The Homemade Heat Pump Manifesto

[waterdigger2]

Originally Posted by NiHaoMike

He was thinking about buying a window heat pump, which is of no extra value in a heating only geothermal build. Geothermal doesn't need defrosting.

sub $45 Homemade chiller
Not as good as a proper heat exchanger but it does work pretty well. Good solution while you either build up a proper unit or wait until spring to do it right. Use distilled water and RV antifreeze (propylene glycol, safer than car antifreeze) as the fluid.

You'll probably want to swap the cap tube for a TXV once you put in a proper heat exchanger since TXVs are cheap on the surplus market and they improve efficiency. Don't forget to replace the filter drier as well.

We wouldnt know what to do if it got below freezing for very long. It is usuallly pretty mild winters butas far as waiting until spring. Im guessing reason ya say that is because snow maybe ? We dont get that here very much thankfully. Although white christmases are nice. Good link though

[jeff5may]

I especially love this one:



If a teenager can do it, you can do it. Water is an awesome secondary refrigerant.

EDIT: Here are the original threads:

http://www.xtremesystems.org/forums/...memade-chiller

http://forums.extremeoverclocking.co...hlight=chiller

[AC_Hacker]

Originally Posted by jeff5may

I especially love this one:



If a teenager can do it, you can do it. Water is an awesome secondary refrigerant.

So what's with a photo with no explanation and no link?

You trying to keep this thing secret?

-AC

[jeff5may]

Originally Posted by AC_Hacker

So what's with a photo with no explanation and no link?

You trying to keep this thing secret?

-AC

The pic is from the thread Mike linked a couple of posts up from me on the $45 chiller. Guy said in his post that he was 15 when he built it. Second hand 5000btu aircon repurposed into -30C PC watercooler. Still working a couple of years later.

Here is a more comprehensive build, roughly the same end product, by another teenager:
First Chiller - EXTREME Overclocking Forums

[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

[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

[waterdigger2]

O and im tryin to get 6000btu right now out of that 240ft to a ton here we dig em 250 to compensate it floatin back up when you remove the hole loader . But when i get th other unit i will try pull the whole ton out of that hole.

[waterdigger2]

We use the same . 240 ft per ton here . This is comein from geothermal installer we drill for. Only reason for the 250 ft . Not sure if its the same with the shallow holes . But that pipe as it goes down the mud that floats up the cuttings actually works against you . Reason we use a huge heavy metal cylinder to drop em down. The second you take that cylinder . You have to hold the loops down or they will literally shoot right back up out of the hole. The 10 ft extra is just to compensate (if) it was to shoot up loose grip or something. I wonder how accurate that map is on the temp. I have 2 wells here . One is shallow one deep. The deeper one is actually warmer than the 14 ft shallow one. Strangely enough.
What are you classifying as (wet sandy clay) Not sure what that is . Unless you are talking about like the water table clay under that that is pourus enough to have water?
For the soil . Yea we have sandy clay. About 85& sand the rest clay,gravel, dry sand . But for the most its sandy clay.
_____________________________

Yeah do have 3 holes dug each 250ft deep. Reason i was going to use only 1 loop is because i thought the more holes it had to go through it would make it not as efficient. In that case . I will go with a bigger 1 1/4 hdpe pipe to connect each hole to the 1 1/4 . Or 1 1/2 . I cant remember what size they use to connect them up .
But being th heat exchanger is 3/4 instead may be better to just run the 3/4 instead of the 1 1/4 ?
I will have to get out there and measure once the rain stops i believe their something like 10ft apart. Their all in a line from each other.
__________________________________________________ _________


On the Heat Exchanger. None yet . Have found one with all sweat fittings that i plan on getting. Only its 10 plate.

10 Plate Copper Brazed Heat Exchanger 5"x12" 3 4" Sweat | eBay

Yea. I dont plan on usin a cooler or nothing crazy like that. From what i under stand the heat exchanger is basically what switches the heat from the refridgerant and exchanges it with the loop water and makes it efficient .

[AC_Hacker]

Originally Posted by waterdigger2

On the Heat Exchanger. None yet . Have found one with all sweat fittings that i plan on getting. Only its 10 plate.

10 Plate Copper Brazed Heat Exchanger 5"x12" 3 4" Sweat | eBay

Yea. I dont plan on usin a cooler or nothing crazy like that. From what i under stand the heat exchanger is basically what switches the heat from the refridgerant and exchanges it with the loop water and makes it efficient .

waterdigger2,

Sorry it's taken me so long to get back to you...

That BPHX you have linked to looks like a good one to me.

There are charts on the Internet that can help you size your HX correctly. But you need to keep in mind that charts that are for water-to-water do not apply to refrigerant-to-water, because the heat exchange rate is different.

I found a Mueller BPHX document called, "MUELLER-BPHE (CR-1242-2BPXSize-Tech).pdf", that has similar, but larger HXs.

I looked at one that had the closest Width x Length dimensions and divided its capacity (many more plates) by the fact that yours is 10 plates...

By my reconing, using your BPHX in an evaporator role (getting heat from your water) your HX should be just fine for a Ton (12,000 BTU.hr).

* * *

But if you are really, really broke, and can scrounge up some copper tubing, and plastic pipe, you could build one similar to the one that Acquario did for his SWIMMING POOL IN SPAIN.

You'd just have to give it your best guess and try it out.

-AC

[NiHaoMike]

I recommend a coax heat exchanger like this one:
TURBOTEC | COILS, STEAM & WATER | 1.70 TON COAX COIL | Surplus City Liquidators
It's physically much bigger (about the size of a small car tire for the 1.7 ton after you account for insulation) but also much less restrictive, meaning that the pump uses less power. I highly recommend oversizing the heat exchanger as that improves efficiency.
While you're at it, also get the TXV (must match refrigerant type and tonnage, a R22 TXV will work with R290 or R433b/ES22a), filter drier (do not open until right before you're going to braze it in), and other accessories like sight glasses and pressure cutouts. That site does not automatically calculate shipping, but you can send them an Email to get the exact amount before accepting the order.