I'm getting close to hi jacking another thread while discussing this point with Bill (as well as getting long winded right after a suggestion of brevity to another pro:), however as we approach the fall rush it's worth covering efficiency again.
#1 efficiency is not just cost to operate, it can be the ability to extract the most heat (or discharge it) through the smallest possible loop. This has no impact on operating cost but can affect ROI.
#2 DX systems are more efficient than water source systems in some circumstances. As the loop length is routinely fixed by manufacturer it is often oversized which has an advantage over right sized water loops.
#3 Water source systems can be more efficient than DX systems depending on circumstances. Dry sand for instance in my area requires extra loop in the ground; not always doable for DX.
#4 No system's advertised efficiency has anything to do with the real world. The COP or EER achieved on a workbench are seldom similar to actual results (just ask Ford why my truck doesn't get 23 MPG). Nor is it necessarily close to average efficiency which is seasonally impacted.
#5 the difference between the highest efficiency units made today and the lowest is often less than 1500 Kw sometimes less than 1000Kw. Again depending on system less efficient units are often better hot water generators mitigating some of the savings.

Factors that have a greater impact on operational cost than advertised efficiencies include; loop design and installation, duct work, homeowner usage, equipment sizing, thermostat and staging, weather, infiltration (tightness of house), hot water demand.

The most important component in the struggle for efficiency.....contractor (designer, installer). The most efficient unit poorly installed uses way more energy than the least efficient unit well installed.

Joe, I'm in general agreement with all of above.

While discussion might be in order on #1, as I think efficiency and ROI are more distinct subjects that perhaps you do, still, I'm in general agreement with the gist of the comment.

Certainly, whoever is providing the 'added value' to the raw HP equipment, will far affect efficiency way more than what brand the equipment is.

Best regards,

Bill

I would like to highlight everything Joe said with extra special attention given to number 4 and 5!!!
Eric Sackett
weberwelldrilling.com

Glad you brought up #1 (again I was trying employ brevity). With water source we can significantly impact average C.O.P. with oversized loops. ROI however plunges with significant loop size increase (thousands in cost to save less than $100/yr). Unfortunately some that watch here misunderstand and demand the extra loop and COP from their contractor (the term we've used is "holy grail" re EWT).
J

I don't think number 4 is necessarily wrong as stated since it isn't stated manufacturer specific.  I think the statement's a little over emphasized, though.  And it's not necessarily true for WaterFurnace.

In my case, I have the ability to accurately analyze actual, real-world EER.  It's shown below for my WaterFurnace Envision 5 ton unit.  (Since I don't have the fancy laboratory instruments the manufacturers do, I have to show it across an entire month using a histogram format to see the actual EER performance.)

In this case, here is an example where the system's advertised efficiency is as realized in the real world.  The EER achieved on the workbench for my particular model matches my actual performance.

Avg Entering Water Temp for June was 78°.  Spec is about 21 EER at this EWT.
Actual average EER from the histogram chart below is at 22.
Pretty close, and, accuracy of my measurement technique can account for the slight offset.

Noting this real world example, I'm inclined to believe that other large manufacturers advertise performance specs that are indeed achieavable in the field.  It's hard to believe WaterFurnace is the only one.

Best regards,

Bill

WEL1000 also verified WF COP to be correct in actual operation.

True if you take the time to read the chart you can find results that are remarkably close. However I said "advertised efficiencies". This is where sales gets disingenuous; your heat pump is not marketed as a 21 EER. Most folks read the sales slick not the performance table. You've captured the finer point that the EER or COP are a moving target.
Your chart does a good job of demonstrating peak and folks who wish to extrapolate can find that the average is lower. Again Bill we don't disagree, we simply are speaking of different things.
J

Just for fun I Googled "Water Furnace Envision."
The first choice I clicked on popped up the Water Furnace boast of "30 EER and 5 COP".
If Bill only gets 21 EER right now (with a darned good August EWT), I think it's reasonable to conclude that advertised efficiency has little to do with reality.
21 is darn good in late August on a closed loop (unless you are expecting 30).
J

Just for fun ...

I looked up what it would take to get 30 EER out of my 5 ton WaterFurnace Envision unit.

Very doable in your part of the country, Joe, where open loop is common, and with your climate where it's not difficult to get 50° or slightly warmer EWT.

You could become a WF dealer, install exactly the same model I've got, put in an open loop with 50° EWT source, run the blower fan motor at 1500 CFM, and golly, your customer would have a 31 EER - better than advertised!  And you could use this fact to generate great future sales!

Based on the fact that I see that my Envision units run at factory spec, properly adjusted for ambient conditions, in this Texas blistering heat, sitting up in a hot attic, I think it's very reasonable that a well qualified installer such as yourself can equally get factor spec performance at another point in the chart.

And gosh, you could bring in much warmer 60° EWT water and still get 27 EER, with the same unit!  All very doable, and much closer to reality than you're giving the manufacturers credit for.

Best regards,

Bill

 

It is all doable (regardless of brand) or they wouldn't write it, but you have stumbled on another important point that most of the claims pertain to open loop with a clean coil. Most of the installs now (in my area and many others) are not. Further EAT has an impact on efficiency as well.
You mis-understand this as a criticism of the manufacturers; it is not. It is directed at the sales types who stick the sales slick under a consumers nose and talk about the 30 EER when they know damn well it ain't gonna happen often (if at all).
The other point you don't want to miss is that average efficiencies (actual usage) are what your electric bill will be based on. That is different from the occasional hit on peak performance.
Bill you are more educated than many consumers who think EER is constant. The same folks think %efficiency is constant in furnaces which is also un-true.
You can argue that the numbers advertised are occasionally accurate but then again you would be agreeing with #4 " The COP or EER achieved on a workbench are seldom similar to actual results".
The end point for shoppers which this thread is directed towards is; if a sales person quotes these fantastic efficiencies ask when and how it is achieved or even better ask average efficiency.
The other point is that most manufacturers are using the same 2 stage compressor which is one of the larger components in the efficiency game. Further your 2 big players Climatemaster and Water Furnace are engineered by the same people.
j

Joe, I've enjoyed and appreciated the stimulating 'conversation' on this topic with you, and am respectful of your point of view.

Many thanks!

Best regards,

Bill

A Footnote about where DX fits into this part of the discussion. Because of the way DX transfers heat to the soil it can do so very quickly and efficiently. This is not always true of the surrounding soil, and as the length of the loops is not expandable (due to the compressor's reach for oil recovery), different soils can cause different average efficiencies.
j

Thanks Joe.

The key think I'm curious about, with respect to DX, is, is it's key advantage that it's more efficient than conventional water loop GSHP technology, or, are the advantages of DX elsewhere (such as smaller amount of land required to install)?

(This is one of the things I'm hoping to learn from Mr. Drao's thread.)

And my specific definition of efficiency is heat rejected/extracted versus KWH consumed (this eliminates the debate on amount of pipe, etc.).  I.e., how much cooling / heating is provided at what cost.

Best regards,

Bill

I understand what you are after. But my mantra about dealer is exactly how I feel. In other words; no key advantage in my mind.
I already told you about the efficiency limitations.
Regarding smaller amount of land, that is not necessarily true either. For example, Our slinkies are about 110' long and fit in a 3 foot trench. Earthlinked horizontal loops are 125' long and must be seperated by 4 feet, so your trench is 125X4' or larger than my water source.
There is no domestic 2 stage DX system that I'm aware of so water source makes headway there.
DX also unfortunately is more attractive to Johnnys Come Lately as it predominantly requires tools any mechanic already has. They are also split systems which is (IMHO) more opportunity for trouble than a clean factory assembled package system.
DX has specific elevation and pitch requirements that make it harder to follow terrain. If you have a hilly lawn, you can't go up and down with DX loops.
Finally, they are expensive. Packages for systems cost almost as much as a water source package with loops installed by a subcontractor. They are a little less (maybe $1,000 but then I have to hire or rent an excavator and install the loops and purchase crusher dust to surround it).

All that said, they work, and if correctly applied they work well. They also have a horizontal field of 1/4" tube that you can use that lays out at about 500sq'/ton. It's a lot of excavation (vs trenches) but it can fit in some tight spaces.
Good new dealers do not have to buy flush carts or fusion tools and likely already have everything they need to install a system.
*I speak in generalities of course and there are exceptions.....*

I don't mind any well built well installed system. I do however mind BS. Which is my aggravation with all disingenuous claims and there is no shortage of these from DX or watersource sales people.
J

Wow!  Thanks Joe!  Learned a lot.

I think for Mr. Drao's thread it's then reasonable to simply expect similar performance from a DX system as compared to a water-to-refrigerant system.

For example, in cooling mode, I get about 15 - 16 KBTU (Heat Rej) for every 1 KWH I burn through, for my water-to-refrigerant technology system.  My conclusion here is that the owner of a DX technology system will get about the same (and not better), of couse with the assumption that both system technologies are properly designed, installed, and working.

I'm learning that there are many differences, such as land required, tools required, ease of installation, etc., for DX.  But, from a view point of how much heat the consumer can extract from the earth, or reject into the earth, for a given amount of KWH, the two technologies perform similarly.

Parenthetically, I didn't know that DX is always single stage.  Thus, for installers willing to do zoned applications, it looks like DX cannot be used.

Many thanks!

Best regards,

Bill

DX should have an installation advantage on applications that require vertical installs via lower drilling costs due to the fact that you drill shallower boreholes(100'/ton for DX vs. 150-200'/ton for water source) and smaller-diameter holes. There also should be less of a site impact since the borholes can be 6' apart instead of 15' for water source. Of course the increased cost of the prefabricated copper loops vs. HDPE erodes some savings. -Adam

Adam states 1 scenario where DX can have an advantage. Truth is all systems have + and -'s. Dealers pick equipment mfgs who's warts bother them least. Bill, Nordic in Canada has a 2stage DX I'm unaware of any in the states.Earthlinked operates similar to variable flow units using least refrigerant for load (lowering pressures and kw usage). You know my feelings on zones:) J