02-12-16, 07:03 PM | #581 |
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Dang, wish I had been following this closer, I have a 24" by 24" water to air exchanger just like that, that I really need to sell. lol
Yes the idea should work, but my question would be are you not stealing btus from the greenhouse? I would think that a solar heater would provide more heat and not take the btus to need to charge your water batteries. Just a thought though.
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02-12-16, 09:48 PM | #582 |
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@SDMCF
Do you know how many gallons the pool was? How many hours did you run yours? Very cool you have done this. I would like the fish water to be at least 70 F right now it is around 63. I probably would not let it go over 82. But @70 I think the fish and plants would be happy. I don't loose that much heat in my fish water each night so maybe I would not need to run it all the time. @MEMPHIS92 I would have loved to save some money and had a bigger heat exchanger. I have days I need to vent the greenhouse those BTU’s just get released into the air. I need to measure the temp at the top vent level. I just ordered a wireless sensor to tell me temp and humidity. I hope that taking the air from the top above the barrels. Where the top vents are. Then blowing the fan through the heat exchanger into the second row of barrels that it will be a net gain. By using the heat I have better. But I don’t know for sure the heat exchanger was $94 shipped with a lifetime warranty. I already have the fan and it was not being used. I already have temp controllers and the ½ 50’ SS coil. So for under $100 it is worth a shot. I really wonder how much heat the barrels get from direct sun versus greenhouse temp. I know the barrels really reduce the heat in the greenhouse. Measuring the temp @5’ I was getting over 100 easily on sunny days now at that height it stops at 90 most days. Right now it is 42 outside and 60 in the greenhouse. I am sure there diminishing returns at some point. I sure don't know where those are yet. So many unknowns…. Most of the passive solar greenhouses I have seen data on are dirt farmers and don’t have to heat fish water. Since this is all theory what do other think will this rob too much heat from my solar batteries?
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02-14-16, 11:51 AM | #583 |
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Yesterday it was nice and sunny. 8:00 Pm it was 32 degrees midnight 28 degrees down to 24 degrees.
The greenhouse did not go below 53 degrees the fish water was 66 degrees. No fossil fuels used. I have disable all venting until it warms up some. Right now it is 12:52 pm and cloudy 30 degrees outside but the greenhouse is 67 degrees. I always wanted a greenhouse but I did not want to dump hundreds of dollars in heating it to get the plants. That why this options is so fun that is not required.
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02-14-16, 12:26 PM | #584 |
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If you have to vent heat then that is good to have something to soak up the heat.
But I do know your barrels are soaking up the air temp too because when you put them in, they kept the air temp much lower. Paint the coils black and have them in direct sun as well. It can't hurt to gain a little more from the sun on it too. $100 ain't bad for a test.
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02-14-16, 03:29 PM | #585 |
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Like I stated before, the closed-loop approach you are taking, combined with the two heat exchangers you have, could be all you may need to heat and cool your greenhouse. From your preliminary results, you seem to be getting more solar gain than you can capture on sunny winter days. Using the shotgun exchanger to sequester more of the BTU's in your fish tank water may help in more ways than one. First, it will transfer all the heat you tell it to into the cool water. Second, it will delay your vents from opening, directly proportional to the BTU's routed to the fish tank. Higher flow rates (water and/or air) will yield a diminishing increase in heat transfer. As you posted, I also suspect the bottleneck in this heat scavenger will be the air to water HX surface area, and to a lesser extent, the airflow through that HX. Whatever dT the water picks up in the process will be gobbled up by your wort chiller coil. Running straight tank water through the shotgun HX would not get you hardly any more heat transfer, but it would highly increase the chances of fouling and corrosion.
The summer use of this closed-loop heat transfer mechanism should not be overlooked. The supply and return lines to the ridge HX could be teed into, and a chiller loop could be plumbed in. During sunny hours, the fan (and possibly water flow) for the ridge HX could be shut off, forcing all the chilled water through the wort coil. Strategically setting up a shady, calm spot below the chiller coil will become the hangout joint for your fish that are not comfortable in hotter water. Even though you might not measure much overall temperature drop, your water chemistry will thank you for it. Last edited by jeff5may; 02-14-16 at 06:33 PM.. |
02-14-16, 08:56 PM | #586 |
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I want to mount the new heat exchanger close to the fish tank so I can keep the closed loop short.
I have a one gallon expansion tank with an 8 Amp 12 dc pump. Here are a couple options I have. I can mount the fan at the top of the roof and have it blow the hot air down to the heat exchanger. I can use a flexible duct or I can build a duct with OSB. I could mount the fan at the heat exchanger and have it suck the air down through duct work. Does anyway know if a car battery will work to run a 8amp 12 Volt dc motor with a small battery charger to top it back off at night. So questions. Is just the volume of the closed loop and a very small expansion tank enough for the closed loop? Have the fan push or pull the air. Flexible or ridged duct. My pump is the UF1215 I have this to help purge the air 1/2" Brass Automatic Air Vent Valve High Temperature
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02-14-16, 09:42 PM | #587 | |
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Quote:
So for example you draw 8amps for a total of 4 hours. That's 32AH So you would need at the very least an 120AH battery. Charging is the reverse so if you have an 8ah charger it will charge in 4 hours. Car batteries are not really designed for long current draws, they are just designed for a quick surge to start the car. Deep cycle will fair better with repeated discharges and can be run as low as 20% of charge, so a 50AH deep cycle would work in place of the above car battery and last longer as it's designed for the long, low current draw. Hope that all makes sense. |
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02-14-16, 09:47 PM | #588 |
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Yes that all makes perfect sense. Thanks for the info.
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02-14-16, 11:42 PM | #589 | ||
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A rigid duct would be better because the concertina type flexible ducts disrupt air flow a lot, which limits throughput. Also it is easier to make a rigid duct larger and volume is important. I think any given fan will move more air if the duct is larger. However, I would not do it the way you propose. I would mount the heat exchanger near the roof so that it is not necessary to move hot air down to it. I think that will be more efficient, simpler, and more reliable. The extra few feet of water pipe will not be a problem re heat loss. You just have to be sure your pump can cope with the extra head. Quote:
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02-15-16, 08:11 AM | #590 |
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Spent about half a day reading this whole thread. Great stuff. You definitely have a lot of hours in the project.
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