In another thread, Dewayne asked a few questions, including:

"Do you have a leak in your system?  Most likely yes,  or the pressure would stay constant." 

"What are you doing to keep the antifreeze  at the proper solution?"

and "Or are you in a warm climate with no need for antifreeze?"

To avoid hijacking the thread (Does Geothermal Make Sense for Seasonal Home), I thought I'd start a new thread to respond to Dewayne's comments/questions.  Here's the new posting.

No, I don't believe I have a leak in my system.  Absent any kind of pressure adjustment system, I don't believe my static loop pressure would stay constant.  Instead, pressure would vary as a function of earth temperature, due to expansion and contraction of the pipe.  I have almost one mile of pipe (HDPE) in my front yard.

I do have a pressure adjustment system illustrated by the below photo.  Domestic city water, at about 60 psi, is connected to my loop once per day, via a timer controlled control valve.

Since I live in Dallas, I not only don't have antifreeze, I don't even have backup/emergency heating coils in my GSHP units - my (minimal) heat needs for Winter season are easily satisfied with the GSHP units I have.

Hope this helps to explain.

Best regards,

Bill

Bill,

I checked out the photos of your job.  They sure made a mess of your front yard.

Glad to hear your system is up and working.  Does the performance meet your expectations?

I am curious why you went to the trouble of the pressure reset system.

Did someone recommend this? 

Not that there is anything wrong with what you have done,  it is not something that is normally installed.  At least in our area.

I have 6000 feet of slinky pipe buried in my yard.  It has been there for four years.  My pressure fluctuates seasonally  between 35 and 40 psi.

System pressure has nothing to do with unit performance as long as there is some pressure.

Again just curious not being critical.

I am quite impressed with your monitoring system.  I hope to do something like that on my unit if business will slow down a little.

I was wondering how geo systems' waterside pressure varies summer and winter - Everything is hotter in summer, so a totally closed loop system's pressure should rise. If the pipe stretches a bit to accommodate this and then contracts during winter, then all should be well.

I agree that so long as system pressure remains high enough to deter formation of air pockets, all should be well whether it is 20 or 60.

Yep, the well hole drillers unexpectedly hit a lot of water.  And in TX, there are considerable laws for what can go down storm sewers, so a lot of effort ended up being expended to keep the mud on the property.  Drilling company was outstandingly competent.  Even so, due to the challenges, it took a week to drill 8 holes 300' deep each.

Images of the project are here: http://www.pbase.com/neukranz/gshpinstall - separated into equipment installation, water loop installation, monitoring, preinstallation, and misc.

My lot is 1/2 acre.  I learned that it's tough to have geothermal HVAC here in my city with a lot much smaller.  I have many friends and associates who certainly wish to invest into geothermal but just don't have enough space to sink the wells.  Those of you with enough land to put in a less expensive horizontal loop are particularly fortunate.

My GSHP installation's performance exceeds my expectations.  My monitoring system, along with some side manual calculations, allows me to periodically check COP and EER.  I did not have difficulty exceeding 5.0+ COP when in heat mode this past winter for my 3 ton WaterFurnace Envision unit, and likewise around 4.5 COP for my 5 ton unit.  Right now I'm not having difficulty getting about 25 EER in cooling mode for my 3 ton unit, and right around 19 or so for my 5 ton unit.  Looking at WF's specs, I'm right in the ballpark, getting the performance they advertise.  And, I have good enough instrumentation such that I have some confidence in my quantitatively arrived at performance numbers.

I used to have COP and EER real-time on my monitoring web page ( http://welserver.com/WEL0043/ ), but ended up concluding I couldn't accurately represent the numbers real-time.  I would need to install another KWH monitor, and figure out how to measure air flow real-time - neither of which I want to invest effort into.

My conclusion, after having geothermal HVAC for 12 months now, is that it's 'the real deal.'  If you can get an accurate Man J, get competent designs for the water loop and air distribution system (Man D), find a very competent HVAC pro who delivers on the installation, and can 'stomach' the up-front cost, geothermal HVAC is phenomenal. 

Unfortunately, each of these items is tough to find in my location, Dallas - the weather's so hot that there's too much HVAC business to be had.  And thus the Dallas area HVAC industry, in general, doesn't have to work hard to make money (I know there are exceptions but they're very hard to find).  And worse yet, the 'bargain basement' 'cut-throat' pricing here 'squeezes out' the really competent pros who don't already have a long track record.

The WaterFurance manufactured equipment I own, as noted above, is working fantastic.  My only disappointment, equipment-wise, is WF's IntelliZone zoning panel.  It's features are few and not advanced.

The water loop pressure management system I have simply came with the installation.  I didn't know, in advance, that I was getting it.  In fact, I haven't bothered to calculate the amount of pipe expansion/contraction caused static pressure change across an entire year - it may indeed be perhaps no more than yours.

I don't know if it's a downside, but I do note that my loop static pressure is up around 60 psi, which is higher than most loops, I understand.

The monitoring system ( http://www.welserver.com/ ) was easy to install.  And given the ease and time savings, well worth the investment.  It's an Internet Appliance that comes in about the size of a deck of cards.  Hook up power to it, an ethernet cable, a few 1-wire technology temp sensors, make a few configuration updates, and within about a couple of hours of time your system too is on the WWW, for anyone to see.  No mess, no fuss with web servers or any of the 'geeky' stuff - save your time to concentrate on setting up an implementation that helps you understand where the (in)efficiencies are and give yourself the data you need to implement decisions / change.

You can a worldwide map of many WEL installations here: http://welserver.com/ww/ .  Lots of ideas on how to save money and be more respectful of our scarce natural resources.  I'm just noticing now that a new entry is on the map, in Ohio, of an individual's DIY geothermal installation's performance.  Might be something useful for jerryg to check out.

Best regards,

Bill