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Old 07-02-14, 01:40 PM   #1701
AC_Hacker
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Regarding any consideration of heating, especially alternative energy heating, your efforts are best directed toward prevention of heat loss, infiltration being the first priority, insulation being the second priority, and window replacement being third.

* * *

From a straight-forward point of view of cost, scenarios for doing a ground source heat pump implementation would be, in ascending cost & effort:
  • Exploit lake water or abundant naturally running water
  • Exploit an existing well and do a "pump & dump"
  • Drilled well(s) and do a "pump & dump"
  • Dig trenches and do a buried loop field, the deeper, the better
  • Vertical bore hole loop field
With this in mind, local climatic, geological, hydrological, and land availability conditions can change the desirability of one option over another.

Quote:
Originally Posted by phreich View Post
...reading your thread on doing a DIY cheap GSHP installation on Portland... I am a handyman by trade, and a jack-of-all-trades by predilection.
Sounds like you have the required gumption... now we just have to determine if you are sufficiently possessed by demons to proceed...


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Originally Posted by phreich View Post
I have been noodling with the idea of a GSHP since I discovered that People's Food Coop in Portland put one in I recall about 10 years ago.
Yes, their success has been an inspiration to many people. I have minor quibbles about how they implemented the radiant floor part, but that is for another thread.

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Originally Posted by phreich View Post
The thing that's been most daunting to me is the trench or bore-hole requirement. I need to put in somewhere between 2 ton and 2.5 ton unit. That means 400-500 combined feet of bore holes...
My initial idea of simply combining hole depth to get the desired heat out put has proven to be naive... not wrong but naive. The boreholes I dug are pretty shallow, and the temperature variation is greater at a shallow depth, and the temperature variations become less pronounced as you go deeper. The following diagram illustrated this idea:


As you can see, the temperature swings are greater at shallow depth, and less so as you go deeper. My bore holes are only 17 ft deep, and are greatly affected. But the variations become less as you go deeper.

This next image is also important as it explains more of the story:


Here you can see the time-delay of the temperature swings. So the 'thermal pulse' as I like to describe it, which is the solar heat working its way down through the ground, is somewhat lost in a shallow bore hole, as it is best, if possible to have heat demand coincide with the 'heat pulse' availability.

So what I'm getting at is that a simple addition of bore hole depths is not a good model, especially at shallow depth. In your case, if you went to 60 ft depths, simple addition would be insufficient, but your error would be less than mine. The moral of the story is that you are going to need more combined depth than you are now estimating.

By the way, these diagrams are from research carried out by the Oklahoma State University, and every attempt was been made by them to develop a universal understanding of ground source heating and cooling, even though local conditions may be somewhat different.

SO, there is a very interesting local exception... I have learned by observation that the frequent rain falls in Portland (annual rainfall = about 34") are in fact Heat Events, and the heat from rainfall is not inconsequential. I saw, and attempted to log (with limited success) these thermal excursions. Every time there was a rainfall (pretty frequent in Portland) there was a measurable thermal pulse that worked its way down through the ground and my loop field. I would see an 'up-tick' about two days after a heavy rain. At the time, I was running my tiny heat pump 24/7, with no thermostat, and the basement temperature would rise with the peaking of the thermal pulse, and fall as it passed... definitely something was going on.

I don't know anyone else who is thinking along these lines, but since we have this phenomenon going on in Portland, we should think about taking advantage of it.


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Originally Posted by phreich View Post
(I live on an acre, but am unwilling to deal with that much yard excavation to put in a slinky system). I also don't think that the slinky system really is all that great since it is only 4 feet underground and so is effected by temperature changes in a negative way (when you need heat the ground at 4 feet is colder, and when you want cooling the ground at 4 feet is warmer).
I think that 4' depth is a bit shallow. I know of an installation here in Portland that successfully used Slinky PEX, in a 6' X 80' trench, per Ton. As I recall, there was 700 feet of PEX in the trench. It had been successfully running, for 10 years when I saw it.

There are fluid friction issues that need to be taken into account, but they are solvable.

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Originally Posted by phreich View Post
Soooo, I have been trying to figure out a way to drill my own 50 foot bore holes. This would put me above the water table (about 67 feet at my location). I have been looking at some web-sites on drilling your own wells -- mostly by folks in the southern US states -- and they seem to think that 30 feet is about the limit to using a water-cutting method.
Southern soils are often very sandy, and water-cutting methods can work well. However, here in Portland we live on top of the aftermath of roughly a 3000 year series of cataclysms that happened between about 10,000 years ago, and about 15,000 years ago. That even came at the end of an ice age, when a gigantic inland lake (the Great Salt Lake is the tiny remnant) was no longer being held back and ice dams broke over time and a series of floods of unimaginable magnitude allowed the vast inland lake to drain into the Pacific Ocean, and the route it took was approximately that of the present day Columbia river, and the series of floods carved the geological feature that we now call the Columbia Gorge. The Indians have myths about such an event, and their mythology coincides quite well with modern gemological theory.

The upshot is that we live on the debris field of all that activity. Beneath our fertile topsoil, there is sand, clay, gravel, rocks up to the size of oranges, cobbles in sizes from an orange to a football, and boulders from the size of a football to the size of a car.

So, southern methods are unlikely to be successful.

(* End of part 1 *)

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Old 07-02-14, 01:42 PM   #1702
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(* Beginning of Part 2 *)

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Originally Posted by phreich View Post
However, there are folks using a recirculating mud method that go deeper, and one guy in Oregon that uses a combination of compressed air and water to go deeper.
Here are some links on the well drilling:
How to Drill Your Own Water Well
(this guy has been doing this in the deep south for years now. Although it's a .com domain, he's not trying to make money selling stuff -- it's really kind of a forum for DIY wells.
On this site, he discusses various methods, and this is where I found out about the recirculating mud method, and about the guy in Oregon using the compressed air and water method. I'm a bit confused about who this is -- the video is by a fellow named Paul Smith, but the kit is ordered from a guy named Lee on the Oregon Coast.
Here's a link to the video of the Oregon guy's stuff:
https://www.youtube.com/watch?featur...NS4awOxrI#t=37
Here's a page on the first guy's website that discusses this air/water method:
How to Drill Your Own Water Well
Their address to order the air/water kit is:
bluewaterenterprises@Safe-mail.net

No offense, but I think the augur method won't work very well for the depth that is needed at my site.
In looking at the photos, from the lay of the land and even more so, from the vegetation, it looks very much like they are in Central or Eastern Oregon. I don't think that the Missoula Flood events reached that far. They probably don't have the rocks/cobble/boulder issues. So I really don't think that their methods would be successful in your location.


Quote:
Originally Posted by phreich View Post
Soooo, I am looking to self-drill 8-10 50 foot drywells and use a recirculating closed-loop system like you are doing.
Again, I was naive about what I would encounter when I tried to drill. I did run into rocks and cobbles, and they are a real problem. The problem is precisely this: the cobbles that exist are about the size of an orange, they are round. That is because they were violently tumbled in the beds of ancient rivers. The are hard because they were not completely worn into grains of sand... in other words, they are the survivors, they are the hardest rocks left over from the Missoula Floods.

So what tends to happen is that you drill down and your drill pushes the hard round rocks out of the way, and when you withdraw your drill string, they fall right back into the way.


Quote:
Originally Posted by phreich View Post
I see that some folks in the south are using extraction wells and pumping ground water and then disposing of it in drywells. Maybe I am missing something, but it would seem the energy needed to move the water up out of the ground would cost more than the better temperature differential the cooler ground water would have over the recirculated water.
When you're pumping like this, if your pipes are purged of air, the down-going water can assist in pumping the up-going water, so the work of pumping is less than you might think.

Quote:
Originally Posted by phreich View Post
I also wonder about the long-term effect of percolating that much water in the summer months into the ground. On the other hand, I could keep my lawn, flower beds, and garden VERY happy in the summer with all that water.

Actually, after writing this last bit about pumping ground water, I am wondering if maybe using ground water might pencil out after-all. Especially if I used it for irrigation purposes, and maybe for a decorative stream and pond. Hmmm, I'll have to think and do some more research on that... I am concerned about what the Oregon DEQ would say about doing this. I think they are scared enough about the possibility of leaking closed loop systems -- what would they think about the possibility of a contamination of an extraction/injection well system?
For one thing, the water table falls in the summer, so you might not have the abundance that you imagine.

Regarding local DEQ, I think that they are reasonable, and if they have hesitation or prohibition about certain practices, it should be observed.

[QUOTE=phreich;38893]The major concern, of course would be the heat exchanger process -- if the heat exchanger ruptured, the compressor oils could go into the ground.[QUOTE]

If you cobble together a HX this could be an issue. But the manufactured HXs I have seen are more robust than the rest of the system.

I'm pretty sure that if you lost refrigerant pressure, your compressor would shut down or destroy itself before all of its lubricant bled into the water side.

Quote:
Originally Posted by phreich View Post
However, I would think that a safety could easily be set up to shut down the system should the pressure drop due to a coolant leak. How worse or better would the contamination of the compressor oil be compared to the ethylene glycol typically used in close-loop systems leaking into the ground?
Good idea.

Quote:
Originally Posted by phreich View Post
I also am wondering about using the heat extracted in the summer to produce my hot water, and wonder how much I would save by using the GSHP to heat it from the ground source in the winter (I currently have a natural gas water heater).
Nat Gas is pretty cheap, but ASHP is cheaper, if ypou hack together a system, and GSHP is cheaper yet, if you can hack one together.

Actually, living in Western Oregon, the weather is fairly mild, and an ASHP can work out pretty good, except for the few days when the weather really gets cold.

But the short answer to your bore hole drilling question is that local drillers have best luck using a percussion drill, also called a cable drill. With this method, the drill is really heavy, maybe 500 hundred pounds or more. You need a big engine to make it go, like maybe a car engine. So the weight is repeatedly lifted and dropped into a hole filled with water. Periodically, a "bailer" is sent down the hole and lifts out the chips. repeat until done.

The percussion device smashes and bashes its way through absolutely anything.

http://www.welldrillingschool.com/co...ingMethods.pdf

-AC
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Old 07-08-14, 05:17 PM   #1703
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Are you still working on this home made ground source heat pump? How is it working out? I am curious about more details about the parts used for the heat exchanger and sizing the compressor. Thanks,
John
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Old 07-08-14, 05:56 PM   #1704
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Are you still working on this home made ground source heat pump? How is it working out? I am curious about more details about the parts used for the heat exchanger and sizing the compressor.
Hi John, thanks for dropping by...

My own project is mostly complete. I suffered a pretty severe arm injury that has had a surprisingly adverse effect on my progress.

However, I am, as I write these words, preparing my back room for a radiant floor that will be driven from the heat pump and the loop field I have put in.

Ironically, there are readers of the Homemade Heat Pump Manifesto who became convinced that it could be done, by reading the 'Manifesto' thread, and have made much better progress than I have. Some have had their units working for two or more years.

My intent was to prove that it would be possible to create your own heat pump from discarded equipment, and in this I have been successful, as have others, some using ground source for heating, others for cooling, although both heating and cooling remain a possibility for anyone.

I also wanted to prove that it would be possible to create your own ground source loop field, by hand if needed. In this I also succeeded. It turned out that the ground conditions where I live were quite difficult, and I didn't have the success I hoped for, but I still have a usable ground loop, only smaller than I had hoped for. If I were to do it again, I would definitely borrow, or rent or make more powerful tools for this part of the project.

There are other parts of the country where hand tools or low-powered tools would work.

For testing, U used a car radiator with fan to warm my basement, and things worked out well, especially considering that my basement has no insulation.

Reports from other folks indicate that a radiant floor works very well with this kind of thing... which I am working on.

As for the HX, my preference is for brazed plate HXs.

Sizing your compressor and HX will depend on the heat load of your house.

More detail about this can be found from searching this thread...

-AC
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Old 07-08-14, 06:29 PM   #1705
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Sorry to hear about your arm and we send our prayers. Thanks for pioneering this since low cost energy should be available for everyone like you said. I will try to find a link to an email a friend sent that you may enjoy. He is a brainy guy and installs solar systems. They took a house that already had large water tanks in the basement for solar hot water and used them to feed the heat pumps. He put monitors on everything and the results are online. Just the pdf of the project took a long time to download. It is fascinating and I will try to get it to you later.
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Old 07-10-14, 09:34 AM   #1706
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Originally Posted by AC_Hacker View Post
(* Beginning of Part 2 *)

The percussion device smashes and bashes its way through absolutely anything.

http://www.welldrillingschool.com/co...ingMethods.pdf

-AC
Hi again AC_Hacker.

Thanks for sharing your thoughts on GSHP in the Portland area.

A few further questions:
1. Did you get the PM I sent you with my contact info?
2. Did you need to apply for any kind of permit to drill your bore-holes, or did you just "do it" and plan on pleading ignorance if any govt agency questions it? If you did get permits, which agencies did you have to deal with?
3. Have you done any thinking about the cost/benefit of closed-loop GSHP (lower temperature differential) vs. pump-and-dump wells (higher temperature differential, but higher cost of pumping water out of a deep well). Have you seen any analysis done comparing the two GSHP methods? (especially locally)
4. Have you seen a cost-benefit analysis done between local GSHP vs. high efficiency natural gas? If so, can you share where it is?

Here are some other thoughts that go into my thinking about the cost/benefit of GSHP....

A concern about a future rise in natural gas prices:
Right now, Natural Gas is inexpensive, but if the big energy companies get their way and are allowed to install facilities for exporting Compressed Natural Gas (CNG), the price of Natural Gas will likely double or triple for us because it will float to the international pricing which I understand is much higher than our current domestic only pricing. There already is and will be increasingly intense pressure from all the natural gas producers to start exporting CNG to drive up the price of natural gas (to increase their profits). If I were a betting man, I would say that we'll probably see this happen within 5-10 years.... At that point GSHP will make even more sense.

Some background on my current heating and cooling systems, and thoughts regarding GSHP:
I originally had forced air oil heat in my home. When the price of petroleum started going up in the 2000's, I started looking for a used high-efficiency forced air gas furnace. I already had installed natural gas in my home, replacing the electric water heater, electric dryer and electric stove, and had stubbed out a pipe from a tee heading towards my furnace in anticipation of the future furnace swap. I got lucky and found a used 100kBTU 93% efficient Lennox furnace at the "Rebuilding Center" (a local used building material recycling/resale place). It had just arrived and hadn't yet been priced -- I talked them into selling it to me for $250. I spent another $600 on materials for the PVC intake and exhaust venting, thermostat wire, condensate pump and tubing, and custom-built transitions to attach the new furnace to my existing plenums. I did the installation myself with the help of a friend over a weekend during the fall I think in 2006. The savings over the inflated cost of heating oil more than paid for the swap-out the first season. (I even recycled the oil furnace -- I sold it to a farmer in Eastern Oregon who will be converting it to burn used motor oil to heat some greenhouses.)

My daughter has Asthma, so I looked to install a better air filtration system as part of this furnace swap. I found a used Honeywell whole-house electrostatic air filtration system on Craigslist for $100, and installed it at the same time -- helping to improve the indoor air quality significantly by reducing the indoor dust, dander and pollen. It meant running the furnace fan on low constantly, but it is worth it. It also keeps the temperature in the house normalized by constantly recirculating the air throughout the home.

The Lennox furnace had a standard PSC AC motor (which are very inefficient -- even more so at at lower speeds), so I found a fellow on Ebay selling an extra high-efficiency "Evergreen ECM retrofit blower motor" and installed it. This effectively reduced the electrical load for running the blower on low from about 250 watts to about 40-50 watts, and also made the blower much more quiet, and soft starting.

My original plan was to later find a used traditional air based heat-pump and keep the natural gas furnace as my backup heat source for when the air temps dipped below 40-45 degrees and the air-based heat-pump became increasingly inefficient.

Now that I am considering installing a DIY GSHP setup, the gas furnace will still act as my air-handler for the heat pump air exchanger coil, but I don't see the gas heating portion being used except as a backup system in case something in the heat pump fails. When I installed the gas furnace, I installed thermostat wiring sufficient to control a heat-pump, and installed a Honeywell 9000 series thermostat that can control a heat-pump and the furnace air handler (and the furnace heat as a secondary heat source if need be) -- so there won't be much more to do to control the heat pump.

My current air-conditioning is not very efficient. I don't have central A/C. On the main floor, I have a fairly new 12000BTU 240V window AC unit (about 11SEER efficiency) that I installed in such a way that it blows the air in a circular pattern through most of the ground floor (purchased used on Craigslist for $100). I have a smaller window AC unit in the upstairs south-facing master bedroom.

Using a central forced-air GSHP for cooling will definitely be more efficient than what I currently have -- both because of the more efficient ECM air-handler, and the better efficiency gained from GSHP over transferring heat via air exchange AC during the heat of the summer.

The question still remains: what savings will the GSHP give me over heating with high-efficiency natural gas? As I mentioned before, when the price of natural gas rises due to the implementation of exported CNG, GSHP will make more sense financially. I just wonder what the difference will be at today's prices.

Of course, there's also a non-financial, but immediate environmental benefit gained by reducing my carbon footprint by eliminating burning natural gas for heating. If I can figure out a way to augment or replace natural gas for heating water -- so much the better.

BTW, I suspect that the carbon produced when generating the electricity needed to run an electric drier and an electric water heater is not much less than (and maybe more than, given the inefficiency in electrical power distribution) the carbon generated by using natural gas to run these devices. It would be interesting to find a calculator that would show the difference in the carbon generated by both options. Certainly it costs less money to use natural gas currently for these appliances.

I look forward to your thoughts on all of this too....

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Old 07-10-14, 11:00 AM   #1707
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phreich,

Not AC, but have some thoughts.

The best way to look at your costs is to look at what it costs to provide a BTU of heat or cooling. There are a number of spreadsheets on the web that do this.

You type in what the costs are per them (natural gas), gallon (fuel oil), electricity (resistance heating or heat pump) etc.

Then you put in the efficiency of the unit. For combustion fuels, this can range from ~ 80-95%. For resistance electricity the value is 1.0 (or 100% depending on the spreadsheet).

For a heat pump with a COP of 4, you put in 4.0 (or 400).

For cooling you out in the SEER of the cooling unit. Most geothermal heat pumps have a COP of 3-5 and a SEER of 25-45.

Bottom line. Even with commercial prices for GT heat pumps, they pay off quickly compared to natural gas - even here in Oklahoma.

You can "play" with future costs to see what happens if natural gas goes up as you suggest.

I would be aware that more and more natural gas is being discovered as more oil is found. A case can be made that it will be many, many years before natural gas doubles/triples in price.

The big gorilla is transporting this fuel to Europe and the far east. It will take some really new and novel ways to compress and refrigerate the gas for shipping out of the continental USA.


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Old 07-10-14, 02:04 PM   #1708
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...I would be aware that more and more natural gas is being discovered as more oil is found. A case can be made that it will be many, many years before natural gas doubles/triples in price.

The big gorilla is transporting this fuel to Europe and the far east. It will take some really new and novel ways to compress and refrigerate the gas for shipping out of the continental USA...
S.H.

I don't want to dilute this thread with any discussion of 'cheapest alternatives' in this country or any other country, except to say that unless the full environmental consequences are carefully considered and included, any decision regarding fossil fuels is misleading to be charitable, and criminally stupid to be closer to the truth.

If you'd care to continue a discussion along these lines, START_A_NEW_THREAD_PLEASE.

Sincerely,

-AC_Hacker
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Old 07-10-14, 02:37 PM   #1709
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1. Did you get the PM I sent you with my contact info?
yes

Quote:
Originally Posted by phreich View Post
2. Did you need to apply for any kind of permit... which agencies did you have to deal with?
You should consult the laws that pertain to this activity for the country, and locale in which drilling will be done.

Quote:
Originally Posted by phreich View Post
3. Have you done any thinking about the cost/benefit...
I think you may need to a bit of research on your own to answer some of these questions. If you don't have the gumption to gather information, you probably don't have the gumption to succeed in a DIY GSHP project.

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4. Have you seen a cost-benefit analysis done...
phreich,

This thread is a very unusual place on the Internet. It is probably the only place on the Internet where where information about actually doing a DIY GSHP is shared.

I sincerely welcome queries from people who are engaged in actually building a DIY GSHP.

I also strongly discourage people who want to dilute this thread with discussion about anything that is not directly involved with the process of building a DIY GSHP. Diluting this thread reduces the value of what I have spent many many hours trying to create.

phreich, if you had ALREADY read the thread, you would already know this.

Steve Hull, also has rambled on before on this thread with blather he deems to be golden. I have tried to communicate to him the purpose of this thread before, but as a testament to the level of his awareness, he persists in filling this space with the debris of his opinions, which makes it less valuable to everyone (this could quite possibly his true aim).

So, I repeat to both of you, this is not a talking shop... this is a thread for people who are BUILDING a DIY GSHP.

Please create a new thread!

Sincerely,

-AC_Hacker
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Old 01-04-15, 12:40 PM   #1710
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AC, etc.
I have read most and skimmed all of this thread and several others related and linked. I have followed many tangents. Whew!
Thank you AC for starting and attempting to maintain focus. Thanks also to all others that have contributed their knowledge and also those searching for answers.
While I have benefitted greatly, no one has attempted to do exactly what I plan to try.
Before I describe my project, allow me to offer what I think may be helpful, especially to you AC.
The label 'Ground source heat pumps' may be leading us astray. AC, you have repeatedly discussed the differing heat exchange rates of air and water when focusing on the HX. Yet, you haven't fully applied this knowledge to what happens under ground.
When you refer to rain as a 'heat event' I suspect you're simply too close to see that the heat carried by the rain is only part of the improved result. Perhaps the smaller part. Rain is also improving heat transfer from your normally dry ground.
I suspect that many of the GSHP systems that fail to deliver satisfactory results are similarly located in dry ground.
For those of us blessed with a high water table, when it comes to the storage of heat, it is important to know what type of water source we have, ponded or flowing. We have a glacial esker in the center of our property. When the truly artesian well was drilled, they logged 35' of gravel. To the east we have 100'+ of brook joining 800'+ of river. These above ground sources drop a combined 30' from north to south and are indicative of what is happening under ground. Our ground water flows from north to south. Any heat or coolth I take from the ground is quickly replaced from the north. Only those with a dry ground or a ponded water table can reasonably expect ground storage to hang around long enough to be useful.
I do hope this is useful. It is all I currently have to offer.
Thanks again,
IWarm


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