Marc&Kem
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| 02/20/2008 1:35 PM |
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I have read and heard about several independant systems. But there aren't to many involved in systems that provide a combination of efficient heat sources. Like Heat pump or recovery, Solar Vacuum Panel, demand, boiler or back up combo....
Is it because of liability, complexity, or efficiency?
If anyone knows of a system, please tell us. |
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Alton
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| 02/20/2008 5:37 PM |
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Marc & Kem,
What do you mean by independent systems. The neatest thing I have seen lately is a heat pump water heater that uses a liquid solar panel to be more efficient. |
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Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
334 329-0957 AT&T Cellular |
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Marc&Kem
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| 02/20/2008 6:57 PM |
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What I mean by independant systems are systems that use just one or 2 heating methods or tanks. It seems that many systems use one water heater or one boiler in combination with maybe a solar panel. Maybe it's because the more you invest the longer it takes for ROI.
I was considering a Indirect water heater, Solar panel, heat pump or de-superheater and some kind of back up, possibly a boiler because of the Radiant floor.
The summer would be fine for hot water. The boiler would not be used for 5 months out of the year. It's hard to balance the summer and winter thing. Is that good for a boiler? |
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PanelCrafters
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| 02/20/2008 7:14 PM |
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Posted By Marc&Kem on 02/20/2008 6:57 PM
The summer would be fine for hot water. The boiler would not be used for 5 months out of the year. It's hard to balance the summer and winter thing. Is that good for a boiler?
If you utilize a boiler, it should also be used for DHW(or as a backup for solar). The best advice that I can give you, is to Super Insulate. When you do, your Heat Loss and Heat Gain will both be lower, and you'll save energy for the life of the structure. And, if you are trying to heat via an alternative method(solar), your solar system will need to generate less BTU's. |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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Marc&Kem
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| 02/27/2008 5:15 AM |
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I know this goofy question but here it goes. Even though the btu efficiency is lower....... Can a person use a boiler with glycol in series with a solar panel going into a indirect water heater. By-pass the solar panel when panel temp is low. Use this for your floor and the direct side for the household potable.???
Or would the boiler be to hot for the glycol and cause residue build up in the coils?
I got it, Maybe use a Heatpump instead of the boiler and have a potable (direct side) Hot water backup. What would be the magic combo for summer and winter use (in TN)?
I hope this makes some kinda sense.
Marc
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bartman99
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| 03/17/2008 8:57 AM |
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Posted By Alton on 02/20/2008 5:37 PM
Marc & Kem,
What do you mean by independent systems. The neatest thing I have seen lately is a heat pump water heater that uses a liquid solar panel to be more efficient.
I'd be interested in reading more about "heat pump water heater that uses a liquid solar panel to be more efficient." Where did you see/hear about this?
Thanks
B
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Alton
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| 03/17/2008 9:27 AM |
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Bartman99,
Look at this web site: www.energieusa.net I saw this at the 2007 International Builders' Show in Orlando.
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Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
334 329-0957 AT&T Cellular |
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bartman99
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| 03/17/2008 9:36 AM |
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Posted By Alton on 03/17/2008 9:27 AM Bartman99,
Look at this web site: www.energieusa.net I saw this at the 2007 International Builders' Show in Orlando.
Thoughts?
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Marc&Kem
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| 03/17/2008 3:50 PM |
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Both of these systems are cool Heat Pump systems. I plan on using my geothermal heat pump for pre-heating and a solar panel to assist. But then a back up is needed..... How about 2 small high eff. propane Demand hot water heaters on both sides of the systems and then by-pass the solar panel at night or when the panel temp is lower than the water in the system tank.
The radiant floor system and solar panel would contain glycol for winterizing and flow on the indirect side of the system.
One big question... Can a small Demand Hot Water heater, heat glycol at a low temp like 130 deg F? Will this cause a problem with the Propane DHW heater?
The direct side of the tank will provide HW to the house and have a small DHW to make up the difference. Only 2 or 3 people in this home.
Marc |
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bartman99
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| 04/21/2008 9:05 AM |
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Has "Tom Gibson" used a heat pump water heater to make a solar panel more efficient? Can you provide specifics?
BM
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Marc&Kem
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| 04/21/2008 7:18 PM |
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| What I mean by independant is a single source for heat. That is why I was hoping someone could answer the question of using a Glycol medium with a demand heater. It opens up the possibilities. |
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clydesdad
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| 05/01/2008 11:25 AM |
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This thread is very interesting to me because I have been asking the same question, but not getting any satisfactory answers and researching it myself is daunting.
We're in the midst of a fire rebuild (1800 sq ft, ICF walls) in South Lake Tahoe, CA and we're planning radiant floor heat as well as solar hot water for domestic HW, with a heat dump loop to a site built concrete hot tub. I would fill all loops with glycol, thus the DHW and hot tub would be heated by heat exchanger. My solar consultants point out that running the potable (DHW) through its own tankless heater would allow for the greatest potential solar energy gain for DHW as the water in the storage unit would be cold (around 40-45 deg F. up here) unless heated by solar gain at the panels. I agree with that idea but I wonder if we might need a very powerful/less efficient unit in order deal with the large temperature gains during periods with no solar gain at the panels. My thought is that it might be better to have a single heating unit and to keep the DHW water tank at usable temperature with a glycol loop from the tankless/boiler we would be using for our floor heat (which would be bypassed by a loop to the panels when solar heat is available). My other thought, which I think is the question that Marc&Kem is asking is: Is there a High output/High Efficiency (modulating) tankless/boiler that could do both glycol and potable heating.
Any input on these questions would be much appreciated as we're pretty overwhelmed with the rebuild process and time/energy for research is limited as is local knowledge about green heating technologies out here in sunny CA....Thanks and sorry if this seems like a thread hijack.... |
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Marc&Kem
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| 05/01/2008 5:40 PM |
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Clydesdad,
That is exactly what I've been wanting to find out. If you hear anything, please let me know. I will do the same for you.
Thanks,
Marc |
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chad
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| 05/10/2008 3:46 PM |
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I am building two homes in Philly a bit north of you guys and have been advised by a few energy modeling pros to use the same basic setup as follow for a home that has radiant heating:
- Schuco Slimline Package II - 80: Includes two solar thermal panels, pump, expansion tank and solar thermal storage tank with two heat exchange loops.
- A 90%+ efficiency gas boiler with two zones to heat the radiant closed loop directly with one zone and the solar storage tank when needed with the second zone.
The fact that we are up north and we have a tight budget does not allow us to install a system capable of effecting both the radiant and domestic hot water. If you were able to, you could use an open loop radiant system, install a larger solar storage tank, more panels and it should work just as well if not better. I would just caution that you be able to handle any excess solar energy that may result from adding additional solar thermal panels.
Not sure if this is exactly the type of system you are looking for, but thought I'd throw what I've recently learned in the thread in case it helps... |
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Build It Green Philly - Philadelphia Green Building specializing in cost-effective new construction and major rehabs. |
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clydesdad
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| 05/19/2008 10:20 AM |
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Continuing with my thread hi-jack....At this point Marc&Kem, I am not finding any boilers with dual inputs (for potable/DHW and glycol loops) so we are now pretty resolved to a set-up much like the one Chad links to in the post above. In fact, I sent the link onto our solar consultants (friends) and they were very impressed by the price, among other things. Like I said in my previous post, IMHO, this sort of stuff is in a fairly primitive stage out here in the West. So...now we're looking at running a glycol loop to Solar Hot Water panels and into an indirect DHW storage tank that also has a heat exchange loop from our boiler. The question now is which boiler/tankless? Perhaps Chad has a good answer as it sounds like he's putting together a similar system on the houses he's building. Again, we're building about 1800 sq ft with ICF walls (to be heated with radiant floors) and the climate here is pretty mild (the coldest I've ever seen is about -5 deg. F) and cold spells are usually quite short. We're very budget minded in putting together our project as building costs here remain obscenely high even though the real estate market is tanking (the area is overbuilt with "woodsy", inefficient, spec houses). Like I said above, as we're awfully busy attempting to keep the project moving, our time and energy for researching these things is limited so....if anyone has any advice for an appropriate heating unit, it would be hugely appreciated. Thanks!
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chad
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| 05/19/2008 3:49 PM |
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I was recommended the following boilers for our application where we have just over 1,000 sf and a heating demand of about 40K BTU's:
Lennox - Constervator 90 (AFUE 90)
Viessmann - Vitodens 200 (AFUE 95)
Buderus - GB142 (AFUE 95)
My mechanical contractor is also looking at Munchkin boilers as they are a bit cheaper than the others. It was stressed that a boiler is much better for this application than a gas tankless unit. Lastly, I stumbled onto http://www.RadiantHeatProducts.com which seems to have a very good selection of boilers and other radiant equipment. All of the boilers listed above are there except for the Lennox. |
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Build It Green Philly - Philadelphia Green Building specializing in cost-effective new construction and major rehabs. |
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rydnek
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| 05/21/2008 12:45 AM |
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Hi, Marc & Kem. You haven't mentioned the area where you live or the climate in your location. First and foremost is the thermal efficeincy of your home's envelope. Here is the web site for a company that may have the answer that you are looking for:
http://www.hydro-temp.com/information.htm I worked with Mike Jones, who was a manufacturer and contractor who participated in a Energy Conservation Program back when we were in the last "Energy Crises". I worked for the local Electric Utility to promote and implement very aggressive leading edge technologies to help our customers deal with rising costs and also to help us shed Overall KW Demand. He has some of the most advanced water heating, humidity control, and Heat Pump designs on the market. Check out his work for Public Buildings (primarily schools). I built my own house using SIPs, Logix Blocks (Below Grade), on a slab with 1" styrofoam under and around all of the slab, efficient casement windows (Semco), most of the duct system in the heated space, and air source heat pumps (I tried for months to find a contractor in this area that would give me a competitive price for an earth coupled heat pump system). Our house is very comfortable with very low energy bills.
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