Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

"blueman" wrote in message

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

It is a common method of commercial and industrial cooling. Big chiller
located on a rooftop and cold water piped to various locations. It has the
advantage of going long distances with no refrigerant lines and the charges
in them. You may get better result talking to a commercial contractor than
someone that only does residential.

One house and 3 furnaces = high energy bills. Water AC system will not
be cheap.

I'm not sure if this would will work, but you should look into a
ground-linked heat pump system. I think some are water systems plus
you might be able to use it to heat your house.

blueman wrote:
Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

On 15 Aug 2006 19:26:17 -0700, "Pat"
wrote:

One house and 3 furnaces = high energy bills.

Bull****.

You have NO IDEA what size house, what environment, what heat
loss, etc. And thusly, your comment is meaningless drivel.

Water AC system will not
be cheap.

I'm not sure if this would will work, but you should look into a
ground-linked heat pump system. I think some are water systems plus
you might be able to use it to heat your house.

blueman wrote:
Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

--
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http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
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First off, the posting was to the OP and I think the OP is the only one
who can truly comment on it. Second off, it's a 300 year old house
with 3 forced air systems. Dollars to donuts, to has numerous
additons, outcroppings, etc. Thirdly, it is 100 years old, so no
matter what, it isn't sealed up and insulated like a new house.
Fourthly, he has furnaces but no central AC, so it is a good guess that
this house isn't in south Florida. It is probably somewhere north of
the Mason-Dixon line. Finally, with oil/gas/electric being up as high
as it is, everyone has high heating costs.

So go chill out.

My point is, and you seemed to miss it entirely, is that if he truly
wants a multi-zone chilled water system, it might be worth looking into
a heat pump. It would add some cost but might also add some benefit.
And if he/she does that, he/she might have some savings on heating to
help pay for a system that will probably be a little on the expensive
side. And please don't say that they might not be expensive, because
yes, they are expensive. But the might be worth the cost ... or they
might not be. That would require a bit of research and would be for
the OP to decide.

wrote:
On 15 Aug 2006 19:26:17 -0700, "Pat"
wrote:

One house and 3 furnaces = high energy bills.

Bull****.

You have NO IDEA what size house, what environment, what heat
loss, etc. And thusly, your comment is meaningless drivel.

Water AC system will not
be cheap.

I'm not sure if this would will work, but you should look into a
ground-linked heat pump system. I think some are water systems plus
you might be able to use it to heat your house.

blueman wrote:
Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

blueman writes:

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Where have you seen that?

Are you sure the water is not cooling separate compressors/evaporators at
each air handler? Rather difficult to cool efficiently without a phase
change.

"Pat" wrote in message
ups.com...
First off, the posting was to the OP and I think the OP is the only one
who can truly comment on it. Second off, it's a 300 year old house
with 3 forced air systems. Dollars to donuts, to has numerous
additons, outcroppings, etc. Thirdly, it is 100 years old, so no
matter what, it isn't sealed up and insulated like a new house.
Fourthly, he has furnaces but no central AC, so it is a good guess that
this house isn't in south Florida. It is probably somewhere north of
the Mason-Dixon line. Finally, with oil/gas/electric being up as high
as it is, everyone has high heating costs.

So go chill out.

My point is, and you seemed to miss it entirely, is that if he truly
wants a multi-zone chilled water system, it might be worth looking into
a heat pump. It would add some cost but might also add some benefit.
And if he/she does that, he/she might have some savings on heating to
help pay for a system that will probably be a little on the expensive
side. And please don't say that they might not be expensive, because
yes, they are expensive. But the might be worth the cost ... or they
might not be. That would require a bit of research and would be for
the OP to decide.


It might actually require a professional to visit the residence, take
measurements, perform calculations, and make a recommendation, rather than
mindless speculation by assumming know-it-alls like you on a friggin'
newsgroup.








wrote:
On 15 Aug 2006 19:26:17 -0700, "Pat"
wrote:

One house and 3 furnaces = high energy bills.

Bull****.

You have NO IDEA what size house, what environment, what heat
loss, etc. And thusly, your comment is meaningless drivel.

Water AC system will not
be cheap.

I'm not sure if this would will work, but you should look into a
ground-linked heat pump system. I think some are water systems plus
you might be able to use it to heat your house.

blueman wrote:
Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

On 15 Aug 2006 21:46:50 -0700, "Pat"
wrote:

First off, the posting was to the OP and I think the OP is the only one
who can truly comment on it.

Then why did you flap your cake-hole ?

Second off, it's a 300 year old house
with 3 forced air systems.

100 years old, asshole. Can't you read ?

Dollars to donuts, to has numerous
additons, outcroppings, etc. Thirdly, it is 100 years old, so no
matter what, it isn't sealed up and insulated like a new house.

How the **** do you know what kind of re-fit has been done to
it in the last 100 years ?

Fourthly, he has furnaces but no central AC, so it is a good guess that
this house isn't in south Florida. It is probably somewhere north of

No, it's not.

the Mason-Dixon line. Finally, with oil/gas/electric being up as high
as it is, everyone has high heating costs.

It's all relative.

So go chill out.

So bite me.


My point is, and you seemed to miss it entirely, is that if he truly
wants a multi-zone chilled water system, it might be worth looking into
a heat pump. It would add some cost but might also add some benefit.

CHW ( that's chilled water' to you ) and 'heat pump' and
ground source heat pump' ( please, TRY to learn the correct
terminology ! ) are 3 different topics.

And 'heat pump' has NOTHING to do with multi-zone, no more or
less than 'straight AC'.

And if he/she does that, he/she might have some savings on heating to
help pay for a system that will probably be a little on the expensive
side. And please don't say that they might not be expensive, because
yes, they are expensive. But the might be worth the cost ... or they
might not be. That would require a bit of research and would be for
the OP to decide.

OK, here's his research for him :

GSHP ( go look it up ), if possible on his lot, will cost at
least 2x any other option. IOW, at least $ 10K + more. He's gonna be
there 5 years, he said. That's $ 2K / year.

The system will hvae minimal impact, if any, on resale value,
as opposed to 'regular AC'.

So, his pay-back is TOTALLY not there.

Good night. Stop arguing with me, because I know this ****
and you don't.


wrote:
On 15 Aug 2006 19:26:17 -0700, "Pat"
wrote:

One house and 3 furnaces = high energy bills.

Bull****.

You have NO IDEA what size house, what environment, what heat
loss, etc. And thusly, your comment is meaningless drivel.

Water AC system will not
be cheap.

I'm not sure if this would will work, but you should look into a
ground-linked heat pump system. I think some are water systems plus
you might be able to use it to heat your house.

blueman wrote:
Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

The "traditional" approach would be to add a separate
compressor/evaporator for each of the 3 heating units.

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

I will be hiring a reputable HVAC contractor for the installation.

Thanks.

--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

On Tue, 15 Aug 2006 23:52:45 -0500, Richard J Kinch
wrote:

blueman writes:

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Where have you seen that?

Are you sure the water is not cooling separate compressors/evaporators at
each air handler? Rather difficult to cool efficiently without a phase
change.

Bull****. That is how ~ 100 % of all large commerical
buildings do it.

The phase change is in the refrigerant, not the circulating
fluid.


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

Not sure, but I think the OP is looking for a system like a "motel
system" that circulates chilled water to all of the systems and a fan
blows when a unit calls for cooling. He is looking for a system with a
heat exchanger rather than a air-based system like a regular AC.

Richard J Kinch wrote:
blueman writes:

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Where have you seen that?

Are you sure the water is not cooling separate compressors/evaporators at
each air handler? Rather difficult to cool efficiently without a phase
change.

wrote:
On Tue, 15 Aug 2006 23:52:45 -0500, Richard J Kinch
wrote:

blueman writes:

I have seen that some high end remodels are using a single chilled
water unit to supply coolant to multiply blower units and that this is
somehow "better".

Where have you seen that?

Are you sure the water is not cooling separate compressors/evaporators at
each air handler? Rather difficult to cool efficiently without a phase
change.

Bull****. That is how ~ 100 % of all large commerical
buildings do it.

Yo man, chill out and adjust your meds. All you're doing is making a
fool of yourself.

Many of us know a little about AC and how chilled water system work.
We also know it is a bit beyond what you see in a typical house. I
think that the point people are trying to make. For example, asking
where he has seen it is a bit vague, but it's a legitimate question.
For all we know, the guys neighbor has a system like that.

So take a pill.


The phase change is in the refrigerant, not the circulating
fluid.


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/

writes:
blueman wrote:

Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

fantastic. after you do a room by room load calc and a room by room
duct calc, you will know if your existing ducts and blowers are
adequately sized for air conditioning.

We had a couple of HVAC contractors in for preliminary estimates and
calculations. Their sense is that while not ideal (the ducts
appear to be sized and located for the original system which seems to
have been coal-fired gravity hot air), the cost of installing new
ducts would be substantial in addition to the need to make a fair number of
holes in the wall. This will mean that even after getting the
calculations there will be some compromises in determining the tonnage
relative to the heat load and duct capacity.

We will still like to get relatively high end AC units so that we get
good efficiency, reliability, and noise performance.

One question though is whether we should hire an independent HVAC engineer
to do the measurements and write the specs or whether we can "trust" a
recommended "reputable" HVAC contractor to measure, spec, and install.


Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

yes. with a freon based, dx system, most anybody can work on and
provide parts for it. on a resi chilled water system, parts are
propriatary, can be outrageously expensive, and very few people can
work on such a system.



I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

go with a high end freon based dx system.


Sounds then like this is the way to go and as mentioned above we
expect to pay for the high end since much of the cost in our project
is labor (we need to have a bunch of ductwork in the basement replaced
too).

If I were you, I think I would find an AC installer who does more
light-commercial work than residential work. I would lose the idea of
doing chilled water because there are issues with that. I would see if
anyone had any experience doing a zoned freon system. You put 1
compressor somewhere out of the way so it doesn't bother you. You run
a manifold to either balance the system or to have electronic switcing
to shut down systems that don't need cooling, and you put in 3 regular
heat exchangers (evaporators) in your forced air system. Except the
switching system, it would be pretty straight forward. There's no
reason you can't move freon rather than chilled water. In fact, it
might move more efficiently.

Oh, and hope and pray it doesn't need to be a 3-phase system. But it
doesn't seem like it should. It's not that big.

BTW, every old gravity fed coal system I ever saw had pretty big ducts.
So you probably have enough size -- maybe even too big. So check for
leaks and make sure your blower is sufficient.

1 issue you will still have is that AC is must better coming out high
than at floor level. So you might need some ceiling fans or something
to help out. This might explain the high cost of ducting.

Good luck with it.



blueman wrote:
writes:
blueman wrote:

Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

fantastic. after you do a room by room load calc and a room by room
duct calc, you will know if your existing ducts and blowers are
adequately sized for air conditioning.

We had a couple of HVAC contractors in for preliminary estimates and
calculations. Their sense is that while not ideal (the ducts
appear to be sized and located for the original system which seems to
have been coal-fired gravity hot air), the cost of installing new
ducts would be substantial in addition to the need to make a fair number of
holes in the wall. This will mean that even after getting the
calculations there will be some compromises in determining the tonnage
relative to the heat load and duct capacity.

We will still like to get relatively high end AC units so that we get
good efficiency, reliability, and noise performance.

One question though is whether we should hire an independent HVAC engineer
to do the measurements and write the specs or whether we can "trust" a
recommended "reputable" HVAC contractor to measure, spec, and install.


Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

yes. with a freon based, dx system, most anybody can work on and
provide parts for it. on a resi chilled water system, parts are
propriatary, can be outrageously expensive, and very few people can
work on such a system.



I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

go with a high end freon based dx system.


Sounds then like this is the way to go and as mentioned above we
expect to pay for the high end since much of the cost in our project
is labor (we need to have a bunch of ductwork in the basement replaced
too).

I don't know if such a system would fit your needs, but it might be
one more option to consider if it can be easily integrated with your
home's existing ductwork. The big advantage is that it could also
supply one or more independent air handlers for areas that require
additional "spot" heating and cooling (or for which installing the
necessary duct work would be too costly or impractical).

http://www.mitsubishielectric.ca/hvac/A01-20.html

Cheers,
Paul

On Wed, 16 Aug 2006 16:03:28 GMT, blueman wrote:
We had a couple of HVAC contractors in for preliminary estimates and
calculations. Their sense is that while not ideal (the ducts
appear to be sized and located for the original system which seems to
have been coal-fired gravity hot air), the cost of installing new
ducts would be substantial in addition to the need to make a fair number of
holes in the wall. This will mean that even after getting the
calculations there will be some compromises in determining the tonnage
relative to the heat load and duct capacity.
[....]

We will still like to get relatively high end AC units so that we get
good efficiency, reliability, and noise performance.

"blueman" wrote in message
...
writes:
blueman wrote:

Our 100+ yr old house currently has 3 separate forced hot air
gas-fired heating units.

We would like to add central air sharing the same ductwork and
blowers.

fantastic. after you do a room by room load calc and a room by room
duct calc, you will know if your existing ducts and blowers are
adequately sized for air conditioning.

We had a couple of HVAC contractors in for preliminary estimates and
calculations. Their sense is that while not ideal (the ducts
appear to be sized and located for the original system which seems to
have been coal-fired gravity hot air), the cost of installing new
ducts would be substantial in addition to the need to make a fair number
of
holes in the wall. This will mean that even after getting the
calculations there will be some compromises in determining the tonnage
relative to the heat load and duct capacity.

We will still like to get relatively high end AC units so that we get
good efficiency, reliability, and noise performance.

One question though is whether we should hire an independent HVAC engineer
to do the measurements and write the specs or whether we can "trust" a
recommended "reputable" HVAC contractor to measure, spec, and install.



What??? You want to slap in a system that isn't right and has lots of
compromises, but yet you want to purchase high-end equipment? That is like
saying you need a car for fishing and hauling the trash up the driveway but
you are going to buy a BMW.

You already know you are going to get a system that doesn't work right and
may not last long, but you want to spend lots of money? That is ****ed.










Can anyone comment on the pros/cons and appropriateness of using such
a system residentially?

yes. with a freon based, dx system, most anybody can work on and
provide parts for it. on a resi chilled water system, parts are
propriatary, can be outrageously expensive, and very few people can
work on such a system.



I am particularly interested in comparing initial cost (equipment &
installation), efficiency, noise-level, and reliability.

go with a high end freon based dx system.


Sounds then like this is the way to go and as mentioned above we
expect to pay for the high end since much of the cost in our project
is labor (we need to have a bunch of ductwork in the basement replaced
too).