Hello. I live in Orlando and would like some feedback from (U.S.coastal plain) area geothermal installers as to preference of open loop or closed loop systems; as well as preferred brands. The reason I ask is because I am a residential contractor (small time re-modeler/builder) with a strong interest in home efficiency. I installed an open loop ground source system (myself) on my personal home five years ago, and have been extremely pleased with it. I bought a ClimateMaster Tranquility 27 outdoor unit and modified it with some unique features, and plumbed it to two dedicated shallow well pipes. My cost for implementing the system, including ground source plumbing and R&D costs, was less than having a 16 SEER system professionally installed. I am trying to gain some ground level tribal knowledge before I start promoting geothermal as an option for projects. I can guess-timate conventional air exchange systems easily, but I would like some guess-timations for closed loop & open loop geo systems, as I am not about to promote my home brew system as a legitimate option. Any input would be greatly appreciated. Thank you, Mark

Do the economics of water-source work in Orlando (vs air source)? Use software for geothermal design. Open loop (or standing column) is a good deal if it's allowed and the water meets the specs. In general, warming up water (ie, geothermal for AC) causes hardness to precipitate out.

Jonr,
I have little experience with geo exchange beyond my own experimentation. I do know this: I have to try hard (actually, my wife trying to cool the patio) to crack $100 on a monthly electric bill in July & August after putting this together. I have a modest house, 1600 sqft, with three occupants. Prior to this system, electric ran $250 for same time period. My design is unique, using the 1/4 Hp pump that came with the CM for ground water transfer. Here the water (EWT) is 72-74F with less than a 10F rise through the exchanger. and works so much better than outside air for exchange. This is primarily an intuitive conclusion on my part validated by power consumption results. I look at what I spent, time and materials, creating a ground source interface (I.E. all elements outside of the modified condenser cabinet) and weigh that against what I read others are spending and doing to create a ground source interface, I see that maybe too many are locked into expensive conventional practices. My AC guy says that most of his experience with water cooled systems are removals, since they used municipal water or well water and dumped it through the sprinkler system, which makes for a soggy yard in summer time. As far as ground water used, I recently opened the water connection at the exchanger coil and noticed no metal degradation, just a thin black film from sulfides that was easily swabbed off. Yes, I ordered the cupra-nickel option.
Regardless, I cannot seem to find anyone in this area that has ground source systems as any significant part of their business to discuss this subject with, much less glean any helpful information. It just seems like an opportunity lost. If I as an electrical engineer and residential building contractor can inexpensively make a working geothermal heat pump system, it would seem that the industry would be way ahead of me.

Interesting post! Good to know about these stuffs.

What is the issue. Your system seems to work well, a open geo system will rock in Florida with 72-74 EWT. As long as you keep your pumping cost down, which you have seemed to figured out, and your water s of good quality, you should be good to go.

docjenser,
My issue is not with my system; it is working great. My issue is with there being a void in my area of HVAC contractors that are practiced in the geothermal field. I am finding it impossible to find out what are the typical conventions for geothermal systems in this area. I have made inquiries to some of the very few listed dealer/installers in this area with no replies. Ground water at ideal temperatures are readily accessible, but I do not see anyone taking advantage of it. Have you seen any response from a regional dealer here? No. Do you see any such discussion on this site? No. I took an off the rack CM TTP outdoor unit, made a few modifications inside, and basically connected it to two shallow well pipes that took me a few hours each to install. I am sure it will work in virtually any area with temperate groundwater reasonably close to the surface. You would think that something of such simplicity would be very popular and profitable, but I can find no one doing such. Has someone convinced the contractors that this is not possible? Have the manufacturers missed an opportunity to pick up an easy market share by not developing such a unit? I would like to offer to customers, as well as recommend to inquires, such a system. I have friends that want me to duplicate my system for them, but setting up an ISO9000 type manufacturing facility is not where I want to go.

I'd a) get the water tested and b) do a cost/payback analysis for various customers (including ones without pre-existing wells). In Florida, the difference between 73F water and 93F air isn't as compelling as say 50F water and 93F (or 0F) air. Monthly AC bills going from $250/mo to $100/mo is NOT typical (the COP doesn't change that much).

There is a member on here named Engineer, He works out of north Florida I believe.

He has said he does a lot of open loop systems.

ChrisJ

Posted By Mark2fis on 02 Apr 2016 12:16 AM
docjenser,
My issue is not with my system; it is working great. My issue is with there being a void in my area of HVAC contractors that are practiced in the geothermal field. I am finding it impossible to find out what are the typical conventions for geothermal systems in this area. I have made inquiries to some of the very few listed dealer/installers in this area with no replies. Ground water at ideal temperatures are readily accessible, but I do not see anyone taking advantage of it. Have you seen any response from a regional dealer here? No. Do you see any such discussion on this site? No. I took an off the rack CM TTP outdoor unit, made a few modifications inside, and basically connected it to two shallow well pipes that took me a few hours each to install. I am sure it will work in virtually any area with temperate groundwater reasonably close to the surface. You would think that something of such simplicity would be very popular and profitable, but I can find no one doing such. Has someone convinced the contractors that this is not possible? Have the manufacturers missed an opportunity to pick up an easy market share by not developing such a unit? I would like to offer to customers, as well as recommend to inquires, such a system. I have friends that want me to duplicate my system for them, but setting up an ISO9000 type manufacturing facility is not where I want to go.

There are many things to consider. Open systems consume more pumping power, are somewhat unpredictable in terms of constant water supply and water quality, By the time I have drilled a couple wells, I prefer the predictability of a closed system. That notion might be different in cooling dominated climate with warmer ground. Still, low to mid 70s is a good EWT for efficient cooling.

docjenser,
I realized early in my investigations into geothermal systems that traditional open loop systems have more pumping energy than closed loop systems. However, I had no inclination to install a closed loop system at such an expense considering the possibility of tree root damage and just dedicating that much yard space. I have contemplated geothermal HVAC for decades knowing that ideal and stable temperatures existed just below my feet. I put my thought process towards open loop simply because I can hit cool shallow water within minutes (OK, a few hours). I have been setting shallow wells since my father put me to task to put one at our family home when I was just twelve years old. It still works today. I have done a few dozen more for friends and some of my properties for irrigation purposes. As to pumping energy, that generally equates to energy to lift the water from the source. What I engineered into my system was a way to eliminate the lift energy required for flow through the exchanger. I wouldn't call it incredibly clever in design, but it was unique enough to obtain a U.S. patent for it. I operate an open loop system at the same energy level as a closed loop system without excavating and burying yards of tubing that I do not have to worry about. I calculated my cooling EER at 24.3 using the combined condenser unit (including water pump) along with the interior air handler. I would need more specialized equipment to calculate a COP for heating mode, but heating mode is not used much here. I just know that EAT at ducts in heating mode is average 106 F (no electric strips) with IAT at 70F. If I was in the business, this seems like an easy sell. What does anyone with experience think?

What is your patent #?

US20130133349 [Edited]

US2013013349 - A method and apparatus for selecting travel related services.

I agree that in a very shallow well (perhaps 20'), running the discharge line down to the water level can offset some of the work involved in moving water up. But go deeper and you get a vacuum at the surface.

jonr,
Granted, you can only lift water thirty three feet with a vacuum. It isn't a matter of how deep the well is, it is a matter of how far down the water table is. The well is put to a depth that allows for easy water flow. If the well is fifty feet down, but the water table is at ten feet, the other forty feet do not figure into the physics of water lift. This is Florida, and there are few if places where the water table is much deeper than ten feet.This is probably true for many planer regions.
"A method and apparatus for selecting travel related services." ?? Sorry, try US20130133349

Vacuum assisted ground source heat pump device and system
US 8955348

Your patent is quite specific, which will allow people to design around it. What do you think the key element is to make it work? It appears that the novelty is the application of a vacuum device.
Is the air removal the key? Since the rest is enabled via open systems with a discharge well for a long time.