Need help with ESES DX installation

[BostonGuy]

Hi,
We installed a geothermal DX system last fall from Earth Source Energy Solutions. They purchased the patents for their design from American Geothermal and is very similar to their model.

Since installation, the heat pump is producing proper temperatures both to and from the field (the field is 12 vertical copper loops - each 65 feet down - arranged in a checkerboard pattern).

The issue is that our electric bills to run the heat pump have been extremely high - on the order of $650 per month during the coldest months. The unit draws about 37 amps during normal operation - the system is a 5-ton unit. We have an electricity meter connected directly to the heat pump so we know exactly how much electricity the unit is drawing. The Earth Source engineers are having a hard time determining what is wrong with the system. We replaced the air handler with a slightly larger unit (5.5 ton) as it was thought the coil was too small and thus a constraint on the system. The larger coil did relieve some pressure but did not reduce electricity usage at all in the heat pump.

Our house is a 3000 sq ft old victorian-style with 3 floors and a basement. Each floor is a separate zone with no heating in the basement.

If anyone has experience with the Earth Source geothermal DX heat pumps or with the American Geothermal heat pumps, please contact me. We would like to resolve our electricity usage issues before next winter!

[engineer]

37 amps sounds high for 5 tons.

[geo fan]

37 is very high
I would expect for combined 26 max for AH and compressor
what is the temp across the coil
Does your return grill make any noise
What size is the return
Do you have a variable speed fan motor
How many pounds of refrigerent are in there
What is the superheat of the vapor line in heat mode
Where are you located ( climate wise )
what do you pay per KWH
and how many KW is the system using in an hour
VS what the amp draw and voltage are

My thinking is 3 fold
Poor duct design specificly undersized return ( which a larger variable speed motor would not fix ) or an over charged unit / non condensibles
or your in NY pay a huge amount for electric and have a lousy PF

[geo fan]

how many zones and where are you dumping the air if it is zoned

[Mark Custis]

a 5-ton water to water geo on a radiant floor and with all three circ pumps running it draws 16.4 amps at 243 VAC. Something is not correct. I have no idea what the DX guys use for metering devices in the loops.

[geo fan]

AXV is the most common
a float style metering device ( similiar to very old school commericial refrigeration units ) in the accumulator are often used as well ( dont require the head that TXV's do to operate normally

Amp draw will range depending on type of compressor , ground temp , air or water temp , system charge, and equipment power factor . which is why I stated what I would veiw as a max . In short I to beleive there is a problem . maybe its short looped

[Mark Custis]

home made. IF I went to DX I would have a TXV on the incoming suction line, and would meter out liquid refrigerant to the loop field. I would have a distributor that could be serviced in the building. I could not google AXV. Even if I added R-11.

This is starting to sound like so much Ju-Ju to me.

Prove me wrong.

Short looped on DX is impossible by definition, the guy has 12 loops at 65feet deep times 2, (up and down equals 2) that is 1,560 feet of copper before we get into the near unit piping.

With that said, being an air head first, he may have other issues. DX or water, this forum lacks folks that know flow.

[BostonGuy]

We are located in Brookline, MA - we pay 12.7 cents generation charge and 6.7 cents delivery charge per kWh.

In March we used 3229 kWh of electricity over 31 days. Average daily usage of 104.1 kWh. Average temperature in March was 32 degrees F.

I'll have the system engineer upload some temperature data on Monday.

Thanks for all the input and ideas so far!

[Mark Custis]

is a person that comes back to see what we think.

Thanks that keeps me coming here.

More Input is needed.

[geo fan]

is 3229 the whole house or just the unit?