How Much Underground Pipe is Needed to Cool Water from 70°F to 60°F?

[kjsigpa]

Hello everyone, I appreciate any help you can provide me in this project.

Here is what I need to know...

How much pipe (probably some form of poly ethelene) do I need to bury to reduce the temperature of the water inside?

My input temperature should be about 70. Output desired is 60 or so. One inch pipe. Five gallons per minute flow rate. Average underground temperature is about 53.

I need to be able to show the calculations so please show me the formulas and what the variables mean.

Thanks for your time,
Jay

 

[russ_watters]

This problem is pretty difficult because it involves accounting for the heat capacity and heat transfer capability of the ground. Except maybe for some rules of thumb on ground source heat pump loops (google for it), it probably doesn't have an easy answer.

 

[kjsigpa]

Thanks Russ,

I am going to have to get through the calculations. Can you help?

Jay

 

[CarlAK]

You can probably assume the ground temerature to be constant and unchanging for first estimate. See this tread for basic equations & suggestions:
http://www.eng-tips.com/viewthread.cfm?qid=171100&page=1