Quote:
Originally Posted by AC_Hacker
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Hi again AC_Hacker.
Thanks for sharing your thoughts on GSHP in the Portland area.
A few further questions:
1. Did you get the PM I sent you with my contact info?
2. Did you need to apply for any kind of permit to drill your bore-holes, or did you just "do it" and plan on pleading ignorance if any govt agency questions it? If you did get permits, which agencies did you have to deal with?
3. Have you done any thinking about the cost/benefit of closed-loop GSHP (lower temperature differential) vs. pump-and-dump wells (higher temperature differential, but higher cost of pumping water out of a deep well). Have you seen any analysis done comparing the two GSHP methods? (especially locally)
4. Have you seen a cost-benefit analysis done between local GSHP vs. high efficiency natural gas? If so, can you share where it is?
Here are some other thoughts that go into my thinking about the cost/benefit of GSHP....
A concern about a future rise in natural gas prices:
Right now, Natural Gas is inexpensive, but if the big energy companies get their way and are allowed to install facilities for exporting Compressed Natural Gas (CNG), the price of Natural Gas will likely double or triple for us because it will float to the international pricing which I understand is much higher than our current domestic only pricing. There already is and will be increasingly intense pressure from all the natural gas producers to start exporting CNG to drive up the price of natural gas (to increase their profits). If I were a betting man, I would say that we'll probably see this happen within 5-10 years.... At that point GSHP will make even more sense.
Some background on my current heating and cooling systems, and thoughts regarding GSHP:
I originally had forced air oil heat in my home. When the price of petroleum started going up in the 2000's, I started looking for a used high-efficiency forced air gas furnace. I already had installed natural gas in my home, replacing the electric water heater, electric dryer and electric stove, and had stubbed out a pipe from a tee heading towards my furnace in anticipation of the future furnace swap. I got lucky and found a used 100kBTU 93% efficient Lennox furnace at the "Rebuilding Center" (a local used building material recycling/resale place). It had just arrived and hadn't yet been priced -- I talked them into selling it to me for $250. I spent another $600 on materials for the PVC intake and exhaust venting, thermostat wire, condensate pump and tubing, and custom-built transitions to attach the new furnace to my existing plenums. I did the installation myself with the help of a friend over a weekend during the fall I think in 2006. The savings over the inflated cost of heating oil more than paid for the swap-out the first season. (I even recycled the oil furnace -- I sold it to a farmer in Eastern Oregon who will be converting it to burn used motor oil to heat some greenhouses.)
My daughter has Asthma, so I looked to install a better air filtration system as part of this furnace swap. I found a used Honeywell whole-house electrostatic air filtration system on Craigslist for $100, and installed it at the same time -- helping to improve the indoor air quality significantly by reducing the indoor dust, dander and pollen. It meant running the furnace fan on low constantly, but it is worth it. It also keeps the temperature in the house normalized by constantly recirculating the air throughout the home.
The Lennox furnace had a standard PSC AC motor (which are very inefficient -- even more so at at lower speeds), so I found a fellow on Ebay selling an extra high-efficiency "Evergreen ECM retrofit blower motor" and installed it. This effectively reduced the electrical load for running the blower on low from about 250 watts to about 40-50 watts, and also made the blower much more quiet, and soft starting.
My original plan was to later find a used traditional air based heat-pump and keep the natural gas furnace as my backup heat source for when the air temps dipped below 40-45 degrees and the air-based heat-pump became increasingly inefficient.
Now that I am considering installing a DIY GSHP setup, the gas furnace will still act as my air-handler for the heat pump air exchanger coil, but I don't see the gas heating portion being used except as a backup system in case something in the heat pump fails. When I installed the gas furnace, I installed thermostat wiring sufficient to control a heat-pump, and installed a Honeywell 9000 series thermostat that can control a heat-pump and the furnace air handler (and the furnace heat as a secondary heat source if need be) -- so there won't be much more to do to control the heat pump.
My current air-conditioning is not very efficient. I don't have central A/C. On the main floor, I have a fairly new 12000BTU 240V window AC unit (about 11SEER efficiency) that I installed in such a way that it blows the air in a circular pattern through most of the ground floor (purchased used on Craigslist for $100). I have a smaller window AC unit in the upstairs south-facing master bedroom.
Using a central forced-air GSHP for cooling will definitely be more efficient than what I currently have -- both because of the more efficient ECM air-handler, and the better efficiency gained from GSHP over transferring heat via air exchange AC during the heat of the summer.
The question still remains: what savings will the GSHP give me over heating with high-efficiency natural gas? As I mentioned before, when the price of natural gas rises due to the implementation of exported CNG, GSHP will make more sense financially. I just wonder what the difference will be at today's prices.
Of course, there's also a non-financial, but immediate environmental benefit gained by reducing my carbon footprint by eliminating burning natural gas for heating. If I can figure out a way to augment or replace natural gas for heating water -- so much the better.
BTW, I suspect that the carbon produced when generating the electricity needed to run an electric drier and an electric water heater is not much less than (and maybe more than, given the inefficiency in electrical power distribution) the carbon generated by using natural gas to run these devices. It would be interesting to find a calculator that would show the difference in the carbon generated by both options. Certainly it costs less money to use natural gas currently for these appliances.
I look forward to your thoughts on all of this too....