Discussion in 'General Discussions' started by Knd, Nov 17, 2010.
Thanks Doc, I will.
Can you clarify what you mean by "distribution system"? If I'm going with normal electric water heaters for the buffer and finishing tanks, do these fall under the geothermal tax credit as a part of my new construction?
free DHW in cooling mode
I'm a homeowner with admitedly very little knowledge but one of the selling points of Geo is the excess hot water that gets discharged during the summer time so it seems ashame to not include the desuperheater in a system right from the beginning unless you are not planning on using the AC much. On another note can someone explain a typical plumbing job for the DSH loop in a open loop well system using water to air exchanger. ( WF ND 049 ) My understanding is that DHW leaves the DSH and goes to a storage tank then onto the electric heater tank by way of a Teed inlet at the bottom. The Geo internal circulator then circulates the hot water from the electic tank back to the DSH by way of taking hot water from a tee on the DHW pipe of the electric tank.and returning it to the DHW inlet on the Geo. If the water temp is below 130 degrees the DSH will heat it up 5 to 10 degrees and send it back to the storage tank and so on. If the water is above 130 degrees then the DSH circulator shuts down and the water is not circulated.
Is that close to what happens?
"A geothermal heat pump model may provide space heating, space cooling, domestic water heating, or a combination of these functions and may also include the functions of liquid circulation, thermal storage, air circulation, air cleaning, dehumidifying or humidifying. Geothermal heat pump system generally consists of one or more geothermal heat pump models, the ground heat exchanger(s), the air and/or hydronic space conditioning distribution system(s), temperature controls, and thermal storage tanks."
Geothermal Heat Pumps Key Product Criteria : ENERGY STAR
This is the official definition from the EPA, which is the basis for the tax credits. Unless there is a different definition/clarification from the IRS, the tanks, the ductwork, the radiators and/or the ductwork are included in the definition of "space conditioning distribution system".
That brings up an interesting question: How about the hot water lines inside your house?
"That brings up an interesting question: How about the hot water lines inside your house?"
Why stop there, how 'bout the fitures that distribute this water and the cold water lines that temper it and the well that feeds it and the softener that conditions it.......the larger parcel required to bury your horizontal loop field.......Heck gotta have a house to put all this in
I am sure someone is out there trying......
I think whatever is reasonable within the intend of the tax code. I am sure we see a clarification letter from the IRS soon or later.
I fear "clarification" may come in the form of rejected returns complete with interest and penalties.
Not our IRS.
I think if it is touching the geo system it is a go for it.
Joe's IRS may win, but my application to join the heat pump police was thrown out.
That is why you should talk to your tax advisor, so everyone can make an informed decision. The EPA specifically includes the thermal storage tanks and the heat distribution system to be part of of the geothermal system. Tough to envision how you can get penalized for following the rules.
I have #4 (well not GE but Rheem, so far so good--seems to function very well but I don't have any power numbers on it yet..Wattnode is coming soon)
I have a Rheem Proheat depowered 50 gallon buffer tank feeding the Rheem. Now my use is low (very low, I live alone) but the system thus far works great..Buffer tank quickly recovers to 125dF and I only hear the Rheem cycle a few times a day (I believe 3, data coming yet)
With the Steibel you are spending a LOT of dollars and not utilizing the desuperheater effectively (without 2 tanks). The Geyser is cool if you want to retrofit (say a good electric tank in a hot garage) but I just don't see that being the ideal install for a NEW setup.
Are the tanks going to be in a conditioned or unconditioned space (house or garage?)
I agree (as a Geyser owner) that it is best applied in a retrofit situation.
If the OP absolutely, positively has to have 80 gallons of hot water available regardless of geo DSH recovery, and doesn't want to deal with temporarily powering buffer tank, there are now 80 gal HPWHs from both AO Smith and Stiebel Eltron
Bring money, though
Thanks. I'm now in a quandry (again). I thought that I was pretty well locked in on a Geothermal heat pump with DSHW and possibly a HPWH, but I'm not sure now. I've asked the question in the geo HP site and think I probably now need to wait until I have actual manual J calculations and working with the mechanical contractor. My dilemma is that the building site is quite steep, and most of the drilling will be in rock (vertical loop). I'm also not sure if a standing column is permitted, and weighing the costs of the drilling in these conditions it might make more sense to use an air source heat pump (high SEER dual stage is what I'm thinking). If this is the route, then the hot water will have to be stand alone.
Since the need for high volumes of hot water is only when the tub would be used or when we have guests, could I use a buffer tank, turned off, with a ciculation pump into the HPHW tank? I could then turn on the buffer tank when we have guests. This would be less expensive than the Steibel system.
One of the advantages of a Geyser is that it can be configured with tanks of any capacity or several in series. I use one to heat a single 80 gallon finishing tank but a couple extra valves would have it able to heat both tanks. I have no need of that.
If you only rarely need the extra capacity, I'd go with an upstream tank with resistive elements. Flip on the breaker when guests arrive. Granted that would be less efficient than circulating an HPWH's contents into a second tank, but it would be simpler and cheaper.
There is a new device out there to recover heat from ASHPs - an exchanger made by Olive Tree Energy. Olive Tree's unit differs from 1980s-era ASHP desupers in that it needs no pump for water. We have one in service at a client's home which I am gearing up to instrument early next month. The Olive Tree heats a buffer tank that feeds tankless heaters. I will use a multichannel TED 5000 to correlate heat pump operation against tankless power use. I expect to log buffer tank temp as well...stay tuned
Sounds interesting and I look forward to seeing the results.
Any update on this project?
Nope - its on the list for January.
I have a nifty new gizmo for the project - a USB stick that records temperatures for days or weeks at a time...looking forward to deploying it.
Can you give more info on your gizmo ?
Lascar EL USB-1, about $60. Programmable sampling time, 16000+ samples. I think when I set it for 30 minute samples it claimed it would run for 11 months.
In prelim tests tucked into the element cavity of a water heater tank it returned data a bit (5-10 degrees) low, likely owing to isolation from the tank, but I've decided I can live with the inaccuracy for now.
This particular model only measures to the whole degree and is less accurate then at least one of their pricier models. I suspect that an ideal one for my purposes would have a detachable thermistor probe that I could foil tape to the metal wall of a tank and get much closer to actual water temperature.
If I become more motivated, I might buy another and dissect it with the goal of detaching the thermistor and running leads. However the surgery could be unsuccessful and most likely fatal to the unit.
EDIT - They have one with a detachable probe EL-USB-TC-LCD...wish I bought it instead!
I can't speak to the GE HPWH but STAY FAR FAR AWAY from the Rheem/Ruud heat pump water heater unit.
I bought one. It worked fine but it was an April, 2010 construction date. It was sold to my installer/geothermal guys by a local distributor who may or may not have known it was already under recall
So I had the recall done over a month ago. The (qualified) tech followed the procedure of removing and then TRYING to put the freon charge back in and the unit wouldn't take the charge. He was basically told by Rheem to not bother trying again and that the entire unit needed to be replaced. Well, that was over a month ago. My installer spent over 5 hours on hold with Rheem and we got no where. No unit and I spent a HECK of a lot of money for a unit that is basically just a VERY overpriced resistant heat water heater.
No progress thus far in getting a replacement. My next move is going to be to ask for my money back from Rheem and probably go AO Smith Vertex/gas instead.
THANKFULLY my DSH system is working great and I don't think the resistance heat is costing me many KWH.
I would avoid Rheem again at all costs given my experience.
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