of 50 °C. The thermal conductivity of the firebrick is $0.65\...
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1answer
692 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 ...
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1answer
63 views

Why do binary cycle geothermal power plants have so low efficiency?

Well, a binary cycle geothermal power plant utilizes the low temperature of the primary liquid to generate heat. I found out that they are only 10% to 15% efficient. Is the continuous flow of the ...