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Posted by dcaster@krl.org on February 11, 2009, 7:40 am
wrote:
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> If you've got decent flow & a temp lower than 50dF you should get some
> decent cooling.
> Warmer temps & slower flow, well... you'll figure it out.
> Above 50dF you won't get much & no real dehumidification...
> geothermaljones
55 dF is the ground temperature so the spring water should be close to
that. My estimate of the flow is a couple of gallons a minute, but I
really need to make a small weir to get a number I really believe in.
The weather has not encouraged playing in the water.
I also need to find where to get a heat exchanger designed for chilled
water.
Dan
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Posted by geothermaljones on February 13, 2009, 9:19 am
2 gpm of 55 dF water isn't much, Most mfgrs will give about 1/2-3/4 tons
w/that flow.
If it's "artesian" & bubbling up on it's own, I wouldn't trust it anyhow,
Odds are (& w/my luck) as soon as I connected to it, It'd run dry...
You really need a pump to induce flow.
geothermaljones
show/hide quoted text
> wrote:
>> If you've got decent flow & a temp lower than 50dF you should get some
>> decent cooling.
>> Warmer temps & slower flow, well... you'll figure it out.
>> Above 50dF you won't get much & no real dehumidification...
>> geothermaljones
> 55 dF is the ground temperature so the spring water should be close to
> that. My estimate of the flow is a couple of gallons a minute, but I
> really need to make a small weir to get a number I really believe in.
> The weather has not encouraged playing in the water.
> I also need to find where to get a heat exchanger designed for chilled
> water.
> Dan
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Posted by Bipolar Bear on February 13, 2009, 1:24 am
> I can see how a controlled freeze could "descale" some of the mineral
build
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> up...
> You & I might give it a try (on our own systems?) but I'd be nervous to
> suggest it to others.
Bingo.
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> What kind of prefiltration do you have in the feeder line?
None except I sometimes use rope if theres a lot of reddish iron in the
domestic end of things.
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> I mentioned the variable speed pump simply because it can save a good 25%
> (or more) in electric consumption.
That's a blanket statement--any domestic sys with std bladder tank can do
the same thing...all that's needed here now is to modulate flow rate based
on LWT and taking into consideration the initial extraction costs.
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> I'm wanting to swap one in soon on my own place, as I've got a 2'rnd +3'
> tall pressure tank in my mech room,
> with a variable speed pump, I'll have a "shoe box" sized unit wall
mounted,
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> leaving more room for my buffer tank...
Place a klixon at the outlet let out water from the tank closed sys only
where the outlet temp is very near freezing.
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> I've seen the lawn sprinkler valves used allot.
It works.
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> I've got a buddy that threw a chilled water coil on his uncles "summer
> cabin" furnace.
Water in my area is appx 51 deg
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> He runs the well water through it when it gets hot, has a sprinkler system
> in the yard...
> Cabin cool, grass watered, kids soaked & happy.
> Of course here in MN (especially the northern regions) our summer cooling
> hours can be around 250 or so.
I think he was looking for actual manufacturer data and to be specific about
water coils--though it's outside of my field of experience this MFG seems to
come up pretty often :
http://www.firstco.com/
Suggest he root around on that site awhile use keywords search some more if
needed usually a few new or used units on ebay if he feels like compiling
empirical data.
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Posted by geothermaljones on February 13, 2009, 9:44 am
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>> I mentioned the variable speed pump simply because it can save a good 25%
>> (or more) in electric consumption.
> That's a blanket statement--any domestic sys with std bladder tank can do
> the same thing...all that's needed here now is to modulate flow rate based
> on LWT and taking into consideration the initial extraction costs.
When I had the well drilled it was sized for the geo as well as domestic,
w/larger casing & pump.
Variable speed pumps were just hitting the street & my installer wasn't
anxious to experiment.
The start & stop of a larger single speed pump via a pressure tank uses a
lot more electricity compared to a variable speed pump that ramps up & down
maintaining proper flow for either geo, domestic, or both.
When targeting flow rates, I try to get 4 gpm or a delta T across the HP of
15dF...
Newer units will rate themselves w/3gpm or even less. I find these rated too
low to trust.
P&D systems often need higher flow rates to avoid LWT dropping below the
(40dF) "freezestat" that locks out the unit.
geothermaljones
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Posted by Bipolar Bear on February 18, 2009, 12:44 am
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> >> I mentioned the variable speed pump simply because it can save a good
25%
show/hide quoted text
> >> (or more) in electric consumption.
> > That's a blanket statement--any domestic sys with std bladder tank can
> > the same thing...all that's needed here now is to modulate flow rate
based
show/hide quoted text
> > on LWT and taking into consideration the initial extraction costs.
> When I had the well drilled it was sized for the geo as well as domestic,
> w/larger casing & pump.
> Variable speed pumps were just hitting the street & my installer wasn't
> anxious to experiment.
Here there is a 300 gal existing tank with the old school float type air
volume control, a 3hp pump the pressure switch setpoints were changed to
cut-in at 40 psi and out at 80
Even at a 15 gpm flow rat the pump doesnt cycle off but but perhaps once per
hour, not a huge drain the sratup inrush IMO
In order to maintain a more constant pressure at the residence, an
additional bladder tank was added having whatever its a flotec about 3 ft x
5 I magine its gives 35 gals reserve for showers toilets etc and is
isolated via check valve from the mains supply--this tends to re-fill at the
end of the main pressure cycle and thus a pressure of ~ 80 psi is maintained
on the domestic side unless someone is wshing a car or some shit.
Hey it works, what can I say.
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> The start & stop of a larger single speed pump via a pressure tank uses a
> lot more electricity compared to a variable speed pump that ramps up &
down
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> maintaining proper flow for either geo, domestic, or both.
See above.
Would be nice I agree but lots can be done on the fly depending on what you
already have--increasing cutin/out differential and adding a second bladder
and check vlve for instance.
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> When targeting flow rates, I try to get 4 gpm or a delta T across the HP
> 15dF...
Not sure you may be typing too fast, delta of 10 to 15 is a good ballpark,
but to rate in gpm then your actual tonnage comes to the forefront.
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> Newer units will rate themselves w/3gpm or even less. I find these rated
too
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> low to trust.
Let me know HERE and Ill send you a private--this is all fairly simple
math--impossible to more heat than exists in the mass flow a basic review is
always good.
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> P&D systems often need higher flow rates to avoid LWT dropping below the
> (40dF) "freezestat" that locks out the unit.
I think the clixon is usually at 38 /40 so yes--AND if the controls need
breaker or stat Y disco then it can indeed be troublesome.
Closed loop is a different aminal, you have a mix that doesnt suddenly turn
hard, a slush that undergoes "glass transition" instead --with glycols
generally at ~ 40~60 % IIRC theres charts and those temps are like -50 deg
dunno ask an ice road trucker.
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> decent cooling.
> Warmer temps & slower flow, well... you'll figure it out.
> Above 50dF you won't get much & no real dehumidification...
> geothermaljones