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Dan Kramer
Registered Users
Posts:2
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| 10/07/2008 12:04 AM |
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| Looking for some advice. I am hoping to install either a traditional geothermal pump 'n dump or a high efficiency Acadia air to air heat pump this fall. I don't know too much about either system, but I know that heating my 2500 sq ft home in Michigan on our propane furnace is going to hurt the pocket book. I'm not a DIY, so I'll be paying the entire bill. Anybody have experience with the Hallowell International Acadia heat pump? |
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senecarr
Registered Users
Posts:158
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| 10/07/2008 9:08 AM |
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Not familiar with that particular model. All heat pumps are limited by having to move air outside. In MI (where I and Joe AMI are) it gets to cold for at least 2 weeks in general for the heat pump to operate. You'll still need propane for the 2 coldest weeks, and if you're buying less, the company will give you a worse rate per gallon.
Joe and I looked at the payback for it. In my particular case, it was a 5 ton heat pump was $4000 and saved 1,000 a year. ~20,000 a year for a geo system paid back ~5,000 a year, so the payback period was pretty much the same, but afterwards, the geo system continued saving a lot more. |
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joe.ami
Registered Users
Posts:370
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| 10/07/2008 9:18 AM |
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Acadia is a multi stage air source heat pump and the problem as always is when it gets really cold out how do you want to make up the difference?
I don't have a problem with ASHP's, I just don't think they belong in a conversation about geo. There's really no comparison.
Joe
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kiphorn
Registered Users
Posts:14
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| 10/08/2008 3:02 PM |
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I used to heat my 2,600 sf home with propane. I live in central PA and my propane bills were about $3,000.00 last year. That was enough for me so we made the switch to geo. I have a Climate Master Tranquility 27 with a closed loop (3-200' wells). My installed cost was around $20K which included, the wells, the unit and installation, rezoning my basement and hooking up the desuperheater. It also included hooking up my gas grill to my 500 gallon buried propane tank. I will never run out of flame in the middle of a steak!
I consistently burn 950-1000 gallons of propane each year. With propane costs going up all the time my payback period was under 5 years. I'm sure you can't go wrong with a good quality top of the line geo unit in the long run. |
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Kip Horn
Tranquility 27 (June 2008) |
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dmaceld
Registered Users
Posts:487
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| 10/08/2008 11:15 PM |
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Posted By joe.ami on 10/07/2008 9:18 AM
I don't have a problem with ASHP's, I just don't think they belong in a conversation about geo. There's really no comparison.
Joe
I mildly disagree with you. My contractor has just installed, but not yet fired up, a 3 ton Daikin heat pump in my under construction ICF house. The reason I chose this heat pump is because it will extract heat from outdoor air down to 10F with a COP of 3 with the capacity I need. The Manual J design temp for my location is 9F. The max heat load for my house calculated out at about 36,000 Btuh. In my case the Daikin heat pump accomplishes the same thing as a geo source heat pump, i.e., heat production with a great COP throughout the entire heating season with an output level quite adequate. The installed cost is thousands less. It won't be quite as efficient as a GSHP, but it's good enough for thousands less, and it avoids having me depend on electric strip heat, the usual killer of overall efficiency of an ASHP.
Another heating contractor nearby installed about a half dozen Daikin systems in this area last year. One of their representatives told me not a single one had to switch to auxillary or back up heat this past winter.
So, in an appropriate climate the Daikin will deliver efficiently produced heat for the entire season, just like a GSHP. So there is a place for some ASHP systems in a conversation about geo if they are a viable alternative to a GSHP.
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Building house - what a way to spend retirement! |
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geodean
Registered Users
Posts:590
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| 10/08/2008 11:26 PM |
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Posted By dmaceld on 10/08/2008 11:15 PM The reason I chose this heat pump is because it will extract heat from outdoor air down to 10F with a COP of 3 with the capacity I need.
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Dewayne Dean
PalaceGeothermal.com
Why settle for 90% when you can have 400%
We heat and cool with dirt!
visit- http://welserver.com/WEL0114/- to see my system |
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joe.ami
Registered Users
Posts:370
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| 10/08/2008 11:54 PM |
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dmaceld, I hope your system works well for you. Our experience in MI, is that systems installed for thousands less, save you thousands less. And as the savings is geometric.... By the way your 36k BTU unit will deliver <30K on a 10 degree day. If that's enough, you must have serious insulation, which is great.
Every system has it's place. Daikin has some exciting possibilities and Senecarr can tell you that we looked at one of their products at his house, but only where there was no existing duct work. In every instance, operational cost calculators favored geo. No matter how you slice it a massive (albeit expensive) underground geo heat exchanger, will always prevail over small air source heat exchanger's if all other things are equal. Don't confuse savings on duct installation as savings on equipment.
I maintain the two are not an apple to apple comparison, but appreciate your efforts to disagree with respect vs antagonism and hope I've accomplished the same.
Regards,
Joe |
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dmaceld
Registered Users
Posts:487
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| 10/09/2008 9:09 AM |
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Posted By geodean on 10/08/2008 11:26 PM
Will you have a way to measure actual COP?[/quote]
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Building house - what a way to spend retirement! |
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dmaceld
Registered Users
Posts:487
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| 10/09/2008 9:27 AM |
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Posted By geodean on 10/08/2008 11:26 PM Posted By dmaceld on 10/08/2008 11:15 PM The reason I chose this heat pump is because it will extract heat from outdoor air down to 10F with a COP of 3 with the capacity I need.
[/quote]
[/quote]
Will you have a way to measure actual COP? I've tried twice to post a response. The system is losing it!!! I'll talk to my HVAC contractor nephew and the local distributor to see if there's a practical way to do this. A Daikin factory rep will be here in a few days to start up the system and do some technician training. I'll ask him also. I'm basing my comments on info in Daikin's official Engineering Data manual, not on sales hype.
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Building house - what a way to spend retirement! |
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dmaceld
Registered Users
Posts:487
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| 10/09/2008 9:42 AM |
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Posted By joe.ami on 10/08/2008 11:54 PM
By the way your 36k BTU unit will deliver <30K on a 10 degree day. If that's enough, you must have serious insulation, which is great.
Every system has it's place.
I agree with both comments. As you know the Manual J design temp is the lowest expected temperature 96%+ of the the time. The heat load for my house at that temp is about 36K Btuh. Here in SW Idaho the 30 year historical temp data shows we have hourly temp readings below 20F only about 10% of the heating season. At 10F I may have to go to supplemental heat, which for me will be a pellet stove! But then on the other hand the ICF construction may very well "fly wheel" me past those low temp hours. 80 to 90% of the heating season the heat pump will have capacity above the heat load. If I remember my calcs correctly the heat load is only about 24K at 30F. In designing a heating system I believe one should look at the economics of under sizing the system with appropriate back up and peaking for the low percentage of time the weather is actually near the the design temp.
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Building house - what a way to spend retirement! |
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Brock
Registered Users
Posts:203
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| 10/09/2008 11:23 AM |
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| Not that my opinion matters, but I see ASHP's as the step between a traditional furnace / AC and full geo system. For 95% of the time they are more efficient then a traditional furnace and I doubt the 5% of the time adds up to make it less efficient over the year. My sister in law has a 10 year old home, they don't have space for a field (living in a city lot and aren’t allowed to do vertical) and their furnace is going to cost more to repair then its worth. So I suggest they look at ASHP's, it sure seems like a better deal then another furnace. |
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Green Bay, WI. - geothermal heated indoor pool with a small solar setup |
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senecarr
Registered Users
Posts:158
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| 10/09/2008 11:23 AM |
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Looked at the Daikin with Joe. It's low operation and ability to use variable refrigerant so you can add to the system is interesting.
I'd still much rather in my climate see them apply the variable refrigerant technology to a geo system, doubly so with tax credits they are enacting for geo systems.
Of course all of the installers on here are perfectly understanding of proper sizing (not undersizing). Almost every system is designed to meet 90 to 95% of maximum need and boost with electric coil for the rare times. Unlike an ASHP, it would be possible to have geo operate for 100% of the lowest requirement, but the additional tonnage would always be uneconomical. |
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