Ways to save energy, carbon, or pollution - NOW!

"Mike Vandeman" wrote in message
...
On Wed, 09 May 2007 22:23:46 GMT, "Jeff Strickland"
wrote:


"Mike Vandeman" wrote in message
. ..
My panels are not PV. They are black rubber/plastic. Black absorbs heat,
watter passes through and absorbs the heat. The panels are raised about
4
inches above the roof tiles.

Then they should keep the roof under them cooler than it would
otherwise be. You would have to measure that underneath the roof.


First, I'd have to care. Second, I'd have to know what the temp was before
the panels went up. Third, the temp inside the attic is the only thing
that
is important, and it's very high -- as attics are in my part of the world.

The purpose of the panels is to heat the water. If there is a side
benefit,
I can't tell and don't care. Any side benefit is so minute as to be
utterly
insignificant. My only point here is that one should buy solar panels for
a
swimming pool because they want to warm the pool. There is no other reason
to consider solar panels, keeping the house cooler is not something that
happens.

I'm not dissing panels, I think they are great and well worth the money to
buy and install them. I just dispute the supposed benefit that they will
cool the house.

I note that you have the ability to easily test that, but prefer to
use your own unscientific judgment -- as usual.



I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the panels
went up onto the roof.

On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland"
wrote:


"Mike Vandeman" wrote in message
.. .
On Wed, 09 May 2007 22:23:46 GMT, "Jeff Strickland"
wrote:


"Mike Vandeman" wrote in message
...
My panels are not PV. They are black rubber/plastic. Black absorbs heat,
watter passes through and absorbs the heat. The panels are raised about
4
inches above the roof tiles.

Then they should keep the roof under them cooler than it would
otherwise be. You would have to measure that underneath the roof.


First, I'd have to care. Second, I'd have to know what the temp was before
the panels went up. Third, the temp inside the attic is the only thing
that
is important, and it's very high -- as attics are in my part of the world.

The purpose of the panels is to heat the water. If there is a side
benefit,
I can't tell and don't care. Any side benefit is so minute as to be
utterly
insignificant. My only point here is that one should buy solar panels for
a
swimming pool because they want to warm the pool. There is no other reason
to consider solar panels, keeping the house cooler is not something that
happens.

I'm not dissing panels, I think they are great and well worth the money to
buy and install them. I just dispute the supposed benefit that they will
cool the house.

I note that you have the ability to easily test that, but prefer to
use your own unscientific judgment -- as usual.



I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the panels
went up onto the roof.

That's irrelevant. The temperature is different now. What you need to
do is compare the temperature under the solar panels (UNDER the roof,
in the attic) with the temperature elsewhere under the roof.
--
I am working on creating wildlife habitat that is off-limits to
humans ("pure habitat"). Want to help? (I spent the previous 8
years fighting auto dependence and road construction.)

Please don't put a cell phone next to any part of your body that you are fond of!

http://home.pacbell.net/mjvande

On May 10, 7:28 am, Mike Vandeman wrote:
On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland"

I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the panels
went up onto the roof.

That's irrelevant. The temperature is different now. What you need to
do is compare the temperature under the solar panels (UNDER the roof,
in the attic) with the temperature elsewhere under the roof.

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

BJ

On 10 May 2007 07:40:54 -0700, Bruce Jensen
wrote:

On May 10, 7:28 am, Mike Vandeman wrote:
On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland"

I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the panels
went up onto the roof.

That's irrelevant. The temperature is different now. What you need to
do is compare the temperature under the solar panels (UNDER the roof,
in the attic) with the temperature elsewhere under the roof.

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

They are called "rafters". Haven't you even been in an attic? The test
is EASY. Just hold a thermometer in the cooler & hotter areas &
compare. What's so hard about that?

BJ
--
I am working on creating wildlife habitat that is off-limits to
humans ("pure habitat"). Want to help? (I spent the previous 8
years fighting auto dependence and road construction.)

Please don't put a cell phone next to any part of your body that you are fond of!

http://home.pacbell.net/mjvande

On May 10, 8:02 am, Mike Vandeman wrote:

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

They are called "rafters". Haven't you even been in an attic? The test
is EASY. Just hold a thermometer in the cooler & hotter areas &
compare. What's so hard about that?

Nothing hard about it, but you won't get an accurate answer. I have
never seen an attic rafter that would substantially prevent conduction
or convection. The slightest breeze would almost immediately mix the
air, and as you know, most attics are ventilated. On top of this, the
slightest slant of the roof would encourage immediate internal
convection and mixing loops, even without an external breeze source.
The mixing of air and transfer of heat from warm to cool would be so
constant and rapid, right from the moment the first solar rays hit the
roof, that your temperature measurement deltas would be meaninglessly
low. The only thing you could do would be to measure the temps of the
roof material itself - and even that is not really accurate.

I have no doubt that siphoning off the heat from solar radiation
incident on a rooftop would result in substantial attic cooling,
whether by hot water flow or absorption and reflection/insulation from
solar cells (which would not only capture and convert some of the
energy, but with the right system design also allow free airflow
underneath the panels, allowing for further heat dissipation). One
could design a good-quality experiment with specially insulated
compartments in an attic - and I am sure this has been done by
somebody - but as Jeff suggests, the insulating or off-conducting
properties of solar systems on roofs may not be the first thing a
customer would be thinking of, even if it is measurable and
significant.

BJ

On 10 May 2007 08:49:36 -0700, Bruce Jensen
wrote:

On May 10, 8:02 am, Mike Vandeman wrote:

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

They are called "rafters". Haven't you even been in an attic? The test
is EASY. Just hold a thermometer in the cooler & hotter areas &
compare. What's so hard about that?

Nothing hard about it, but you won't get an accurate answer. I have
never seen an attic rafter that would substantially prevent conduction
or convection. The slightest breeze would almost immediately mix the
air, and as you know, most attics are ventilated. On top of this, the
slightest slant of the roof would encourage immediate internal
convection and mixing loops, even without an external breeze source.
The mixing of air and transfer of heat from warm to cool would be so
constant and rapid, right from the moment the first solar rays hit the
roof, that your temperature measurement deltas would be meaninglessly
low. The only thing you could do would be to measure the temps of the
roof material itself - and even that is not really accurate.

I have no doubt that siphoning off the heat from solar radiation
incident on a rooftop would result in substantial attic cooling,
whether by hot water flow or absorption and reflection/insulation from
solar cells (which would not only capture and convert some of the
energy, but with the right system design also allow free airflow
underneath the panels, allowing for further heat dissipation). One
could design a good-quality experiment with specially insulated
compartments in an attic - and I am sure this has been done by
somebody - but as Jeff suggests, the insulating or off-conducting
properties of solar systems on roofs may not be the first thing a
customer would be thinking of, even if it is measurable and
significant.

BJ

One test is worth a thousand opinions.
--
I am working on creating wildlife habitat that is off-limits to
humans ("pure habitat"). Want to help? (I spent the previous 8
years fighting auto dependence and road construction.)

Please don't put a cell phone next to any part of your body that you are fond of!

http://home.pacbell.net/mjvande

"Mike Vandeman" wrote in message
...
I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the panels
went up onto the roof.

That's irrelevant. The temperature is different now. What you need to
do is compare the temperature under the solar panels (UNDER the roof,
in the attic) with the temperature elsewhere under the roof.


Dude! I've been in the attic. It's the same everywhere. The question is, is
it cooler now than it was before? I have no way of knowing because I don't
know what it was before, but I do know that it is very hot up there now.

The relevence is that I need a benchmark to know if it is cooler now. As a
practical matter, it is no cooler. It is not cooler enough to warrant that
as a reason to buy solar panels.

"Mike Vandeman" wrote in message
...
On 10 May 2007 07:40:54 -0700, Bruce Jensen
wrote:

On May 10, 7:28 am, Mike Vandeman wrote:
On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland"

I haven't the ability to easily test anything. I have no benchmark from
which to compare what I have currently with what I had before the
panels
went up onto the roof.

That's irrelevant. The temperature is different now. What you need to
do is compare the temperature under the solar panels (UNDER the roof,
in the attic) with the temperature elsewhere under the roof.

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

They are called "rafters". Haven't you even been in an attic? The test
is EASY. Just hold a thermometer in the cooler & hotter areas &
compare. What's so hard about that?


My panels extend from the front edge of the roof all of the way to the rear.
I cannot simply measure the heat under a set of rafters, then measure again
under another set.

I say again, solar panels to heat swimming pool water is a very good idea --
if a bit costly. Buy them because you want to extend the swimming season or
have a hot pool that is not heated via natural gas. Do not buy solar panels
because there is any evidence they cool the space underneath them. They are
black, and they heat all of the way through, and radiate heat from the
underside.

Buy them to heat the pool, not to cool the house.

"Mike Vandeman" wrote in message
...
On 10 May 2007 08:49:36 -0700, Bruce Jensen
wrote:

On May 10, 8:02 am, Mike Vandeman wrote:

In theory an OK idea, but real-world internal convection and
conduction would make this test very difficult, unless the attic were
compartmentalized so as to reflect the covered vs. uncovered area.

They are called "rafters". Haven't you even been in an attic? The test
is EASY. Just hold a thermometer in the cooler & hotter areas &
compare. What's so hard about that?

Nothing hard about it, but you won't get an accurate answer. I have
never seen an attic rafter that would substantially prevent conduction
or convection. The slightest breeze would almost immediately mix the
air, and as you know, most attics are ventilated. On top of this, the
slightest slant of the roof would encourage immediate internal
convection and mixing loops, even without an external breeze source.
The mixing of air and transfer of heat from warm to cool would be so
constant and rapid, right from the moment the first solar rays hit the
roof, that your temperature measurement deltas would be meaninglessly
low. The only thing you could do would be to measure the temps of the
roof material itself - and even that is not really accurate.

I have no doubt that siphoning off the heat from solar radiation
incident on a rooftop would result in substantial attic cooling,
whether by hot water flow or absorption and reflection/insulation from
solar cells (which would not only capture and convert some of the
energy, but with the right system design also allow free airflow
underneath the panels, allowing for further heat dissipation). One
could design a good-quality experiment with specially insulated
compartments in an attic - and I am sure this has been done by
somebody - but as Jeff suggests, the insulating or off-conducting
properties of solar systems on roofs may not be the first thing a
customer would be thinking of, even if it is measurable and
significant.

BJ

One test is worth a thousand opinions.


All you have is an opinion. You have no test. You have no experience in this
field. And, you have no practical exposure to that which you stand behind.

I too only have an opinion, but my opinion is backed by practical
experience -- 10 years of practical experience. My attic is one ****ing hot
place to be, with or without the solar panels.

You might be able to show some other kind of home construction where solar
panels help to cool the house beneath them, but none of the homes in my
community appear to be any different than mine in this respect.

PS
I was mildly pleased that you posted a list of stuff that is actually
beneficial, and that I agreed with almost entirely. I point out a tiny,
miniscule really, point of contention, and you completely turned it around.

I used to think you were a complete idiot. Now I know. There is no hope for
you as a human. We'll all be better off if you just went away.

Mike Vandeman wrote:
Ways to save energy, carbon, or pollution - NOW!:

1. Replace incandescent bulbs with compact fluorescent bulbs -
especially those you leave on for an extended period.

No, *Only* those you leave on for an extended period of time.
Fluorescents have a much greater start-up energy requirement than do
incadescents so if you have a light somewhere that is usually only on
for brief periods (closet, some bathrooms, storeroom) an incadescent
can be more energy efficient.