jpespisa,
The best solution would be to reduce pump pressure. The noise you and I hear, is wasted pump energy. Reducing pump/system pressure is easy to do if have a constant pressure variable speed well setup... and if you are okay with lower domestic pressure.
Otherwise you could add another valve or 2 downstream of the "flow valve(s)", to spread the pressure drop over more valves.
Finally, if the previous 2 don't work ... or if you just want it quiter yet... you can insulate the mechanical room(or where-ever the noisy valve is) from the rest of the house. This type of sound coming from the water flow control is most likely higher frequency and should be much easier to attenuate with cheap insulation... compared to lower frequency drone of a loud compressor. I guess I'm assuming that there are no hard connections between the noisy valve and the rest of your house plumbing as the plumbing (if copper) would tend to transmit the noise throughtout the house and could even amplify it in just the right conditions.

For me... I have several valves in my open loop stream. One near the well where the hard water splits direction and heads towards the geo and south yard spigots. One right after the T feeding the geo unit. One right before and one right after the boiler drains (to allow isolation during cleaning) and one just before the flow control ball valves that in the future should allow me to direct leaving water during cooling to another water-to-water heat pump unit for heating my domestic water during the summer. Between all these valves and with enough "experimentation" (my wife calls this fooling around)... I can usually find a combination of valve positions that result in quiet operation. However it takes a bit to ballance the 1stage and 2nd stage as you have to check both flows after you make each change to ensure you didn't just make the other stage flow louder !!

I did find out by accident that valves placed downstream of the flow regulation device (in my case ball valves) are much more effective at reducing noise. With all upstream valves wide open, one ball valve located downstream from the flow valve had almost the same effect as all 4 or 5 upstream ones at optimal position! One caution with all these valves, crossovers, and bypas options plumbed in it starts looking like a refinery "christmas tree"... which is cool to have in your basement if your a geo geek..... but you have to be careful when you are making adjustement that when you leave... you still get water flow through the unit next time the thermostat calls for heating or cooling !

If you look at the kW usage across the range of flow 4.5 to 9 gpm, and compare that  to the pump energy I think your going to find that your pump energy is going to be lots more....  For example at 50 EWT, @ 4.5 gpm unit kW in heating is 2.49 @ 9.0 gpm its 2.56.... thats a difference of only 70 watts.  

 

If you have a bit of time you can watch use your electric meter to figure this out.  All you need is a stop watch or digital camera with video function....

1.  Turn off breakers or unplug items like freezers/frigerators, dehumidifiers, etc..

2.  Make sure any lights that are on stay on throughout the course of the "experiment". (Make sure noone starts are stops anything during your test... it works best when everyone is sleeping or gone).

3.  Go out to the meter and time with watch or take video of 10 revolutions of the meter.  (if you want best accuracy you can do it 3 different times, or time 20 or 30 revolutions).  This is your "baseline" time.

4.  Use your heat pump plumbing (possibly manually overide a control valve) to get a specified water flow coming up your well and through your unit.  Ensure the unit itself isn't on if your just looking to determine pump power.

5.  Go back out and record time it takes for 10 revolutions of your meter. 

6.  Change your flow to your second point (ie 9 gpm).

7.  Go back out and record time it takes for 10 revolutions of your meter.

8.  Repeat steps 6 and 7, for as many different flow rates as you want.

9.  Look up the multiplier printed on your meter.  This allows you to convert revolutions to kWH's.  Then you use your time for 10 revolutions to get the power consumption in kW or watts.  The difference between your baseline and other operating points will be the pump power.  You can apply this to process to anything in your house, however for smaller 115 volt items that have a plug... you can't beat a $25 Kill-a-Watt meter (look up in google). 

You might be suprised what you find out. 

Reducing my flow from 6 gpm to 4.5 (min at second stage), I was able to save ~ 130 watts in pump power while the unit draws only about ~35 or 40 more watts due to the reduced flow.  So net savings of almost 100 watts just by making a slight adjustment.  I guess you might say on an open system, the ball valves can pay for themselves !

jpespisa

With a 6 ton unit running on 1st stage (67%) capacity is about 4 tons. 4tons x 2gpm=8gpm for 1st stage. At 10 gpm for first stage you are running 2.5 gpm per ton for 1st stage.

The only risk to lower flow rates at lower EWT's on open loop systems is lowering the LWT to a point where the water will freeze in the coil. The ClimateMaster Tranquility 27 has a sensor on the refrigerant line that will lockout the compressor when that sensor hits 30F in setups for open loop. If it is operating properly the unit will shutdown before any freeze damage occurs. Generally you would not want your LWT (Leaving Water Temp) to drop much below 40F in a system without antifreeze to avoid nuisance lockouts.

My TTV038 catalog says leaving water temperature sensor will trip unit if LWT goes below 40. It says... that below this point there is a potential that refrigerant temperature would be 32 or lower and cause freezing. If you have glycol open loop you can cut a jumper and unit won't trip until something quite a bit colder... 30 or 35 degress.

Experienced installers can better comment on this, but I would be cautious when turning back flow and not blindly rely on unit tripping out before it frosts. I'm thinking a burst coax will not be cheap to replace.

Just wanted to report in on my general experience after changing the CPM to 1...

The outside temperature has dropped into the low teens. While this is a variable I can not control, it is probably a good way to see if the house stays comfortable with a CPM of 1. The answer is... yes, the house stays perfectly comfortable varying less than 1 degree between cycles (remember, my house is superinsulated, so your mileage may vary). We also - appear - to be making more hot water with the longer run times. No real data yet, but the pipe leaving the desuperheater feels significantly warmer than usual.

Ed
www.GouinGreen.com

Jokin

Thanks for the tips. I’ll experiment with the noise issue once I install the second solenoid valve.

I’m starting to get concerned with the LWT statements. With the low outside temperature today, my LWT in consistently in the mid to high 30’s. Especially when second stage kicks in. I really need to get the second solenoid valve installed to increase the gpm during second stage.

Should I be concerned with the LWT this low? It will gradually recover as the outside temps increase. I can increase the bleed rate again. Currently bleed at 2gpm.

http://welserver.com/WEL0167/

jpespisa

I not sure that you understand the math that I have done 3 times in previous posts on this thread. If your running 2nd stage you need 6 tons x 2gpm =12gpm total flow. 1st stage needs 4tons x 2gpm = 8gpm. LWT should be monitored so as not to drop much below 40F.

If you do not have the controls and solenoid valves in place you must flow 12 gpm until you do in case it does jump to second stage.

Jokin

I believe older model ClimateMasters monitored LWT temp. The newer and current models monitor water coil refrigerant temp, they say it is a better indication of freeze potential.

Sorry G.O. Joe,

I do understand your math. My concern is a am already running at 12gpm and my LWT is in the high 30's. Should I be concerned?

jpespisa - To keep your source water constant temperature and allow lower flow(reduced pump power), You could explore another discharge method. You could discharge your water to a nearby body of water (drainage ditch, stream, pond, or lake), drywell, or drainfield. I had a separate drainfield put in when they did my septic drainfield. It was ~$650, and has worked great so far.

jpespisa

I'm sorry if I misunderstood. You said in a previous post you changed it to 10 gpm.

LWT in the high 30's is fine.  You have to make sure that EWT doesn't start going down hill because of it, further degrading your LWT. A SCW is not adjustable. It will only allow so many BTU's/hr to be extracted. If the SCW can not keep up with the HP a bleed is introduced to bring in more ground temp water.

It doesn't matter to the well if you pump 18gpm of 6F delta t water or 12gpm of 9F delta t water it is the same amount of btu's/hr extracted.

The main point here is - there is a balance point between supplying enough flow to make the HP efficient and paying to much to over pump water (either flow to HP or bleed). Each SCW has it's own characteristics. The figures I gave you are a good starting point. The feed back from that will tell us which way to go. Not counting any bleed issues you may have, for example, if you can save pumping 2 gpm less to the HP by adding 1gpm to the bleed you've gained.

Unless someone has removed safety devices the hp will lockout be for any damage happens. Then you will know if you have gone to far.

jokin - I did have a dry well installed. It's a 1000 gallon perforated cement vault buried in the ground surrounded by crushed stone. There is a 4" overflow tube exiting from vault that drains into a small wooded area in my front yard. One of the concerns the well contactor mentioned was the possibility that bleeding water might end up flooding the street. The dry well/vault is ~70 feet from the street. I live on a hill so there is a gradual downward slope from the dry well to the street. So this issue is sitting in the back of my mind as I calculate bleed rates.

The real solution to this issue is to add a couple hundred feet to well. But the well contractor and I decided last spring to give the well a try at its current depth and hopefully bleed enough water to maintain the well temp. That’s why I’m following my EWT/LWT very closely.

I guess I’ll keep increasing the bleed rate to bring up the well temp on these extremely cold dates. The 2gpm bleed rate works fine with moderate outdoor temps. I have never observed water exiting the dry well overflow pipe. Maybe I’m making a mountain over a mole hill and should just wait and see what happens.

G.O. Joe

I really appreciate the feedback. I should have mentioned I changed the flow rate to 12gpm as I got nervous with the cold temps coming and didn’t want to take a chance at 10gpm.

It’s good to know the high 30’s are OK as my LWT has been in the high 30’s off and on for a couple weeks now. Typically in the morning when outside temps are the coldest.

As you stated, finding the balance point is the challenge. Especially with the number of variables involved. I’m checking the data logger constantly monitoring the HP as I make adjustments. Hopefully I’ll find that balance point over the next couple of months.

Desuperheater Update...

I wanted to let everyone know that changing the thermostat cycles per hour (CPH) from “3” to “1” has had a positive impact on hot water production from the desuperheater. Previously, the best we had ever gotten was ~90F water in the tank. This morning the tank storing water heated by the desuperheater is at 105F.
So, if our groundwater is coming in at 47F and we heated it to 105F, how much energy did we essentially get for “free”?

A BTU is defined as the amount of energy required to raise one pound of water by 1 degree F. One gallon of water weighs 8.3454 pounds. The desuperheater raised 50 gallons of water (417.27 lbs) by 58 degrees F. Therefore: 417.27lbs x 58F = 24,201 BTUs. Since one gallon of propane (which is what we would otherwise have to use to heat our hot water) contains 92,000 BTUs, and our burner is 94% efficient (we only get 86,480 BTUs per gallon) we avoided burning (at least) 0.28 gallons of propane to heat this water.

I say, at least, because we have also had our normal usage during that time period… laundry, bathing, dishes, etc., and we still have more hot water in storage. Neat.

Ed
www.GouinGreen.com

Ed, good to hear you are observing better HWG results. I’m also very happy the CPH change. My 80g electric water tank reaches ~105*F overnight. I’m sure my HP runs longer overnight then yours as my house is not super insulated. I almost didn’t install the HWG as I’m exceeding the specifications of the Climatemaster HP. Unfortunately my HP is at one end of my basement and the water heater on the other. The manual warns not to exceed a one way length of 50’. I haven’t measured the length of pipe but it’s closer to 70’. Anyway the fact that it’s working is a pleasant surprise.

Hearing all this, I'm going to reduce the on time on our water heater timer.

Ed, for fun, extend your propane savings by your heating days and multiply by your propane cost for season savings!

I don't think I can come up with a meaningful number for the hot water just yet. The other day it was 8F outside, but it was bright and sunny. We made 120F water with the solar HW system (and passively heated our house to 71F BTW). If it was cloudy, we would have made nothing and the heat pumps would have ran. I do not get propane delivered regularly, so I have to wait and see.

This is our first winter in the house. If anyone cares to compare, we condition 5,257 ft2 (3,845 ft2 living space, 1,412 ft2 storage space). The internal temperate is always 69F (or above) in winter. Our family consists of 2 adults and 3 kids (plus 5 dogs and 4 cats). We used 1,870 kWh from 11/12/09 - 12/14/09. We cook with electric. We use an electric dryer. Basically, everything is electric except hot water, which is finished off to 130F by an on-demand propane unit.

Ed