The Homemade Heat Pump Manifesto

[AC_Hacker]

Originally Posted by waterdigger2

It is 3 holes dug 250 deep. Loops set right close to 250 may be 248 or 249. But lets round it 250 still 3 ton thats for the whole house well pump house and the shop. (never had money for unit or ductwork yet) And we sized it for the additions i will be doin also

Bein their just sittin taped waitin to be hooked up. I will just use 1 hole at the 250ft. Thats 1 ton. I understand that a ton will do 600-700sq ft But That should be plenty to heat and cool the 450sq ft . 8ft celins. Unless you think thats overkill on the depth. I do know how to dig em my self by hand around 40 to 60ft.

Horzontal i will run 10ft lenght to that closest hole still use the 3/4. so all togather 530ft of 3/4 pipe

Your estimate of 1 Ton per hole might be not be quite the correct number.

In the 'Manifesto' I use that number because it is the one that is commonly used in Western Oregon where I live, when the average ground temperature is taken into account. The map indicates my soil temperature would be 56 F, but my holes aren't as deep as you have been able to achieve, and when I measured the temp in the winter time, which is when I need it, it is 52F... still pretty close. The map indicates that your soil temperature is around 67F. I can testify that as far as geothermal goes, the difference between 52 and 67 is huge.

Also the typical soil characteristics...

For instance, sandy clay (where you live) is considered to be sort of 'average to poor' classification, regarding geothermal... but wet sandy clay is the best you can get. This is also a big deal.

For heating, I think that 1 Ton per hole is too low. I'm not sure how much higher your situation will be, but I would recommend that you find some people in your area, who you can ask regarding their estimates.

For heating, your higher ground temp is very favorable. For cooling, your higher ground temperature is not so favorable... so your cooling capability will be less.

But if it is wet sandy clay that you have there, it will be to your benefit, whether you are heating or cooling.

* * *

I'm a little confused here... You said that you have three holes and you're only going to use one of them? I think that it would be to your benefit to use all of them, especially if they are not too far apart.

It's one of those situations where bigger actually is better.

If they are all available, run pipe from each of them to your house and do the combining and plumbing there.

And you should run them all in parallel, it will greatly reduce the size and power consumption of your pump.

* * *

Also, as I recall, you already have a heat exchanger? That will be part of the total resistance that the pump will need to pump through.

So if it is true that you do have your heat exchanger, I'll need to know what is is you have there.

By the way, you are well on your way to constructing a high class geothermal system. Your system will very much be influenced by your heat exchanger. Don't even consider fooling around with a little radiator in an ice chest... that's for experiments, and for children. You need a serious heat exchanger, which you can buy or build.

But whatever it is, I need to know about it to calculate your pump size.

-AC