Using water at 57 degrees to cool house

Posted by on September 5, 2008, 12:40 am

The standard chilled water systems use water cooled to about 45
degrees going into the heat exchanger and a 10 degree rise in water
temperature in the heat exchanger. I am not sure what the temperature
of the air leaving the heat exchanger, but expect it would be about 58
to 60 degrees.

What I am contemplating doing is using water circulated through
geothermal lines instead of the chilled water. This water would be
about 57 to 60 degrees. If it rises 10 degrees , it would require
about 285 gallons of water per hour for 2 tons of cooling. The air
coming out of the heat exchanger would be about 73 to 75 degrees.
There would not be much, if any dehumidifying. And the house
would likely be about 80 to 85.

I see this as something to do when one was not home. It should reduce
the time for the air conditioner to get the house comfortable. It
would require the addition of a heat exchanger and probably some way
to duct the air either through the regular evaporator or the added
heat exchanger. Maybe the smarter thing would be to have the air
conditioner / heat pump chill or heat water. And not have both an
evaporator and heat exchanger to deal with.

Has anyone seen such a lashup? And are my numbers reasonable? Does
anyone think it would save money over just using a standard geothermal
heat pump with a timer to turn on the air conditioning before one
expects to arrive home?

Note I am not asking for a design. Just wanting the opinions of
practical people with experience. There is likely to be some thing
obvious to you all, that I do not see.

Dan

Posted by Noon-Air on September 5, 2008, 9:40 am

Actually it will be a little cooler than that

> What I am contemplating doing is using water circulated through
> geothermal lines instead of the chilled water. This water would be
> about 57 to 60 degrees. If it rises 10 degrees , it would require
> about 285 gallons of water per hour for 2 tons of cooling. The air
> coming out of the heat exchanger would be about 73 to 75 degrees.
> There would not be much, if any dehumidifying. And the house
> would likely be about 80 to 85.

Won't be any dehumidifying without the coil temp being below dew point.

> I see this as something to do when one was not home. It should reduce
> the time for the air conditioner to get the house comfortable. It
> would require the addition of a heat exchanger and probably some way
> to duct the air either through the regular evaporator or the added
> heat exchanger. Maybe the smarter thing would be to have the air
> conditioner / heat pump chill or heat water. And not have both an
> evaporator and heat exchanger to deal with.

If your trying to save money on the utility bills, your going about it the
wrong way as the jury rigged set-up your talking about will far ofset any
savings.

> Has anyone seen such a lashup? And are my numbers reasonable? Does
> anyone think it would save money over just using a standard geothermal
> heat pump with a timer to turn on the air conditioning before one
> expects to arrive home?

Just use a quality, programmable, setback thermostat.

> Note I am not asking for a design. Just wanting the opinions of
> practical people with experience. There is likely to be some thing
> obvious to you all, that I do not see.
> Dan

Posted by Mark on September 5, 2008, 10:06 am

On Sep 5, 12:40=A0am, dcas...@krl.org wrote:

> The standard chilled water systems use water cooled to about 45
> degrees going into the heat exchanger and a 10 degree rise in water
> temperature in the heat exchanger. =A0I am not sure what the temperature
> of the air leaving the heat exchanger, but expect it would be about 58
> to 60 degrees.
> What I am contemplating doing is using water circulated =A0through
> geothermal lines instead of the chilled water. =A0This water would be
> about 57 to 60 degrees. =A0If it rises 10 degrees , it would require
> about 285 gallons of water per hour for 2 tons of cooling. =A0The air
> coming out of the heat exchanger would be about 73 to 75 degrees.
> There would not be much, if any dehumidifying. =A0 =A0 =A0 =A0And the hou=

> would likely be about 80 to 85.
> I see this as something to do when one was not home. It should reduce
> the time for the air conditioner to get the house comfortable. =A0It
> would require the addition of a heat exchanger and probably some way
> to duct the air either through the regular evaporator or the added
> heat exchanger. =A0Maybe the smarter thing would be to have the air
> conditioner / heat pump chill or heat water. =A0And not have both an
> evaporator and heat exchanger to deal with.
> Has anyone seen such a lashup? =A0And are my numbers reasonable? =A0Does
> anyone think it would save money over just using a standard geothermal
> heat pump with a timer to turn on the air conditioning before one
> expects to arrive home?
> Note I am not asking for a design. =A0Just wanting the opinions of
> practical people with experience. =A0There is likely to be some thing
> obvious to you all, that I do not see.
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Dan

set up your heat ex to feed the water cooled air to the condensor of
your AC... that would be more effective...

Mark

Posted by Stormin Mormon on September 5, 2008, 2:05 pm

They make water cooled condensors.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

set up your heat ex to feed the water cooled air to the condensor of
your AC... that would be more effective...

Mark

Posted by KJPRO on September 5, 2008, 2:44 pm

> The standard chilled water systems use water cooled to about 45
> degrees going into the heat exchanger and a 10 degree rise in water
> temperature in the heat exchanger. I am not sure what the temperature
> of the air leaving the heat exchanger, but expect it would be about 58
> to 60 degrees.
> What I am contemplating doing is using water circulated through
> geothermal lines instead of the chilled water. This water would be
> about 57 to 60 degrees. If it rises 10 degrees , it would require
> about 285 gallons of water per hour for 2 tons of cooling. The air
> coming out of the heat exchanger would be about 73 to 75 degrees.
> There would not be much, if any dehumidifying. And the house
> would likely be about 80 to 85.
> I see this as something to do when one was not home. It should reduce
> the time for the air conditioner to get the house comfortable. It
> would require the addition of a heat exchanger and probably some way
> to duct the air either through the regular evaporator or the added
> heat exchanger. Maybe the smarter thing would be to have the air
> conditioner / heat pump chill or heat water. And not have both an
> evaporator and heat exchanger to deal with.
> Has anyone seen such a lashup? And are my numbers reasonable? Does
> anyone think it would save money over just using a standard geothermal
> heat pump with a timer to turn on the air conditioning before one
> expects to arrive home?
> Note I am not asking for a design. Just wanting the opinions of
> practical people with experience. There is likely to be some thing
> obvious to you all, that I do not see.
> Dan

Yeah, like the point that you don't understand anything about how a GEO
system works and operates.

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