I live in Florida close to the beach in a 2900 sq ft house that has 2 FHP Geothermal units, specifically EM028-1VTN and a EM036-1VTN.  Both units pull from the same well which appears to be an artesian well although currently there doesn't seem to be natural pressure.  I"m not that familiar with this type of well or wells in general.  Anyways, in the garage there are three pumps that draw from the well, one is a sprinkler pump I think its a 1.5hp, the EM036 is hooked up to a standard Flotec 3/4 hp jet pump, and the smaller E028 is hooked up to a 1/2hp jet pump.  The larger unit is pumped back into a separate return well and the smaller unit is pumped in what appears to be just the side yard into a mini pond.  The previous owner told me that if all three pumps kick on, the well struggles to keep up although I haven't had a chance to try this since I moved in.

So my question, is there a more efficient pump system out there besides the jet pumps?  Seems like there should be a variable speed pump with an ECM similar to all the new pool pump technology that ideally was connected to a flow meter and depending on the natural pressure of the artesian well adjusted its output.  Recently the 3/4hp pump went out so now is the time to upgrade.  My A/C repairman is telling me his pump suppliers are saying there really isn't anything out there.  From my research, it looks like they are out there but designed to be underground or in larger systems.  His recommendation is to replace it with a 1/2 hp pump.

Any help is greatly appreciated as I'm very uneducated on geothermal units.

Thanks,
Brandon

Some more information on the well itself would help out greatly. Jet pumps are not ideal for geothermal. They produce small amounts of water for the same size hp submersible pump. If you have a 3" or larger well I would abandon your current system all together and go with a Grundfos SQE constant pressure system to run the geo, and irrigation system. But first you need to have more info on the well. Diameter, depth,static water level, pumping water level, and what does (struggle) ,ean when all pumps are running?

I would consider a low pressure pump to supply the geo and then a booster for anything that needs higher pressure. Perhaps something like this:

http://towle-whitney.com/files/2_TW1000-50W-50_12T-3K_CHAIR_BOOSTER.pdf

Thanks for the replies. Unfortunately I am new to the house and have no information on the actual well itself. The owner never stated any of the specifics you mention, and he may not have known any of the specifics either as he was not the original owner and I bet the well is original to the house. I'm assuming when he said "struggle" he meant the well couldn't replenish itself quick enough when all 3 pumps were running and perhaps he saw this by sputtering sprinklers? Thats really just a guess and like I said I haven't got a chance to try this out as 1 of the 3 pumps is currently out.

It sounds like instead of working with the A/C guy, I should get someone out there that is knowledgeable about installing wells and pick their brain.

I'm in the process of deploying a somewhat similar system - 3 and 4 ton Waterfurnace splits operating off a single dedicated supply well and discharging into a return well.

My well guy briefly mentioned the SQE but backed off when he read that its lowest pressure setpoint is 40#

We'll have a dedicated submersible in the supply well (depth to water 16'), a Franklin 1/2 hp 15 GPM controlled by a Monodrive. Lowest setpoint is 25, so I'll have throttling valves at the discharge side of each heat pump.

There will be a shallow well irrigation pump sharing the return well.

Where are you in Florida?

I live in Florida close to the beach

How close are you to the beach and is the water from that well brackish at all?

I'm in Melbourne Beach, FL, about a block away from the beach maybe like 1500' away. I don't think the well has salt water intrusion in it making brackish water, but then again never really checked.

Posted By engineer on 20 Jun 2012 09:56 AM We'll have a dedicated submersible in the supply well (depth to water 16'), a Franklin 1/2 hp 15 GPM controlled by a Monodrive.

What model Franklin pump? The "SH_SeriesV" appears to only produce 7gpm at the far end of it's pump curve...See http://www.franklin-electric.com/media/documents/SH_SeriesV.pdf for the perf curve.

I am reviewing my own shallow pump choice and am interested.

A grundfos SQE controller can easily be fooled into delivering whatever pressure you want. A $1.99 variable resister from Radio Shack dropped in parallel across the transducer can adjust pressure to 0 psi with the stock transducer. Or, just use a transducer with a different range. You can even get into vacuum if you'd like with a compound transducer.

I wouldn't get hung up on the psi to much. We have been installing these pumps on open loops for a few years now with no issues set at 40 psi. We Also have them on open loops that are combinations wells with the house supply too and the homeowners have them set at 60 psi. IMHO The flow is way more important them the psi!

A properly sized pump running at the lowest possible pressures will use significantly less power than a pump running at 40psi. Case in point - I've got an SQE pumping 7 GPM when the geo is running. My water table is at 100 feet. At the pressures I operate the pump is drawing less than 1 amp. When I take a shower in the morning (geo not running) I'm using only 1.6 GPM but at 45 psi -- the same pump draws 3.2 amps.

We are not trying to split hairs here,are we? The post was asking about a "more efficient" system then his current jet pumps set-up. I agree that the right sized will save the most energy. IMHO the SQE is taylormade for geothermal heat pumps .

Posted By Blake Clark on 20 Jun 2012 08:28 PM
the pump is drawing less than 1 amp.

Is that @ 220?

I'll let the OP and other readers determine if an 80% reduction in pumping energy by lowering pressures is "splitting hairs". Not for me to make the call. Your post seemed to indicate that pressure did not have a significant impact on pumping energy. Just want to get the facts straight.

Properly sized pump at lower pressures = lower pumping energy. Variable speed by itself without reducing pressure = questionable energy savings. Any of the above vs jet pump - a major improvement.

Your talking about 80% but it's still less than 1 amp. I'm not disagreeing with, just saying a would not be turned away from an SQE if my current set up is a jet pump.

I agree with always using as little pressure as possible and avoid throttling to save energy. Variable speed pumps do OK but every pump has a peak efficiency point and so multiple pumps will outperform single pumps when trying to cover a wide range of pressures and/or flows.

If I pump 7 GPM at 40 PSI the pump draws 5 amps. When I pump 7 GPM at low pressure it draws 1 amp. That's a savings of 4 amps - 80%. In context, in stage one cooling my compressor uses less than 5 amps. If I pumped at 40 psi, my pump would be drawing more than my compressor.

Truly, I'm not in this to win a game of semantics. There are very real and significant efficiency gains to be made by lowering open-system pumping pressures.

A variable speed pump rated at 10 GPM at 240 feet head will pump 7 GPM at 117 feet head using 1/3 the power. This is one example where varying flows and pressures are best served with a single pump. Peak efficiency for single speed pumps is a single point, but for variable speed pumps "peak" efficiency is a curve and all points along that curve are more or less equally efficient. (That curve, by the way, looks nothing like the big "shaded area" in variable speed marketing material - that's just hype)

This is also how one can have cake and eat it too with an open system. 10 GPM @ 240 feet to feed the house when needed, and 7 GPM @ 117 feet to feed the geo most of the time. Different installs call for different specs, but the approach would be the same. Trouble is, no one makes a control system that makes it easy for installers to set it up this way, which is why no one does it.

all points along that curve are more or less equally efficient.

Once you get down to ~1/4 of max flow, efficiency drops way off.

At 1/4 max flow, the head on the pump curve would be 1/16 (square of the reduction in flow) which would be an impractical reduction in head for most applications. So, yes, I totally agree there are limits to what you can expect out of a variable speed pump. Pump selection is still hugely important. You can't just stick the biggest pump you can fit down the hole and expect variable speed to make up for poor design.