Was my geo installed correctly?
I am trying to decide if my geo was installed correctly. The individual doing it has been installing these units for quite some time but my power consumption seems high. I am attempting to figure out why usage is so high (90kwh/day) for a 3000 square foot home (well insulated, great windows etc). I have tried to work on all area's to decrease my consumption but need help.
The geo is a 5 ton waterfurnace that has 1500 feet of pipe installed vertically. The installer hit limestone at 25 feet and it continued to over 100 foot. After attempting to drill one well for literally weeks (I was his first drilling job as he contracted that out before) he finally decided that multiple shallow wells would be better. So, he installed the 1500 feet of pipe into not 5 wells but 10. This obviously means my wells are not the normal depth but he said this would not be an issue as if he did a horizontal well then all of my pipe would be 6 foot in the ground. He also stated that the limestone would act like a good heatsink and therefore increase my efficiency.
What are your thoughts? Is there anything wrong with this setup? Is there a way to check my unit's efficiency ie power consumption? Thanks in advance for your help!
Could be lots of things.
Heat of rejection can be measured by your HVAC guy to see if the heats going into the ground or not. This will show if it’s a well / piping issue. Could be ducting issues, sizing or leakage maybe.
Could be a problem with the house, lots of insulation does not = a tight energy efficient home.
Clocking the meter to measure power consumption is pretty easy, a google search and a stop watch should get you that info. I’m not sure if this sites non DIY policies will allow posting the step by step “how to” on clocking a meter.
I don't know either Ed.
Clocking a meter is pretty dangerous. A sudden wind could blow dust in his eyes.
There are a lot of things to consider. As Ed mentioned.
Is this a new house? or did this system replace an exsisting system?
Are there back up heat strips, are they coming on with the a/c?
Is this 3000sq.ft. all ground level or is part ground level and the rest an upper level?
Not trying to be defensive but there are other things in a home that are big energy consumers Water Heater/Clothes Dryer/Oven.
You can put the most energy efficient unit in a home, but if the house is not energy efficient it doesn't do any good. Lots of windows/ lots of can lights/ whole house attic fan/ unsealed chases that run crawl space to attic.
Just a few things to consider.
Remember it is a system not an appliance. The unit, the ducting, and the home are all part of the system.
I never let schooling interfere with my education... Mark Twain
Our house was built in 1986 and is a ranch home with a crawlspace. This unit was put in the beginning of June and replaced our old propane furnace/central air. We replaced our washer/dryer a week ago with a new energy star unit. Our fridge and dishwasher are not bad on the energy either according to their ratings. The home is heavily insulated both in the crawl and attic as well as the walls. My windows are very tight and are double paned although I do not know what is inbetween the panels of glass (ie argon etc). Even our duct work and pipes are insulated. Finally, we are all florescent in the house with one small exception (ie one bulb that we cannot replace).
How would one tell if the heat strips are on with the a/c?
A tech can use his meter.
Its a new install. I'd have them come out and check it. Its under warranty.
I looked at this for a while - my observation is it's hard to tell.
Originally Posted by griz7674
I have the same GSHP manufacturer - WaterFurnace - I average 38 KWH daily for HVAC (tstat generally set at 76 - 77°, low 40% indoor RH). Add in another 46 KWH for everything else non-HVAC related, again daily avg, and that equals about 84 KWH daily avg for me.
I have a 3400 sf, single-story, 16 yr old home that's not energy efficient. And I have 2 GSHP units for a total of 8 tons, with a closed water loop in my front yard. And outside heat is about 100° these days.
My home's 'base' electric load is about 1500 watts - about 36 KWH on an average daily basis. This is refrigerators, computers, and other electric things that are running 24x7. Cooking, entertainments, lights, etc. adds another 12 KWH daily, to get to the 46 KWH mentioned above.
I do have exclusively CFL lights everywhere - no tungsten at all. (This cut 12 KWH daily when I did this this past Winter).
I'd say you need to find out what portion of your 90 KWH daily consumption is HVAC related, before you can start concluding if you have a GSHP efficiency problem.
Or perhaps look at how much time your GSHP unit runs each day on average, and then estimate your KWH consumption based on WaterFurnace power consumption charts (they're all listed in WF's published material).
I.e., my 5 ton GSHP is averaging running 7.2 hrs/day (all 1st stage), and my 3 ton unit is averaging running 9.1 hrs/day (again, 100+°F heat outside, poor structure energy efficiency).
Not exactly apples-to-apples comparison, but, maybe some material to help you.
Bill, thank you for the data! I never was notified that another post was made hence my delay. Here's an update:
My installed came back out and check the furnace. During 1st stage, it is pulling 13.5 amps at 234 volts which he said was right. He looked at the pumps and verified that there was no air in the lines. He also took a temp test at both entries and it was in the mid 80's which he said was fine as well for a new system. He did check the heat strips and they did not turn on when the unit called for cold air so he said there was no way they could be on then.
My family and I were gone from 9am until 5 pm on Sunday and then again yesterday. My daily average of 95kwh was down to 62kwh simply by us being gone and the thermostat set to 85. After 8 hours of being gone, neither thermostat read more than 80 degree's so I assume that means the geo never ran? OR will the geo run occasionally even if the thermostat is not calling for it? Either way, between the geo savings and us not being home, we save 33kwh. I would put most of that on the geo which tells me that it is probably pulling more KWH then yours on a daily basis. What is the best way to tell exactly how many kwh it is pulling and how many hours a day it is running?
Unless you have a short, miswire, or a humidistat set to cool to dehumidify, the geo won't run without a stat call.
I'd track down what is using an average of 7.75 KWH an hour while I'm gone.
Something other then the geo is causing the high electric bills.
The spec sheet, and ARI rating can tell you the KW rating or your geo per hour.
The 62kwh was our total usage for the 24 hour period. Our reader gives automated reads at midnight of each night. I will see if I can find the info on the spec sheet. Thanks.
With the change in well design from 5 to 10 wells - did they install a reverse return well field? If not, there could be an issue with balancing in the earth heat exchanger... But, as others have said, you need to assertain your base load before crucifying the GCHP...
Bob, here are some further thoughts, noting our homes are similar with respect to size (3000 vs 3400 sf) and GSHP (identical WaterFurnace 5 ton unit), and noting our homes may be different with respect to climate (I'm in Dallas where it's daily over 100+°F), number of stories (I'm single story w/ attic temp consistently at 130°), energy efficiency (mine is poor), HVAC capacity (I also have a 3 ton unit) and indoor humidity (mine's consistently around 40% RH).
Originally Posted by griz7674
My climate at the moment is intense for cooling - see http://welserver.com/WEL0043/OutsideWeather2.gif - with for this month a high of 106°, an average of 88°, and at 633 degree-days for the month so far.
My 5 ton Envision's 1st stage power consumption is about 3320 watts, including the pumps (770 watts). If your measurements (13.5 Amps, 234 V) include the pump(s) too, then I'd say that at least w/ respect to power consumption your unit is working fine.
How did your HVAC professional check and affirm there's no air in the line? (In my case I've got Spirotop Air Release valves in my loop.)
W/ respect to your entering water temps, this will highly depend on your geographic location and borehole field performance. For my Dallas location and my 4800' / 8 wells borehole field, my EWT ranges from 78 - 83° during the course of each day right now - you can see this here: http://welserver.com/WEL0043/EnteringWaterTemps.gif (last 20 hours) and here: http://welserver.com/WEL0043/Enterin...reDailyAvg.gif (last 30+ weeks). Note that at the moment I'm dumping 600 - 800 KBTU daily into my borehole field. And I do not have enhanced grouting thermal performance - my holes are grouted with conventional BenSeal.
I would think a 5° difference between your tstat set point (85°) and the tstat's reading (80°), after the house has been sitting vacant for 8 hours, says that your HVAC didn't turn on. That would also be consistent with your statement of having a high efficiency home. Even in my climate, my HVAC would only run minimally with tstats set to 85° (although I'd pay for it the next day with the HVAC working all day to remove the stored heat and moisture from the previous day).
So my guess is you burned through 62 KWH mostly on stuff that's not HVAC, on the day you were gone. 62 KWH spreadly evenly across 24 hours is about 2600 watts. In comparison, my 'base load' is about 1500 watts - you can see this here: http://welserver.com/WEL0043/PowerUsage.gif (red line). I.e., I'm going to burn through 36 KWH each day before my family turns on any lights, does any cooking, washes any dishes, watches any TV, etc. I've learned that my base load is mostly computers (4 that stay on 7x24) and associated communications equipment, and 2 refrigerators.
Overall, based on what you've written so far, my guess is you've got 2600 watts of non-HVAC power usage to go find, and that your HVAC is running fine.
(With respect to accurately measuring KWH and HVAC run-time, one alternative is to use instrumentation available from here: http://www.welserver.com/ . Very simple and very powerful - it would only require a few hours of work on your part to easily obtain KWH and HVAC run-time info, available in a data file and in charts like the examples I pointed to above. My summary and charts are at http://welserver.com/WEL0043/ .)
Hope this helps.
Bill, that is some GREAT information! I will study up on the Web Energy Logger. And, it's good to know that I am not going crazy here but am actually using more power then what I should.
As for no air in the lines......my pump is mounted to my inside wall and the installer simply removed some screws and fiddled around with it. I was trying to catch my 1 year old son at the time so I did not see exactly what he did.
So, did I read your description correctly in that you have one inch pipe at 600 feet (down and up) per hole with 8 holes total? I have 1 inch pipe but my holes were only scheduled to be 300 feet (down and up) total. I ended up with 10 or 11 holes altogether due to drilling issues. However, my local utility company had indicated to me that this should make my system more efficient. I believe the water temps in the line were at 88 and 87 degree's which he said was a bit warmer then he wanted but not surprised given the system is not even 2 months old. He said that this number would drop as the system matured.