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Join Date: Jul 2014
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Earth Air Tunnel System

07/31/2014 4:50 PM

hello,I am a student doing my masters dissertation on geothermal energy, part of my project requires a simulation for earth air tunnel system.I have collected all required data such as soil temp and properties but I don't have a simulation software.
Is there any chance to help me with that please?
thanksfadi

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Guru

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#1

Re: Earth Air Tunnel System

07/31/2014 5:07 PM

Did your instructor take into consideration that you don't have the software?

Is it part of the course requirements to be able to find a program that you could use for this exercise?

You can use this list as a starting point.

List of computer simulation software - Wikipedia, the free ...

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#2

Re: Earth Air Tunnel System

07/31/2014 5:42 PM

Is an earth air tunnel system a tunnel underground that air is pumped through? If so, is the air in the tunnel for the purpose of changing its temperature, just for transporting the air or for some other reason? You will probably need to furnish more information if anyone is to help you.

Furnishing additional information also helps people better understand you and how much work you have put into this university task.

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#3
In reply to #2

Re: Earth Air Tunnel System

07/31/2014 5:54 PM

Hi Bruce,

this is exactly what i need to simulate.

we suppose to pass 1620 m3/hr fresh air with a temperature of 47.0 C and then pump it to the building for ventilation, but that depends on how much the air temperature will drop.

the soil temperature at 6 meters depth is 30.0 C, the project is in Dubai which is know as hot climate.

what i need to find out is the outlet air temperature, number of tubes, tubes arrangement, diameter, etc.

Thanks

Fadi

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#6
In reply to #3

Re: Earth Air Tunnel System

07/31/2014 6:09 PM

The outlet air temperature is never going to be lower than 30.0┬░C.

This is a masters dissertation? What part of the problem are you having difficulties with?

Just say 10 miles of tunnels and lots of outlets. That'll get you in the ball park.

Earth tunnel Air conditioning | Alternative Sustainable ...

Good luck.

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#7
In reply to #3

Re: Earth Air Tunnel System

07/31/2014 10:27 PM

30 deg C is nothing you want to circulate into a building.

Suggest to review the concept.

Dig deeper or add another cooling process.

How long you think you can use this process anyway? Suggest to take into consideration the formation temperature uptake as well.

Not a cheap tunnel for a two weeks usage until the formation is hot enough!

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#8
In reply to #3

Re: Earth Air Tunnel System

08/01/2014 1:42 AM

Learn how to ask the right questions. You didn't even indicate what you wanted to simulate... i.e. that you want to simulate a heat transfer problem.

You also didn't even make any indications about the purpose of this project. No background or anything useful to allow these kind people to help you. Do your own homework before you try to get other people to help you.

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#4

Re: Earth Air Tunnel System

07/31/2014 5:59 PM
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#5

Re: Earth Air Tunnel System

07/31/2014 6:01 PM
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#9

Re: Earth Air Tunnel System

08/01/2014 3:29 AM

Create your own model from some basic principals and a little experiment. It will likely give you far more understanding than plugging numbers into some anonymous software that you have blind faith in!
Remember maths is a tool, not a solution.

After all the air will come out somewhere between the temperature it went in at and the temperature in the tunnel, the slower the air flow the closer to the tunnel temperature, but the less efficient (low flow and poor temperature gradient). Fast airflow gives better heat transfer but less temperature rise.
If I had to choose between simulation and experimental data I'd go with the experimental every time.

Easy to make an experimental rig. Adjustable heat source, various types of insulation to simulate the thermal conductivity of the rock, speed adjustable fan, couple of temperature probes. And a log book to write the results in

Understanding is what is needed, not a half ar$ed simulation

Del

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#10
In reply to #9

Re: Earth Air Tunnel System

08/01/2014 4:09 AM

So Excel it is!

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