My Heat Pump will use either a drilled vertical closed loop, or a semi-open loop (Standing Water Column design) off my water well in Southern New Hampshire.  I'm curious to hear about how other folk's loops are working in New England or similar northern climates.

What loop temps do you see in cold winter conditions?  What type of loop do you have and how many feet of loop per ton?

thanks for any info!

Here is some reference info that may be helpful.

At this location: http://welserver.com/ww/ you'll see a WW map showing locations of people who have information online about their heating and cooling.  Zoom in to the New England states and you'll see:

A NJ GSHP installation: http://welserver.com/WEL0082/ (72° EWT at the moment)
A Maryland WaterFurnace closed loop vertical installation: http://welserver.com/WEL1000/ (66° EWT)
Another Maryland WaterFurnace open source installation: http://welserver.com/WEL0036/ (66° EWT)
A Virginia non-presurized closed loop installation: http://welserver.com/WEL0058/ (78° EWT)
A Montreal Canada GSHP installation: http://welserver.com/WEL0068/ (? EWT)
A Nova Scotia GSHP installation: http://welserver.com/WEL0080/ ( 72° EWT)

(I'm at http://welserver.com/WEL0043/ but my location, Dallas, with our 100+° days right now, isn't in your subject area of interest!)

Best regards,

Bill

thanks Bill, these WEL dataloggers are nice! 

I gotta put it on my to-do list to log back in around Christmastime to watch the temps...and on my Christmaslist to get one of them temp loggers!

My EWT hit a low of 59°F this past Winter.  I don't have anti-freeze, nor do I have backup/emergency heating coils.  My attic, where my GSHP units and pumps are, only got down to 32° once this past Winter.  With my cooling-dominated climate, hitting heating COPs of 5 or greater is not difficult.  My WaterFurnace units are working great.

Best regards,

Bill

 

thanks Bill, sounds like you'll have no trouble heating with that 59 deg water!

I know it's not the most popular type of ground loop, but what exactly are your biggest goals in doing the SCW loop instead of a more conventional loop?

What I'm learning is the standing column wells are fairly popular in Northern New England because the bedrock is so close to surface, often 10' or less.  The rock provides a decent heat exchange surface and high static water levels provide the transfer media.  The real draw is that since we already have a deep well for drinking water, the existing well can do double duty.  We may or may not have to have it drilled a little deeper, and we may or may not have to upsize the pump.  So, if done correctly we already have most of our loop system in place, making a geo heat pump installation much more affordable.

There are many people with these 300 - 450' wells in my neck of the woods, so the potential for less expensive geo installs in the North country is real.  Will let you all know what we wind up doing!

A variant of SCW is SCW with bleed. If well conditions depart from specified limits (too hot or cold) some water is bled off. I've seen data online of bleeds up to 15%. Essentially such a system has elements of both closed and open loop.

w/ Bleed - Exactly Engineer!  A fairly simple temperature control can monitor EWT and when it goes below (in heat season) the desired low limit  - maybe 40 deg or so -  dump some % of water that would have otherwise been returned to the well, until EWT comes back up above 42 deg or so.  
 
Building in this ability can "save" an otherwise undersized well.  

For  purely practical reasons (cheap, cheap, cheap) - we're thinking about using our well as is, without additional drilling, for the first season, with bleed, and review the results afterwards to decide if we should do additional drilling.

One more note, because we use the well for our domestic water supply, there is a built in bleed, every day, a win-win...

The daily bleed owing to domestic use is part of the appeal. You might notice that during summer you no longer get a cool glass of water from a sink. OTOH, domestic water heating cost should drop during cooling season as incoming well water is warmer. The opposite will be true in winter.

Do consider getting your water tested to be sure it is compatible with heat exchangers. WF manual for Envision is on their public website and lists allowed range of many water parameters. Their numbers are likely good for any system with similarly-constructed heat exchangers.

Let us know how this works out

thanks Engineer!

When you think about heating hot water, EWT of 40 - 50 degs does make you think some simple, low temp solar assist to preheat to 80 degs or so would be helpful.  Also preheat the loop in the heat mode, you can see some low-tech approaches are worth looking at.

Water Quality.  You will recall we were talking about a possible plate and frame heat exchanger if needed.  This is my fallback position.  One "old hand" I spoke with said the iron in my water - while above the water furnace spec - might not be a problem.  He said, at least on some of the coaxial water to refrig heat exchangers, there is a lot of flexing of the copper as the refrig temp goes from cold to something like 180 deg. and iron tends to flake off.  This is still a question in my mind but I am a little more optimistic now.

Will keep you posted on what happens here!

thanks for the interest and input.

Solar thermal has its place. Gotta evaluate its first cost, additional mechanical complexity (cold weather installs need to be especially wary of freezing conditions), roof penetrations, roof weight loading, roof wind loading, etc.