First post, sorry if I missed the answer someplace else, the search function doesn't seem to be functioning currently. I have been talking to different GSHP companies in the Charlotte, NC area for a new house I am planning currently. Seems lake loop is the most cost effective option for me (I will be waterfront), but the last contractor I spoke to mentioned yearly or every-other year cleaning of the lake loop to remove algae build up which starts to insulate the loop. Said that is an issue here because the lake isn't really deep and tends to warm up in August. Has anyone ever heard of cleaning the lake loops with a pressure washer as normal maintenance? Seems like I would need to invest in some SCUBA gear if I installed this. Please let me know if there is any other information you need to answer the question. Thanks

Perhaps some type of flat plate (thin sheet HDPE?) could be attached to the top of the loops to prevent light from reaching the coils. Or perhaps allow the loops to sink into the bottom (mud?) and use more of them to compensate for the lack of convection (which is a significant performance issue, whether blocked by mud of algae).

Maintenence is hogwash, saturated alge conveys heat almost as well as water. Lake depth is more important. Marginal conditions could mean you have no AC in august. Your contractor obviously doesn't like the application what's his thoughts?

Thanks for the thoughts, I think I have the lake depth that he is looking for:
measured 14 ft depth at deep end of my pier
8ft at shallow end
currently the lake is about 2.7 ft above low pond

I think am right on the edge of it, so if we have low pond situations in the heat of summer, then I think you are right about possible no AC.

He didn't give me thoughts other than it may be a 10-12K difference in price for a vertical loop vs lake loop and that lake loop would come with the pressure washing maintenance. As for preventing light, if the coils are under my pier (which is covered), do you think that will be enough light blocking?

" As for preventing light, if the coils are under my pier (which is covered), do you think that will be enough light blocking?"

If I'm not concerned about algae, you might surmise I'm not concerned about light.

If you go down to 12 feet and look at the pier pilings, is there much algae on them? Probably not.

Thank you Joe and Jon. It's pretty cold water right now so will have to look at that in the summer, but seeing as Joe doesn't believe algae to be a problem, and no other geo company I talked to mentioned it, I think I am feeling better about the lake loop.

I surmise marginal depth would be more of a problem in the case of a very small pond. How big is this lake and how warm does it become in August? As long as water temp stays under 90 and there are several feet of water atop your properly sized heat exchanger you should be OK.

The lake has 3,281 acres of surface area and is the primary drinking water reservoir for the Charlotte, NC area. The surface temps of the water can get warm in the summer (to the point of feeling like a warm bath and not very refreshing), but don't think that warmth drops much further than 5 or so feet below the surface. I would say I have seen it 90 degrees at the surface in August on my boat thermometer.

Sounds like it should be OK.

Check out product from this company:  http://www.limnion.com/

I'm aware of them because they use the Web Energy Logger (WEL) for their research efforts, and in the past, I have done WEL related implementation support work for them (you can to the live, 3-D animated WEL system diagram picture via their home page).

Based on what I've seen when working with the raw data coming out of the WEL during their testing periods, their product indeed works (at least in a cold Canada lake environment).


"Introducing LIMNION and LIMA-1.  Now anyone with a waterfront, riverfront or pond home can heat and cool it without using any fossil fuels ...

... LIMNION LIMA-1 is the first product in a family of Geothermal Transfer Systems we are planning to introduce over the next several years. LIMA-1 is a high performance, highly engineered energy transformer compatible with all premium quality geothermal water to air or water to water heat pumps.
 
The leading manufacturers in heat pump technology have correctly focused their efforts on high performance refrigeration technology bringing geothermal capability to the forefront. These companies are building wonderful geothermal heat pumps. These heat pumps are so good the problem now is how to extract the energy from the ground. This is why we formed LIMNION Corporation, dedicated to learn, invent and develop highly efficient Geothermal Transfer Systems to provide these great heat pumps with the energy they need to really perform.

It has long been recognized that our lakes and seas contain the energy to heat and cool our homes but to date, getting this geothermal energy out has required the use of a heat pump along with hundreds and thousands of feet of polyethylene plastic pipes, often carelessly strewn onto lake bottoms covering large areas. These pipes are damaging the eco system and are destroying swimming and fish habitats with an ugly and largely non-serviceable coil.
 
These systems are called lake loops or lake mats and are becoming an environmental nightmare. The practice of throwing bundles of tubes that has gone on uncontrolled for years is currently under investigation by many environmental authorities in the USA and Canada. The practice has already been banned in many areas as it is not only considered environmentally wrong, it also possesses inherent safety hazards during and after installation as clothing can become tangled in the various caged structures.
 
The LIMNION LIMA-1 is suitable for common 5 ton capacities and is 1/600 of the size of a lake loop.
 
LIMA-1 does not adversely affect the ecosystem as it suspends itself harmlessly within the lake water anchored with a 132 pound ball that of which only the bottom 4 inches is in contact with the lake bottom. The LIMA-1 will not rust or corrode as it is of non-metal construction and all components are manufactured of modern polymers. LIMA-1 is non-toxic and the protective cage actually provides a habitat for tiny fish and other aquatic animals and vegetation.
 
The unit can be raised and lowered as required if service or cleaning is ever deemed necessary. Everything has been thought out right down to the tether rope. It is made with materials proven not to rot or fail even in salt water and once the knot is tied it will not slip. The LIMNION LIMA-1 has many unique design features that are not obvious but play an important role, such as the non-slip rope."

 
Best regards,

Bill

LIMA-1 also costs alot more than HDPE.

Recent Drought and record high temperatures threatened a large lake loop of mine. I frankly do not find them as reliable as you would like for the kind of money invested.

Posted By Bill Neukranz on 20 Dec 2013 11:53 AM
Check out product from this company:  http://www.limnion.com/

I'm aware of them because they use the Web Energy Logger (WEL) for their research efforts, and in the past, I have done WEL related implementation support work for them (you can to the live, 3-D animated WEL system diagram picture via their home page).

Based on what I've seen when working with the raw data coming out of the WEL during their testing periods, their product indeed works (at least in a cold Canada lake environment).


"Introducing LIMNION and LIMA-1.  Now anyone with a waterfront, riverfront or pond home can heat and cool it without using any fossil fuels ...

... LIMNION LIMA-1 is the first product in a family of Geothermal Transfer Systems we are planning to introduce over the next several years. LIMA-1 is a high performance, highly engineered energy transformer compatible with all premium quality geothermal water to air or water to water heat pumps.
 
The leading manufacturers in heat pump technology have correctly focused their efforts on high performance refrigeration technology bringing geothermal capability to the forefront. These companies are building wonderful geothermal heat pumps. These heat pumps are so good the problem now is how to extract the energy from the ground. This is why we formed LIMNION Corporation, dedicated to learn, invent and develop highly efficient Geothermal Transfer Systems to provide these great heat pumps with the energy they need to really perform.

It has long been recognized that our lakes and seas contain the energy to heat and cool our homes but to date, getting this geothermal energy out has required the use of a heat pump along with hundreds and thousands of feet of polyethylene plastic pipes, often carelessly strewn onto lake bottoms covering large areas. These pipes are damaging the eco system and are destroying swimming and fish habitats with an ugly and largely non-serviceable coil.
 
These systems are called lake loops or lake mats and are becoming an environmental nightmare. The practice of throwing bundles of tubes that has gone on uncontrolled for years is currently under investigation by many environmental authorities in the USA and Canada. The practice has already been banned in many areas as it is not only considered environmentally wrong, it also possesses inherent safety hazards during and after installation as clothing can become tangled in the various caged structures.
 
The LIMNION LIMA-1 is suitable for common 5 ton capacities and is 1/600 of the size of a lake loop.
 
LIMA-1 does not adversely affect the ecosystem as it suspends itself harmlessly within the lake water anchored with a 132 pound ball that of which only the bottom 4 inches is in contact with the lake bottom. The LIMA-1 will not rust or corrode as it is of non-metal construction and all components are manufactured of modern polymers. LIMA-1 is non-toxic and the protective cage actually provides a habitat for tiny fish and other aquatic animals and vegetation.
 
The unit can be raised and lowered as required if service or cleaning is ever deemed necessary. Everything has been thought out right down to the tether rope. It is made with materials proven not to rot or fail even in salt water and once the knot is tied it will not slip. The LIMNION LIMA-1 has many unique design features that are not obvious but play an important role, such as the non-slip rope."

 
Best regards,

Bill

Highly skeptical about this device. Checked out the 3 D animation. Was annoyed that they wanted my name and email before showing anything. Delta T on the source site was 0.12 degree celcius. Delta T on the load air side was 5 C. Lake temperature was -17C. The numbers simply don't match up. Flow through area is too small for 5 ton heat exchange via without gravity circulation. Your post sounds very promotional, but the product cannot beat the physics.
Don't loose your credibility by posting statements like the one above.

Doc, much appreciate the comments and feedback.

For unknown reasons to me, Limnion principles have always wanted to intercept any viewing of Web Energy Logger output associated with their product.

At the beginning of their WEL use a couple of years ago, they made an enhancement request to the WEL manufacturer, asking for an option in the WEL setup process to always prompt for a password when anyone attempts to view a WEL's information.  The manufacturer decided not to implement the enhancement request (a lot of work and little market pressure for it), but, did it via unique coding for Limnion's WEL.  (The manufacturer since is no longer doing this for other WEL units due to some difficulties presented when the Manager Interface was implemented.)

This allows for Limnion to obtain everyone's name and email address in return for granting access to their product's illustration data.  I too believe this is actually a market reduction action on their part, but, it's what they want to do.

It also allowed for Limnion to contract out to a person to do animated graphics.  This was implemented by configuring the WEL (one of many standard options) to additionally output logged data via XML to the LAN, and an attached computer to the LAN is picking up the data, and is producing the screen that Limnion wants you to see.  This explains why there's no WEL number in the URL.

Last year, I did the 'back end' for Limnion, configuring their WEL to implement various performance and efficiency measures.  At this time their screen showed various real-time measurements, including heating capacity (kBTU/hr), kBTUs transferred from the lake each day, and a good, solid COP measurement that filtered through enough noise such that it was a excellent high quality number.

At the time I did this work for Limnion, the numbers looked good.  I thought performance was excellent noting the product design.  And since I was working directly from the sensor values, there wasn't any way for the incoming data to be 'faked.'

Fast forward to this year.  Limnion has moved to another WEL unit, for reasons I'm not aware of.  And the heat related performance numbers are not on the current screen, again for reasons I'm not aware of.  I'm aware of this because Limnion asked for a little bit of help recently with implementation of this new WEL.

Bottom line is, having just looked at Limnion's WEL implementation and thus having it recently brought to my memory, coupled with having seen good performance numbers last year, I thought I'd try to be helpful here on this forum for someone who might want to research an alternative product to the conventional dump-a-bunch-of-HDPV-pipe-into-the-lake 'product.'

The good news is via this forum the OP gets to consider the pros and cons.

Hope you and your family have a great Christmas!

Best regards,

Bill

The conventional "dump-a-bunch-of-HDPV-pipe-into-the-lake 'product'" has a proven track record, works excellent and is relatively reasonable in terms of costs. Now you are presenting a product which cost more, at least in theory cannot perform or cannot perform as well, and where all the data and performance numbers are not visible.

But you went further to post the following statements, although in quotation marks:




"... getting this geothermal energy out has required the use of a heat pump along with hundreds and thousands of feet of polyethylene plastic pipes, often carelessly strewn onto lake bottoms covering large areas. These pipes are damaging the eco system and are destroying swimming and fish habitats with an ugly and largely non-serviceable coil.

These systems are called lake loops or lake mats and are becoming an environmental nightmare. The practice of throwing bundles of tubes that has gone on uncontrolled for years is currently under investigation by many environmental authorities in the USA and Canada. The practice has already been banned in many areas as it is not only considered environmentally wrong, it also possesses inherent safety hazards during and after installation as clothing can become tangled in the various caged structures."

I disagree with their statements, they are not only false but misleading. They are trying to trash the current proven method, in order to promote their own unproven technology.

OK.

Best regards,

Bill