Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.

Just a hunch.

Robatoy wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.

The need for the aux heat should be minimal at most for an
adequately-sized geothermal system. Some t-stats may demand it if the
temperature differential from setpoint gets too large, though, so it
should be ensured the rampup doesn't force that.

In general, the same rules apply -- a setback at night, for example,
will result in a lower average temperature so the effect is still there.

As a side note, had a ground-loop geothermal system in TN and liked it a
bunch. Am considering it for a replacement here...

--

On Mon, 26 Nov 2007 17:58:20 -0600, dpb
wrote:

Robatoy wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.

The need for the aux heat should be minimal at most for an
adequately-sized geothermal system. Some t-stats may demand it if the
temperature differential from setpoint gets too large, though, so it
should be ensured the rampup doesn't force that.

In general, the same rules apply -- a setback at night, for example,
will result in a lower average temperature so the effect is still there.

As a side note, had a ground-loop geothermal system in TN and liked it a
bunch. Am considering it for a replacement here...

Hello again,

Your reasoning is similar to mine...

We do not have any auxiliary source of heat: Our (9 ton
rated) heat pumps are more than sufficient to do the deed
even at 20 below.

For the life of me, I can't understand why the folks who
design the system say it is best (that is, less costly) to
keep the temp constant.

One possibility that I have thought of:

The cooler the water in the well, the lower the efficiency
of (and thus, the higher the costs of running) the system.

Suppose that each night, we allow the temp of the house to
drop, say, 10 degrees F.

Then, in the morning, lots of energy would have to be
extracted from the well in order to rapidly bring the house
up those ten degrees.

That would (obviously) cool the well, thus decreasing the
efficiency of the system, until the house warmed up. As a
result, the costs per BTU would go up during that period of
(relatively rapidly) re-heating the house.

Assuming that reasoning to be correct, the issue boils down
to whether the cost of that loss of efficiency is greater or
less than the savings to be had with the lower overnight
temperatures.

Thanks for any further thoughts,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Kenneth wrote:
On Mon, 26 Nov 2007 17:58:20 -0600, dpb
wrote:

Robatoy wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."
Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.
The need for the aux heat should be minimal at most for an
adequately-sized geothermal system. Some t-stats may demand it if the
temperature differential from setpoint gets too large, though, so it
should be ensured the rampup doesn't force that.

In general, the same rules apply -- a setback at night, for example,
will result in a lower average temperature so the effect is still there.

As a side note, had a ground-loop geothermal system in TN and liked it a
bunch. Am considering it for a replacement here...

Hello again,

Your reasoning is similar to mine...

We do not have any auxiliary source of heat: Our (9 ton
rated) heat pumps are more than sufficient to do the deed
even at 20 below.

For the life of me, I can't understand why the folks who
design the system say it is best (that is, less costly) to
keep the temp constant.

One possibility that I have thought of:

The cooler the water in the well, the lower the efficiency
of (and thus, the higher the costs of running) the system.

Suppose that each night, we allow the temp of the house to
drop, say, 10 degrees F.

Then, in the morning, lots of energy would have to be
extracted from the well in order to rapidly bring the house
up those ten degrees.

That would (obviously) cool the well, thus decreasing the
efficiency of the system, until the house warmed up. As a
result, the costs per BTU would go up during that period of
(relatively rapidly) re-heating the house.

Assuming that reasoning to be correct, the issue boils down
to whether the cost of that loss of efficiency is greater or
less than the savings to be had with the lower overnight
temperatures.

All depends on the capacity of the well and how the loop is configured.
Unless the well is stagnant and of marginal size and the exchanger is
closed loop, I would expect that to be a minimal problem. If the well
weren't a well but a closed tank, maybe, but that's unlikely to be a
realistic model. Would have to know more to do a real
calculation/estimate, but I think it's not likely such a big issue.

I have been told by one installer here that owing to our very dry
climate there's an issue w/ ground loops and heat transfer. I've not
yet delved into it in sufficient detail to decide whether I think that's
hokum or not -- this guy hasn't yet actually installed a system, he's
just going on what somebody else has told him.

Would be interested in the capacity of the well, amount of exchange
tubing, etc., to support the system you have as a comparison. They
wanted to punch two or three holes here for deep ground loop, but at
$1500/ea, that gets terribly pricy quickly. Would have to have a second
well to go that route, but I'd think it could be only one although it
would not suit me to have it be a once-through in an arid area.

--

On Mon, 26 Nov 2007 18:51:12 -0600, dpb
wrote:


Would be interested in the capacity of the well, amount of exchange
tubing, etc., to support the system you have as a comparison. They
wanted to punch two or three holes here for deep ground loop, but at
$1500/ea, that gets terribly pricy quickly. Would have to have a second
well to go that route, but I'd think it could be only one although it
would not suit me to have it be a once-through in an arid area.

Hi again,

Trusting my memory here...

Our well was designed for the 9 ton capacity. It is 460'
deep, and is 8" in diameter. It has a sleeve for just under
400'.

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Mon, 26 Nov 2007 15:55:03 -0800 (PST), Robatoy
wrote:

On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.

Just a hunch.

Howdy,

There is no auxiliary heat...

So, whatever heat energy lost by the house is replaced by
the heat energy extracted (at some cost of electricity) from
the well water.

My reasoning was that keeping the house warm when empty
would have greater cost than keeping it cool when empty
(that part seems obvious) and heating it up to comfort would
take less energy than that which would be lost were it kept
warm continuously.

What am I missing?
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Nov 26, 7:07 pm, Kenneth wrote:
On Mon, 26 Nov 2007 15:55:03 -0800 (PST), Robatoy



wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.

Just a hunch.

Howdy,

There is no auxiliary heat...

So, whatever heat energy lost by the house is replaced by
the heat energy extracted (at some cost of electricity) from
the well water.

My reasoning was that keeping the house warm when empty
would have greater cost than keeping it cool when empty
(that part seems obvious) and heating it up to comfort would
take less energy than that which would be lost were it kept
warm continuously.

What am I missing?
--
Kenneth

If you email... Please remove the "SPAMLESS."

It keeps coming back to the building's phase. It doesn't cycle at the
same speed your internal temperature does.
As you turn down the thermostat, the building's stored heat is given
up, some to the interior, but some to the exterior (loss).
To reheat the building's interior, the heat is not only heating the
interior, but also the building's mass.
So, when you turn down the thermostat, you need to later replace the
heat you lose. Once the building is up to temperature, you just
overcome the building's heat loss...like Lew's Ball.

I was going to try to equate this with the reason why when you
increase the waterflow through your car's radiator by taking out the
thermostat, your engine will overheat. The water HAS to spend time in
the rad to be able to give up its heat. So the thermostat slows down
the waterflow. Conventional thinking would suggest that by increasing
the waterflow, it should cool better. (There are a few caveats in
there too, so everybody keep their shirts on.)

Robatoy wrote:
On Nov 26, 7:07 pm, Kenneth wrote:
On Mon, 26 Nov 2007 15:55:03 -0800 (PST), Robatoy



wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,
This is way OT...(again), but:
We heat and cool our home geothermally (water to air
system.)
We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.
The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.
Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.
Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?
Sincere thanks,
--
Kenneth
If you email... Please remove the "SPAMLESS."
Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.
Just a hunch.
Howdy,

There is no auxiliary heat...

So, whatever heat energy lost by the house is replaced by
the heat energy extracted (at some cost of electricity) from
the well water.

My reasoning was that keeping the house warm when empty
would have greater cost than keeping it cool when empty
(that part seems obvious) and heating it up to comfort would
take less energy than that which would be lost were it kept
warm continuously.

What am I missing?
--
Kenneth

If you email... Please remove the "SPAMLESS."

It keeps coming back to the building's phase. It doesn't cycle at the
same speed your internal temperature does.
As you turn down the thermostat, the building's stored heat is given
up, some to the interior, but some to the exterior (loss).
To reheat the building's interior, the heat is not only heating the
interior, but also the building's mass.
So, when you turn down the thermostat, you need to later replace the
heat you lose. Once the building is up to temperature, you just
overcome the building's heat loss...like Lew's Ball.
....

No, you don't need to "replace" the heat you lost for the period the
setpoint was lower -- that's the gain.

--

On Nov 27, 9:01 am, dpb wrote:
Robatoy wrote:
On Nov 26, 7:07 pm, Kenneth wrote:
On Mon, 26 Nov 2007 15:55:03 -0800 (PST), Robatoy

wrote:
On Nov 26, 6:48 pm, Kenneth wrote:
Howdy,
This is way OT...(again), but:
We heat and cool our home geothermally (water to air
system.)
We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.
The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.
Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.
Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?
Sincere thanks,
--
Kenneth
If you email... Please remove the "SPAMLESS."
Cycling a building in and out of extremes will bring into play the
building's phase.
The lower extremes may force the auxiliary heating to start up (maybe
electric?).
It might be cheaper to keep things at a low wick rather than replacing
lost heat with expensive heat.
Just a hunch.
Howdy,

There is no auxiliary heat...

So, whatever heat energy lost by the house is replaced by
the heat energy extracted (at some cost of electricity) from
the well water.

My reasoning was that keeping the house warm when empty
would have greater cost than keeping it cool when empty
(that part seems obvious) and heating it up to comfort would
take less energy than that which would be lost were it kept
warm continuously.

What am I missing?
--
Kenneth

If you email... Please remove the "SPAMLESS."

It keeps coming back to the building's phase. It doesn't cycle at the
same speed your internal temperature does.
As you turn down the thermostat, the building's stored heat is given
up, some to the interior, but some to the exterior (loss).
To reheat the building's interior, the heat is not only heating the
interior, but also the building's mass.
So, when you turn down the thermostat, you need to later replace the
heat you lose. Once the building is up to temperature, you just
overcome the building's heat loss...like Lew's Ball.

...

No, you don't need to "replace" the heat you lost for the period the
setpoint was lower -- that's the gain.

--

Only if you decide to keep the building's mass at that temperature.
If you want to restore the temperature of the model, you also have to
re-heat the container.

dpb wrote:
Robatoy wrote:
On Nov 26, 7:07 pm, Kenneth
wrote:
On Mon, 26 Nov 2007 15:55:03 -0800 (PST), Robatoy



wrote:
On Nov 26, 6:48 pm, Kenneth
wrote:
Howdy,
This is way OT...(again), but:
We heat and cool our home geothermally (water to air
system.)
We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.
The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.
Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.
Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?
Sincere thanks,
--
Kenneth
If you email... Please remove the "SPAMLESS."
Cycling a building in and out of extremes will bring into play
the
building's phase.
The lower extremes may force the auxiliary heating to start up
(maybe electric?).
It might be cheaper to keep things at a low wick rather than
replacing lost heat with expensive heat.
Just a hunch.
Howdy,

There is no auxiliary heat...

So, whatever heat energy lost by the house is replaced by
the heat energy extracted (at some cost of electricity) from
the well water.

My reasoning was that keeping the house warm when empty
would have greater cost than keeping it cool when empty
(that part seems obvious) and heating it up to comfort would
take less energy than that which would be lost were it kept
warm continuously.

What am I missing?
--
Kenneth

If you email... Please remove the "SPAMLESS."

It keeps coming back to the building's phase. It doesn't cycle at
the
same speed your internal temperature does.
As you turn down the thermostat, the building's stored heat is
given
up, some to the interior, but some to the exterior (loss).
To reheat the building's interior, the heat is not only heating the
interior, but also the building's mass.
So, when you turn down the thermostat, you need to later replace
the
heat you lose. Once the building is up to temperature, you just
overcome the building's heat loss...like Lew's Ball.
...

No, you don't need to "replace" the heat you lost for the period the
setpoint was lower -- that's the gain.

If the structure had no thermal mass then that would be the case. But
it does have thermal mass and changing the temperature of that thermal
mass requires the addition or removal of heat.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

"Robatoy" wrote

I was going to try to equate this with the reason why when you
increase the waterflow through your car's radiator by taking out the
thermostat, your engine will overheat. The water HAS to spend time in
the rad to be able to give up its heat. So the thermostat slows down
the waterflow. Conventional thinking would suggest that by increasing
the waterflow, it should cool better. (There are a few caveats in
there too, so everybody keep their shirts on.)

I had an old volvo that had a thermostat that would die on a regular basis.
So I just ran without the thermostat. The problem with this particular
configuration is that it took over twenty minutes for it to heat up. And
until it heated up, you had no heat, defrosters and the engine did not run
well.

But volvo engineers had a unique solution. They had a window shade type
device located in front of the radiator. You pulled a chain under the dash
to pull the shade up over the radiator and it heated up quick! This model
also had a baby bottle warmer under the dash as well.

On Nov 27, 7:26 am, Robatoy wrote:

...

I was going to try to equate this with the reason why when you
increase the waterflow through your car's radiator by taking out the
thermostat, your engine will overheat. The water HAS to spend time in
the rad to be able to give up its heat. So the thermostat slows down
the waterflow. Conventional thinking would suggest that by increasing
the waterflow, it should cool better. (There are a few caveats in
there too, so everybody keep their shirts on.)

That is the first I ever heard of that.

The higher the flow rate the higher the Reynolds number and
therefor the higher the convective heat-transfer coefficient.
You may get less heat transferred per gram of water flowing
through the radiator, but not in inverse proportion to the
rate at which grams of water flow through. IOW you might
get only 75% of the heat loss per gram of water but will
have twice as many grams of water flowing through.

--

FF

Fred the Red Shirt wrote:
On Nov 27, 7:26 am, Robatoy wrote:
...

I was going to try to equate this with the reason why when you
increase the waterflow through your car's radiator by taking out the
thermostat, your engine will overheat. The water HAS to spend time in
the rad to be able to give up its heat. So the thermostat slows down
the waterflow. Conventional thinking would suggest that by increasing
the waterflow, it should cool better. (There are a few caveats in
there too, so everybody keep their shirts on.)

That is the first I ever heard of that.

The higher the flow rate the higher the Reynolds number and
therefor the higher the convective heat-transfer coefficient.
You may get less heat transferred per gram of water flowing
through the radiator, but not in inverse proportion to the
rate at which grams of water flow through. IOW you might
get only 75% of the heat loss per gram of water but will
have twice as many grams of water flowing through.

Yes, it's simply wrong in general. If one didn't get additional cooling
capacity when the thermostat opened as compared to when it is closed,
there would be insufficient cooling capacity to prevent overheating at
almost any operating condition.

Whatever "caveats" were suggested to counteract that would have to be
extreme, indeed...

--

On Tue, 27 Nov 2007 01:36:07 GMT, Larry Kraus
wrote:


There is no auxiliary heat...

You might want to verify that..

Hello again,

Other than repeating it, and assuring you that I know what I
am talking about in this regard, there is little more I can
do.

When we installed the system, we discussed this issue at
length with our contractor, the designer is the system, and
the system's installation folks.

Based upon their input, we opted for a design with capacity
sufficient to eliminate the necessity for any auxiliary
system. In fact, there is a box in the air handler that
would allow for the installation of such a resistance heat
supply, but it is empty.

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Larry Kraus wrote:
Kenneth wrote:

Howdy,

There is no auxiliary heat...

You might want to verify that...

Our WaterFurnace heat pump maintains temperature very well when it
drops to below zero here in central Ohio. But if you raise the
thermostat by more than two degrees at a time, the auxiliary heat
coils in the "furnace" do kick on, and the electric meter spins like
crazy until the house temp is back within two degrees of the set temp.
In our case, the "auxiliary" heat is for quick temperature changes.

This is different than our old house with an air-to-air heat pump,
where the auxiliary heat came into play whenever the outside air was
too cold for the pump to generate sufficient heat. Fairly often, in
other words, since air-to-air pumps lose efficiency as the temp drops.

To use a setback thermostat, we would need one that raised the
temperature only two degrees at a time and/or would need to disconnect
the internal resistance coils. We are satisfied with a fixed
temperature of 69, and heating bills that are a third the size of
friends who have gas heat and homes that a half the size of ours.

The thing to do is to add an exterior thermocouple to the aux heat
control so the aux heat doesn't come on unless exterior temperature is
at some preset temp. This can eliminate the mostly gratuitous usage.

What we did for the Water Furnace unit we had. (Unfortunately, I had
completely forgotten doing so and when we had moved and the new buyer's
inspection showed up the elements didn't work, I was gone and we ended
up w/ a service call to re-enable them to close the sale. ).

Anyway, there was also a setting on the thermostat that overrode the
"high" heat setting that could be used as well. Seems like that
thermostat was an option over the base one that came w/ the unit,
however. It had a setback option built in this worked with iirc,
whereas the other was a simple setpoint t-stat. This is quite a while
back now, memory's getting dim on precise detail.

I agree the units are well worth the initial extra installation cost,
particularly if don't have relatively cheap gas available...

--


--

On Tue, 27 Nov 2007 07:59:03 -0600, dpb
wrote:

The thing to do is to add an exterior thermocouple to the aux heat
control so the aux heat doesn't come on unless exterior temperature is
at some preset temp. This can eliminate the mostly gratuitous usage.

Hi,

As I described just above your comment, we do not have
auxiliary heat at all.

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Kenneth wrote:
On Tue, 27 Nov 2007 07:59:03 -0600, dpb
wrote:

The thing to do is to add an exterior thermocouple to the aux heat
control so the aux heat doesn't come on unless exterior temperature is
at some preset temp. This can eliminate the mostly gratuitous usage.

Hi,

As I described just above your comment, we do not have
auxiliary heat at all.

I was responding to the guy who does, not you...

-

"Kenneth" wrote in message
...

Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?



The fellow you are talking to may not be able to tell you!
One point to consider is you can "stress" the ground by pulling a bunch of
heat out of it at one time. If you leave an area colder, then bump it up
5-10 degrees the heat pump will run longer than normal and pull an abnormal
amount of heat from the ground. Once the ground gets too cold, the
equipment does not as efficiently also. Same with air conditioning, but then
you are putting heat into the ground.Generally with heat pumps they are
slower to heat up the home than say gas or electric, so the equipment runs
longer to get to the occupied temps.
I am with your heating contractor, leave the temperature constant, unless
you have an area of the home you can close off and leave cold for many days.
I would not bother to set back the temperature once or twice a day like you
might with electric or gas heat. If you want to save money, wear a sweater,
and turn the temps down a couple degrees.
Greg

On Mon, 26 Nov 2007 18:32:56 -0600, "Greg O"
wrote:



The fellow you are talking to may not be able to tell you!
One point to consider is you can "stress" the ground by pulling a bunch of
heat out of it at one time. If you leave an area colder, then bump it up
5-10 degrees the heat pump will run longer than normal and pull an abnormal
amount of heat from the ground. Once the ground gets too cold, the
equipment does not as efficiently also. Same with air conditioning, but then
you are putting heat into the ground.Generally with heat pumps they are
slower to heat up the home than say gas or electric, so the equipment runs
longer to get to the occupied temps.
I am with your heating contractor, leave the temperature constant, unless
you have an area of the home you can close off and leave cold for many days.
I would not bother to set back the temperature once or twice a day like you
might with electric or gas heat. If you want to save money, wear a sweater,
and turn the temps down a couple degrees.
Greg

Hi Greg,

Your explanation makes sense to me (and is essentially what
I offered to someone else in this thread) but...

Though, indeed, the efficiency of the system decreases as
the temperature of the well goes down, could that loss of
efficiency compensate for the significant savings we would
have if we were to drop the temp of our house by, say, 10
degrees for 8 or 10 hours each day?

My intuition tells me that it would not.

What do you think?

Thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

"Kenneth" wrote in message
...


Though, indeed, the efficiency of the system decreases as
the temperature of the well goes down, could that loss of
efficiency compensate for the significant savings we would
have if we were to drop the temp of our house by, say, 10
degrees for 8 or 10 hours each day?

My intuition tells me that it would not.

What do you think?

Thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

I don't think you will see significant savings setting back the temps. Also
consider the time it takes to recover after a 10 degree setback. It is very
possible that equipment may run longer to recover the temps than it would to
just maintain a "normal" occupied temp, more possible when you consider the
stress it may put on the well.
Again, I would set the temps and leave them at one set point, unless the
home is not occupied for days.
Can I ask where you may be located?
Greg

"Kenneth" wrote:


We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?


In a nutshell, thermal inertia.

Once the system is balanced, it requires minimum energy to maintain
the balance.

Change the set point to a lower level, remain there for a while, then
return to the higher level requires a lot of thermal work.

Heat intensive industries such as steel, refineries, etc, run 24/7 for
just this reason.

Lew

On Mon, 26 Nov 2007 16:44:48 -0800, "Lew Hodgett"
wrote:

In a nutshell, thermal inertia.

Once the system is balanced, it requires minimum energy to maintain
the balance.

Change the set point to a lower level, remain there for a while, then
return to the higher level requires a lot of thermal work.

Heat intensive industries such as steel, refineries, etc, run 24/7 for
just this reason.

Lew


Hi Lew,

I don't deny it... I just don't understand it:

(Though there may be parallels to industrial applications,
I'll stick with home heating for my example.)

For a given outside and inside temperature, the house loses
a constant amount of heat per hour, and that amount must be
replaced if we are to keep the internal temperature
constant.

If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp; but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

So, for the eight hours or so that the interior temperature
was lowered, there are savings for two reasons: We are
providing less heat to the house, and we are losing less per
hour of what heat we do supply.

When we decide to go back to the original interior
temperature, at every stage (prior to reaching that temp)
the hourly rate of heat loss is something less than it would
be when we reach the desired internal temperature.

Now, of course, heating up the house those 10 degrees will
take a bushel of BTUs, but (unless I am way off here) that
would have to be fewer than those saved.

I well understand that the efficiency of the system goes
down as the well cools, but it seems to me that the
diminished efficiency, though regrettable, is more than
balanced by the savings at the lower temperatures.

With all of this, I may be completely out to lunch, but I'd
love to understand where I am going astray.

Thanks for any further thoughts,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Mon, 26 Nov 2007 21:44:01 -0500, Kenneth
wrote:

On Mon, 26 Nov 2007 16:44:48 -0800, "Lew Hodgett"
wrote:

In a nutshell, thermal inertia.

Once the system is balanced, it requires minimum energy to maintain
the balance.

Change the set point to a lower level, remain there for a while, then
return to the higher level requires a lot of thermal work.

Heat intensive industries such as steel, refineries, etc, run 24/7 for
just this reason.

Lew


Hi Lew,

I don't deny it... I just don't understand it:

(Though there may be parallels to industrial applications,
I'll stick with home heating for my example.)

For a given outside and inside temperature, the house loses
a constant amount of heat per hour, and that amount must be
replaced if we are to keep the internal temperature
constant.

If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp; but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

So, for the eight hours or so that the interior temperature
was lowered, there are savings for two reasons: We are
providing less heat to the house, and we are losing less per
hour of what heat we do supply.

When we decide to go back to the original interior
temperature, at every stage (prior to reaching that temp)
the hourly rate of heat loss is something less than it would
be when we reach the desired internal temperature.

Now, of course, heating up the house those 10 degrees will
take a bushel of BTUs, but (unless I am way off here) that
would have to be fewer than those saved.

I well understand that the efficiency of the system goes
down as the well cools, but it seems to me that the
diminished efficiency, though regrettable, is more than
balanced by the savings at the lower temperatures.

With all of this, I may be completely out to lunch, but I'd
love to understand where I am going astray.

Thanks for any further thoughts,

I have a closed loop slinky coils in three trenches as deep as the
backhoe could dig. Covered back with the clay that came out of the
trenches. I think it is a 3 ton unit conditioning 2700 sf, a little
east of Atlanta Ga. No booster heat. Hot water heater option. When it
is extremely cold, ie 10F or extremely hot 100F the unit runs a lot.
It makes lots of hot water when the delta T is enough for the unit to
run more than a few minutes. I think the thermostat is at 74 in the
winter and 78 in the summer. My wife my cycles the thermostat a degree
when she is too cold or too hot. No 68F in the winter that I grew up
with. Warm blooded woman I married.

I have no idea if setback works as she is awake when I sleep. Rolling
the thermostat when you have people living different shifts does not
work so swell.

The neighbor down the road has a couple of geothermal units that they
zoned for the main part of the house they lived in and another zone
and unit for the extra bedrooms. They claimed power bills less than my
house even though their house was much bigger. Makes me mad enough to
finish insulating the concrete walls in my conditioned basement.

I have not thought about how dry the earth might be and how that might
affect the efficiency of the unit. Not a lot of rain over the summer.
I do know I have added dirt to the trenches once in 10 years. I need
to add a few more inches to some of the trenches close to the house as
they have settled. Settled is good suggesting better heat transfer,
maybe.

If you can get the same night to happen back to back read your power
meter. My house seems to do about 1000 kwh a month or about 38-45 kwh
per day average in the coldest of winter days. You could read the
meter before you go to bed on a normal night and read it at 8 am. Next
night assuming same wind conditions, cloud cover and night temps do
the setback and rollup. You might get your answer. Or put an
hour/minute meter on the air handler and get similar results. The
hour/minute meter might be more accurate. You could also attach
thermometers to the two water lines to see the delta T and what if any
measurable influence the setback does to the well temps.

On Mon, 26 Nov 2007 22:59:57 -0500, Jim Behning
wrote:


The neighbor down the road has a couple of geothermal units that they
zoned for the main part of the house they lived in and another zone
and unit for the extra bedrooms. They claimed power bills less than my
house even though their house was much bigger. Makes me mad enough to
finish insulating the concrete walls in my conditioned basement.

Hey, don't feel bad about that...

Someone I work with used exactly the same equipment to heat
a home about the size of ours, and her costs are about half
of ours...

Though she is only a few miles away, she is served by a
different power company.

Her's has a dual-rate policy. Mine, does not.

As a result, she pays slightly more than half of what I pay.

'Feels great...

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

"Kenneth" wrote:

I don't deny it... I just don't understand it:
snip

OK, let's try a different way.

Moving thermal energy from place to place is at best a very
inefficient process.

You pay to move energy(heat) into the building, but not all the energy
is used due to efficiency losses.

Then you turn down the thermostat and move energy from the building to
a colder source, but again, efficiency losses come into play.

Then you turn the thermostat back up, and you need to move energy back
into the building, again with efficiency losses.

System efficiencies are the problem.

Other examples where efficiency bites you.

1) Wet cell batteries.

For every 100 ampere-hours you consume out of a wet cell battery, you
must replace 125 ampere-hours.

Batteries are convenient, not efficient.

2) A big ball.

It takes a lot of energy to get a big ball rolling.

Once it is up to speed, to keep it rolling, all that is needed is to
replace the frictional losses.

If you let the ball slow down, it takes a bunch of energy to bring the
ball back up to speed.

Maybe these are poor analogies, but it's late, and I'm lazy tonight.

I'd refer you to one of my old thermo text books, but it's easier to
run a field test than wade thru one of those books.

I'd keep my sticky fingers off the thermostat.

Lew

In article ,
Kenneth wrote:
On Mon, 26 Nov 2007 16:44:48 -0800, "Lew Hodgett"
wrote:

In a nutshell, thermal inertia.

Once the system is balanced, it requires minimum energy to maintain
the balance.

Change the set point to a lower level, remain there for a while, then
return to the higher level requires a lot of thermal work.

Heat intensive industries such as steel, refineries, etc, run 24/7 for
just this reason.

Lew


Hi Lew,

I don't deny it... I just don't understand it:

(Though there may be parallels to industrial applications,
I'll stick with home heating for my example.)

For a given outside and inside temperature, the house loses
a constant amount of heat per hour, and that amount must be
replaced if we are to keep the internal temperature
constant.

If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp;

_THOSE_ BTUs are just 'deferred spending'. you spend exactly
that amount to raise the temp back to the original setting.

but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

That is the -totality- of the energy savings -- the lowered losses.
from the reduced temperature.

So, for the eight hours or so that the interior temperature
was lowered, there are savings for two reasons: We are
providing less heat to the house, and we are losing less per
hour of what heat we do supply.

FALSE. you are double-counting the same saving there.

to maintain any system 'at equilibrium', all you do is replace
the losses. if you are maintaining a lower equilibrium point,
the 'savings' are exactly equal to the difference in the losses
at the two equilibrium points.

When we decide to go back to the original interior
temperature, at every stage (prior to reaching that temp)
the hourly rate of heat loss is something less than it would
be when we reach the desired internal temperature.

Now, of course, heating up the house those 10 degrees will
take a bushel of BTUs, but (unless I am way off here) that
would have to be fewer than those saved.

I well understand that the efficiency of the system goes
down as the well cools, but it seems to me that the
diminished efficiency, though regrettable, is more than
balanced by the savings at the lower temperatures.

authoritative answer: "it depends".

1) _how_much_ lower are the building thermal losses for the temperature
reduction employed?
2) _how_much_ less efficient is the heat plant as the -rate- of draw
increases?

Depending on the _quantitative_ answers to those two questions the
'savings' can 'net' to either a positive or negative result.

The exact answers to both questions will be specific to a particular
installation.

Getting an answer by 'science' is -very- messy. It's much simpler to
use the 'experimentalist' approach and simply 'measure' what actually
happens.

The building loss rates are relatively easy -- measure the required heat
input at both equilibrium points. It _is_ reasonable to assume that the
delta on the loss rates is the same for both temperature rising and falling,
so the cool-down, and warm-up phases effectively cancel each other.

The changing 'efficiency' of the heat plant is harder. You really need
to have a running monitor on the well-water temperature for that. (with
that you can tell 'when' things have 'recovered' from the excessive
consumption to raise the building back to the higher level.

Failing instrumentation on the water temperature, one can use outside
air temperatures as a -rough- basis for comparison. (it helps greatly if
you have historical power usage data [at stable inside temperature operation]
that you can correlate with 'heating degree days' for various periods)

If you have the above-mentioned historical data, you'll see that 'cost of
operation' goes up as the heat demand increases. both in absolute terms
and on a per unit basis.

Now, run the system for a while in 'set-back' mode. Total the 'heating
degree days', and the cost. See where that 'per unit' cost falls relative
to the same degree-days for stable temperature operation.

NOTE: this is all figuring 'cost' on the basis of "how cold it is outside"
-not- on a "per BTU of heat added" basis, so you have a direct comparison
of the 'efficiency' of the methods, and can reasonably predict what, if any,
the overall savings will be.


Heat pumps are, by their nature, less efficient, the larger the temperature
differential between the 'external' and 'internal' sides. And that efficiency
does degrade significantly with relatively small increases in that
differential.

Things will depend 'a whole lot' on the thermal conductivity of the external
heat reservoir, and how fast stuff in the vicinity of the 'radiator' there
recovers to equilibrium after a draw-down.

W/o extensive geological testing, that's hard to quantify.

I _would_ tend to believe that the designers/installers *DO* know what
they're talking about when they recommend stable (and not 'set back')
operation, counter-intuitive though it may seem.

On Tue, 27 Nov 2007 18:07:39 -0000,
(Robert Bonomi) wrote:


Hi Robert,

I thank you for your detailed response...

Perhaps I am not understanding what you have written, but
allow me to ask something further.

Please see my comments inline below:


I wrote:
If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp;

You responded:
_THOSE_ BTUs are just 'deferred spending'. you spend exactly
that amount to raise the temp back to the original setting.

I wrote:
but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

You responded:
That is the -totality- of the energy savings -- the lowered losses.
from the reduced temperature.


In my attempt to understand this...

Suppose I lowered the temperature of the house 10 degrees,
but not merely overnight. Instead, I left them lower for a
month.

Would I not have very significant savings for that month?

If so, would not the reasons for those savings apply as well
to my overnight lowering of the house's internal temperature
(though with decreased benefit because of the diminished
duration)?

Thanks again,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Tue, 27 Nov 2007 13:43:34 -0500, Kenneth
wrote:

On Tue, 27 Nov 2007 18:07:39 -0000,
(Robert Bonomi) wrote:


Hi Robert,

I thank you for your detailed response...

Perhaps I am not understanding what you have written, but
allow me to ask something further.

Please see my comments inline below:


I wrote:
If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp;

You responded:
_THOSE_ BTUs are just 'deferred spending'. you spend exactly
that amount to raise the temp back to the original setting.

I wrote:
but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

You responded:
That is the -totality- of the energy savings -- the lowered losses.
from the reduced temperature.


In my attempt to understand this...

Suppose I lowered the temperature of the house 10 degrees,
but not merely overnight. Instead, I left them lower for a
month.

Would I not have very significant savings for that month?

If so, would not the reasons for those savings apply as well
to my overnight lowering of the house's internal temperature
(though with decreased benefit because of the diminished
duration)?

Thanks again,


Why do you need a second electric meter to excrement with? You can
read your own meter every day at the same time. As long as you record
when you are drying clothes or other significant electricity burning
events you should be able to test for no hardware costs.

Are you torturing the group by not doing your own meter reading and
reporting back?

In article ,
Kenneth wrote:
On Tue, 27 Nov 2007 18:07:39 -0000,
(Robert Bonomi) wrote:


Hi Robert,

I thank you for your detailed response...

Perhaps I am not understanding what you have written, but
allow me to ask something further.

Please see my comments inline below:


I wrote:
If the internal temperature of the house is allowed to drop,
two things happen. First, there is the direct energy savings
because it takes fewer BTUs to keep the house at the lower
temp;

You responded:
_THOSE_ BTUs are just 'deferred spending'. you spend exactly
that amount to raise the temp back to the original setting.

I wrote:
but perhaps less obviously, the rate of heat loss to
the outside environment is decreased. (Because the greater
the temperature differential, the more rapid the rate of
equalization.)

You responded:
That is the -totality- of the energy savings -- the lowered losses.
from the reduced temperature.


In my attempt to understand this...

Suppose I lowered the temperature of the house 10 degrees,
but not merely overnight. Instead, I left them lower for a
month.

Would I not have very significant savings for that month?

Relative to what you would have 'spent' at the 10degree higher
temperature yes.

If so, would not the reasons for those savings apply as well
to my overnight lowering of the house's internal temperature
(though with decreased benefit because of the diminished
duration)?

Yes and no. grin

There are three intervals to consider.
1) while the temperature is falling from 'X' to 'X-10',
2) while the temperature is stable at 'X-10',
3) while the temperature is rising from 'X-10' to 'X'.

As the house cools from 'X' to 'X-10', you aren't providing any heat input
at that time. *THAT* 'savings', is cancelled by the 'extra' energy you
have to put back into the building the next day, to raise the temperature
from 'X-10' back to 'X'. For complicated reasons, it usually takes a little
more energy to go from 'X-10' to 'X' than was 'saved' by letting things
fall from 'X' to 'X-10'. This differential is usually fairly minor, however
it can be magnified if the -rates- at which the temperature falls and rises
are different.

The heat input required to maintain the house at a constant "X" is exactly
the heat losses being radiated by the house to the exterior.

The heat input required to maintain the house at a constant "X-10" is exactly
the heat losses being radiated by the house to the exterior.

In both cases the rate of loss is a function of (a) the temperature
differential, _and_ the quality of the insulation.

The point is, however, that the difference in heat input is exactly the
difference in thermal losses, at a constant temperature. You cannot count
a savings for less heat input, -and- a savings for lower thermal losses.

On Nov 27, 12:44 am, "Lew Hodgett" wrote:
"Kenneth" wrote:
We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

In a nutshell, thermal inertia.

Once the system is balanced, it requires minimum energy to maintain
the balance.

Change the set point to a lower level, remain there for a while, then
return to the higher level requires a lot of thermal work.

Heat intensive industries such as steel, refineries, etc, run 24/7 for
just this reason.


No, the reason is that it costs them money to keep it warm and it also
costs them money to warm it up , but they can produce a product while
it is warm and not while it is warming up.

It is not how much they are spending on energy, it is their return on
that investment--less than zero (due to other operating costs)
while warming up, and greater than zero (hopefully) when at operating
temperature.

There are other considerations such as thermal stresses during warm-up
and cooling down.

--

FF

Because you have no control over the systems ability to "produce" more or
less. It's out put is a relative constant.
If you request more out of the system you pay more through an external
source.


"Kenneth" wrote in message
...

Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Leon wrote:
Because you have no control over the systems ability to "produce" more or
less. It's out put is a relative constant.

Water Furnace uses avariable speed (or at least two-speed) units so
there is some control.

If you request more out of the system you pay more through an external
source.

Beyond high-speed, correct, but that can also be controlled as to
whether it is used or not in a couple of different ways.

It's possible (probable?) the initial installation didn't not take
advantage of any of those options and the installer isn't clever enough
to recognize/implement them, but there are alternatives for most of the
issues.

When/if the unit does "max out" w/ the ground source, then the only
choice is an aux heat output, but OP has indicated they chose not to use
one anyway owing to having sized the unit(s) at a quite high output.

So, my conclusion is still that it would be very unusual set of
circumstances in this case if the setback would not reduce overall usage.




"Kenneth" wrote in message
...
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Tue, 27 Nov 2007 08:51:19 -0600, dpb
wrote:

Leon wrote:
Because you have no control over the systems ability to "produce" more or
less. It's out put is a relative constant.

Water Furnace uses avariable speed (or at least two-speed) units so
there is some control.

If you request more out of the system you pay more through an external
source.

Beyond high-speed, correct, but that can also be controlled as to
whether it is used or not in a couple of different ways.

It's possible (probable?) the initial installation didn't not take
advantage of any of those options and the installer isn't clever enough
to recognize/implement them, but there are alternatives for most of the
issues.

When/if the unit does "max out" w/ the ground source, then the only
choice is an aux heat output, but OP has indicated they chose not to use
one anyway owing to having sized the unit(s) at a quite high output.

So, my conclusion is still that it would be very unusual set of
circumstances in this case if the setback would not reduce overall usage.




"Kenneth" wrote in message
...
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."



Hi again,

Of course, the experiment is a very simple one, but right
now, we have only one electric meter.

We will soon have two, and with that, I should know.

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."

On Tue, 27 Nov 2007 14:09:49 GMT, "Leon"
wrote:



"Kenneth" wrote in message
.. .

Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."


Because you have no control over the systems ability to "produce" more or
less. It's out put is a relative constant.
If you request more out of the system you pay more through an external
source.


Hi Leon,

Yes, its output is constant, but does that lead to the
conclusion that we would, or would not save with a setback?

Thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Kenneth wrote:
On Tue, 27 Nov 2007 14:09:49 GMT, "Leon"
wrote:


"Kenneth" wrote in message
...
Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,
--
Kenneth

If you email... Please remove the "SPAMLESS."

Because you have no control over the systems ability to "produce" more or
less. It's out put is a relative constant.
If you request more out of the system you pay more through an external
source.


Hi Leon,

Yes, its output is constant, but does that lead to the
conclusion that we would, or would not save with a setback?

Are you sure it is constant--at least I was unaware that W-F used
single-speed units--they weren't when we did ours anyway, but that's
been quite a while ago.

Even if so, it does not lead to the conclusion. The savings of a
setback depend on the integral of the the demand over the time
period--if the average demand is lower, then the input required is lower
for a similar set of external conditions.

The only kicker in the mix is whether there really would be such a
significant loss in efficiency owing to the heat source "drawdown" that
the overall system efficiency drops sufficiently to cause more energy to
be used than is saved. I have an extremely difficult time believing
that to be at all likely.

See my other response for some suggested places to look for some more
definitive research and sources.

--

Kenneth wrote:

[...asking about setback and subject...]

Don't know if you gave up or got an answer but I mentioned the OSU site
earlier. Being bored, I went and found it -- here's the current link.
Didn't find a specific answer in the faq's, but they have a couple of
contact ways you can get to them.

http://www.igshpa.okstate.edu/index.htm


hth...

--

Kenneth wrote:


Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,


hi all!

i sent this email to Alliant Energy Geothermal
===============
there is a discussion underway with this as topic: -
We heat and cool our home geothermally (water to air system.) We
would, of course, like to decrease our costs further if we can, and so
have explored the benefits of setting our thermostat lower at those
times when the house (or parts of it) are not occupied. The folks who
designed the heating system say that with these systems, it is best to
leave the set temp unchanged. Of course, I have asked "why", but when I
do, it seems that smoke starts to come out of the phone. In essence,
they say that it is "best" but seem unable to say why. Might any of you
know what would be best in this regard , and particularly whether the
issue of thermostat setback is actually any different for geothermal
systems?
could you help me understand the issues involved? thanks in advance
for any input! chuck b:-)
==============
and i got this reply
-----------------------

Dear Chuck,

Set-up of a Geo system temperature during the cooling time of year
should allow a Geo system to recover the cooling and dehumidify as
quickly and more efficiently than other air sourced cooling systems.

Set-back is not typically recommended during the heating time of year
due to 1) a slower recovery time for heating, 2) the potential for the
back up electric elements kicking in to boost the reheating rate but, at
an added electric expense to you, 3) dependent on if you use a straight
well water open loop or only a minimal to non freeze protected closed
loop fluid, the lack of normal flows may allow for a potential for a
loop to freeze up and 4) many people who own set-back thermostats are
easily confused by the instructions for operating them and re-setting them.

All of these can cause contractor callbacks, they hate callbacks.

We do have a few of our regional Geo system owners who do a slight
setback for heating at maybe 2 to 4 degrees F maximum for 4 to 6 hours
but, all must realize the potential results.

During AC season and the daytime hours of unoccupied homes, they might
also do set up to minimize On Peak energy charges when they choose Time
of Use electric rate options.

I hope this helps. Thanks for the inquiry.

Leo

From: Alliant Energy Geothermal Web Forms
]
Sent: Wednesday, November 28, 2007 9:29 PM
To: Geothermal
Cc: Webmaster
Subject: Alliant Energy Geothermal -- Contact Us Form



chuck b:-)

On Fri, 30 Nov 2007 20:56:41 GMT, chuckb wrote:

Kenneth wrote:


Howdy,

This is way OT...(again), but:

We heat and cool our home geothermally (water to air
system.)

We would, of course, like to decrease our costs further if
we can, and so have explored the benefits of setting our
thermostat lower at those times when the house (or parts of
it) are not occupied.

The folks who designed the heating system say that with
these systems, it is best to leave the set temp unchanged.

Of course, I have asked "why", but when I do, it seems that
smoke starts to come out of the phone. In essence, they say
that it is "best" but seem unable to say why.

Might any of you know what would be best in this regard ,
and particularly whether the issue of thermostat setback is
actually any different for geothermal systems?

Sincere thanks,


hi all!

i sent this email to Alliant Energy Geothermal
===============
there is a discussion underway with this as topic: -
We heat and cool our home geothermally (water to air system.) We
would, of course, like to decrease our costs further if we can, and so
have explored the benefits of setting our thermostat lower at those
times when the house (or parts of it) are not occupied. The folks who
designed the heating system say that with these systems, it is best to
leave the set temp unchanged. Of course, I have asked "why", but when I
do, it seems that smoke starts to come out of the phone. In essence,
they say that it is "best" but seem unable to say why. Might any of you
know what would be best in this regard , and particularly whether the
issue of thermostat setback is actually any different for geothermal
systems?
could you help me understand the issues involved? thanks in advance
for any input! chuck b:-)
==============
and i got this reply
-----------------------

Dear Chuck,

Set-up of a Geo system temperature during the cooling time of year
should allow a Geo system to recover the cooling and dehumidify as
quickly and more efficiently than other air sourced cooling systems.

Set-back is not typically recommended during the heating time of year
due to 1) a slower recovery time for heating, 2) the potential for the
back up electric elements kicking in to boost the reheating rate but, at
an added electric expense to you, 3) dependent on if you use a straight
well water open loop or only a minimal to non freeze protected closed
loop fluid, the lack of normal flows may allow for a potential for a
loop to freeze up and 4) many people who own set-back thermostats are
easily confused by the instructions for operating them and re-setting them.

All of these can cause contractor callbacks, they hate callbacks.

We do have a few of our regional Geo system owners who do a slight
setback for heating at maybe 2 to 4 degrees F maximum for 4 to 6 hours
but, all must realize the potential results.

During AC season and the daytime hours of unoccupied homes, they might
also do set up to minimize On Peak energy charges when they choose Time
of Use electric rate options.

I hope this helps. Thanks for the inquiry.

Leo

From: Alliant Energy Geothermal Web Forms
]
Sent: Wednesday, November 28, 2007 9:29 PM
To: Geothermal
Cc: Webmaster
Subject: Alliant Energy Geothermal -- Contact Us Form



chuck b:-)
Now that has a few good answers. I would not have thought about the
freezing closed loops.

On Fri, 30 Nov 2007 22:21:13 -0500, Jim Behning
wrote:

Now that has a few good answers. I would not have thought about the
freezing closed loops.

Howdy,

Any responsibly designed system protects against such
freezing...

All the best,
--
Kenneth

If you email... Please remove the "SPAMLESS."