Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > sci.electronics.design > #447363 > unrolled thread
| Started by | rickman <gnuarm@gmail.com> |
|---|---|
| First post | 2017-02-11 22:02 -0500 |
| Last post | 2017-03-01 17:33 -0800 |
| Articles | 20 on this page of 92 — 24 participants |
Back to article view | Back to sci.electronics.design
Window Heater rickman <gnuarm@gmail.com> - 2017-02-11 22:02 -0500
Re: Window Heater bill.sloman@ieee.org - 2017-02-11 20:57 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 01:02 -0500
Re: Window Heater whit3rd <whit3rd@gmail.com> - 2017-02-11 23:07 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 03:52 -0500
Re: Window Heater whit3rd <whit3rd@gmail.com> - 2017-02-12 18:32 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 21:42 -0500
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-13 10:04 -0600
Re: Window Heater makolber@yahoo.com - 2017-02-13 10:17 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-13 15:30 -0500
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-13 15:39 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-13 20:28 -0500
Re: Window Heater krw@notreal.com - 2017-02-13 20:48 -0500
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-13 13:47 -0800
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 06:56 -0800
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-14 07:17 -0800
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 13:20 -0800
Re: Window Heater George Herold <gherold@teachspin.com> - 2017-02-14 16:17 -0800
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-14 16:28 -0800
Re: Window Heater George Herold <gherold@teachspin.com> - 2017-02-14 17:42 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 21:18 -0500
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 19:20 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 22:42 -0500
Re: Window Heater George Herold <gherold@teachspin.com> - 2017-02-15 06:51 -0800
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-15 06:06 -0800
Re: Window Heater George Herold <gherold@teachspin.com> - 2017-02-15 06:54 -0800
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-15 09:15 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-15 15:02 -0500
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-15 16:38 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-15 19:50 -0500
Re: Window Heater Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-17 11:18 +0000
Re: Window Heater Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-16 08:28 +0000
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 14:07 -0500
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 12:57 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 17:32 -0500
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 19:12 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 14:16 -0500
Re: Window Heater dagmargoodboat@yahoo.com - 2017-02-14 12:53 -0800
Re: Window Heater John S <Sophi.2@invalid.org> - 2017-02-14 16:14 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 17:35 -0500
Re: Window Heater John S <Sophi.2@invalid.org> - 2017-02-15 10:45 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-15 15:06 -0500
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-15 16:46 -0500
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 17:34 -0500
Re: Window Heater bill.sloman@ieee.org - 2017-02-12 04:57 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 18:19 -0500
Re: Window Heater Winfield Hill <hill@rowland.harvard.edu> - 2017-02-12 10:42 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 18:30 -0500
Re: Window Heater Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-12 08:45 +0000
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 03:57 -0500
Re: Window Heater Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-12 09:34 +0000
Re: Window Heater Jon Elson <elson@pico-systems.com> - 2017-02-11 23:52 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 01:07 -0500
Re: Window Heater Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-14 10:40 +0000
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 06:00 -0500
Re: Window Heater John S <Sophi.2@invalid.org> - 2017-02-14 16:17 -0600
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-14 14:28 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-14 17:36 -0500
Re: Window Heater Mikko OH2HVJ <mikko.syrjalahti@nospam.fi> - 2017-02-12 14:54 +0200
Re: Window Heater Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-12 08:56 -0700
Re: Window Heater Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-02-12 20:14 +0200
Re: Window Heater Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-11 00:30 -0500
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 18:56 -0500
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-12 06:35 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 19:01 -0500
Re: Window Heater "dcaster@krl.org" <dcaster@krl.org> - 2017-02-12 17:29 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 21:37 -0500
Re: Window Heater Jon Elson <jmelson@wustl.edu> - 2017-02-13 15:08 -0600
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-13 13:32 -0800
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-12 08:20 -0800
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-12 11:48 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 19:03 -0500
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-13 09:58 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-13 15:33 -0500
Re: Window Heater Jon Elson <jmelson@wustl.edu> - 2017-02-13 15:10 -0600
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-13 13:36 -0800
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-13 15:40 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-13 20:34 -0500
Re: Window Heater krw@notreal.com - 2017-02-13 20:52 -0500
Re: Window Heater Tim Wescott <seemywebsite@myfooter.really> - 2017-02-12 12:02 -0600
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 19:05 -0500
Re: Window Heater Tim Wescott <seemywebsite@myfooter.really> - 2017-02-14 17:49 -0600
Re: Window Heater bitrex <bitrex@de.lete.earthlink.net> - 2017-02-12 13:06 -0500
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-12 19:05 -0500
Re: Window Heater Clifford Heath <no.spam@please.net> - 2017-02-13 11:21 +1100
Re: Window Heater krw@notreal.com - 2017-02-12 19:28 -0500
Re: Window Heater Martin Riddle <martin_ridd@verizon.net> - 2017-02-12 21:57 -0500
Re: Window Heater "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-13 10:01 -0600
Re: Window Heater Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-13 13:49 -0800
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-02-13 20:36 -0500
Re: Window Heater rickman <gnuarm@gmail.com> - 2017-03-01 19:44 -0500
Re: Window Heater George Herold <gherold@teachspin.com> - 2017-03-01 17:33 -0800
Page 2 of 5 — ← Prev page 1 [2] 3 4 5 Next page →
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 21:18 -0500 |
| Message-ID | <o80dmj$lua$1@dont-email.me> |
| In reply to | #447688 |
On 2/14/2017 8:42 PM, George Herold wrote: > On Tuesday, February 14, 2017 at 7:28:58 PM UTC-5, dca...@krl.org wrote: >> On Tuesday, February 14, 2017 at 4:20:49 PM UTC-5, dagmarg...@yahoo.com wrote: >> >> >>> >>> I'm not sure what you mean here by 'up' and 'down'--in this context of a >>> refrigerator and a window, the surfaces are both vertical and the heat >>> flow is horizontal, through the insulation >> >> I was commenting on heat flow in general. Not just about the window case.. >> So if you are insulating an attic, in summer the heat flow is down and in the winter the heat flow is up. So in the summer the foil will help a lot and in the winter foil will have almost no effect. > > OK, I'm not sure in practice, but in theory I don'think it > should matter much which side of the foil is hot or cold. > It's an IR reflector, pretty much the same from both sides.. > (What's the peak wavelength/ frequency at ~300K) It's not which side of the foil is hot or cold. It has to do with the other mechanisms of heat transfer. If the heat is rising, in theory it will contact the foil and convect/conduct the heat to the foil while a cold room won't do that so much. I'm not sure the theory is sound as you get convection regardless of which way the "heat" is moving. Its the same transfer mechanism. But I have seen ratings of foil lined insulation and they do have different ratings for different uses and orientations. The foil will work best if adjacent to a vacuum, but that's not practical other than in a thermos bottle. The point is the foil prevents radiation emission and/or absorption. -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-02-14 19:20 -0800 |
| Message-ID | <4a8a92c5-e574-4c49-ade7-27bb1c370761@googlegroups.com> |
| In reply to | #447688 |
On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote: > On Tuesday, February 14, 2017 at 7:28:58 PM UTC-5, dca...@krl.org wrote: > > On Tuesday, February 14, 2017 at 4:20:49 PM UTC-5, dagmarg...@yahoo.com wrote: > > > > > > > > > > I'm not sure what you mean here by 'up' and 'down'--in this context of a > > > refrigerator and a window, the surfaces are both vertical and the heat > > > flow is horizontal, through the insulation > > > > I was commenting on heat flow in general. Not just about the window case. > > So if you are insulating an attic, in summer the heat flow is down and in the winter the heat flow is up. So in the summer the foil will help a lot and in the winter foil will have almost no effect. > > OK, I'm not sure in practice, but in theory I don'think it > should matter much which side of the foil is hot or cold. > It's an IR reflector, pretty much the same from both sides.. > (What's the peak wavelength/ frequency at ~300K) > > George H. I think the difference is this--if the foam's exposed, IR hits and warms the foam. Then you have warmed foam contacting foil, facing the refrigerator (cold). OTOH with the foil facing out, the IR is reflected rather than absorbed, and you also get the insulation value of the (cool) foam between the foil and fridge. Cheers, James Arthur
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 22:42 -0500 |
| Message-ID | <o80ija$p46$1@dont-email.me> |
| In reply to | #447697 |
On 2/14/2017 10:20 PM, dagmargoodboat@yahoo.com wrote: > On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote: >> On Tuesday, February 14, 2017 at 7:28:58 PM UTC-5, dca...@krl.org wrote: >>> On Tuesday, February 14, 2017 at 4:20:49 PM UTC-5, dagmarg...@yahoo.com wrote: >>> >>> >>>> >>>> I'm not sure what you mean here by 'up' and 'down'--in this context of a >>>> refrigerator and a window, the surfaces are both vertical and the heat >>>> flow is horizontal, through the insulation >>> >>> I was commenting on heat flow in general. Not just about the window case. >>> So if you are insulating an attic, in summer the heat flow is down and in the winter the heat flow is up. So in the summer the foil will help a lot and in the winter foil will have almost no effect. >> >> OK, I'm not sure in practice, but in theory I don'think it >> should matter much which side of the foil is hot or cold. >> It's an IR reflector, pretty much the same from both sides.. >> (What's the peak wavelength/ frequency at ~300K) >> >> George H. > > I think the difference is this--if the foam's exposed, IR hits and warms > the foam. Then you have warmed foam contacting foil, facing the refrigerator > (cold). > > OTOH with the foil facing out, the IR is reflected rather than absorbed, > and you also get the insulation value of the (cool) foam between the foil > and fridge. So you can use two pieces of foiled foam side by side, but facing opposite ways. Then connect the two via a Stirling engine and get free energy! -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | George Herold <gherold@teachspin.com> |
|---|---|
| Date | 2017-02-15 06:51 -0800 |
| Message-ID | <b40c0e7a-96ee-4b7d-aa91-55d72af5d83c@googlegroups.com> |
| In reply to | #447697 |
On Tuesday, February 14, 2017 at 10:20:10 PM UTC-5, dagmarg...@yahoo.com wrote:
> On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote:
> > On Tuesday, February 14, 2017 at 7:28:58 PM UTC-5, dca...@krl.org wrote:
> > > On Tuesday, February 14, 2017 at 4:20:49 PM UTC-5, dagmarg...@yahoo.com wrote:
> > >
> > >
> > > >
> > > > I'm not sure what you mean here by 'up' and 'down'--in this context of a
> > > > refrigerator and a window, the surfaces are both vertical and the heat
> > > > flow is horizontal, through the insulation
> > >
> > > I was commenting on heat flow in general. Not just about the window case.
> > > So if you are insulating an attic, in summer the heat flow is down and in the winter the heat flow is up. So in the summer the foil will help a lot and in the winter foil will have almost no effect.
> >
> > OK, I'm not sure in practice, but in theory I don'think it
> > should matter much which side of the foil is hot or cold.
> > It's an IR reflector, pretty much the same from both sides..
> > (What's the peak wavelength/ frequency at ~300K)
> >
> > George H.
>
> I think the difference is this--if the foam's exposed, IR hits and warms
> the foam. Then you have warmed foam contacting foil, facing the refrigerator
> (cold).
>
> OTOH with the foil facing out, the IR is reflected rather than absorbed,
> and you also get the insulation value of the (cool) foam between the foil
> and fridge.
OK it's complicated. In my simple model the foil is at some
intermediate temperature between the cold and hot... (Maybe this is
a bad model, 'cause I'm not thinking about other mechanisms effecting the foil
temperature.) You get a win because of the low emmisivity of the Al.
But it's not something I know a lot about....
Hmm this says that getting rid of the air is important!
https://accelconf.web.cern.ch/accelconf/e00/PAPERS/TUP5A13.pdf
George H.
>
> Cheers,
> James Arthur
[toc] | [prev] | [next] | [standalone]
| From | "dcaster@krl.org" <dcaster@krl.org> |
|---|---|
| Date | 2017-02-15 06:06 -0800 |
| Message-ID | <b9097aa8-6109-4923-bc42-dcd476d5eadf@googlegroups.com> |
| In reply to | #447688 |
On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote:
nter foil will have almost no effect.>
> OK, I'm not sure in practice, but in theory I don'think it
> should matter much which side of the foil is hot or cold.
> It's an IR reflector, pretty much the same from both sides..
> (What's the peak wavelength/ frequency at ~300K)
>
> George H.
As far as blocking radiation , it does not matter. But as far as blocking heat flow it does.
Say you have a horizontal surface with the air below the surface is hot and the air above the surface cold. The heat from below heats the aluminum foil. THe air immediately above the aluminum foil is warmed and rises. Almost no heat flow effect.
Now with the same surface by cold below and warm above. The air above heats the aluminum foil. The air immediately under the aluminum foil is warmed. But it can not rise because the aluminum foil is above it. It does not radiate down.
So little heat flow.
Dan
[toc] | [prev] | [next] | [standalone]
| From | George Herold <gherold@teachspin.com> |
|---|---|
| Date | 2017-02-15 06:54 -0800 |
| Message-ID | <3ad44371-01da-4f6a-b5f9-847bf915428c@googlegroups.com> |
| In reply to | #447732 |
On Wednesday, February 15, 2017 at 9:06:36 AM UTC-5, dca...@krl.org wrote: > On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote: > > nter foil will have almost no effect.> > > OK, I'm not sure in practice, but in theory I don'think it > > should matter much which side of the foil is hot or cold. > > It's an IR reflector, pretty much the same from both sides.. > > (What's the peak wavelength/ frequency at ~300K) > > > > George H. > > As far as blocking radiation , it does not matter. But as far as blocking heat flow it does. > > Say you have a horizontal surface with the air below the surface is hot and the air above the surface cold. The heat from below heats the aluminum foil. THe air immediately above the aluminum foil is warmed and rises. Almost no heat flow effect. > > Now with the same surface by cold below and warm above. The air above heats the aluminum foil. The air immediately under the aluminum foil is warmed. But it can not rise because the aluminum foil is above it. It does not radiate down. > So little heat flow. OK, but in either case does it matter if it's foam on top or foil on top? George H. > > Dan
[toc] | [prev] | [next] | [standalone]
| From | "dcaster@krl.org" <dcaster@krl.org> |
|---|---|
| Date | 2017-02-15 09:15 -0800 |
| Message-ID | <9c55f4ca-8fe3-4c33-9faf-65953ddb6c4a@googlegroups.com> |
| In reply to | #447739 |
On Wednesday, February 15, 2017 at 9:54:44 AM UTC-5, George Herold wrote:
>
> OK, but in either case does it matter if it's foam on top or foil on top?
>
> George H.
> >
> > Dan
I do not think it matters.
I tried to find the source document , but failed. I believe it was a gov publication on insulation for buildings. It was about a forty page pamphlet and covered pretty much everything. It had soil temperature measurements of various places in the U.S. as well as air temp measurements. The material would still be good, but it was published before 1965 and is probably no longer .
Dan
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-15 15:02 -0500 |
| Message-ID | <o82c0k$p3g$1@dont-email.me> |
| In reply to | #447732 |
On 2/15/2017 9:06 AM, dcaster@krl.org wrote: > On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote: > > nter foil will have almost no effect.> >> OK, I'm not sure in practice, but in theory I don'think it >> should matter much which side of the foil is hot or cold. >> It's an IR reflector, pretty much the same from both sides.. >> (What's the peak wavelength/ frequency at ~300K) >> >> George H. > > As far as blocking radiation , it does not matter. But as far as blocking heat flow it does. > > Say you have a horizontal surface with the air below the surface is hot and the air above the surface cold. The heat from below heats the aluminum foil. THe air immediately above the aluminum foil is warmed and rises. Almost no heat flow effect. > > Now with the same surface by cold below and warm above. The air above heats the aluminum foil. The air immediately under the aluminum foil is warmed. But it can not rise because the aluminum foil is above it. It does not radiate down. > So little heat flow. What you just described is foil agnostic. You described the heat flow from conduction and convection. Take the foil out of the picture and you get the same results except there will also be radiation in both cases while with foil there will be very little radiation in both cases. You have not shown a difference in functioning of the foil in the two cases. -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | "dcaster@krl.org" <dcaster@krl.org> |
|---|---|
| Date | 2017-02-15 16:38 -0800 |
| Message-ID | <73b36cc7-b4f5-44c1-a571-4fb79167d468@googlegroups.com> |
| In reply to | #447779 |
On Wednesday, February 15, 2017 at 3:02:14 PM UTC-5, rickman wrote:
> On 2/15/2017 9:06 AM, dcaster@krl.org wrote:
> > On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote:
> >
> > nter foil will have almost no effect.>
> >> OK, I'm not sure in practice, but in theory I don'think it
> >> should matter much which side of the foil is hot or cold.
> >> It's an IR reflector, pretty much the same from both sides..
> >> (What's the peak wavelength/ frequency at ~300K)
> >>
> >> George H.
> >
> > As far as blocking radiation , it does not matter. But as far as blocking heat flow it does.
> >
> > Say you have a horizontal surface with the air below the surface is hot and the air above the surface cold. The heat from below heats the aluminum foil. THe air immediately above the aluminum foil is warmed and rises. Almost no heat flow effect.
> >
> > Now with the same surface by cold below and warm above. The air above heats the aluminum foil. The air immediately under the aluminum foil is warmed. But it can not rise because the aluminum foil is above it. It does not radiate down.
> > So little heat flow.
>
> What you just described is foil agnostic. You described the heat flow
> from conduction and convection. Take the foil out of the picture and
> you get the same results except there will also be radiation in both
> cases while with foil there will be very little radiation in both cases.
>
> You have not shown a difference in functioning of the foil in the two
> cases.
>
> --
>
> Rick C
Keep thinking. You might get what I said.
Dan
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-15 19:50 -0500 |
| Message-ID | <o82std$in9$2@dont-email.me> |
| In reply to | #447807 |
On 2/15/2017 7:38 PM, dcaster@krl.org wrote: > On Wednesday, February 15, 2017 at 3:02:14 PM UTC-5, rickman wrote: >> On 2/15/2017 9:06 AM, dcaster@krl.org wrote: >>> On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold wrote: >>> >>> nter foil will have almost no effect.> >>>> OK, I'm not sure in practice, but in theory I don'think it >>>> should matter much which side of the foil is hot or cold. >>>> It's an IR reflector, pretty much the same from both sides.. >>>> (What's the peak wavelength/ frequency at ~300K) >>>> >>>> George H. >>> >>> As far as blocking radiation , it does not matter. But as far as blocking heat flow it does. >>> >>> Say you have a horizontal surface with the air below the surface is hot and the air above the surface cold. The heat from below heats the aluminum foil. THe air immediately above the aluminum foil is warmed and rises. Almost no heat flow effect. >>> >>> Now with the same surface by cold below and warm above. The air above heats the aluminum foil. The air immediately under the aluminum foil is warmed. But it can not rise because the aluminum foil is above it. It does not radiate down. >>> So little heat flow. >> >> What you just described is foil agnostic. You described the heat flow >> from conduction and convection. Take the foil out of the picture and >> you get the same results except there will also be radiation in both >> cases while with foil there will be very little radiation in both cases. >> >> You have not shown a difference in functioning of the foil in the two >> cases. >> >> -- >> >> Rick C > > > Keep thinking. You might get what I said. I don't know why you think the foil has any impact other than reducing the radiation. If you replace the foil with any other material it works exactly as you describe. The only difference is that the foil prevents radiation which otherwise happens in both directions using some other film. -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | Martin Brown <|||newspam|||@nezumi.demon.co.uk> |
|---|---|
| Date | 2017-02-17 11:18 +0000 |
| Message-ID | <o86m6u$1l8o$1@gioia.aioe.org> |
| In reply to | #447732 |
On 15/02/2017 14:06, dcaster@krl.org wrote: > On Tuesday, February 14, 2017 at 8:42:46 PM UTC-5, George Herold > wrote: > > nter foil will have almost no effect.> >> OK, I'm not sure in practice, but in theory I don'think it should >> matter much which side of the foil is hot or cold. It's an IR >> reflector, pretty much the same from both sides.. (What's the peak >> wavelength/ frequency at ~300K) > > As far as blocking radiation , it does not matter. But as far as > blocking heat flow it does. If you have air present. > Say you have a horizontal surface with the air below the surface is > hot and the air above the surface cold. The heat from below heats > the aluminum foil. THe air immediately above the aluminum foil is > warmed and rises. Almost no heat flow effect. > > Now with the same surface by cold below and warm above. The air > above heats the aluminum foil. The air immediately under the > aluminum foil is warmed. But it can not rise because the aluminum > foil is above it. It does not radiate down. So little heat flow. ITYM it does not *convect* down. It remains trapped as a thin barrier layer against the warm foil surface and heat transfer downwards is only by radiation and slow diffusion (and not by bulk convective motion). If you have an idealised radiation balance problem with source temperatures T, t either side of a flat plate in vacuum then at equilibrium the plate temperature x is given by energy balance. Unless the plate is a perfect idealised mirror it will absorb a small amount of radiation from each source and emit the same power at equilibrium. 2x^4 = t^4 + T^4 Hence x = 0.841T[1 +(t/T)^4)]^(1/4) -- Regards, Martin Brown
[toc] | [prev] | [next] | [standalone]
| From | Martin Brown <|||newspam|||@nezumi.demon.co.uk> |
|---|---|
| Date | 2017-02-16 08:28 +0000 |
| Message-ID | <o83nqr$1e3r$1@gioia.aioe.org> |
| In reply to | #447680 |
On 15/02/2017 00:28, dcaster@krl.org wrote: > On Tuesday, February 14, 2017 at 4:20:49 PM UTC-5, > dagmarg...@yahoo.com wrote: >> I'm not sure what you mean here by 'up' and 'down'--in this context >> of a refrigerator and a window, the surfaces are both vertical and >> the heat flow is horizontal, through the insulation > > I was commenting on heat flow in general. Not just about the window > case. So if you are insulating an attic, in summer the heat flow is > down and in the winter the heat flow is up. So in the summer the > foil will help a lot and in the winter foil will have almost no > effect. Although it is true that in summer the effect of coating the inner surface of the roof with a thin layer of insulator and a reflective coating is extremely effective at stopping radiative heat getting in and since the warm air stays trapped against the upper parts a simple vent at the top will be very effective. The main reason though is that the temperature difference is huge. Roof in strong sunshine can be ~70C - well above the point where thermal radiation flow is important. In winter the radiation barrier is still effective provided that the temperature difference across it is ~30K or so but the air convection of heat from below upwards is now the dominant process and summer vents at the top of the roof are invariably in exactly the wrong place. You can gain a lot by insulating the floor of the loft with thick glass fibre in what amounts to space blanket aluminised polythene bag. This is the more common way to do it in the UK since we hardly ever have days so sunny that the roof space over heating is a problem. Even if the aluminising doesn't do much the bag makes it a lot nicer to handle. Typical winter inside to outside temperature seldom exceeds 30K here and with the mild winters recently 15K is about average. So most of the time the radiative contribution to winter losses is small. -- Regards, Martin Brown
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 14:07 -0500 |
| Message-ID | <o7vkdl$h9$1@dont-email.me> |
| In reply to | #447642 |
On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: > On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: >> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: >>> On 2/12/2017 2:07 AM, whit3rd wrote: >>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: >> >>>> Have you considered that, rather than a draft, your chill is due to >>>> radiated heat loss? >> >>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? >> >> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths >> are transparent to longer wavelengths. You can't see UV light, because >> the human eye lens is a cloudy white in that part of the spectrum. >> Good insulation has to be opaque. >> >> Unless, the styrofoam is the foil-backed kind? > > You're on the right track (as is krw). > > A couple years ago I investigated improving the efficiency of a > refrigerator by adding external insulation. Measuring the temperature > differential across the insulation allowed measurement and calculation > of the actual loss. > > It took 4" of rigid foam insulation[1] to produce the same temperature > differential as was achieved with 1/2" of foil-backed polyisocyanurate > foam.[2] > > [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 > > [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 > > So, the foil barrier is stunningly useful. (The foil has to be installed > facing the heat source. Anything contacting the foil eliminates the benefit, > since heat is then simply conducted straight through.) > > I applied this insight to the exact drafty window problem Rick's solving. > Two aluminized car dashboard shades, held in place at night with tension > rods[3] works amazingly well. > > [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 > > It was a cheap experiment. > > The soft dashboard shades were $1 each at the local DollarTree. They're not > fully opaque--enough daylight shines through to yield useful illumination, > should you choose to leave them up on a super-cold day. > > There's still a draft, but markedly less. Rick will still probably prefer > his heater. 200w for one heater, though, is as almost much as my whole house > (280w, average draw last month). You've got the heat draw off by nearly a factor of ten. Who said 200 watts? -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-02-14 12:57 -0800 |
| Message-ID | <ea929410-f6e5-4d5a-a4cc-0e2bf9735b62@googlegroups.com> |
| In reply to | #447655 |
On Tuesday, February 14, 2017 at 2:07:19 PM UTC-5, rickman wrote: > On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: > > On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: > >> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: > >>> On 2/12/2017 2:07 AM, whit3rd wrote: > >>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: > >> > >>>> Have you considered that, rather than a draft, your chill is due to > >>>> radiated heat loss? > >> > >>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? > >> > >> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths > >> are transparent to longer wavelengths. You can't see UV light, because > >> the human eye lens is a cloudy white in that part of the spectrum. > >> Good insulation has to be opaque. > >> > >> Unless, the styrofoam is the foil-backed kind? > > > > You're on the right track (as is krw). > > > > A couple years ago I investigated improving the efficiency of a > > refrigerator by adding external insulation. Measuring the temperature > > differential across the insulation allowed measurement and calculation > > of the actual loss. > > > > It took 4" of rigid foam insulation[1] to produce the same temperature > > differential as was achieved with 1/2" of foil-backed polyisocyanurate > > foam.[2] > > > > [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 > > > > [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 > > > > So, the foil barrier is stunningly useful. (The foil has to be installed > > facing the heat source. Anything contacting the foil eliminates the benefit, > > since heat is then simply conducted straight through.) > > > > I applied this insight to the exact drafty window problem Rick's solving. > > Two aluminized car dashboard shades, held in place at night with tension > > rods[3] works amazingly well. > > > > [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 > > > > It was a cheap experiment. > > > > The soft dashboard shades were $1 each at the local DollarTree. They're not > > fully opaque--enough daylight shines through to yield useful illumination, > > should you choose to leave them up on a super-cold day. > > > > There's still a draft, but markedly less. Rick will still probably prefer > > his heater. 200w for one heater, though, is as almost much as my whole house > > (280w, average draw last month). > > You've got the heat draw off by nearly a factor of ten. Who said 200 > watts? > > -- > > Rick C Sorry, that was Mikko. If 30w your heater would only increase my usage 10%. Cheers, James Arthu
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 17:32 -0500 |
| Message-ID | <o800do$eo7$1@dont-email.me> |
| In reply to | #447660 |
On 2/14/2017 3:57 PM, dagmargoodboat@yahoo.com wrote: > On Tuesday, February 14, 2017 at 2:07:19 PM UTC-5, rickman wrote: >> On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: >>> On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: >>>> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: >>>>> On 2/12/2017 2:07 AM, whit3rd wrote: >>>>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: >>>> >>>>>> Have you considered that, rather than a draft, your chill is due to >>>>>> radiated heat loss? >>>> >>>>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? >>>> >>>> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths >>>> are transparent to longer wavelengths. You can't see UV light, because >>>> the human eye lens is a cloudy white in that part of the spectrum. >>>> Good insulation has to be opaque. >>>> >>>> Unless, the styrofoam is the foil-backed kind? >>> >>> You're on the right track (as is krw). >>> >>> A couple years ago I investigated improving the efficiency of a >>> refrigerator by adding external insulation. Measuring the temperature >>> differential across the insulation allowed measurement and calculation >>> of the actual loss. >>> >>> It took 4" of rigid foam insulation[1] to produce the same temperature >>> differential as was achieved with 1/2" of foil-backed polyisocyanurate >>> foam.[2] >>> >>> [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 >>> >>> [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 >>> >>> So, the foil barrier is stunningly useful. (The foil has to be installed >>> facing the heat source. Anything contacting the foil eliminates the benefit, >>> since heat is then simply conducted straight through.) >>> >>> I applied this insight to the exact drafty window problem Rick's solving. >>> Two aluminized car dashboard shades, held in place at night with tension >>> rods[3] works amazingly well. >>> >>> [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 >>> >>> It was a cheap experiment. >>> >>> The soft dashboard shades were $1 each at the local DollarTree. They're not >>> fully opaque--enough daylight shines through to yield useful illumination, >>> should you choose to leave them up on a super-cold day. >>> >>> There's still a draft, but markedly less. Rick will still probably prefer >>> his heater. 200w for one heater, though, is as almost much as my whole house >>> (280w, average draw last month). >> >> You've got the heat draw off by nearly a factor of ten. Who said 200 >> watts? >> >> -- >> >> Rick C > > Sorry, that was Mikko. If 30w your heater would only increase my > usage 10%. You didn't answer my other questions. The 30 watt heater (which is pumping out 40 watts until I can get an adjustable PSU) will cost me about $2.50 to run for a month continuously. Are you saying your electric bill is only around $25 a month? You must live somewhere that doesn't need heating or cooling by electricity. -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-02-14 19:12 -0800 |
| Message-ID | <f76bd78b-3a7a-4be2-a1c1-ff0b2ee0f78b@googlegroups.com> |
| In reply to | #447668 |
On Tuesday, February 14, 2017 at 5:32:09 PM UTC-5, rickman wrote: > On 2/14/2017 3:57 PM, dagmargoodboat@yahoo.com wrote: > > On Tuesday, February 14, 2017 at 2:07:19 PM UTC-5, rickman wrote: > >> On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: > >>> On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: > >>>> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: > >>>>> On 2/12/2017 2:07 AM, whit3rd wrote: > >>>>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: > >>>> > >>>>>> Have you considered that, rather than a draft, your chill is due to > >>>>>> radiated heat loss? > >>>> > >>>>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? > >>>> > >>>> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths > >>>> are transparent to longer wavelengths. You can't see UV light, because > >>>> the human eye lens is a cloudy white in that part of the spectrum. > >>>> Good insulation has to be opaque. > >>>> > >>>> Unless, the styrofoam is the foil-backed kind? > >>> > >>> You're on the right track (as is krw). > >>> > >>> A couple years ago I investigated improving the efficiency of a > >>> refrigerator by adding external insulation. Measuring the temperature > >>> differential across the insulation allowed measurement and calculation > >>> of the actual loss. > >>> > >>> It took 4" of rigid foam insulation[1] to produce the same temperature > >>> differential as was achieved with 1/2" of foil-backed polyisocyanurate > >>> foam.[2] > >>> > >>> [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 > >>> > >>> [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 > >>> > >>> So, the foil barrier is stunningly useful. (The foil has to be installed > >>> facing the heat source. Anything contacting the foil eliminates the benefit, > >>> since heat is then simply conducted straight through.) > >>> > >>> I applied this insight to the exact drafty window problem Rick's solving. > >>> Two aluminized car dashboard shades, held in place at night with tension > >>> rods[3] works amazingly well. > >>> > >>> [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 > >>> > >>> It was a cheap experiment. > >>> > >>> The soft dashboard shades were $1 each at the local DollarTree. They're not > >>> fully opaque--enough daylight shines through to yield useful illumination, > >>> should you choose to leave them up on a super-cold day. > >>> > >>> There's still a draft, but markedly less. Rick will still probably prefer > >>> his heater. 200w for one heater, though, is as almost much as my whole house > >>> (280w, average draw last month). > >> > >> You've got the heat draw off by nearly a factor of ten. Who said 200 > >> watts? > >> > >> -- > >> > >> Rick C > > > > Sorry, that was Mikko. If 30w your heater would only increase my > > usage 10%. > > You didn't answer my other questions. The 30 watt heater (which is > pumping out 40 watts until I can get an adjustable PSU) will cost me > about $2.50 to run for a month continuously. > Are you saying your > electric bill is only around $25 a month? Yes. > You must live somewhere that doesn't need heating or cooling > by electricity. My neighbors spend about as much as you. But instead of heating a whole house to tropical temperature you can dress warmly by day, and only heat the room you're in. Exercise in the morning too--it's good for you, and warms you for hours. At night several lofty comforters and an electric mattress heater set on 'low' keep things comfy in the coldest of times for perhaps 30W. (The nameplate on my mattress heater says "70W max.") Oh, and wrap extra insulation around your fridge--it saves electricity. :-) Cheers, James Arthur
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 14:16 -0500 |
| Message-ID | <o7vkvg$3bo$1@dont-email.me> |
| In reply to | #447642 |
On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: > On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: >> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: >>> On 2/12/2017 2:07 AM, whit3rd wrote: >>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: >> >>>> Have you considered that, rather than a draft, your chill is due to >>>> radiated heat loss? >> >>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? >> >> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths >> are transparent to longer wavelengths. You can't see UV light, because >> the human eye lens is a cloudy white in that part of the spectrum. >> Good insulation has to be opaque. >> >> Unless, the styrofoam is the foil-backed kind? > > You're on the right track (as is krw). > > A couple years ago I investigated improving the efficiency of a > refrigerator by adding external insulation. Measuring the temperature > differential across the insulation allowed measurement and calculation > of the actual loss. > > It took 4" of rigid foam insulation[1] to produce the same temperature > differential as was achieved with 1/2" of foil-backed polyisocyanurate > foam.[2] > > [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 > > [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 > > So, the foil barrier is stunningly useful. (The foil has to be installed > facing the heat source. Anything contacting the foil eliminates the benefit, > since heat is then simply conducted straight through.) > > I applied this insight to the exact drafty window problem Rick's solving. > Two aluminized car dashboard shades, held in place at night with tension > rods[3] works amazingly well. > > [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 > > It was a cheap experiment. > > The soft dashboard shades were $1 each at the local DollarTree. They're not > fully opaque--enough daylight shines through to yield useful illumination, > should you choose to leave them up on a super-cold day. > > There's still a draft, but markedly less. Rick will still probably prefer > his heater. 200w for one heater, though, is as almost much as my whole house > (280w, average draw last month). Your number for electricity usage is a bit low. My usage last bill was 2350 kW average. 1692 kWhr / 720 hr = 2.35 kW costing under $200. Was your bill in the $20 range? If not I suspect you missed a decimal point. -- Rick C
[toc] | [prev] | [next] | [standalone]
| From | dagmargoodboat@yahoo.com |
|---|---|
| Date | 2017-02-14 12:53 -0800 |
| Message-ID | <43c1a6b7-1ed1-4822-9a4f-e40c1685ae21@googlegroups.com> |
| In reply to | #447657 |
On Tuesday, February 14, 2017 at 2:16:49 PM UTC-5, rickman wrote: > On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: > > On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: > >> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: > >>> On 2/12/2017 2:07 AM, whit3rd wrote: > >>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: > >> > >>>> Have you considered that, rather than a draft, your chill is due to > >>>> radiated heat loss? > >> > >>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? > >> > >> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths > >> are transparent to longer wavelengths. You can't see UV light, because > >> the human eye lens is a cloudy white in that part of the spectrum. > >> Good insulation has to be opaque. > >> > >> Unless, the styrofoam is the foil-backed kind? > > > > You're on the right track (as is krw). > > > > A couple years ago I investigated improving the efficiency of a > > refrigerator by adding external insulation. Measuring the temperature > > differential across the insulation allowed measurement and calculation > > of the actual loss. > > > > It took 4" of rigid foam insulation[1] to produce the same temperature > > differential as was achieved with 1/2" of foil-backed polyisocyanurate > > foam.[2] > > > > [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 > > > > [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 > > > > So, the foil barrier is stunningly useful. (The foil has to be installed > > facing the heat source. Anything contacting the foil eliminates the benefit, > > since heat is then simply conducted straight through.) > > > > I applied this insight to the exact drafty window problem Rick's solving. > > Two aluminized car dashboard shades, held in place at night with tension > > rods[3] works amazingly well. > > > > [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 > > > > It was a cheap experiment. > > > > The soft dashboard shades were $1 each at the local DollarTree. They're not > > fully opaque--enough daylight shines through to yield useful illumination, > > should you choose to leave them up on a super-cold day. > > > > There's still a draft, but markedly less. Rick will still probably prefer > > his heater. 200w for one heater, though, is as almost much as my whole house > > (280w, average draw last month). > > Your number for electricity usage is a bit low. My usage last bill was > 2350 kW average. 1692 kWhr / 720 hr = 2.35 kW costing under $200. Was > your bill in the $20 range? If not I suspect you missed a decimal point. Why do you seem never to believe other people? I used 207 kWhr, and yes, paid about $20 plus $10 service charge. Cheers, James Arthur
[toc] | [prev] | [next] | [standalone]
| From | John S <Sophi.2@invalid.org> |
|---|---|
| Date | 2017-02-14 16:14 -0600 |
| Message-ID | <o7vvcg$cd9$1@dont-email.me> |
| In reply to | #447659 |
On 2/14/2017 2:53 PM, dagmargoodboat@yahoo.com wrote: > On Tuesday, February 14, 2017 at 2:16:49 PM UTC-5, rickman wrote: >> On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: >>> On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: >>>> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: >>>>> On 2/12/2017 2:07 AM, whit3rd wrote: >>>>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: >>>> >>>>>> Have you considered that, rather than a draft, your chill is due to >>>>>> radiated heat loss? >>>> >>>>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? >>>> >>>> Sure. Long-wavelength IR; things that look cloudy white at visible wavelengths >>>> are transparent to longer wavelengths. You can't see UV light, because >>>> the human eye lens is a cloudy white in that part of the spectrum. >>>> Good insulation has to be opaque. >>>> >>>> Unless, the styrofoam is the foil-backed kind? >>> >>> You're on the right track (as is krw). >>> >>> A couple years ago I investigated improving the efficiency of a >>> refrigerator by adding external insulation. Measuring the temperature >>> differential across the insulation allowed measurement and calculation >>> of the actual loss. >>> >>> It took 4" of rigid foam insulation[1] to produce the same temperature >>> differential as was achieved with 1/2" of foil-backed polyisocyanurate >>> foam.[2] >>> >>> [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 >>> >>> [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 >>> >>> So, the foil barrier is stunningly useful. (The foil has to be installed >>> facing the heat source. Anything contacting the foil eliminates the benefit, >>> since heat is then simply conducted straight through.) >>> >>> I applied this insight to the exact drafty window problem Rick's solving. >>> Two aluminized car dashboard shades, held in place at night with tension >>> rods[3] works amazingly well. >>> >>> [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 >>> >>> It was a cheap experiment. >>> >>> The soft dashboard shades were $1 each at the local DollarTree. They're not >>> fully opaque--enough daylight shines through to yield useful illumination, >>> should you choose to leave them up on a super-cold day. >>> >>> There's still a draft, but markedly less. Rick will still probably prefer >>> his heater. 200w for one heater, though, is as almost much as my whole house >>> (280w, average draw last month). >> >> Your number for electricity usage is a bit low. My usage last bill was >> 2350 kW average. 1692 kWhr / 720 hr = 2.35 kW costing under $200. Was >> your bill in the $20 range? If not I suspect you missed a decimal point. > > Why do you seem never to believe other people? I used 207 kWhr, > and yes, paid about $20 plus $10 service charge. He doesn't know. His numbers and arithmetic are inconsistent. You should not be surprised that he does not believe you.
[toc] | [prev] | [next] | [standalone]
| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-14 17:35 -0500 |
| Message-ID | <o800kj$eo7$3@dont-email.me> |
| In reply to | #447664 |
On 2/14/2017 5:14 PM, John S wrote: > On 2/14/2017 2:53 PM, dagmargoodboat@yahoo.com wrote: >> On Tuesday, February 14, 2017 at 2:16:49 PM UTC-5, rickman wrote: >>> On 2/14/2017 9:56 AM, dagmargoodboat@yahoo.com wrote: >>>> On Sunday, February 12, 2017 at 9:32:52 PM UTC-5, whit3rd wrote: >>>>> On Sunday, February 12, 2017 at 12:52:10 AM UTC-8, rickman wrote: >>>>>> On 2/12/2017 2:07 AM, whit3rd wrote: >>>>>>> On Saturday, February 11, 2017 at 10:02:38 PM UTC-8, rickman wrote: >>>>> >>>>>>> Have you considered that, rather than a draft, your chill is due to >>>>>>> radiated heat loss? >>>>> >>>>>> Radiated heat loss through 3/4 inch of Styrofoam??? Really? >>>>> >>>>> Sure. Long-wavelength IR; things that look cloudy white at visible >>>>> wavelengths >>>>> are transparent to longer wavelengths. You can't see UV light, >>>>> because >>>>> the human eye lens is a cloudy white in that part of the spectrum. >>>>> Good insulation has to be opaque. >>>>> >>>>> Unless, the styrofoam is the foil-backed kind? >>>> >>>> You're on the right track (as is krw). >>>> >>>> A couple years ago I investigated improving the efficiency of a >>>> refrigerator by adding external insulation. Measuring the temperature >>>> differential across the insulation allowed measurement and calculation >>>> of the actual loss. >>>> >>>> It took 4" of rigid foam insulation[1] to produce the same temperature >>>> differential as was achieved with 1/2" of foil-backed polyisocyanurate >>>> foam.[2] >>>> >>>> [1]http://www.homedepot.com/p/Owens-Corning-FOAMULAR-250-2-in-x-48-in-x-8-ft-R-10-Scored-Squared-Edge-Insulation-Sheathing-52DD/202085962 >>>> >>>> >>>> [2]http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981 >>>> >>>> >>>> So, the foil barrier is stunningly useful. (The foil has to be >>>> installed >>>> facing the heat source. Anything contacting the foil eliminates the >>>> benefit, >>>> since heat is then simply conducted straight through.) >>>> >>>> I applied this insight to the exact drafty window problem Rick's >>>> solving. >>>> Two aluminized car dashboard shades, held in place at night with >>>> tension >>>> rods[3] works amazingly well. >>>> >>>> [3]https://www.walmart.com/ip/Mainstays-Spring-Tension-Rod-White/50015124 >>>> >>>> >>>> It was a cheap experiment. >>>> >>>> The soft dashboard shades were $1 each at the local DollarTree. >>>> They're not >>>> fully opaque--enough daylight shines through to yield useful >>>> illumination, >>>> should you choose to leave them up on a super-cold day. >>>> >>>> There's still a draft, but markedly less. Rick will still probably >>>> prefer >>>> his heater. 200w for one heater, though, is as almost much as my >>>> whole house >>>> (280w, average draw last month). >>> >>> Your number for electricity usage is a bit low. My usage last bill was >>> 2350 kW average. 1692 kWhr / 720 hr = 2.35 kW costing under $200. Was >>> your bill in the $20 range? If not I suspect you missed a decimal >>> point. >> >> Why do you seem never to believe other people? I used 207 kWhr, >> and yes, paid about $20 plus $10 service charge. > > He doesn't know. His numbers and arithmetic are inconsistent. You should > not be surprised that he does not believe you. What is inconsistent in my numbers or math? -- Rick C
[toc] | [prev] | [next] | [standalone]
Page 2 of 5 — ← Prev page 1 [2] 3 4 5 Next page →
Back to top | Article view | sci.electronics.design
csiph-web