Re: [TRNSYS-users] About Type-952 for geothermal cooling

[Jeff Thornton <thornton@tess-inc.com>]

Re: Type 952 - You can't have a zero thermal conductivity.  An error message in the resulting list file should have pointed that out.  Do you check the list file when you have problems?  That's the VERY first place to start.

To simulate a pipe without insulation, simply set the insulation material properties to something reasonable and set the thickness to zero.

If the model had refused to allow a thickness of zero (this is true of some models) you could have specified a material with a HIGH thermal conductivity and the smallest thickness allowed in order to minimize the resistance to heat transfer of the insulation.

Jeff

Sent from my iPhone

On May 1, 2015, at 6:29 AM, SANJEEV JAKHAR <sanjeev.jakhar@pilani.bits-pilani.ac.in> wrote:

Dear Mr. Jeff,

First of all thank you for your reply I have checked the Type 952 as per your suggestion. However for zero insulation thickness and with zero thermal conductivity it is not working at all.  For zero thickness means there is no thermal conductivity of the insulating material. But when I put default value of thermal conductivity with zero thickness it works.

Thanks & Regards,

Sanjeev Jakhar
Research Scholar
Center for Renewable Energy and Environment Development (CREED)
Mechanical Engineering Department

Birla Institute of Technology & Science, Pilani
Rajasthan - 333031

On Wed, Apr 29, 2015 at 7:02 AM, Jeff Thornton <thornton@tess-inc.com> wrote:

Dear Sir,

I just dragged out a Type 952 from the GHP Library, set the insulation thickness to zero and it ran just fine - with and without flow.  I checked the source code and there is no mention of a recent bug fix dealing with the insulation thickness.  Are you sure that you don't have som other error causing you problems?

As for the average surface temperature, for most applications it's relatively close to the average air temperature for the site - but not always.  It is also close to the average deep earth temperature for many locations as well.

 

Jeff

 

---
Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577  Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton@tess-inc.com

On 04/27/2015 1:05 am, SANJEEV JAKHAR wrote:

Dear sir/madam,

I have a doubt on Type-952 (Buried horizontal pipes) for geothermal cooling in which the system supposed to be buried inside the soil. In the parameters how to define the thickness of insulation since I don't want to give thermal insulation to allow heat transfer between the pipe and soil. If I gave insulation as zero value it is showing some error and simulation no running. Please guide me how to solve the problem.

Also please clarify what is average surface temperature. Is it equivalent to average annual ambient temperature or temperature of soil at a certain depth.

Thanks & Regards,

 

Sanjeev Jakhar
Research Scholar
Center for Renewable Energy and Environment Development (CREED)
Mechanical Engineering Department

 

Birla Institute of Technology & Science, Pilani
Rajasthan - 333031

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