Ontario 5 ton Geo running 24/7

how can i measure the glycol percentage?
I have the means to remove some water from the loop, and add pressure if I need to.


The pipes from the pound through the foundation are 1.5" od, rigid HDPE to the valves, then 1" id flex pipe to the HP's

 

The best method without special tools would be to put a sample in your freezer and measure its temperature at the point it turns to slush. A few ounces in a container slender enough to submerge your temp probe a couple inches.

If you can't get it to freeze you will have to try another method. If you go to far and it freezes just let it warm until you have a fluid slush. Read your temperature while stirring.

 

If you have a Prestone Antifreeze tester for you vehicle, you could use it. a 50% mixture will read -34 degree protection. A ratio & proportion calculation using this fact could be used to figure your lop percentage based on the loop glycol reading.

50%/-34 degrees = X %/ As Read Loop protection in degrees

.5/-34 x As Read Loop protection = X % Glycol Mixture

Also a hydrometer would work, using some internet references for specific gravity of Glycol water mix.

The freezer works as also.

 

i have a hydrometer to measure alcohol levels in wine.
otherwise i will order a refractometer and hopefully get it next week.
I have some in the freezer at this time...

 

It turned into slush, 22.5 F.
What else do we need?

 

I am coming up with 15% PGlycol. The pressure drop correction factor is 1.2 interpolated from chart posted.

The R65 unit reported 3 psid. 3 psid / 1.2 correction factor = 2.5 psid water
Lookup pressure drop table for water in Nordic manual and interpolate gets 8.9 gpm.

Reported DeltaT of loop at 5.7F x 8.9gpm x 485 = 24,600 btu/hr = HE(HAB)
Performance tables say HE(HAB) should be 37,954 with 38F entering water.
This unit is performing 35% less than expected.

It is time to check the refrigerant circuit.

 

It appears you posted numbers for the R-25 unit in stage1. Please confirm. Can you get numbers for stage2? (R-65 unit off with valves closed) Nordic capacity tables do not show stage1 conditions.

Then in a separate post for clarity when you can, numbers (particularly psi) at each unit while both units and flow centers are confirmed running in stage2. I would like to compare to your techs previously reported 2 psid at each unit while both are running.

 

I use a hydrometer I bought on ebay for $10 to measure the Methanol in my closed loop. It's also an antique. A hydrometer would cost less than a refractometer.
Measuring antifreeze concentration in your loop will be something you do very rarely, so why spend too much when a simple device will work just as well.

Having a loop that contains a liquid that will freeze at 22 degrees would be a problem in my loop since the lines are exposed at the point of entry to my home. they are insulated with a foam jacket, but they eventually will reach outside air temperature if I lower the heating temperature in the house.

I entered the house at the wooden Band Joist around the house, rather than going below ground level and core drilling the basement block. I don't modify anything below ground where water could find it's way in, or cause a concrete block to crumble over time.

 

The issue is not the antifreeze, which seems a bit low, but you have a pond loop which runs warmer than a ground loop. So put this on the back burner for now and ask you installation company to check the glycol, and increase the concentrations a bit.

You need to have the refrigerant checked, as Geonxe mentioned. Low refrigerant would explain your symptoms. This can be fixed hopefully easily.

The bigger issue is the low flow you have despite an huge amount of pumping power you are using (wasting). If you indeed have a 1" pipe serving the 300ft out to the pond and back (600ft total) and you are trying to pump 21 gpm through it, you need a wasteful very powerful pumping, which is what you have.

In other words, your installer used a pipe size which is way too small. They should have used 2" pipe, not 1". 1" pipe has an outside diameter of 1.315", please confirm that. Also, please let both HPs run in second stage at the same time, and

In short, your 5 ton might not have enough refrigerant in there, your antifreeze is a bit low, both can be fixed quickly. The real issue is your header pipe going out to the loop in the pond. You need to have a serious conversation with your installer/designer. Chances are that your high electric bills are coming from your many inefficient pumps they have in there to mask the lack of flow due to a too small header pipe. However, even then you don;t seem to get the flow your heat pump should have.

 

Doc, Maurice posted this-

From that I assume 1 1/4" HDPE to the pond which has an OD of ~1.6".

When trying to reconcile the total system Ft/Hd with R-65 HP and one flowcenter (2)UP26-116 running based on info we have so far-
* at ~10 or 11 gpm with pure water, estimated and rounded just to get us in the ball park*

07.0 Unit Ft/Hd
02.4 Unit S&R Ft/Hd 40ft 1" HDPE
12.0 Pond Loop Mains S&R 630ft 1 1/4" HDPE
07.5 HyperLoop x4 piped in series
28.9Ft/Hd Total System 10.67 GPM

HyperLoop info here-
http://tevaenergy.com/wp-content/uploads/2012/09/hyperloop_brochure_20120906_web.pdf
Pump Curve info here-
http://www.geo-flo.com/GPM Module Pump Curves1and2 .html

That head and flow is consistent with ONE UP26-116 running. You will need to confirm how the pumps are controlled and wired. And determine operation.

 

We need to confirm that he does not have 1" lines going to he loop field. O.D. for 1" pipe is 1.315, and for 1.25" pipe it is 1.66".

I would argue that with 1" lines (needs confirmation), and all the elbows, and if indeed the 4 hyper loops are piped in series (why would one do that?) (Maurice, can you confirm that the hyper loops are pipes in series, and the pressure drop of the Hyperloop (not sure how you get to 7.5ft hd total PD for the hyper loop), taken all of this in consideration, and if both flow centers running, the PD through both units are down to 2 PSI, the data is more consistent with both circulators running.

Keep in mind that the flow data for the hyper loop is at 80F water, whereas Maurice has 15% Glycol and it is 35F cold. PD will be very different
Something is severely obstructing the flow, chances are that it is the design itself, and turning on the second flow center is not pumping very much more water through the loop.

Again, I would have a sincere talk with my installer. The flow rates are outside the envelope required by the manufacturer, simply by un-evolved design. Putting more power consuming pumps there which increase the electricity consumption without increasing the flow won't help much and simply displays their lack of knowledge.

 

If I account for 15% Glycol, about 9 gpm flow and 35F degree water, the 4 hyper loops in series alone would have a PD of 28 ft/hd, but the PD data on the hyper loops is not very detailed.

Even with 1.25" header pipes, you end up at about 60 ft/hd at 9 gpm, which is exactly where pump curve is with (2) 26-116 running.

I always get suspicious when a manufacturer publishes data only at unreasonable settings, in this case 80F water PD data. That might have thrown you off.

Now if you are going up to 12 gpm total when both flow centers are running (2 PSI PD over each coil) you are up to 90 ft/hd. And that is with 15% glycol at 35F EWT. It indeed gets scary.

 

Thank you.
I will try to get them to come over and check the refrigerant. They have not been returning any of my messages...

 

I will post the numbers for the R 25 unit at stage 2 and separate numbers for the units running with valves open.

 

I will confirm the pipe sizes, and will try to get the installer to give me the exact specs on the installation, to see if the did the right calculations.
There may be an issue with the trench that the pipes are running in from the pond.
If the installer cooperates I will have him dig it out... and see if there is a pinched pipe...

 

Once I get the other problem fixed, could I replace the 32 elbows with a flex pipe?
it should give those pumps a little help...

 

One place to delete elbows is at the two flow centers where water is piped down through the pumps then back up to the incoming elevation. I would leave the lines at the elevation where they leave the flow centers.

You could use any type of pipe you like, since there is no need for geothermal pipe unless that's what you want. It will be covered in insulation again I'm sure.

From what geoxne said below, you have a pump issue to take care of first.

"That head and flow is consistent with ONE UP26-116 running. You will need to confirm how the pumps are controlled and wired. And determine operation".

 

When they first installed the systems they had wired the pumps so they ran all the time, later they returned and wired them so the would run only when the compressor is on....
So, at this time, the pumps are wired so they both run only when the compressor kick in.

 

The impact of the elbows is really not that much. Count on one elbow account as much as 3 ft of pipe. So it is like adding 100ft total. Much more of an issue is the smaller pipe (even 1.25 " pipe is too small) and the potential of having the hyper loop piped in series.
These are really the 2 main issue, besides you potentially missing some refrigerant.

Edit: you only gain about a 3% better overall pressure drop if you are going from 32 elbows to 4.
If you dig things up and bring the loops up, which is really not that much effort, you need a put in a 2" line from the house to the loop field, and make sure the loops are piped in parallel, not in series. That would bring down your pressure drop down to less than 40ft/hd and you would get 16 gpm flow. Then you put in a single central variable speed pump using 100-130 watts and a couple zone valves in the units, and you have a rockstar system.

 

Thank you Docjencer.

Once i have fixed the other issues, i will concentrate on making the system more economical, something the installers should have done...