I,m a DIY with and usual situation. I'm going into a spring fed under ground stream that is about 9ft down about 40ft back of my house. Check and found one forum where someone had done this they said 450ft 3/4" per ton should be enough. I'm in Southern Indiana about 10 miles from Louisville, KY. I got 500ft easier to cut. The flow from Oct.15 till Jun. 15 is about a 4" pipe running constantly full. It tapers down in summer to about a 1/3th of that but never stops. My question should the line going to the loop be at the lower level with the rest of the loop, or should it be higher. Also should it be up stream or down stream. I have a good back hoe and a huge amount of construction experience. Already have set up dewater. John Miley E. A.
Welcome. It does not matter where the header pipe is. It should be below the frost line, usually at least 4 " down. It depends on lenght how is your configuration. Slinky? Straight pipe? You can stay with 500' since you can always add a loop. If straight, keep the pipe in the trench 2' apart, if possible. What is your flow requirements, and what size system do you put in. Pressure drop and flow is crucial and the main reason some loopfields fail.
I,m going with slinky loops about 8ft down with fine river p gravel a foot below and above. I'm installing two 2 ton units with separate loop fields 500 ft. parallel. My house is 1400 sq. ft. well insulated few windows. The unit I'm going to use for primary is an Addison with a de super. The secondary one is a Carrier Commercial wired 230. There should be a least 1ft. of water over the loop field from Oct15 till Jun15 some years earlier and some later. I'll put in a manifold and fix it were it is easy to add a line if needed. I have a fusion machine but think part at least is going to be mechanical joints. Will have manifolds in mechanical rm. The problem may be cooling as the flow doesn't stop in summer just slows down considerably. This is a wonderful forum. I've gained a wealthy of knowledge. I've worked helping with heating and primarily cooling in chemical plants and refinery's. Used to work for a thermal engineer. Commercial is different. I'm thankful for this wonderful forum. Need to get back digging. Because of these other springs I've hit won't get it done this year .
Off the top of my head I'd be exploring ways to more intensely / compactly interact with that constant flow of water. Would it be possible to bury a septic tank below the frostline such that the spring feeds through it all the time? The tank could contain a reasonable amount of coiled pipe to transfer heat to and from the water moving through the tank. If the flow is as you describe the water would be completely changed in a 1000 gallon septic tank every few minutes in summer and once or twice per hour in winter. I gotta figure a pond loop type coil of pipe would perform really well in what amounts to a continual forced convection arrangement. Mark Custis posited such a system a couple years back. I think he went with a several hundred gallon poly ag tank. I remember suggesting that a much smaller coil (say 50-100') of 3/4" copper tubing immersed in a tank of flowing water might achieve a much greater heat transfer than a whole lot more plastic pipe. Conductivity of the wall of plastic pipe is not a limiting factor in the case of pipe buried in ground, whether vertical, horizontal or slinky, but that same conductivity might well be a limiting factor in the case of a constantly moving stream of water.
How many circuits of 500ft are you planning? Are there any sharp edges on the gravel? I would prefer sand.
Sorry about not stating the loop field numbers. Been busy trying to beat the weather. I'm installing 500ft. per ton intend to fix it where, if need be, I can add one if needed. Going to plump the system separate but where, if need be, I can add or switch the loops. The septic tank deal sounds real good. Would have given loop field more thought, the 2 streams I hit when I started digging aren't the one I was going for. There is another bigger steam about 100ft away that is larger than the two I hit. That is the one I intended to use the water from. I have a retention basin for the main stream that is 11ft deep and about 1/4 acre about 300ft away. One end and the two 6" discharge pipes never freeze. They p gravel I'm using is almost like course sand. Smaller than regular 3/8 p gravel. Have about a week left then I'll have to quit for winter. Used to help run water and sewer lines and work caissons. Freezing and thawing ground is the most frequent for cave ins. Appreciate all the advice. John Miley E.A.
That all appears to be reasonable, you just have to ensure that the water never stops flowing. 4 ton seems to be overshooting for a 1400 sqf well insulated house. Any reason you would not want to use a combined loopfield for both heatpumps. When only one is running you would benefit from the flow through the combined loopfield. Also you would only need one pump, one header line. Much easier....
I plan on using the commercial one with out de super as back up. Not always easy to get service help here. I do taxes for a guy who used to work 4 companies. Now he is down to a rental real estate partnership and commercial HVAC for The Federal Government. He says I can get him when I need him, but he may take a day or two to get here. These type compressors is his job. There is a commercial guy right down the road, but he wants no part of geothermal. My retention basin lets me know,fairly close,how much the flow is by the over flow pipes. Got two pumps and valves, real reasonable,plan on fixing it so I can use the fields as I need to. I'm a decent plumber. Electric water heater has been in 25yrs and not even a heating element. Our water is terrible and pressure sometimes over 110psi. We have water hammers that shake the pipes and ground, when they flush the lines twice a year. Regulators, shock chambers. air tanks to control pressure. Line back to bottom off water heater. Cost a little more to operate,but helps stop corrosion Tried to get two guys,who work for two local companies,to help with Geo. They tried to talk me out of it. Said at my age I would never recoup the investment. The septic tank idea would have been safer faster and less costly. But then,I figure,it may not have worked as well In the summer. Appreciate All The Advice John Miley EA.
Seems summer might be a problem, with the loop under only a foot of water, in the summer it might end up just embedded in the gravel, think y0u said you're backfilling with gravel. I'd think though that your summer load might well be lower, so it won't be the end of the world. Might be in a heatwave only the living room and bedroom gets AC and you close the other duct dampers. Someone thought maybe a copper coil for that really fascinating septic tank idea, I read alot on heat transfer through copper and plastic, including a head pounding amount of math, and while it's counter intuitive, the improvement with copper isn't that striking. The real kicker was the "thin film" "insulating effect" on the inside of the tubes. It's like that R value for the inside / outside air film in wall assemblies. The reality check came when I remembered what happens when you drain down an old water system and recharge it. You get dirty water scoured off the inside of the pipe. As long as the pipe stays filled all the time, whenever the water flowed, the stationary thin film hugging the sides of the pipe kept turbulence from scouring the dirt. So, that stationary water film becomes the limiting factor in heat transfer. Didn't help that we are dealing with low delta T's, low temps, small diameter thin wall tube either. Well, I think that was it. At any rate, I ran the numbers and it was almost as expensive to use copper as plastic, so why bother with the corrosion risk?
Yes. Summer may be a problem. When I started the known stream is about 120 ft. from where I'm putting mechanical room at. The steams I hit,that has a flow of about 10,000 gals a day right now, is about 30 ft. from mechanical room It is about 30'' deeper in the ground that the other stream that runs perpendicular. These streams set on solid sand stone. I am shutting down for winter. Getting busy with Tax business work and to unsafe to dig 10ft in freezing and thawing ground. Naturally I'm leaving dewater pits in and I'll use them for observation There is now a fairly large creek about 300ft from me that wasn't there 160 yrs. ago There was a stagecoach livery operation on this farm and the springs where the only place to get water. The stage barn is still standing. I can control water flow some with retention basin I installed. When I dug the dewater pit to put in the basin I pulled out 7 old rusty , coach horse shoes, in the blue muck. You could still make out the block heal stickers on the shoes. I may be in a situation where there will be a pool area where the loops are in the summer. Won't work as well as in winter but will still work. Also,like you say,don't air condition the whole house. Worked in refineries that made Vietnam look cool. Some days over there it didn't go below 90 at night. All the chopper pilots, especially on the Chinooks,knew how to dead fly.
I have photos of the tank installation if you would like to see them. We had an issue with the water in our spring fed instalation. The water did not hurt the horses that drank it, but it perffed the copper in less than three months. We had to scrap the copper and replace it with HDPE. Mark
The photos would be interesting, if you can find the time. I'm going with 3/4" HDPE SDR11. Haven't tested my water ph. because I planed on using HDPE. Have seen it used under extreme environments at DuPont and other chemical plants. Copper in low concentrations isn't toxic to horses. It has a sweet taste to them and passes there smell test. Some people use copper bits on dry mouth and or nervous horses. Aluminum is toxic to them. Lot of cheap curb bits where made out of aluminum. The horses would usually go berserk and the owners would have no idea what caused it. Unless a horse is real hungry about the only toxic thing they will eat is wheat or urea blocks. Have to watch and not bed on wheat straw. Haven't yet learned how to load files on this forum yet. The bucket picture shows my hillbilly bucket cleaner. The second is my first set up on my second dewater point. There is a pump running that 1 1/2" line about 75% full constantly. If you look the bottom steam in only 4" to 6" deep. There is about 2ft. of clay muck with fossilized bones scattered threw it. Above that there is a some what up and down stream bed, 2ft to 3ft. deep, then about 5ft of clay. Some winters there is water in the upper steam by Oct15 some not till Dec15. Our ground moisture has been down for past 5 yrs. Third picture is my first dewater point with an automatic sewage pump. There is a steam there that is about 12" higher than the other one. The HDPE sticking up is 1" Sch7 that I had. Put it in in a hurry when my pump went down one night and banks started to slide. May need to fuse it to the Sch. 11 for the other two loops. There is a other ditch 4ft away I' m sending return lines up. The big house in the back ground, of third image, has a 4 ton unit, installed by Algier Air. As soon as I can I'm going to look at the install. I think it has about 4 loops 1200 ft. long. There installed in the drier ground at 6ft. Shutting down now for the winter. Will be interesting to see what I have in the spring. I'm not back filing the lines going up to where the mechanical room is for now. J Miley
