I would start by verifying your units are within spec with respect to power consumptions.  Are you handy enough to obtain current draw measurements for your three units?  Something like:

Unit #1 (X tons), 1st stage: 99.9 amps
Unit #2 (Y tons), 1st stage: 99.9 amps
Unit #3 (Z tons), 1st stage: 99.9 amps

Likewise for 2nd stage.

Your units should have some manufacturer specs that you can check these against.

If these are fine, then I would next look to see if your units are producing the correct cooling capacity, first in 1st stage, then in 2nd stage.  This should be easy to measure on a one time basis, or, easy to continuously monitor with some instrumentation.  If you want to do this yourself, there are many here who can articulate the temperature and power measurements needed along with the calculations.

If these two subjects are fine, then I would next look to see if you have excessive run time.  If so, you can conclude you have structure envelope problems.  And that you really are saving (a lot) of money compared to if you had conventional heat/AC.

I would think the first two subjects I suggest above would be straight forward for an HVAC professional to not only determine, but to demonstrate to you that all is fine with respect to the specific HVAC equipment.  The calculations to determine cooling capacity, for example, on either the air output side, or the refrigerant input side, only require a few temperature and power measurements.

Good luck.

Best regards,

Bill

Without answers to some of the questions above, still, it may be possible to offer a reasonable guess on where the problem is.

If I understand your numbers correctly, you consumed 489 KWH just for HVAC purposes, for a 6 day period.  That's 82 KWH per day, on average.

As a comparison, I have what I and many others believe to be a well functioning GSHP implementation, here in the blistering heat of Dallas.  It's conventional water technology, not DX, so it may not be producing the best of DX-technology performance, but it's probably 'in the ball park.'

I also have an instrumentation system, so I have access to a lot of performance numbers.

For last month, July, I consumed 1174 KWH just for HVAC, which is 38 KWH per day on average.

To rationalize your 82 KWH/day and my 38 KWH/day numbers, we can use the square footage of our residences.  Your residence is 8600 sf - mine is 3400.  Thus, you've got a 9.5 KWH/day/Ksf number, and I've got an 11 KWH/day/Ksf number.

If you assume your basement is not conditioned, and it's about 1400 sf, then your 9.5 KWH/day/Ksf number changes to the same as mine: 11 KWH/day/Ksf.

The next step is one where I don't have enough information to finish - rationalize your 11 KWH/day/Ksf number to your climate.  My 11KWH/day/KSF was for a July climate with many 100°+ days.  I don't know if you have it this hot.

One way to do this rationalization is to use Cooling Degree Days.  For example, for the same measurement period for me (July), I had 644 CDDs, which is 21 CDDs per day.  On a per CDD basis, then, using my 11 KWH/day/Ksf number, it becomes 0.53 KWH/day/Ksf/CDD.

Perhaps you can look up your CDDs for the same 6 day period you measured your KWH.  If so, you can get an average number of CDDs per day for the 6 day period, and similarly rationaize your 11 KWH/day/Ksf number.

Finally, let's say that for some strange reason it was very hot in Michigan, during your 6 day measurement period, such that your CDDs per day average was close to 21.  Then you'd know that your equipment performance is at least to the same as the most current model WF conventional water technology GSHP units.  And thus your problem is most like the residential structure envelope.

But, let's say, as another example, your CDDs per day average is half of what it's here in Texas at the moment (i.e., your statistical average of each day's temperature is about 75 - 76°F).  Now you're looking at about a 1.0 KWH/day/Ksf/CDD number, double my number, which would say something's wrong with your DX equipment, at least as compared to conventional water GSHP technology.

If it were me I'd go off and get the CDD numbers for your area, and do the calculation.  While not an exact, precise calculation, I'll bet it's in the 'ball park' to eliminate either the structural envelope or the DX equipment as your source of problem.

Hope all this helps.

Best regards,

Bill

 To answer your questions, my geothermal units were retrofitted- ie the airhandlers except for the motor -now variable speed are the same.  So, I only have 3 boxes outside-being monitored by the sub meters.  

               My electricity (main meter in July 2009) states our home consumed a total of 2129 kwh although our average HIGH  for the month of July 09 was 75.8 degs F   with temps at night in the 50s and sometimes dipping as low as 47 degs F.  The sub meters were put in on Aug 13th 09 after tremendous pressure on the wholesaler who sold the units to my contractor that I was going to  seek legal advice.   My electricity consumption at the same time  last year(July 08) was 2007 kwh with CONVENTIONAL A/C!  July is typically the warmest month in Michigan.   Also my basement that never requires cooling has 3200 sq ft.  I feel as if I have been taken on a ride.    

I have 11 holes - one hole for each ton.  I am told they are about 50 ft deep(vertical bore) with an umbrella pattern and 10 ft apart in a straight line

        I am going to dig deeper -no pun intended, and persist in getting the system fixed or the energy guzzling equipment removed from my premises.  In the meantime, please feel free to offer dignostics.

I'm really curious about this one.

If the data offered is accurate, and the GSHP system is working per manufacturer's specs, then Mr. Drao is extracting about 1.4 *million* BTUs from his 5600 sf residence and putting it into the earch - daily!  That's a big hole in the structure, noting that on average a day at the moment is zero Cooling Degree Days (Michigan climate)

If the data offered is accurate, and the GSHP system is not working per manufacturer's specs, then Mr. Drao is burning through 82 KWH of electricity - daily - for zero CDD days.  That's an incredible amount of eletrical energy being consuming by a malfunctioning GSHP system, for zero CDD days.

Either way, something's grossly wrong.  It hard for me to understand why it's difficult to troubleshoot this one (by someone on-site).

Best regards,

Bill

My meter reads are accurate and as follows:

Hello Brian

Thanks for clearing up the depths, as a V1 100' pattern. And Welcome!

I'm sure Mike is your Dist. has he got involved.

Yes, Mike knows what's going on

I remember seeing concrete like(grey) grouting material.  I'm not sure what it is called.  Come to think of it,on one side of the house (where the 2 ton equipment is installed), every time there is heavy rain,  a hole opens up(like a cave in)  and has already been filled in thrice.  On the other side no such issues, but from the reads, you can see my 4 ton equipment seems to be the biggest guzzler.
   Regarding duct leaks, I would imagine that any retrofitted home may be expected to have some and mine is only 4 years old!  Anyone heard of aeroseal or similar product to seal existing duct leaks.  As you are already aware, I have a finished basement. 

I wonder if anyone knows of a local aeroseal contractor in Michigan?  I would like to check into that.  Also yesterday's reads are:

                                   2 Ton                    4 Ton                        5 Ton                     Main

I beg to differ.

                        I may be noted that when my geothermal units are barely on as below on 08/23/09, I consumed 29 kwh my avg summer consumption without A/C.  It is obviosus that I do not have outrageous household power usage -it is not as if I turn on more lights as it gets warmer outside!

                       

Interesting.

I'm familiar with conventional water-to-air GSHP technology, but not with DX.  I've always thought DX was a more advanced technology, capable of producing similar or better efficiency performance.  I've been looking forward to learning from this thread if indeed this is the case.

With data collection directly on the 3 HVAC units, it seems to me that discussion on the total structure power consumption just adds uneeded complexity to the subject.

Focusing on the one "normal" day, the HVAC related data published is: 8/24, 18 KWH (just for HVAC), 0 or less CDDs, 5600 sf home.

For this particular day, assuming the HVAC KWH consumption is in cooling mode, and assuming the DX system is operating similar in efficiency to conventional technology GSHP systems, then approx 280 KBTU of heat was extracted from the structure and put into the earth.

Again, this is on a 0 CDD day.  Depending on what the low was for the day, it may well have been an x HDD day.

So my question is, is about three-tenths M BTU removal for this structure, for a 24 hour period, on a zero or less CDD day, 'normal?'

Best regards,

Bill

Joe, thanks for the note.  I'll learn right along with the rest here about DX technology.

Based on Mr. Drao's latest post, for the 18KWH day, it was approximately a -1 CDD day.  Still, I'm assuming the structure has enough latent heat in it that the 18 KWH consumed was in cooling mode.

I don't agree that higher efficiency is defined by the amount of pipe in the ground.  Thus, I think you and I are agreeing here.

I think the definition most consumers have of efficiency includes operating cost.  Thus, for your examples of a vertical closed loop using 300' of 3/4" pipe/ton vs. a horizontal 600' slinky, if the KWH cost is the same for removal or injection of the same amount of heat, then I believe most consumers would agree the two systems are equivalent in efficiency.

I know little about DX.  I've been under the impression that amongst the advantages of DX, one is that, for a KWH of power, more heat can be removed or injected, than with conventional technology water-to-air GSHP units (generally).  I'll learn over time if this is indeed the case.

Best regards,

Bill

Good morning everyone! Take a look at these reads:

My take on the different reads for the same high of 81F on 08/17/09 and 08/25/09  are:



In the first case(08/17/09) temps are cooling down from a high of 89F the previous day and hence the units consumed more(low -nightime on 08/16/09  is 65F) requiring A/C units to work during the night as well on 08/16/09(my reads are taken in the evening )

In the second case(08/25/09), temps are going up from a high of 76F the prevoius day with a nightime low of 51F on 08/24/09 requiring minimal A/C use at night. 

           Does anyone still believe I have high household usage that varies with outside temps?

Posted By airhead1164 on 08/25/2009 9:12 PM
... Using the delta T at the air coils and thr measured CFM I determined the system output at the airhandlers.
... System #1 4 ton is putting out 36,054 BTUH
System #2 5 ton is putting out 50,225 BTUH
System #3 2 ton is putting out 9,623 BTUH

At this moment, I don't think conclusion can be drawn.  For a few reasons:

(1) You have one of the most well respected installers in MI, per what Joe has already said.  Thus, my guess is that if you have a really obvious GSHP performance problem, it would have been fixed by now.

(2) The data is disjointed, collected at different time points, and is incomplete.  Thus, it's hard to draw conclusion yet.

(3) If the GSHP units are working fine, or even marginally, the HVAC related KWH data just doesn't make sense.  The data would thus suggest there's one big hole in the structure somewhere, which in actuality I doubt.

(4) The structure was recently constructed, with many advanced insulation properties.

I recommend you do a few things, some quickly before you lose your cooling climate:

(1) Don't change anything with respect to HVAC at the moment.  Change at this point makes it hard / impossible to compare to previous data and draw conclusion.

(2) Get someone to come in and carefully / accurately measure sensible cooling capacity and power draw on a day where there's a need for cooling, compute the EER numbers, figure out what manufacturer specs should be (properly adjusted for actual ambient conditions), and compare the two.  Some judgement on latent cooling will be needed but this can be looked up in the specs (or actually measured but requiring additional time, effort and sophistication).

(3) Include the daily low temps on your KWH data recording, enabling CDD numbers to be calculated.

(4) Ignore total KWH consumption since you have submeters on the HVAC equipment.  I believe the analysis on the variance of the total KWH numbers confuses the subject at hand.

(5) Check your accuracy reading the HVAC related KWH meters, ensuring the data is absolutely correct.

All just my opinion - hope it's helpful.

Best regards,

Bill

I had some COP calculations here, but have now removed them, due to later receiving some very helpful counsel (see below, later in the thread) on the COP algorithm.

The numbers above are air Heating Capacity, not Heat of Extraction. 

Best regards,

Bill

(deleted COP comments.  Mr. Cnygeo pointed out correct details of the COP algorithm, which was much appreciated (see later in this thread).)

Best regards,

Bill

Posted By tinoue on 08/26/2009 11:31 AM
Consolidating the recent numbers, you have:
8/16: heat pump consumption: 13+37+40 = 90kwh.
8/17: heat pump consumption: 40+48+18 = 106kwh.
8/24: heat pump consumption: 2+9+7 = 18kwh.
8/25: heat pump consumption: 3+11+16 = 30kwh.

... If they're pumping out the BTUs expected, then the only conclusion to draw is that there's a huge thermal hole in the house. If they're not, then the only conclusion is that there's a fault with the ground loops or system operation.

Curt, thanks.

(deleted COP comments)

Parenthetically, I believe measurements today are being made, in cooling mode.  Don't know if the measurements will include preasure readings though.

Best regards,

Bill

Posted By cnygeo on 08/27/2009 11:37 AM

... he did quote heat output at the air coil
... Your method is correct if he was quoting heat absorption from the ground loop, but my impression was that he posted heat output.

If WF used the method above to calculate their COPs the ARI would probably have something to say about it!

You asked about energy consumption in winter?
 
Here's my wallet blowing -OUTRAGEOUS electric bill for January 09.

Total KWH consumption :
                                        6749 KWH in addition to 276 ccf gas consumption(back up for my 4 ton and 5 ton units). Only my 2 ton unit has aux electrical strip heat. My utility bill a WHOPPING $ 1040.21.  Price per kwh 6.25 cents.

                                       In comparison, my Jan 08 utility bill, with conventional natural gas heating was $641.39 (electrical consumption 1339 kwh and gas -486 ccf).

  Brian  consulted the company/Mike several times prior to this and they did very little!  Mike made one visit in January 09 and was so patronizing!
                              They would ask Brian to tweak this and that and change this or that part that Brian very religiously did.   In frustration I sent a 18-20 page fax of bills present and past on 02/12/09 to their leadership to get the problem fixed and confirmed receipt.  When I received no response back, I called this individual and even had a not so pleasant conversation in the presence of their certified contractor-Brian who was on one more of his trips to FIX the problem! Even then no urgency to take care of the problem.  To put, a stop to the hemorrhage, I asked Brian to switch my 4 and 5 ton systems to emergency back up gas which he did and my March 09 bill for February usage dropped to $736.09(4470 Kwh because of partial month geo thermal and 224 gas ccf).  It was finally the end of March 09 before their engineer Russ showed up and did a "thorough" analysis of the system based on different  data points and suggested some major changes all of which was promptly done by Brian including a redig of my yard on the side of my 4 ton and 5 ton units in early May 09.  

                                  Summer temps have been so cool to moderate making it difficult to measure usage till finally with  intense pressure  to take care of the issue before the weather turns, the sub meters were put in Aug 13th 09.  One thing is certain, my hand is forced to take care of this issue one way or the other!  

Oops I got  a little ahead of myself!  Sorry for not explaining earlier. When I talk about the bill, I talk about the consumption pertaining to that month. 


 I also looked at the wrong month by mistake. My Jan08(consumption in January) bill was actually $523.71(1071 kwh electrical and 397 ccf gas for a total of $523.71).   

My Feb 08(consumption in February) utility bill, with conventional natural gas heating was $641.39 (electrical consumption 1339 kwh and gas -486 ccf)-my HIGHEST ON RECORD WITH CONVENTIONAL NATURAL GAS HEATING!

All electric and gas reads are actuals-not estimates.  Brian was unable to come today to shut off the units but has promised to be here first thing in the morning tomorrow.

Posted By airhead1164 on 08/31/2009 4:25 PM
... Amp draw 28.49 at 247.8 Volts
... Total BTUH delivered 4.5X 1875 (measured cfm at the airhandler) X 6.77 (enthalpy change) = 57,121.8 BTUH
... Latent BTUH = 20,444
... Blower draw 6.92 Amps 115 Volts G E ECM Motor ! HP

I'm surprised ESP wasn't measured for the units, noting the high ECM blower fan motor power draws.  It would quickly indicate possible ductwork restriction.  It doesn't require expensive instruments to measure, and it's not terribly time consuming.  And if separate static pressure measurements are made at the supply and return points, then further diagnosis may be possible on the return ducts alone.

I recommend the HVAC professional return to get ESP measurements.  Should help a lot to eliminate/confirm ductwork problem(s).  These measurements don't require the units to be in cooling or heating mode.

Can do the measurements in fan only mode, first getting the fan RPMs to match the fan's current draw to what was previously measured.  Then do ESP measurements.

Best regards,

Bill

Good luck!  Look forward to seeing the results next Wed. or Thur.

Best regards,

Bill

Hi everyone,

                        Thanks to all of of you for your helpful suggestions and input.  I truly appreciate it that everybody is trying to help  take care of my problem.  Brian has been truly wonderful to work with and is genuinely interested in correcting the problem.  We are hoping that " the heart transplant" ie compressors on the 4 ton and 5 ton units will take care of the problem.  If that takes care of the matter, it will make us very happy.  As Brian states, I truly believe in the technology of the system and just need it to work as advertised.  Further, I am not averse to suggestions on how to make my home " hole " free after "the elephant in the room" has left.

Hello everybody!


Here are the meter reads for the last 11 days that my systems were off.  Brian and Mike are here this morning, changing compressors on the 4 and 5 ton units.  Will get more detail on that soon.  I am sure Brian will post data for you to chew on.

                                            2 Ton                      4 Ton                            5 Ton                            Main

I'm impressed that you can run an 8600 sf home at an average of 1 KW over a 24 hour period.  The best I can do for a 3400 sf home is 1.7 KW avg over a 24 hour period (40 KWH / day base load).

When you think about it, even if you have gas hot water, there's lighting, home entertainment, computers, UPS units, electric ovens, toasters, telephones, dish washers, vacuums, refrigerators, washing machines, dryers, security system, networking equipment, fax machine, ceiling fans, communications, sprinkler system, hair dryers, etc., which all add up.

I'm impressed!

Good luck today with the compressor replacements.

Best regards,

Bill

Unfortunately,     I do not have the equipment to measure running time.

Here are the final reads -COOLING MODE! I very reluctantly switched to heating mode yesterday after taking the reads.




                                           2 Ton                            4Ton                          5Ton                             Main