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)

Filter by
Sorted by
Tagged with
-1
votes
0answers
9 views

How to calculate the thermodynamics properties of the LiBr/H2O solution?

When modelling an absorption heat pump cycle one would need to calculate the state properties of absorbent, absorber, and the mixture of these two; in order to find out the cycle properties. Is there ...
4
votes
2answers
32 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 ...
0
votes
1answer
37 views

Method for comparing efficiency of heater block designs?

How would I go about comparing the efficiency of different heater block shapes for the outlined system? So, in the attached diagram there is a cylindrical heater cartridge (A) that is used to ...
-1
votes
1answer
29 views

What is the average energy loss due to rolling friction in contemporary motor vehicles?

Around what percent of energy provided by gasoline is lost as heat due to rolling friction in vehicles? Is this number higher for larger vehicles likes trucks than smaller vehicles like bikes? ...
-1
votes
0answers
32 views

Insulating toaster oven

I opened my taster oven to make it stay always on instead of using the timer. I noticed that the space between cooking chamber and outter mantle is empty and Im thinking about adding insulation like ...
1
vote
2answers
63 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 ...
0
votes
0answers
27 views

How to calculate heat transfer between two solids in a medium?

If I have a cuboid block of metal and there is a cylindrical source of heat input (A) and I want to determine the heat energy at B (also cylindrical) how would I do this? I understand considerations ...
0
votes
0answers
28 views

Temperature rise of a block of aluminum under constant heat flux

Consider a block of Al. insulated all around except on one side, where a heat-pipe is to be inserted. On the opposite side of the heat-pipe, there's a heat source (Resistor) with a given heat flux. ...
0
votes
0answers
11 views

Transient Heat Transfer Problem for a parabolic PDE of Rectangular Plate

I was able to write the elliptic PDE for the steady-state temperature of the plate but I am having a very hard time doing the same for the transient problem. Now consider the transient problem for ...
2
votes
1answer
39 views

Placement of supporting boiler in heating circuit

In my thesis, I deal with heating circuits, where several heat generators are present, e.g. a combined heat and power unit and a supporting boiler. Usually, the boiler is placed in front of the heat ...
1
vote
0answers
37 views

How can we dissipate the heat from a block of 10*10*3 mm with 100 degree Celsius without losing the portability of the block?

I have a Peltier's device of 10*10*3mm and the material is Bismuth Telluride. The hot side is 100 $^oC$ and I want to dissipate the heat, and at the same time, the device should be portable i.e. it ...
5
votes
2answers
104 views

Heat transfer coefficient of a cylindrical hot water storage tank depending on its size

I have a simulation model of a cylindrical hot water storage tank. The heat loss is determined by the surface area and the heat transfer coefficient. A configuration of the storage tank with 900 ...
2
votes
1answer
71 views

Storage losses of a heat storage tank

Suppose I have a heat generator with a connected heat storage tank. If the heat generator remains the same and the heat storage tank is dimensioned larger, the running time of the heat generator ...
1
vote
1answer
64 views

Heat Exchangers

LMTD of a counter flow heat exchanger is 20°C and cold fluid enters at 20°c & hot fluid at 100°C, mass flow rate of cold fluid is twice that of mass flow rate of hot fluid. $C_p$ of hot fluid is ...
0
votes
1answer
31 views

Why adding less than optimal level water but just enough water to drench the sausage in general isn't the quickest way to cook?

The exact reason why adding less than optimal level water but just enough water to drench and dive the whole sasuage in during boiling in a pot isn't the optimal quicking cooking method? My intiuion ...
0
votes
0answers
19 views

How to calculate the two parameters in the red box about Required ventilation rate and Calculated CO2-loss?

I dont know how to calculate the two parameters.I think The total energy of the light is 700w/m2*3600s=2520Kj,then I will not do it.
0
votes
1answer
15 views

Relationship between Heat Flux and Engine RPM

I'm doing a project that involves knowing the average steady-state heat dissipation rate of a single cylinder air-cooled engine (through the engine wall and fins) at a given RPM. The problem is that I ...
0
votes
1answer
45 views

Average Nusselt number or heat transfer coefficient to compare better heat transfer?

I'm simulating different arrays for cylinders in a simple cross flow heat exchanger (cylindrical pipes) as shown below: Inlet temperate(300K) is constant and the cylinders are at constant temperature(...
0
votes
0answers
18 views

Heat transfer and rise in temperature

Consider an object of mass M and specific heat C, and initial temperature T1. Let energy is transferred to the object at the rate of W watt. I want to calculate temperature of the object at time t. ...
1
vote
0answers
26 views

Heat sink Design

I have a problem where there is an 80 Watt thermal load that needs to be cooled to maintain 80 Celsius. The base of the heat sink is 5" x 7" and is oriented vertically with cooling via natural ...
1
vote
0answers
23 views

Final temperature of an isolated vessel - Thermodynamics

8) Consider an inextensible tank of 10 m3 of volume, isolated by an adiabatic wrap. The tank contains nitrogen at 2 bar and 300 K. This tank is connected to a piping by which more N2 (at 300 K) is ...
0
votes
0answers
15 views

When Convection exceeds radiation loss

A very hot small metal cylinder of mass, 50 g and surface area, 2 x 10^-3 m^2 , specific heat capacity, 500 J kg^-1 K^-1 and thermal conductivity, 25 W m^-1 K^-1 is to be rapidly cooled from 800°C and ...
1
vote
1answer
67 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 ...
0
votes
0answers
11 views

Compute equilibrium temperature under a roof

I want to compute the equilibrium temperature below the roof (inside a building) to analyze the efficiency of an insulation layer. I impose the environment temperature $T_{env}$, the insulation layer ...
0
votes
3answers
54 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 ...
0
votes
1answer
63 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 ...
1
vote
1answer
80 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 ...
-1
votes
1answer
31 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?
1
vote
0answers
49 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 ...
1
vote
2answers
107 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 ...
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 ...
1
vote
1answer
44 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
vote
1answer
59 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
53 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
37 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
11 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
19 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
36 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
28 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
12 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
55 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
170 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
23 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
69 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
41 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
38 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
34 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
51 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
80 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 ...