Greetings- This may be thought of as a continuum of the (many) prior posts asking for advice on a DIY chiller.....with a twist
Specifically, I have a lake to use as my heat sink. I have a 300+g system heated by 3 400w MH HQI's, one 250w MH, 12' of VHO, a Sequence 5700, Iwaki 100rlt. At least those are the primary culprits.
Currently I am running a 1/2hp chiller (remote outside) set to keep the system at 76-77 degrees. It does run periodically in the winter due to the 70-72 degree house temp. In the summer it struggles, even with the house AC on. The issue is the eastern sunrise, which beams directly into the three 6'x9' windows. Also the open concept of the house itself.
My intent is to add a primary lake-cooled chiller and keep the 1/2hp as backup, set a few degrees higher, in case the lake doesn't do the trick (too much solar gain, lake too warm, etc.). We have few 100 deg days here but numerous 90 plus in the peak of summer. I have data from fisheries studies that show lake temp. to max in August at 65 degrees and min in January at or close to freezing. These were taken at 10’ depth. Today it was 38 deg.
What I am considering is a closed system with:
• a titanium tube or coil in the sump (don’t yet know which). Cost and efficiency are leading factors.
• a Medusa or Runco controller (I have both) running to a pressure pump (uncertain as to what size pump will be needed). Hoping to make the pump as electrically modest as possible.
• ¾†flex tubing running down to the lake and back (pex?) buried underground.
• either coiled tubing or a titanium tube/coil submerged 10-15’ in the lake. Again cost and efficiency reign.
Better to run a more powerful pump, less frequently? Example would be one of the large Iwakis, pressure rated, at 2.5-3.4 amps.
Efficiency of a coil of PEX or otherwise compared to a ¾†titanium tube 6-8’ long in the lake. I have lots of protected space under the dock for either. 8’ of straight tube would run me about $130, whereas 500’ of ¾†PEX is $200. I could do lots of coils for the money, but acknowledge the increased friction loss due to the longer length. Where is the breakeven? This will help to determine which pump to use as well. I have found a coil type heat exchanger here: Heat exchanger
And a Ti tube here:
Ti tubing
If I do end up using the Ti, the coil reads as 20" long.... arguably more space efficient. Would the 3/4" tube serve as well if at least that long? Is there an advantage to the "coil" versus a straight tube?
Is there a type of tubing which has reasonable cost similar to above and low friction inside, which would be reef appropriate? One of the varieties of PEX or otherwise?
The surface of the lake is roughly 25' lower than the sump room. As it would be a closed loop, with water seeking its own level, I am thinking that all the pump would have to overcome is the internal pipe friction....correct?
I have read a bunch of great input on earlier threads pertaining to Geothermal cooling..... hoping for some sharp folks to weigh in on my idea.
Thanks for your input! D
Specifically, I have a lake to use as my heat sink. I have a 300+g system heated by 3 400w MH HQI's, one 250w MH, 12' of VHO, a Sequence 5700, Iwaki 100rlt. At least those are the primary culprits.
Currently I am running a 1/2hp chiller (remote outside) set to keep the system at 76-77 degrees. It does run periodically in the winter due to the 70-72 degree house temp. In the summer it struggles, even with the house AC on. The issue is the eastern sunrise, which beams directly into the three 6'x9' windows. Also the open concept of the house itself.
My intent is to add a primary lake-cooled chiller and keep the 1/2hp as backup, set a few degrees higher, in case the lake doesn't do the trick (too much solar gain, lake too warm, etc.). We have few 100 deg days here but numerous 90 plus in the peak of summer. I have data from fisheries studies that show lake temp. to max in August at 65 degrees and min in January at or close to freezing. These were taken at 10’ depth. Today it was 38 deg.
What I am considering is a closed system with:
• a titanium tube or coil in the sump (don’t yet know which). Cost and efficiency are leading factors.
• a Medusa or Runco controller (I have both) running to a pressure pump (uncertain as to what size pump will be needed). Hoping to make the pump as electrically modest as possible.
• ¾†flex tubing running down to the lake and back (pex?) buried underground.
• either coiled tubing or a titanium tube/coil submerged 10-15’ in the lake. Again cost and efficiency reign.
Better to run a more powerful pump, less frequently? Example would be one of the large Iwakis, pressure rated, at 2.5-3.4 amps.
Efficiency of a coil of PEX or otherwise compared to a ¾†titanium tube 6-8’ long in the lake. I have lots of protected space under the dock for either. 8’ of straight tube would run me about $130, whereas 500’ of ¾†PEX is $200. I could do lots of coils for the money, but acknowledge the increased friction loss due to the longer length. Where is the breakeven? This will help to determine which pump to use as well. I have found a coil type heat exchanger here: Heat exchanger
And a Ti tube here:
Ti tubing
If I do end up using the Ti, the coil reads as 20" long.... arguably more space efficient. Would the 3/4" tube serve as well if at least that long? Is there an advantage to the "coil" versus a straight tube?
Is there a type of tubing which has reasonable cost similar to above and low friction inside, which would be reef appropriate? One of the varieties of PEX or otherwise?
The surface of the lake is roughly 25' lower than the sump room. As it would be a closed loop, with water seeking its own level, I am thinking that all the pump would have to overcome is the internal pipe friction....correct?
I have read a bunch of great input on earlier threads pertaining to Geothermal cooling..... hoping for some sharp folks to weigh in on my idea.
Thanks for your input! D