Concrete Slab water cooler loop - Hooked up!!!

Gigs nice use of your melon... certainly outside of the square for the idea....

personally i would have set them much higher or into the frame myself

 

Haha, nah mate. Bit over my head atm for that kind of purpose. Was more so a joke than a valid reccomendation

Mechanical Engineer/Whoever studies Hydraulics and Thermal stuff at Uni would be able to help. Im more so Civil/Structural.

 

No worries, I will try and gets some tests up soon. This may help his decision.

Yer basicaly what I plan to do

I wanted it at floor level so I can mount the pump under the desk. Thats the only reason why its down low as well as not wanting to introduce any heat into the copper pipe where it leaves the coolness of the slab.



On another note I have been worried about condensation and think I have finaly got my head around it. This is what I have found so far:

If the ambient temperature of the air is 20 degrees Celsius and humidity is set at 90% condensation will occur on any object that is 18C or lower. If humidity is 70%, condensation will happen on objects 14C or lower.

Here is a Humidity Calculator

I have found that Tassie has very high humididty year round according to Wiki

Inside a house the humidity sits around 50% maybe a bit higher in tassie. So on average the inside temp will be 23deg at 60% humidity will give me a dew point of 14.8deg so I think I am going to just slip under the condesation level.

 

Hey gigs, only just stumbled across this thread by accident (gotta love OCAU for all the truly awesome random shit you can find here ) I gotta give you props for your application of such a system; I've investigated geo-thermal transfer systems (Ground-Coupled Heat Exchange Systems) for use in passive "green" temperature regulation systems for housing, but hadn't made the logical leap you have.

Only skimmed the thread, so not sure if anyone else has mentioned it, but you might want to consider a dual loop heat exchange system to safeguard your pc/whatever else you're hooking up. Basically, you want to seperate the cooling fluid in your pc from the cooling fluid going into your slab. That way, if you have any contamination (possible) or leakage (unlikely) issues with the copper in/under your slab, it is kept out of the cooling fluid running through your pc. So, what you want is a coil immersed in a tank (dodgy pic attached) where the tank is full of coolant from your slab cooler (ordinary ethylene glycol, for instance) and your coolant from your pc running through the immersed coil.


Click to view full size!

The benefit of this is twofold. Firstly, it keeps your coolant running through your pc nice and clean at all times, and you can change just the pc coolant easily without having to flush the ground coil out. Secondly, if there is a problem with the ground coil, ie- it cracks, the remaining coolant in the tank will provide some passive cooling capacity to prevent damage to your system. of course, in this case, you need to place the inlet and outlet of the coolant tank at appropriate heights and with appropriate check valves in place to prevent the whole tank leaking through the ground coil; this is not shown in my pic.

I have built large heat exchangers for regulating commercial aquaria in a similar manner (but with titanium tubing!! and chillers rather than ground coils), so have a little bit of experience with this. Hope that's of some help mate!

 

I like it warpspider Someone else mentiond having two loops and I wasnt really sure what they meant. I like your pic and I agree on the merits of such a system. I could knock up a reserve out of perspex that houses the circ pump and the copper induction pipe for the second PC loop. Thanks for the info. How long a length of copper would I need for induction from the under slab loop within the reserve? Hope that sentence make sense

 

Plx send me kk thx

 

The systems I did were in a big, well, Esky I guess. The commercial version of anyway, the kind you see on charter boats, etc. But these were for behind the scenes use, and you'd want something that looks a bit nicer, so an acrylic tank would do the trick, with nice fittings to suit. Wouldn't even have to be that big, a 200mm x 200mm x 300mm reservoir will hold 12L of coolant.

The length of the coil run in the heat exchanger will depend on the material you're using (copper in this case), it's diameter (the Surface Area to Volume ratio is important), the flow rate through the two systems, and the temperature differential between the two cooling fluids. For what you're trying to achieve, I'd think only a couple of metres at most would be heaps, coiled into a helix that will fit into the tank (have fun bending that up ).

Hmm, now you've got me thinking... If I was going to do this project, I'd set up the heat exchanger tank as a cylinder with the exchange coil inside, and the plumbing routed to a flow setup to provide a counter current exchange of heat (ie- hot pc coolant in one end of the coil, cool ground loop coolant coming into the opposite end of the cylinder. See pic.) This will give the most effective cooling result. You could use standard sewer pipe, 200mm or 300mm diameter, and pretty it up all you like. Or clear acrylic tubing and go the full bling with LED lighting, etc.


Click to view full size!

 

Hahaha, you don't want to know what that cost. Seriously.

'Twas necessary though, as you don't want to be introducing copper into tanks full of (revoltingly expensive) invertebrates... it tends to cause, well, death.

 

ok here is my 2 cents.

http://i31.tinypic.com/9kzcya.jpg

The basic idea, is that you can operate the pc WITHOUT having to pump it all through the copper under the house, unless you want to. With my design, you have two pumps, one in the computer, and a larger one under the house (or in a different area where noise isn't an issue)

I've been thinking about this for a while lol.

 

You might look into designing your system to make use of thermosyphon, basically taking advantage of the natural water flow created by differing temperatures in the water. Many radiant floor heating set up use this to help reduce the time their pumps have to run to circulate the water and in some cases only have it come on when any air pockets build up and hinder flow.

BTW guys that are saying put it higher in the slab, why? In every aspect its better to have the pipes lower as your getting closer to the earths constant temp range. I forget how deep it is but its like a meter under the ground and the earth stays at a constant temperature within about 1-2 degrees year round meaning you'll have very consistant cooling.

 

Hi Guys sorry I havent got back to you sooner. I took the day off work yesterday to "help" with the slab. Thanks for your ideas WarpSpider Davo1111 and Orphan. I will have a think about it and get back to you Some pics of the slab, sorry for the bad quality they are from the iphone.


Click to view full size!


Click to view full size!

 

looks good mate, i'm actually looking forward to seeing the results! Hurry up and build the house! LOL

 

I am currently building a house, and want to run my own cat6 before walls go up. However because im not owner/builder, and going through another mob, there a bit iffy.

Well, as far as I am concerned, its my house, I'm paying for it, not interfering with any of the existing building to be done. If, by some miracle that cabling happens to appear one sunday while walls are stiff off, I cannot be held accountable for that.

 

lol you sound like the wife

I think I will setup a test soon to try and work out how many degrees I can obsorb over a period of 5hrs. Thinking about heating a 44 drum of water to about 50deg and holding at that temp while pumping it through the tube over a period of a few hours. I will take readings at 15min intervals....

mate its your house just DO IT! There is an old place on my property that was built pre 1880 (an old lady came to visit us one day and told us her grandfater was born in the house in 1880) and it has sat on rocks - no concrete since that day. It is still dead level and has not moved 1 inch.

The council has made us take GPS readings and have surveyors out to measure river heights for the 100 year flood (which cost over $1k) for the new house built next to the old one that has been there for 230 years FFS! I have got enough steel in my new slab to sink the Titanic. There has to be a point where the local council BS has to stop.

 

FEM is a simple numerical technique to solve any partial differential equation. If you know what a partial differential equation is and have heard of Laplace/Newton etc, then you have all the information you need to work it out!

I would imagine that most structural design programs would use FEM, so I would imagine if you are civil/structural then its something you are going to become very familiar with.

It is also used to solve the St Venants (probably a bit of FDM in there to estimate the gradually varied flow characteristics) equation in hydraulics which is how they would have estimated the 100 year flood event.

Also to the OP, good work!

 

Looks like the size of a shed not a house

 

already got a shed floorplan was posted earlier in this thread.

 

Yea, they do look tiny when it's just a slab, all houses do. Now you know.

I guarantee it will look much larger and like a house when the frame goes up.

 

In Tasmania, particularly in the winter my bet would be bulk amounts of heat ROFL.

More seriously, it will depend on whether your slab is coupled to the ground or insulated from it - most likely coupled. Check http://www.yourhome.gov.au/technical/fs512.html for some general stuff.

I am very impressed gigs. Very.

 

A few years ago I tried a passive system with a Athlon XP1700 (65W)

Two 5m 20mm copper coils in parallel and a ehiem 1500L pump.
Worked ok if I sank it in a flat wide container of cooled water, but buried I was not getting enough heat transfer via the sand.

Interested to see how you go in concrete.