The digging has begun - Go Marvin Go

[seawillow]

Looks like it's gonna be awesome...someday I'll have a huge room empty for an enormous tank....just have to wait for a couple of kids to move out Isn't it funny that in MA a licensed plumber has to do the plumbing work, but you, as a homeowner, can pull a permit to do your own wiring....

 

[RobboT]

Yes SW that is one of the most a**-backwards things about building codes. Supposedly its to keep people from plumbing their sewer lines to the wrong places but I think it's really that the Plumbers Union has better reps in government thats all.

 

[RobboT]

Greg - Is your tank water itself going to run through the geothermal loop or do you have something else in mind?

 

[denvig]

It is kind of strange that in Massachusetts you are allowed to fry your own a** but not allowed to install a place to sit your own a**.

 

[Greg Hiller]

Rob,

>Greg - Is your tank water itself going to run through the geothermal loop or do you have something else in mind?<

No, I'm not going to put tank water through for several reasons:

1. If the line were to break outside it would be VERY ugly.

2. Tank water will have sediments in it that might silt out in the wrong place in the line.

3. Tank water will have critters like filter feeding organisms that might set up camp in the line...not good.

4. Tank water could precipitate out calcium over time - not good.

5. Tank water will have sulfate in it that could be converted to hydrogen sulfide in the low oxygen environment that will exist whenever the line is not being circulated. When the line comes on again the H2S will dump into the tank - not good. I have found that small quantites of H2S going into a tank are no big deal, but 300 ft of 3/4 line filled with H2S might be a bit much.

The cooling water will run outside through the ground, then into an expansion tank of some kind, then though a long coil of tubing in the bottom of my sump.

My plan is to use either just DI water, or perhaps DI water with a high concentration of sodium chloride (table salt, I'll probably use the stuff from Home Depot for water softeners). The salt in the line will reduce the risk of freezing in the winter, and will also increase the heat capacity of the solution. As Marvin has pointed out, the line is probably deep enough that freezing is not likely to be a problem...but to be safe..... I will do some quick calculations for the freeze point of various salt solutions, and also for the increase in salinity in the tank should the line burst or leak into the sump.

The thing I don't have a good answer for is I would like to have a low flow, low electrical draw pump that I can use for this loop. Anyone have suggestions?

 

[RobboT]

Doesn't sound like you've really thought it through Greg

That sounds excellent. I was thinking of all the potential pitfalls of runing tank water through 300 feet of plastic tubing buried under 5 feet of sand and was sure you had some other plan.

 

[RobboT]

How about an electric diaphragm Greg. Most draw very little current and they're good for intermittent use. McMaster-Carr carry's a number of them. There are probably cheaper places to get them but you could take a look at them at the McMaster website.

 

[JustDavidP]

Greg/Marvin... that project, even in concept is frikin' amazing. Have fun..good luck and make sure you keep the pics coming. I can't even park my own car in my garage because of all the kids toys etc. How can I get MY wife to agree to an addition for my tanks?!? Do tell the secret.

Jeff... 48' Garage???? I know where I'm going to store my boat NEXT Winter!!

Dave

 

[RobboT]

David - tie the tank upgrade into an upgrade of thiers as well. When I told my wife about the 365g tank she went right for it. She has long complained that she doesnt like the laundry setup we have. Conveniently the wall I want the 365 on abuts the laundry so . . . I'm moving the laundry to a better location for her, I get the 365. Of course if I ever get my a** in gear on the project it'll be a miracle.

 

[JustDavidP]

Ooooh you guys are good...or is that deviant? Naw...in your case, not deviant... you ARE gonna come through with the laundry digs..

Now I know why I'm going out drinking with you guys this weekend. I'm bringing a notebook...there is a plethora of deviant knowledge to be gained here

 

[Chuck Spyropulos]

Geothermal Loop

It is 12 X 12 with a full basement under. We are installing a geothermal loop for cooling of the tank.

The room has a skylight and two bay windows with a slider to the outside.

I considered the same thing a while back b4 I bought my chiller but opted for the chiller. I designed a similar system and consulted with Bob Fenner on WetWebMedia. The system would have worked but is much more complex than a simple chiller. In the end, after I moved my sump into my garage my chiller only goes on during really hot days in the summer, much less than before with the sump under the tank, which finally ruled out the geothermal loop due to diminishing gains in the way of electricity savings.

But good luck with the project...would love to see the "chiller" in action !

 

[Chuck Spyropulos]

Greg,

The first system I envisioned would have the outside loop pumping water as fast as possible via a circ pump located inside my garage. Moving the water quickly would prevent freezing in the line segments above the frost line. Then, inside the house I was going to tap off of this "cooling" loop and add cool water from the loop into my tank and take warm water from the tank and tap it into the cooling loop. This could be done with motorized ball valves and a maniflod. But in the end you risk "dirty" water contamination if the exterior loop cracks.

The second system would be the same "loop" design but it would be filled with a coolant liquid similar to the fluid in chillers and air conditioners. The loop would enter the house and flow thru a coil that would be submersed in my sump or other vessel...the risk here is antifreeze or another coolant liquid getting into your tank !!!! yikes!! But there is a similar solution in all chillers so in theory, this should be possible.

Good Luck...let's see more pics !

Rob,

>Greg - Is your tank water itself going to run through the geothermal loop or do you have something else in mind?<

No, I'm not going to put tank water through for several reasons:

1. If the line were to break outside it would be VERY ugly.

2. Tank water will have sediments in it that might silt out in the wrong place in the line.

3. Tank water will have critters like filter feeding organisms that might set up camp in the line...not good.

4. Tank water could precipitate out calcium over time - not good.

5. Tank water will have sulfate in it that could be converted to hydrogen sulfide in the low oxygen environment that will exist whenever the line is not being circulated. When the line comes on again the H2S will dump into the tank - not good. I have found that small quantites of H2S going into a tank are no big deal, but 300 ft of 3/4 line filled with H2S might be a bit much.

The cooling water will run outside through the ground, then into an expansion tank of some kind, then though a long coil of tubing in the bottom of my sump.

My plan is to use either just DI water, or perhaps DI water with a high concentration of sodium chloride (table salt, I'll probably use the stuff from Home Depot for water softeners). The salt in the line will reduce the risk of freezing in the winter, and will also increase the heat capacity of the solution. As Marvin has pointed out, the line is probably deep enough that freezing is not likely to be a problem...but to be safe..... I will do some quick calculations for the freeze point of various salt solutions, and also for the increase in salinity in the tank should the line burst or leak into the sump.

The thing I don't have a good answer for is I would like to have a low flow, low electrical draw pump that I can use for this loop. Anyone have suggestions?

 

[MarkO]

Greg, looks great. I'm jealous!!! I wouldn't worry about any lines freezing, especially if they are 4' (or so) deep w/ a brine sol. From my experience, only very exposed areas with no tree cover will freeze at or near 3 feet or so and only during the nastiest non-snowcovered winters. I'm surprised the local con com didn't bust your ba!!$ Looking forward to the progress.

 

[Tstone]

Greg, looks great.
I'm surprised the local con com didn't bust your ba!!$ Looking forward to the progress.

Greg can tell you all about that issue.

 

[Randy Holmes-Farley]

The thing I don't have a good answer for is I would like to have a low flow, low electrical draw pump that I can use for this loop. Anyone have suggestions?

Your favorite ones: the Reef Fillers.

 

[Greg Hiller]

Randy,

>Your favorite ones: the Reef Fillers<

Well, I was thinking of flow just a Tad faster than than! Besides, I'm glad to be rid of that horrible grinding noise.

Chuck,

Thanks for your comments. I can see how you considered your system to be complicated...it is!! I really don't think my system is complicated at all, just pump water around a loop of tubing buried in the yard (no motorized ball valves here!). I plan to have NO fans on the tank upstairs (I want it to be SILENT, I mean SILENT upstairs), the lighting fixture will be quite close to the water, and I plan to attempt to mimimize evaporation (tired of making RO/DI water), so cooling the tank will be a major concern. I also do not have central air, and I tend to be pretty stingy about electrical use, searching out the most efficient lighting, etc. You only have to look around my house and notice that every room lighting fixture uses the power compact screw in bulbs!

>The first system I envisioned would have the outside loop pumping water as fast as possible via a circ pump located inside my garage. Moving the water quickly would prevent freezing in the line segments above the frost line<

I understand the freezing issue, and I think I'm all set there. The reason I DON'T want a powerful pump on this loop is two fold, first, it adds heat to the water and is therefore counter productive. Also, I invision the pump being controlled by the temp controller for the tank. The pump will only come on when needed. If the pump moves water at a really high rate of speed through the loop it's possible that there will be unnecessary oscillations in the water temp. For example, the pump's been off a long time then comes on and pumps a whole bunch of cold water into the loop in the sump, then the tank cools down more than necessary, and in a worst case actually triggers the heater. I will probably be controlling the pump by an old Aquacontroller that I have, the Aquacontroller allows for some tricks with respect to the way you control things (dead band, max on, etc.)

Rob,

Thanks for the tip, I'll check out the pumps.

 

[Chuck Spyropulos]

Reef Filler

Randy, my Reef Filler has been running flawlessly in my topoff system!

The thing I don't have a good answer for is I would like to have a low flow, low electrical draw pump that I can use for this loop. Anyone have suggestions?

Your favorite ones: the Reef Fillers.

 

[Chuck Spyropulos]

Advice

I don't think the slow flow loop will be too efficient. Remember you are trying to take away heat from your sump and the efficiency depends on how well the closed outside loop will act as a heat sink for the "heat path". However, as you know, you will lose efficiency due to loss of heat transfer between the soil and the pipe, loss of heat transfer between the pipe and your water and also due to slow water movement through your heat transfer coil in your sump. If the dwell time thru your coil is really slow, then the system's cooling capacity is diminished even further; you will essentially heat up the coil in your sump until equilibrium is reached and the cooling effect is diminished or even prevented! Using a faster flow pump that circulates the cooling loop water continuously would be more efficient in my opinion. Then inside, two Tees could be inserted into this loop: one that feeds the cold water to the coil in your sump and one that removes the "heated up" water in your coil. The water through the Tees could be controlled via motorized ball valves that in turn could be controlled by a thermostat. The valves would open when you need cooling and close when you do not need cooling. This would not bring down the temperature too quickly since you have to overcome the "insulation" effect of the pipe walls. In my opinion, the effect of the pump heating the water is negligible compared to the effect of the water in the coil being heated by your sump water. I guess the main point here is to allow yourself enough water flow through your coil to maximize cooling effectiveness, regardless of the design you choose.

I understand the freezing issue, and I think I'm all set there. The reason I DON'T want a powerful pump on this loop is two fold, first, it adds heat to the water and is therefore counter productive. Also, I invision the pump being controlled by the temp controller for the tank. The pump will only come on when needed. If the pump moves water at a really high rate of speed through the loop it's possible that there will be unnecessary oscillations in the water temp. For example, the pump's been off a long time then comes on and pumps a whole bunch of cold water into the loop in the sump, then the tank cools down more than necessary, and in a worst case actually triggers the heater. I will probably be controlling the pump by an old Aquacontroller that I have, the Aquacontroller allows for some tricks with respect to the way you control things (dead band, max on, etc.)

Rob,

Thanks for the tip, I'll check out the pumps.

 

[Randy Holmes-Farley]

Well, I was thinking of flow just a Tad faster.

How fast were you thinking would be optimal?

 

[Greg Hiller]

Chuck,

>I don't think the slow flow loop will be too efficient<

You are correct that slow flow will be less efficient, but it doesn't matter once you get to equilibrium.

Time to get your heat transfer book out Chuck!

You are making this too complicated. If the flow is slow enough, and the loop is long enough (300 feet I think Marvin said, of specialized tubing to maximize heat transfer), and small enough diameter the water in the loop will come to equilibrium with the medium outside the loop. Therefore, you can assume that the water coming through the wall of the foundation (out of the ground) will be at ambient temp year round. I forget what it is here in the northeast, but 52F comes to mind for some reason.

From there it's a simple calculation to assume that the water temp of the tank without any cooling would reach some particular temp without any cooling (85F, or you could even assume 90), and then to calculate how much heat the 52F water warmed to about 80F would remove (that of course assumes that the loop in the sump is long enough to also come to equilibrium, but I'm guessing that also will not be a problem). I ran through these calculations a few months ago, and came to the conclusion that I would have far more than enough cooling capacity, and that I would only need a slow pump rate (cannot remember what it was)....I don't have time at the moment to run through them again.