let the insanity begin

rick rottet said:
It seems like the sunlight itself, no matter what the temp in the greenhouse, contributes to heat gain in the water.
Click to expand...

Sunlight is 60% infared. This time of year I would guess we are about 500 W/ m^2 of peak incoming solar. In the summer we will go slightly over 1000 W/m^2. I dont know what your surface area is or how much shade you will use in the summer, but this gives you some idea how much heat you will get from solar.

The rock is looking very nice. Good enough to snorkle in.

cseeton: I am in 2428 MEL, drop by and say high some time. I probobly pass you in the hall all the time.

Steve
 
Get a light meter

Get a light meter

Wether its a lux meter or a multimeter with the proper probe to read actual par readings. I bought a $100 meter and it has a submersible probe. heres some food for thought

In GH at 12pm, No clouds, No shadecloth, my lux at mid tank level (submersed in water) is 60,000 Lux

In my 220g w/3 HQI-250w 10k Mid tank level (submersed in water) is 9,300 Lux

The tanks both had same depth. So in my location compared to the equator I was getting over 6x's the lighting that my 220g was getting utilizing natural sunlight.
 
Geo thermal

Geo thermal

some wisconsin geo-therm apps

http://www.wisgeo.org/works.html

here's some from tennessee

http://www.tva.gov/products/business/geothermal.htm

The above links mostly are for heat xchange pumps which I believe h2oeng refers to as a true geo-thermal. The type of geothermal I used on my greenhouse involved the SW from my systems actually circulating underground thus mediating the temperature of the tankwater. This approach I have found out is much cheaper to install from the beginning and if you build it to where you can adapt it to a heat xchanger type Geo-Thermal was my thought mainly because of finances for something like this.

So here is my make shift diagram of an actual heat xchanger pump once h2oeng and others helped me to understand it from a laymens point of view




2934heatxchng.jpg


Sorry for the shotty diagram...hopefully you will understand the engineering of it.
 
scubadude-thanks for the links. I will check them out. Your diagram was my basic understanding of a geothermal loop. Underground loop circulates cooler water in a pipe through a big container of water, thereby cooling it off. The tank water also circulates in another pipe through the same container and gives up some of it's heat. That way, the tanks water never mixes with each other or the underground loop's water, or the containers water. Just seems like it would take up some space that could otherwise be growing corals. Unless it is outside the greenhouse?

tschopp- how does your formula equate to heat gain? Do you have a conversion formula/ factor?

matt-there are HAF (high air flow) fans, four of them which do a nice job of moving the air around inside the greenhouse. I don't think taking up enough space to put in 10,000 gallons is an option for me. The whole place only will have 4,200 in tanks, 425 in live rock vat, and another 1,000 or so for changes/ topoff.

cseeton-I understand how the industrial desiccants are employed, hence my statement that they would not be appropriate for this application. What I am interested in is why you think/ say salt wont work? Salt is a desiccant, if you pass air over it, the air will become drier. Is it just the quantity that would be required? Would the ambient humidity overwhelm the salt's capacity? Yes please do go into this with more detail, I am very much interested in this issue.
 
cseton- Did you catch my earlier reference to the DIY evap pads made from kitchen scrubber material, wall paper troughs and a power head? What would be your thoughts on the efficiency of something like that?
Remember, there is already cooling mechanics in place with the HAF fans, shutters, exhaust fan, and evap from the tanks. So any one method does not have to provide the total cooling necessary.
 
Don't get me wrong, salt CaCl is a desiccant but it saturates at a relatively low level, clumps easily and thus you will need ALOT of it - that trek back and forth to the oven will get old. Also the problem with all desiccant systems is that as they remove water from the air, the temperature of the air increases (constant enthalpy process) so you will need to remove the heat or the net effect is zero - (edit:well, not really, there is a finer point here, but it is basically zero).

Your pad and pump idea is good, if you can find the salts that absorb at constant humdity; however, you will reach saturation quickly with the amount of water you are going to want to remove. This will also heat the air, by the way.

Running straight evaporative cooling with probably provide all of your cooling. It is simple, effective and you already have the fans in place. You will be limited by the dewpoiont however. A foundation or spray will help make this process more effective and expose more water to the atmosphere.

If you want tighter control, they make small dessicant wheels for residental use, combined with an AC unit and your propane, you can achieve whatever condition/stability you are after.

Or maybe evap cooling alone will be tolerable, I think the dewpoints in Aug/Sept are a little high though combine with the sun load though. There are other creative options think about swimming pool with spray during the evenin to drop the temp and the it will make up the ground leg of the geothermal loop - which can be operated without the cooling unit.

Such a quandry - the corals need sun to grow, and the sun heats everything up
 
Hi guys,
Rick, this is such a killer thread! Good to see so many people jumping in!
Rocky,
Your comment about the pool is true, and Rick sees this too. Some buildings use cooling ponds, with fountain sprays rather than actual cooling towers. And some even have roof ponds with sprinklers to stave off some of the direct suns heat. So theres a lot of evaporative area there.
Remember that with geothermal (or any other heat transfer application) that the bigger the temp differential, the faster the heat will flow. This is why the heat pump (compressor) based systems are so efficient, but we need a lot of extra tubing to get closer to our temps
Rick, in your application, you could bury coils in ground and have an exchanger in one of your system tanks, or a separate tank. It would not have to be too big. The most exchange in the smallest footprint would come in a plate heat exchanger (get your wallet out). The 80 ton chiller we had to cool 350,000g to 55degF only used 2 plate / frame exchangers the size of a cupboard door about 3" thick!!!
I definately would not run system water through the loop for control and dieoff issues. I think it worked decent for Rocky because of their warmer ground temps. In your location, you should get decent cooling from Geothermal, but it IS a lot more digging. But hey, you are good at it now!:D
Maybe cseeton could crunch some geothermal exchange #s for you to figure out how much tubing, flowrates, etc.
 
One other neat cooling strategy is night sky radiation. Basically you use solar panels at night to radiate the heat into space. The water temp can actually get lower than the ambient air temp!
I know some people use their pool solar heaters this way in hot climates- to COOL the pool.
 
well, you can always double/ quadruple up the pipe in any holes dug.. put 2 on the outside of the trough 8'down, 2 more 6' feet above that, etc..

just rent the John Deere again, :) and go deep!

even if it takes only a few degrees off, you would be that much ahead/ and several methods that take off 3-4 degrees = really powerfull cooling- but you knwo that already
 
rick rottet said:
scubadude-thanks for the links. I will check them out. Your diagram was my basic understanding of a geothermal loop. Underground loop circulates cooler water in a pipe through a big container of water, thereby cooling it off. The tank water also circulates in another pipe through the same container and gives up some of it's heat. That way, the tanks water never mixes with each other or the underground loop's water, or the containers water. Just seems like it would take up some space that could otherwise be growing corals. Unless it is outside the greenhouse?
Click to expand...


if i understand correctly, what you say will work, however this may work better.

a geothermal loop can be run underground. it doesnt need a "big container of water" you can have a closed loop system of water (or any other viscous material, you may want to use something that won't freeze in the winter) with a big(or long) enough pipe (the bigger the pipe, the large the surface area, the longer the pipe, the larger surface area) and a pump to push the water, then run this pipe underground. generally speaking, ground temperature remains a constant 55^. this will cool your closed loop water to pretty close to 55^. you then run the pipe through your tanks. as the 55^ water runs through the pipe, it will pick up heat from your tanks. as the water progresses from tank to tank, it will gradually warm up and eventually become so warm, it will no longer effectively cool the tank. at that point it is time to send that water back underground for a cooling loop.
your cooling loop can be completely vertical and take up a very small surface area. or you can just go down ~4' and run it horizontal, which would involve tearing up much more of your yard

i can think of a ton of ways to do this(the most basic is just running the pipe underground, then through each tank, more complex involves having each tank have its own dedicated loop and running the actual tank water through it, and even more complex would be to have a valve after each tank, and it opens once the closed loop water reaches a certain temp, and sends that water back underground), however it all hinges on calculations which will tell you how much your water temp will be, and hinge on how much cooling you want, and therefore would tell you how long your loop needs to be, which i do not have the expertise to do.
 
H20ENG said:
I think it worked decent for Rocky because of their warmer ground temps. In your location, you should get decent cooling from Geothermal, but it IS a lot more digging. But hey, you are good at it now!:D
Click to expand...

once you get down about 4 feet, anywhere in the non-frozen world(outside of the arctic circle), ground temperature stabilizes at 55^.
 
boxer,
A fellow in FL (gpajon on RC) tried a geo loop and he was down 8' and still getting 80+ deg temps down there.

By using larger pipes, you also need to use a bigger pump, to keep the water turbulent. If it slows down, it will turn to laminar flow in the pipes. This is bad because the water contacting the pipe wall will create a boundary layer against the inner pipe water and less heat transfer will occur. I guess this could be overcome with contact time (Rocky used tons of 4" pipe), but it not as efficient.
 
Instead of having it hold the water in the tank till it no longer cools the tank water why not just have it continously flow through, just at a reduced pressure for a slower flow rate. That should be just as effective, shouldnt it?
 
H2OENG is right I could crunch numbers and get a good approximate on a ground sourced heat pump. But, wouldn't you and your family like an above-ground "heated" swimming pool this summer - the bigger the better? Toss a heat exchanger on the filtration system and a variable speed pump to circulate through tubing installed in the tanks then use the night sky and night evaporation to cool it down at night. You would have a giant heat resiovor to dump heat into all day long and it would be just the right temp when you get home from work...

Just an idea...
 
Rick and Rocky,

I have misunderstood a little on the geothermal. I had thought of it the way you said it Rick, with just two loops. But the way Rocky has shown it it has a third loop that has a compressor. What would you put in that loop? Am I looking at this wrong? The geothermal loop is outside and the exchanger is in a sump or a guess it could be multiple sumps depending on how good it is.

The sun not only heats the water in the tanks. It heats the plastic which in turn heats the entire house. I have a constant problem with that on my first GH. The second one I did with the roll up sides and it seems to help considerable. I get a little more dusat but I don't think that as a problem.
 
H20ENG said:
boxer,
A fellow in FL (gpajon on RC) tried a geo loop and he was down 8' and still getting 80+ deg temps down there.
Click to expand...

That makes sense based upon the work I do in caves - they are about 54 degrees in the Midwest up here, but considerably warmer than that down in New Mexico, for instance.
 
Treeman,
The added compressor is a refrigeration compressor, called a heat pump. There are many air source heat pumps- looks just like a house A/C. A heat pump has a reversing valve that allows you to remove heat form either the evaporator or the condenser side. This way, you can heat with it in the winter, and cool with it in the summer.
The ground loop carries the heat away from the condenser, and the refrigerants evaporator loop will chill your water.
HTH
 
boxer85 said:
once you get down about 4 feet, anywhere in the non-frozen world(outside of the arctic circle), ground temperature stabilizes at 55^.
Click to expand...

I wish that were true. I would be a happy camper:) I have pumped water from 120' down and it is only 74 degrees. At the 6' depth I have my geothermal I think it is about 77 if my gauges are right.
 
but if there is only a 3-4 degree differential it wouldn't be very efficient would it? What is in the compressing loop?
 
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