I would really appreciate everyone's opinion about the TRIEA water-to-water heat pump system that uses two water tanks instead of wells, trenches or ponds:  www.trieasystems.com/
Will this type of system be reliable and be more efficient than regular geothermal?

I have heard claims that it could cost 40% less than Geothermal systems since there is no drilling and have a COP up to 9 in a balanced load situation.

That website's a mess - lots of verbiage and incorrect/misleading statements, but very little actual info. As far as I can tell all the system is doing is moving heat between a hot tank and cold tank - nothing new, they've been doing that on the commercial side for a long time. It can be very efficient IF your heating+DHW loads and cooling loads match perfectly and the tanks have enough capacity. For most residential situations this happens very few times in the shoulder seasons. The rest of the time it will need to add/reject heat as any other heating cooling system.

What I can't understand is where they dump excess heat if the cooling load exceeds the heating/DHW load. For heating they apparently use resistance heat (though somehow they magically get a COP of 4 doing so). Hopefully a misunderstanding between their engineering and marketing, otherwise it's an out and out scam.

I'm a proponent of this type of system where you have significant heating and cooling loads within a 24-hour period, but it just won't work as described - they need a ground/pond/water loop or air coil to add or reject additional heat as needed.

I have the same concerns as cnygeo.

Alton, do you know of any one who has installed one of these?

I concur with the foregoing. Site has lots of sizzle and zero steak.

There are some potential applications where something like this might work - laundromats, full service restaurants, hotels, etc wherein both heating and cooling are needed at nearly the same time.

Single family residential is the application least likely to favor a partially or completely closed system.

Thanks to everyone for their input.

I know an HVAC installer that has been to Maryland to review and test the TRIEA system.  He now has plans to install one in his own home for further testing.  As I get more info I will try to pass it on to the readers of this forum.

Definitely keep us informed - some hard data would go a long way to either bolster or negate our conjecture so far.

OK, I'II be the first to call bullshit . Its not the first guy to claim to have circumvented the laws of thermodynamics, but maybe he's coupled the cold fusion machine to a heat pump.

Actually, by my count, you would be the 4th to make that call. The first three of us did so more gently...

and here I bit my tongue for a change to maintain propriety........

Boy, does this bring back memories. Back in 1978 I worked for a company that did just what is being discussed. What we did then was called an "annual cycle system". The company sold a super insulated building system that produced a very tight and highly insulated envelope. The advantage of this was that it reduced the heating load and increased the cooling load due to retaining internal gains. The outdoor temperature where the building needed heating versus cooling was unusually low, say 40 degrees F. In fact, with this envelope, there were occasions when the "people load" was high (usually at family gatherings) when the buildings would over heat and require cooling even when the out door temperature was 20 degrees or less.
What we did back then was construct a water vessel under the building (basically a basement filled with water) and used a water to air heat pump to heat and cool the building. When you heated the building you cooled the tank and when you cooled the building you heated the tank. Simple enough, right? The tank was sealed as best we could and it served as the energy reservoir. Determining the water volume was an intersting exercise because we had to have good estimations of the loads and the use of the building. The average water volumes were 40,000 to 80,000 gallons. We had to determine how much water it would take to hold the annual btu requirements within a reasonable water temperature swing. The target swing was about 50 degrees with 90 degrees maximum and 40 degrees minimum. Despite the increase in cooling load, we often found that the heating load was higher than the cooling load and we needed some kind of supplimental heat source. Because we were using a medium temperaure water, we used flat plate solar collectors to add additional heat to the water when ever possible. The system worked very well.
Like many early concepts, this system worked very well from a thermal perspective. It cost very little to operate and the comfort in the buildings was very good. But the reason we don't see it today is mostly due to other issues. For instance, when one considers the varpor pressure on the surface of a vessel of water at 90 degress, the power of water vapor to penetrate the physical strucure is substantial. Controling this moisture was very difficult and added significant expense with the techlology, materials and techniques of the late 70's and early 80's. Also, the water quality, chemical treatment, all sorts of interesting organisms had to be addressed. Then there were leaks from time to time. If a leak occurred, it meant all the water (and the energy in it) had to be pumped out to gain access to the site of the leak and repair was not simple.
With the advancments in technology, materials and techniques, this might be an idea worth revisiting. The basic engineering task is thermal energy storage and how we do it. One of the things we tried was utectic salts that phase changed at about 81 degrees. There was not a cost benefit.
From my experience, it sounds like this company is looking at a really small niche market where the loads are closley balanced and occur in a short time span. The storage tanks would have to be massive, thousands of gallons of water to able to handle the energy typical volumes.
I'm certainly not discounting this concept, but like so many ideas, they must be fully investigated and all unforseen issues identified and resolved before it is comercially marketed.

I understand that the TRIEA system uses two small volume tanks such as 200 to 300 gallons for a home.

With that volume of storage these guys are using a great deal of auxiliary heat and some sort of dissipation in cooling or there is a lot of hocus-pocus! The physics just don't make sense.

Posted By Geo junkie on 03 May 2010 05:07 PM
With that volume of storage these guys are using a great deal of auxiliary heat and some sort of dissipation in cooling or there is a lot of hocus-pocus! The physics just don't make sense.

Ah, but quoting from their website, "Engineers and contractors will most often question whether the TRIEA System should run out of heat to pump into the higher temperature range. The TRIEA System uses a patent pending process to recharge itself with electrical resistance energy that consumes less than a fourth of the electricity used in modern high efficiency equipment."

I'd love to see that patent application. This is the line that really triggered my scam detector, but I suppose it could be simple ignorance on their part.

I agree.
If these guys are really pushed on their claims, the truth will be exposed. That phrase "electrical resistance energy that consumes less than a fourth of the electricity used in modern high efficiency equipment" is so revealing. Isn't there a definition of a watt of electric resistance in Btu's?? Maybe they've come up with the "perpetual motion machine". It takes all kinds to make the world go round.

I also couldn't see where built-up heat could escape this system, so I called them for more info. I found out that (in cooling mode) when the hot water side reaches a set high temp, it is cooled with a cooling coil and fan, and the hot air is vented outside. The temp thresholds favor this being done at night. In heat mode, a 1500 watt resistance heater is used to warm the cold water, then the heat pump can leverage that heat to a substantially higher efficiency than a resistance to air heating situation.

This is the best I can understand the situation, and I hope it is close to correct and not misleading. Could this additional info make the system viable? Perhaps TRIEA can respond or make better info available. They are in the process of getting energy star approval. But then, our gov. gave approval to a gasoline powered alarm clock!.....

Posted By denwayne on 08 May 2010 10:46 AM
In heat mode, a 1500 watt resistance heater is used to warm the cold water,
then the heat pump can leverage that heat to a substantially higher efficiency
than a resistance to air heating situation.

Frayed knot. Dumping BTUs into the source-side and then using a heat pump to
transfer them to the load-side is pure insanity. There's zero chance of improving
efficiency. You can't possibly extract more BTUs than you added without making
the source-side water even colder than it was initially.

OTOH, energy wasted by the heat pump would be helpful to make up for the
anemic 1500W heater. Might as well try to heat your house with a hair dryer.

Put another way, heat pumps are great at Moving heat from one place to another. Having to create that heat (with a resistance heater or other means), and then moving it, is senseless since at most you will get 100% efficiency. If you can't get the heat for free from the earth, lakes, etc., and get 300%+ efficiency, then why bother with the (geothermal) heat pump at all?

Maybe I misunderstood the heat side. Does the cooling side make any sense?

Too much about this just doesn't jive. I will continue to seek answers.

Posted By denwayne on 08 May 2010 01:30 PM
Does the cooling side make any sense?

Nope. Dumping heat into the air requires the water to be hotter
than the outdoor air; and unless it's MUCH hotter, the required
"cooling coil and fan" will be large, power-hungry and expensive.

No benefit in using a HotRefrigerant-to-WarmWater exchanger
followed by a WarmWater-to-air exchanger. Much cheaper and
more efficient to go directly from refrigerant to air.

Alton,

Anything happen with the Triea System?  Did your buddy get anything delivered yet?