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[intensedrive]

Has anyone tried modifying the water to air exchanger in their plenum to cool.  Running 60 degree well water through the exchanger would probably work, you would need a discharge area for the water.  Also, when the house calls for cooling it would need a mechanism to turn the water on.

[mlappin]

Basically in a nutshell and it depends where you live, but no.

If you check a AC system in a car, home or cooler, the cold side is a LOT colder than 60 degrees.

It may help some, but here today for example it was 94 but felt like 103 because of the humidity.

The cold side of the evaporator will have ice on it nd could barely keep up, 60 degree water ain’t gone make ice.

Don’t get me wrong, it might help, but when it gets dangerous hot to where old people might be dying in their homes, it aint gonna help enough.

AC does two things whether it be car, tractor or house, and it always does it in this order, first it removes humidity, then it lowers temperature. 60 degree water ain’t gone remove humidity like an evaporator that has ice on it.

[RSI]

If it has ice on it then it is low on freon or not enough airflow.

[RSI]

It would take more water than it was worth and condensation probably wouldn't drop off in a desirable place. After you figure in the cost of running the well pump, you will probably be paying more than running an air conditioner.
If you were running the water for another purpose anyway then I would try it and find a way to catch the condensation.

[greasemonkoid]

Perhaps a smart individual on here could do some math and determine how many gpm it would take at 60 degrees to equal a...  2 ton AC unit, and the the size and cfm of a heat exchanger to achieve the same task. Curious to see what the numbers would look like.

My dehumidifier runs constant in the summer season, if humidity is over 50% that thing is running. The AC pulls a lot out, but it also drops the temperature in turn raising the RH%. Mold is not welcome here. I spent 3 hard years of my life and thousands of dollars ripping down drywall, carpet, trashing wooden furniture, ect.

[mlappin]

If it has ice on it then it is low on freon or not enough airflow.

Sorry for the confusion on that, tractors commonly have ice on the line from the expansion valve to where it enters the evaporator. Zero airflow on the part of the system if all gaskets are in place.

[shepherd boy]

 I'm not very smart but a little common sense on how an ac unit works will tell you that 60 degree water will never match your ac unit no matter on gpm. You could only drop your air temp about 5 degrees going across the coil and that's not going to lower the humidity. You need to get your air temp below the dew point to draw out the humidity. Air out of the ac unit is going to be under 40 degrees, this means the freon is considerably colder. Stop the airflow and you freeze quick. For cooling to equal your 2ton unit with 60 degree water, you would need about 7000 cfm air flow on a coil 9' square and a river of water, and still not be bringing down the humidity. Chillers use big coils and water close to freezing as possible. If it's 100 degrees outside and you want to cool to 90 inside you may have a chance.

[E Yoder]

Talked to my HVAC brother-in-law- so these are his numbers:
Refrigerant typically changes from liquid to a vapor in an AC coil at about 37-42 F. Leaves the coil at  no more than 10 degrees warmer, average coil temps probably mid 40's?. Air temps range from 50-62F depending on airflow.
Two things are going on here tho, one is that you have a change of state going on in the coil and so it pulls way more BTUs off to vaporize the refrigerant then just what you would expect with the temperatures that the refrigerant is at. This allows a much smaller coil to absorb a high BTU rate. With change of state happening in the airflow it makes cooling very efficient. The same effect happens with water when it crossed 212F, it absorbs BTUs just to change state into steam.
The other thing is that at 40-ish degrees you will condense moisture on down to a pretty low relative humidity. Whereas with 60 degree well water it will only pull down the relative humidity probably 10 or 20% before it stops condensing.

So my guess is that a coil with well water running through will need to be much much bigger with several times more airflow than the coil that you heat with, and it will only dehumidify on very very sticky days. I hope I'm wrong though.

I like the idea, I just had a fellow call me last month about a gravity fed system he was setting up off a spring behind his house. That eliminated running the well pump, but not the air handler. I haven't heard how it turned out for him.

[E Yoder]

Interesting-
I think I'm reading that cooling runs about 1/4 the btu's that heating does for the same size coil? Not sure I understand if it's referring to 30F entering water temp or that it runs a 30F Delta t with what degree water I'm not sure.
What I'm reading elsewhere is that hot water coils typically run 1-3 rows deep (I use 3 row), chilled water use 3-12 row coils.

[E Yoder]

This was one response I got posting a thread on another forum:

 You would have to oversize the coil to get adequate cooling. But the real problem is humidity control. You need to get a coil to about 50 deg to remove much humidity. And humidity removal (latent heat removal) is just as or maybe more important that sensible temperature change.

Normal chilled water temperature is about 54 chiller return and 44 chiller supply putting the average coil temperature at about 49 deg. In chilled water a few degrees makes a huge difference. Normal water flow is 2-2.5 gpm / ton of cooling (12,000 btu/hr). 2 gpm will result in about a 12 degree change in water temperature, 2.5 is about 10 degrees
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[RSI]

I think the only way you could make it work is to coil up enough bare copper pipe in the return side (setup similar to the coil in a dehumidifier) of the furnace to condense water. The fins on the heat exchanger are going to raise the surface temp above the dew point and not condense any humidity.
You could run it through the heat exchanger after  to extract the rest of the cooling potential and shouldn't have water in that area to deal with.

[juddspaintballs]

With the use of refrigerant, you could use well water as the heat sink instead of an air-finned coil to shed the heat extracted from the home.  You're talking big money on a Geothermal system, however, and you're still tied to an electric meter for your heating and cooling needs.  Essentially you still have a heat pump, but instead of air fins to exchange the heat, it uses water.  A closed system (most common) uses either buried coils with liquid in them to exchange the heat over a large area of ground or they drill multiple well casings and run the liquid lines down them and fill them with grout to exchange the heat with the ground.  An open system uses water from a well and dumps it into another area to exchange the heat. 

[E Yoder]

At that point a high seer reg air source heat pump begins to make sense costwise. To me anyway. And things like reflective roof metal, extra insulation, shade, etc.

[RSI]

From the numbers I have seen, you would be way better off with a low seer system and putting the price difference into solar panels.

[E Yoder]

Good point. My roof is shaded or I'd have done panels several years ago.