O'Fallon, MO results tracking.

Discussion in 'Geothermal Heat Pump Testimonials' started by tstolze, Aug 28, 2010.

  1. tstolze

    tstolze Member

    This will be my success story thread for our Geothermal system installed on 8/6/2010, after help from others from these forums.

    A little history on our home located in O'fallon, MO.
    It is a ranch built in 1994, just under 1200 square feet.
    The system replaced an original 2-1/2 ton A/C and strip heat.
    Load Calculations:
    St. Louis, MO area
    Summer outdoor drybulb 95, indoor 75
    Winter outdoor drybulb 0, indoor 70
    Heating-24580 Btuh, Cooling-23238 Btuh

    We installed a Bryant GT-PX 2 ton, it is a 2 stage system with 12 KW of backup strips. The system is linked to 2-200 ft vertical wells.

    Just received our latest bill, 1134 KWH/ 453 cooling degree days, the last two months were 1356/467, 1462/426. Our new system was only in place 20 of the 30 days on this bill, and the desuperheater wasn't hooked up until the last 10 days of the period.
    I am only home during the evenings on weekends and have only heard the system in second stage during the 2 degree drop for night and 1 other 93 degree day when everyone was home and we were cooking a big meal.

    We are very happy so far, the system is quiet, and the house is very comfortable at all temperatures. The old system left the house humid on days below 90. We have had a high of 98 and the system handled it with no problems, although run time increased it was cycling and not running continuous.

  2. tstolze

    tstolze Member

    September usage update:

    September 09: 113 Cooling Degree Days, 1150 KWH used
    September 10: 160 Cooling Degree Days, 921 KWH used :D
    I am happy to see a decent usage difference in the mild weather.
    Everything seems to be operating well.

    I have added a WEL to track air/loop temperatures.

    I also recently added a Bayweb thermostat, they really have some neat futures for tracking run times for each stage and plotting them with weather data.

    Our older Honeywell seemed to cycle often, I tried adjusting the cph settings with no difference in performance. Called and spoke with customer service and they said it sounded as if it needed replaced.
  3. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    thanks for posting.

    What is you WEL number ?
  4. tstolze

    tstolze Member

    I told myself to add that, oops. :eek:

    Temperature and Energy logging by: Web Energy Logger

    I am still working on the graphs, and not a bunch of run time currently.
    I look to add run times within the next month, particularly before the height of the heating season kicks in. I can see them through my thermostat interface, but I am not able to display them on an outside website.

  5. tstolze

    tstolze Member

    October was fairly mild, we used both the A/C and Heat(for the first time) this month.

    The closest month weather wise I could find was October 2008.

    October 2010: 254 heating degree days, 63 cooling degree days, 731 KWH used
    October 2008: 279 heating degree days, 34 cooling degree days, 887 KWH used

    So about 10% less heating, almost double on the cooling side, and just over 17% reduction in electrical usage.

    Again, pleased with the results in another mild usage month.

    I have ordered the run time monitor for my wel, it should arrive this week, hopefully I will have it installed this weekend.
  6. tstolze

    tstolze Member

    November 2009: 452 Heating Degree Days, 1626 KWH used
    November 2010: 570 Heating Degree Days, 965 KWH used
    661 KWH less electric usage with a 26% increase in heating load.
    With our winter electric rates this is about a $35 savings for the month.
    The next 3 months typically have 900-1300 heating degree days.

    (edit/add) Thought I would add, so far I have seen temperatures down to 21° F, the unit has done well in first stage. Tonight it is 21 @ midnight and the unit looks to be barely gaining, we have some low teens coming the next couple of nights. I am sure I will see 2nd stage heat for the first time other than testing. I am very curious as to how far 2nd stage will take me. :)

    Still working with the DSH, tweaked the flow and it seems to be working better.
    As most have stated I am considering changing from a single tank to a dual buffer setup.
    Last edited: Dec 6, 2010
  7. tstolze

    tstolze Member

    As noted, December was the month that we expected to start seeing this systems capabilities.

    December 2010: 1138 Heating Degree Days, 1412 Kwh, 45.55 Kwh/day, Avg Temp. 28
    January 2010: 1228 Heating Degree Days, 3460 Kwh, 108.13 Kwh/day, Avg Temp. 26
    February 2010: 1011 Heating Degree Days, 3026 Kwh, 104.34 Kwh/day, Avg Temp. 30

    The unit had a total of 450 hours of run time for the month, 17.23 of those were in 2nd stage with no auxillary strips used. 2-3 of these 2nd stage run hours were during testing or after the contractor had the unit off while finishing my humidifier install. The coldest 3 days were consecutive and had lows of 7, 1, and 3 degrees.

    I am very happy with my loop performance at this time, the lowest EWT I recorded was 49.26. The loop is showing good recovery as recent EWT have been 52-53 after long overnight runs.
  8. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Do you think your house base use (no heating or cooling is about 20 kWh / day?

    I'd expect a 2 ton unit with 50 EWT to draw around 1250-1500 Watts (including pump and blower) on low stage and maybe another 500 Watts in high stage.

    If I'm right about base load then heating used around 25 kWh / day in December, although if the desuper is properly plumbed to a buffer tank the house base load might drop to 15 kWh / day owing to hot water savings on days with long heating / cooling run time.

    That leaves 30 kWh / day essentially for heating and hot water in December...not bad at all!

    Does anyone else have a thought on my guesstimates here?
  9. tstolze

    tstolze Member

    Your base is very close, I figure between 20-24 kWH/day, although with a 18 and 10 year old in the house it can be frustrating to figure at times. :p

    From watching my energy monitor I figure 1500 watts 1st stage and 2000 watts for 2nd(heating). It's hard to nail down to an exact number with the blower ramping up to speed and pressures building in the system. With an average of 15 hrs/day that would be 22.5 kWH for the heating per day average without any 2nd stage run time, that would add another 8.6 kWH for the month or just over .25 kWH per day average.

    We installed our buffer on Dec 31, changing from a single stage setup.
  10. tstolze

    tstolze Member

    January Update

    January was just a little bit colder than December, results were within my expectations. I do have some thoughts on a snow covered roof. While I have a decent idea on when 1st stage has reached it's limit, we have had a couple decent snow storms lately. I noticed after the first that dropped ~10 inches of snow on us that my unit seemed to be better handling the cold. One night we hit a low of 1°F, our unit never hit 2nd stage that night, normally it has started falling behind between 10-14. I am guessing that our ridge vent being blocked allowed some heat to build and maintain in the attic. Any thoughts?

    On to our January update! :p

    January 2011: 1212 Heating Degree Days, 1527 Kwh, 49.26 Kwh/day, Avg Temp. 25.7
    January 2010: 1228 Heating Degree Days, 3460 Kwh, 108.13 Kwh/day, Avg Temp. 25
    February 2010: 1011 Heating Degree Days, 3026 Kwh, 104.34 Kwh/day, Avg Temp. 30

    The unit had a total of 494 hours of run time for the month, 9.75 of those were in 2nd stage with no auxillary strips used. As in December the coldest night was 1° with no 2nd stage that night?(see beginning of post)

    The loop continues to perform as in December: EWT low was 49°.
  11. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'm a big fan of sealing attics for the reason you describe, but I typically recommend doing it with spray foam insulation - using snow for that purpose here in Florida would require constantly replacing the snow.

    I wonder if you'd have been a few bucks ahead using just a single stage 1.5 ton unit, since that's about all the load you seem to have.

    Other than that, unit seems to be doing a great job. 49 EWT sounds peachy for MO.
  12. tstolze

    tstolze Member

    Interesting thought and I can say it never crossed my mind.

    I need to re-think the placement of my EWT/LWT sensors. They are currently inside the unit under the factory insulation. Attached with a wire tie, then a wrap of ShurTape, the conductors are wrapped around the pipe 4 times under the tape. I had the access cover open the other day and noticed a temperature drop on my Wel graph that matched the time I had the cover off. Seems the heat buildup inside the air handler may be artificially raising my temperature readings.
  13. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    interesting indeed
  14. tstolze

    tstolze Member

    Well now that we are through our meteorological winter, I can't stop smiling! :)

    February summary:

    342 hours of first stage and 20 hours of 2nd stage, no need for backup for the month or winter, our lowest temperature recorded was -1.2. EWT low was 47.1, that was the low for the winter. As stated previously I still have yet to move my sensors outside the air handler, I would guess my EWT/LWT are a couple degrees cooler than recorded due to heat buildup within the airhandler.

    February 2011: 853 Heating Degree Days, 1307 Kwh, 46.68 Kwh/day, Avg Temp. 34.6
    February 2010: 1011 Heating Degree Days, 3026 Kwh, 104.34 Kwh/day, Avg Temp. 30
    February 2009: 791 Heating Degree Days, 2720 Kwh, 97.14 Kwh/day, Avg Temp. 36.8

    Summary for the 3 months of meteorlogical winter:
    4279 kWH for 2010-2011, 3186 heating degree days.
    9466 kWH for 2009-2010, 3328 heating degree days.
    5187 less kWH, 142 less heating degree days compared to previous winter with heat strips.
  15. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    That is great, tell us again what kind of loop you have.

    EWT low of 47 ° is great unless you have an open loop.
  16. tstolze

    tstolze Member

    Vertical closed, 2 X 200 ft, we went an additional 50 ft per bore. At the last minute the driller and installer decided on the extra loop. With the warm summer they had heard of some marginal loops having issues with high EWT.
  17. tstolze

    tstolze Member

    I guess we now get into the blah months of Geo usage, what really bites is watching the water heater actually have to work to keep the tank hot.

    March 2011: 641 Heating Degree Days, 1121 Kwh
    March 2010: 583 Heating Degree Days, 1621 Kwh
    March 2009: 548 Heating Degree Days, 1527 Kwh

    I have added some more insulation over my EWT/LWT sensors and noticed a drop in my EWT temperature. Lowest recorded was 46.6, I will be moving them outside the unit this month.
  18. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    We haven't used HVAC since late February...went an entire electricity bill cycle with zero heat pump runtime. That's been great for confirming base load use, in our case 21 kwh / day.

    Heat pump water heater has had some very long days since it is toting the whole load
  19. tstolze

    tstolze Member

    Just thought I would post that I will continue this thread once we get into the summer cooling season. Over the last month or so we have been switching from heat to cool what seems like every few days, without any extended run times in either mode.

    I am very interested to watch to buffer tank this summer, yesterday with a high of 86 and a lot of heat producing activity's in the house the buffer was up to ~89 with some hot water usage during the day.
  20. tstolze

    tstolze Member

    I still check in almost daily to the forums, you all are doing a wonderful job as usual guiding people through their bid/install/troubleshooting times.

    Here's our results for June, 2011

    June 2011: 324 Cooling Degree Days, 936 Kwh
    June 2010: 369 Cooling Degree Days, 1462 Kwh
    June 2009: 311 Cooling Degree Days, 1268 Kwh

    I really like the 2 stage setup, the house is very comfortable everyday now. The old unit was a 2-1/2 ton setup, when it was in the mid 80's the house didn't have that "cool" feel to it. As far as the system handling our home's cooling load, it's going well. We had a high of 95 degrees, the system had no need for 2nd stage that day, you can really see the solar load during the 4-6 pm time frame. We did get in several hours of 2nd stage usage last weekend. My son had 13 friends over, 17 total in the house. They were making a humorous cooking video so the oven was used for several hours during the heat of the day.

    The desuperheater buffer tank typically is running into the mid 90's in the evening. On some of the hotter days it has poked its head just above 100 a couple of times. It looks like we are feeding the hot water tank with 20-30 degree warmer water than it would be seeing without the desuperheater.

    Did I mention I am happy! :D

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