morlock
New Member
Posts:6
 |
| 07 Aug 2012 10:00 AM |
|
I'm in fact finding mode regarding open loop from an artesian spring on my property about 100' horiz and 50' vertically from my house. The issue is last year the spring ran at at steady 6gpm, but right now in Missouri we're under a severe drought and it's running in the 2gpm range. I would estimate the final house needs at 3 ton when it's retrofit is complete. Based on the manuf numbers I've seen that puts me at a need for 4.5gpm.
This may be a stupid question, but I'm assuming I only need that flow rate under full load, correct? Would it be unreasonable to divert a spring box into a large underground holding tank to use as a reserve for load/no load cycling? I'm sure the devil is in the details on this one, but is this a common practice or should I abandon the open loop thought out of hand? |
|
|
|
|
|
|
jonr
Veteran Member
Posts:3335
|
| 07 Aug 2012 12:58 PM |
|
You need to size and build a system to handle close to sustained full load. If the water tests out as being suitable for open loop, you could look into some minimal drilling to get you the 4.5-6 gpm you need. Or a hybrid system that is partially open loop and partially a horizontal loop (with all the free water you have, add a soaker hose). |
|
|
|
|
geodean
Veteran Member
Posts:1524
|
| 07 Aug 2012 01:49 PM |
|
Posted By morlock on 07 Aug 2012 10:00 AM
Would it be unreasonable to divert a spring box into a large underground holding tank to use as a reserve for load/no load cycling? I'm sure the devil is in the details on this one, but is this a common practice or should I abandon the open loop thought out of hand?
This can work very well. You can even put a coil in the holding tank and have a closed loop. |
|
Dewayne Dean
www.PalaceGeothermal.com
Why settle for 90% when you can have 400%
We heat and cool with dirt!
visit- http://welserver.com/WEL0114/- to see my system |
|
|
morlock
New Member
Posts:6
|
| 07 Aug 2012 02:30 PM |
|
Geodean,
That's an interesting thought there. I hadn't put that one together... |
|
|
|
|
engineer
Veteran Member
Posts:2627
|
| 08 Aug 2012 12:00 AM |
|
I like it.
A holding tank (pond, fish pool, cistern) large enough to store a day's flow at 2 GPM would meet the load needs of a 3 ton unit needing 4.5 GPM in high stage 6-8 hours per day. Might even get away with sizing the tank at 1/2 a day's flow.
I think we went through a similar excercise here a year or so ago where we suggested a coil of a roll of copper tubing in a plastic tank fed by the spring flow, and it wound up working well. |
|
Curt Kinder
Without data, you have just an opinion.
No thing done well is as simple as it seems
www.greenersolutionsair.com
|
|
|
jonr
Veteran Member
Posts:3335
|
| 08 Aug 2012 09:20 AM |
|
A tank works if the system is off for ~13 hours/day - not likely under all conditions unless 3 tons is oversized.
How much you can throttle back the already minimal 4.5 gpm and get non-optimal but acceptable performance is an interesting question. |
|
|
|
|
joe.ami
Veteran Member
Posts:3578
|
| 08 Aug 2012 10:04 AM |
|
That's why a tank that the spring simply passes through has promise. |
|
| Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
|
|
jonr
Veteran Member
Posts:3335
|
| 08 Aug 2012 10:37 AM |
|
I don't think it holds up to a week of cold winter weather - the btus simply aren't there to be extracted. If there are some additional facts, for example, drought never occurs in the winter or drought is so rare that you don't mind adding substantial resistance heat, then that changes the math.
|
|
|
|
|
morlock
New Member
Posts:6
|
| 08 Aug 2012 11:09 AM |
|
I am almost certain the flow rate is coupled to the Missouri river in some way since we're only 1/4 a mile away. I have not personally witnessed the flow rate this low, but I have only been monitoring for a year. I looked back at USGS flow rates for the river from 2007 and January can dip down as low as it is currently. According to their charts, July should be the peak flow! That's a few assumptions, but they seem logical at least. What about adding some kine of solar collector in the loop for additional heat? |
|
|
|
|
joe.ami
Veteran Member
Posts:3578
|
| 08 Aug 2012 11:23 AM |
|
Posted By jonr on 08 Aug 2012 10:37 AM
I don't think it holds up to a week of cold winter weather - the btus simply aren't there to be extracted. If there are some additional facts, for example, drought never occurs in the winter or drought is so rare that you don't mind adding substantial resistance heat, then that changes the math.
I'm not sure what this is reference to, but if you mean the tank that artesian well flows through and a heat exchanger within;a known temp and flow rate (say 2 GPM minimum)would not be a big deal to design. Whether loop or tank size is practical is the real question. |
|
| Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
|
|
jonr
Veteran Member
Posts:3335
|
| 08 Aug 2012 12:10 PM |
|
The tank isn't practical for this case, according to my probably reasonable assumptions and math. |
|
|
|
|
How
New Member
Posts:72
|
| 08 Aug 2012 12:22 PM |
|
Or you put on a heat exchanger and run it as a closed loop. We did that once when we had not enough flow from the well. PM me with your email if you are interested. |
|
|
|
|
geome
Advanced Member
Posts:962
|
| 08 Aug 2012 12:50 PM |
|
Posted By engineer on 08 Aug 2012 12:00 AM
I think we went through a similar excercise here a year or so ago where we suggested a coil of a roll of copper tubing... If this is the same project I'm thinking of, didn't the copper develop holes and replaced with some type of plastic pipe loop? I recall Mark C. on geoexchange.net worked on this project. |
|
| Homeowner with WF Envision NDV038 (packaged) & NDZ026 (split), one 3000' 4 pipe closed horizontal ground loop, Prestige thermostats, desuperheaters, 85 gal. Marathon. |
|
|
joe.ami
Veteran Member
Posts:3578
|
| 10 Aug 2012 10:10 AM |
|
Yes it has been done- built on reasonable assumptions. Copper was to shrink size of heat ex due to artesian springs ability to convey btus faster than HDPE. I beleive Custis did switch to plastic but employed a thinner wall (PEX) maybe. Almost anyone can read about it at geoexchange. |
|
| Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
|
|