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billhuntersemail(at)gmail
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 Posted: Sat Jul 28, 2018 4:26 pm Post subject: 220 VAC Circuit Breaker Question |
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Greetings,
If you all would be so kind as to entertain another slightly off topic
electrical question.
In my hangar I just installed an evaporative cooler and it is powered by a
newly purchased 20 amp 220 volt circuit breaker.
Due to an internal problem in the toggle switch out at the unit there was a
direct short because when I closed the 20 amp circuit breaker(s) about 3
seconds later the entire power to the hanger was shut off because the 60
amp feed circuit breaker out at the house opened.
This was kind of surprising because I assume that if there was a short out
at the evaporative cooler unit then the new 20 amp circuit breaker that
I've installed for that circuit would have opened before the main 60 amp
circuit breaker that feeds the entire hanger would open.
I removed the toggle switch at the unit and directly wired the 220 volt
wires to the unit wires and it's working perfectly (so I have a discussion
with Mastercool about getting a replacement toggle switch) but regardless I
have concluded that the wires out to the unit are fine and the unit motor
is working fine so my only concern at this point is why would the 20 amp
circuit breaker not open and why would it stay closed long enough to
require the main feed 60 amp circuit breaker to open?
I have another 20 amp circuit breaker that I could install in circuit
however I figured I would ask the collective what their thoughts were first
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user9253
Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan
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| Posted: Sat Jul 28, 2018 6:23 pm Post subject: Re: 220 VAC Circuit Breaker Question |
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When two circuit breakers (or fuses) are in series, either one or both could trip (or blow) when there is a short circuit. A friend told me that he was working on an electric range outlet without shutting off the power. He stuck his screwdriver where it shouldn't be and shorted out the circuit. The main breaker for the whole apartment building tripped. He had to get the manager to unlock the utility room to reset the main breaker. I do not know if the 40 amp range breaker tripped or not.
The above scenario might be one reason why aircraft main bus feeders are not normally fused. I know that the major reason given for not fusing the feeder is that it is not needed. Another reason is that if it is not installed, then it can not blow.
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barber_seville(at)msn.com
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| Posted: Sat Jul 28, 2018 6:38 pm Post subject: 220 VAC Circuit Breaker Question |
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I live in Florida and it is arguably cooler (insert grin), I insulated my shop that is probably the size of your hanger with insulation that is metal foil with foam insulation sandwiched between layers. Bought it online and applied it to all the surfaces including the metal door. Spray adhesive holds it in place. Have had 100 degree days ! Air conditioner will freeze you out of shop.
Chuck
Sent from my iPad
On Jul 28, 2018, at 8:33 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | Greetings,
If you all would be so kind as to entertain another slightly off topic electrical question.
In my hangar I just installed an evaporative cooler and it is powered by a newly purchased 20 amp 220 volt circuit breaker.
Due to an internal problem in the toggle switch out at the unit there was a direct short because when I closed the 20 amp circuit breaker(s) about 3 seconds later the entire power to the hanger was shut off because the 60 amp feed circuit breaker out at the house opened.
This was kind of surprising because I assume that if there was a short out at the evaporative cooler unit then the new 20 amp circuit breaker that I've installed for that circuit would have opened before the main 60 amp circuit breaker that feeds the entire hanger would open.
I removed the toggle switch at the unit and directly wired the 220 volt wires to the unit wires and it's working perfectly (so I have a discussion with Mastercool about getting a replacement toggle switch) but regardless I have concluded that the wires out to the unit are fine and the unit motor is working fine so my only concern at this point is why would the 20 amp circuit breaker not open and why would it stay closed long enough to require the main feed 60 amp circuit breaker to open?
I have another 20 amp circuit breaker that I could install in circuit however I figured I would ask the collective what their thoughts were first.
And BTW... the evaporative cooler is taking 100 degree outside Arizona air and making it 80° as it enters the hanger however a 3000 square foot steel building without insulation in the Arizona Sun is a bit hard to cool. Any suggestions on hanger insulation?
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 12:32 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:08 PM 7/28/2018, you wrote:
| Quote: | Sorry for the slightly off topic post (however this is for a machine installed inside my airplane hangar).
I am looking for a pushbutton switch to replace the broken one on my hydraulic lift.Ă‚
It's a push button momentary contact on single pole single throw switch.Ă‚ The diameter of the hole in the panel is 0.894 inches / 22.72 MM.Ă‚
The switch that broke is labeled CHNT NP4 and it has other numbers on it such as GB140 48.5 and it's a 10 amp switch.Ă‚ Ă‚
It is a switch that you push and hold in the button and then a relay closes to energize the electric motor that moves the hydraulic pump.
Again, sorry about the off-topic post however I've spent 30 minutes on the Google with no success but I'm sure there's a guy on this forum that will recognize this switch immediately and know exactly where to find one (or one that will work).
Thanks!!!Ă‚
Bill Hunter |
There is nothing electrically special about this
switch other than the fact that it's normally open.
You probably want to get the door operable ASAP
so go to a hardware store and get ANY normally open
P.B. Here's one example at Lowes.
https://goo.gl/66gez5
Wire it into place temporarily . . . mgiht even let it
dangle on the wires wrapped with tape to keep the
electrons from tunning onto the floor.
Then order one of these:
https://goo.gl/pTKXPT
It will directly replace the switch that's broken
and will be delivered to your door in a few days
for free.
Bob . . .
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billhuntersemail(at)gmail
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| Posted: Sun Jul 29, 2018 7:29 pm Post subject: 220 VAC Circuit Breaker Question |
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What is this "airconditioner" black magic we speak of?Â
All I have to run with is an evaporative cooler.Â
Yes installation is definitely needed. The Arizona Sun bakes the steel box that I am working in and I can feel the heat radiating off of the roof and walls.Â
Would you be so kind as to give me a hint as to what insulation product you bought?
The evaporative cooler converts 100 degree outside air to 80 degree air as it enters the building however the 120 degree walls and roof are counterproductive.
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 19:42 Charles Plumery <barber_seville(at)msn.com (barber_seville(at)msn.com)> wrote:
| Quote: | I live in Florida and it is  arguably cooler (insert grin), I insulated my shop that is probably the size of your hanger with insulation that is metal foil with foam insulation sandwiched between layers. Bought it online and applied it to all the surfaces including the metal door. Spray adhesive holds it in place. Have had 100 degree days ! Air conditioner will freeze you out of shop.
Chuck
Sent from my iPad
On Jul 28, 2018, at 8:33 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | Greetings,Â
If you all would be so kind as to entertain another slightly off topic electrical question.Â
In my hangar I just installed an evaporative cooler and it is powered by a newly purchased 20 amp 220 volt circuit breaker.Â
Due to an internal problem in the toggle switch out at the unit there was a direct short because when I closed the 20 amp circuit breaker(s) about 3 seconds later the entire power to the hanger was shut off because the 60 amp feed circuit breaker out at the house opened.
This was kind of surprising because I assume that if there was a short out at the evaporative cooler unit then the new 20 amp circuit breaker that I've installed for that circuit would have opened before the main 60 amp circuit breaker that feeds the entire hanger would open.
I removed the toggle switch at the unit and directly wired the 220 volt wires to the unit wires and it's working perfectly (so I have a discussion with Mastercool about getting a replacement toggle switch) but regardless I have concluded that the wires out to the unit are fine and the unit motor is working fine so my only concern at this point is why would the 20 amp circuit breaker not open and why would it stay closed long enough to require the main feed 60 amp circuit breaker to open?Â
I have another 20 amp circuit breaker that I could install in circuit however I figured I would ask the collective what their thoughts were first.
And BTW... the evaporative cooler is taking 100 degree outside Arizona air and making it 80° as it enters the hanger however a 3000 square foot steel building without insulation in the Arizona Sun is a bit hard to cool. Any suggestions on hanger insulation?
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 12:32 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:08 PM 7/28/2018, you wrote:
| Quote: | Sorry for the slightly off topic post (however this is for a machine installed inside my airplane hangar).
I am looking for a pushbutton switch to replace the broken one on my hydraulic lift.Ă‚
It's a push button momentary contact on single pole single throw switch.Ă‚Â The diameter of the hole in the panel is 0.894 inches / 22.72 MM.Ă‚
The switch that broke is labeled CHNT NP4 and it has other numbers on it such as GB140 48.5 and it's a 10 amp switch.Ă‚ Ă‚
It is a switch that you push and hold in the button and then a relay closes to energize the electric motor that moves the hydraulic pump.
Again, sorry about the off-topic post however I've spent 30 minutes on the Google with no success but I'm sure there's a guy on this forum that will recognize this switch immediately and know exactly where to find one (or one that will work).
Thanks!!!Ă‚
Bill Hunter |
There is nothing electrically special about this
switch other than the fact that it's normally open.
You probably want to get the door operable ASAP
so go to a hardware store and get ANY normally open
P.B. Here's one example at Lowes.
https://goo.gl/66gez5
Wire it into place temporarily . . . mgiht even let it
dangle on the wires wrapped with tape to keep the
electrons from tunning onto the floor.
Then order one of these:
https://goo.gl/pTKXPT
It will directly replace the switch that's broken
and will be delivered to your door in a few days
for free.
 Bob . . .
|
|
|
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http://www.matronics.com/Navigator?AeroElectric-List |
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barber_seville(at)msn.com
Guest
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| Posted: Mon Jul 30, 2018 5:24 am Post subject: 220 VAC Circuit Breaker Question |
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Insulation4less.com Or similar product.
Sent from my iPad
On Jul 29, 2018, at 11:36 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | What is this "airconditioner" black magic we speak of?
All I have to run with is an evaporative cooler.
Yes installation is definitely needed. The Arizona Sun bakes the steel box that I am working in and I can feel the heat radiating off of the roof and walls.
Would you be so kind as to give me a hint as to what insulation product you bought?
The evaporative cooler converts 100 degree outside air to 80 degree air as it enters the building however the 120 degree walls and roof are counterproductive.
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 19:42 Charles Plumery <barber_seville(at)msn.com (barber_seville(at)msn.com)> wrote:
| Quote: | I live in Florida and it is arguably cooler (insert grin), I insulated my shop that is probably the size of your hanger with insulation that is metal foil with foam insulation sandwiched between layers. Bought it online and applied it to all the surfaces including the metal door. Spray adhesive holds it in place. Have had 100 degree days ! Air conditioner will freeze you out of shop.
Chuck
Sent from my iPad
On Jul 28, 2018, at 8:33 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | Greetings,
If you all would be so kind as to entertain another slightly off topic electrical question.
In my hangar I just installed an evaporative cooler and it is powered by a newly purchased 20 amp 220 volt circuit breaker.
Due to an internal problem in the toggle switch out at the unit there was a direct short because when I closed the 20 amp circuit breaker(s) about 3 seconds later the entire power to the hanger was shut off because the 60 amp feed circuit breaker out at the house opened.
This was kind of surprising because I assume that if there was a short out at the evaporative cooler unit then the new 20 amp circuit breaker that I've installed for that circuit would have opened before the main 60 amp circuit breaker that feeds the entire hanger would open.
I removed the toggle switch at the unit and directly wired the 220 volt wires to the unit wires and it's working perfectly (so I have a discussion with Mastercool about getting a replacement toggle switch) but regardless I have concluded that the wires out to the unit are fine and the unit motor is working fine so my only concern at this point is why would the 20 amp circuit breaker not open and why would it stay closed long enough to require the main feed 60 amp circuit breaker to open?
I have another 20 amp circuit breaker that I could install in circuit however I figured I would ask the collective what their thoughts were first.
And BTW... the evaporative cooler is taking 100 degree outside Arizona air and making it 80° as it enters the hanger however a 3000 square foot steel building without insulation in the Arizona Sun is a bit hard to cool. Any suggestions on hanger insulation?
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 12:32 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:08 PM 7/28/2018, you wrote:
| Quote: | Sorry for the slightly off topic post (however this is for a machine installed inside my airplane hangar).
I am looking for a pushbutton switch to replace the broken one on my hydraulic lift.Ă‚
It's a push button momentary contact on single pole single throw switch.Ă‚ The diameter of the hole in the panel is 0.894 inches / 22.72 MM.Ă‚
The switch that broke is labeled CHNT NP4 and it has other numbers on it such as GB140 48.5 and it's a 10 amp switch.Ă‚ Ă‚
It is a switch that you push and hold in the button and then a relay closes to energize the electric motor that moves the hydraulic pump.
Again, sorry about the off-topic post however I've spent 30 minutes on the Google with no success but I'm sure there's a guy on this forum that will recognize this switch immediately and know exactly where to find one (or one that will work).
Thanks!!!Ă‚
Bill Hunter |
There is nothing electrically special about this
switch other than the fact that it's normally open.
You probably want to get the door operable ASAP
so go to a hardware store and get ANY normally open
P.B. Here's one example at Lowes.
https://goo.gl/66gez5
Wire it into place temporarily . . . mgiht even let it
dangle on the wires wrapped with tape to keep the
electrons from tunning onto the floor.
Then order one of these:
https://goo.gl/pTKXPT
It will directly replace the switch that's broken
and will be delivered to your door in a few days
for free.
Bob . . .
|
|
|
|
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http://www.matronics.com/Navigator?AeroElectric-List |
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ceengland7(at)gmail.com
Guest
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| Posted: Mon Jul 30, 2018 6:08 am Post subject: 220 VAC Circuit Breaker Question |
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Bill,
Just search for 'foil faced insulation' If it's a typical flat walled building, try 'foil faced polystyrene' or 'radiant barrier polystyrene'. For keeping heat out, you'll probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe in your a/c cowl.
Charlie
On Mon, Jul 30, 2018 at 8:23 AM, Charles Plumery <barber_seville(at)msn.com (barber_seville(at)msn.com)> wrote:
| Quote: | Insulation4less.com Or similar product.
Sent from my iPad
On Jul 29, 2018, at 11:36 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | What is this "airconditioner" black magic we speak of?Â
All I have to run with is an evaporative cooler.Â
Yes installation is definitely needed. The Arizona Sun bakes the steel box that I am working in and I can feel the heat radiating off of the roof and walls.Â
Would you be so kind as to give me a hint as to what insulation product you bought?
The evaporative cooler converts 100 degree outside air to 80 degree air as it enters the building however the 120 degree walls and roof are counterproductive.
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 19:42 Charles Plumery <barber_seville(at)msn.com (barber_seville(at)msn.com)> wrote:
| Quote: | I live in Florida and it is  arguably cooler (insert grin), I insulated my shop that is probably the size of your hanger with insulation that is metal foil with foam insulation sandwiched between layers. Bought it online and applied it to all the surfaces including the metal door. Spray adhesive holds it in place. Have had 100 degree days ! Air conditioner will freeze you out of shop.
Chuck
Sent from my iPad
On Jul 28, 2018, at 8:33 PM, William Hunter <billhuntersemail(at)gmail.com (billhuntersemail(at)gmail.com)> wrote:
| Quote: | Greetings,Â
If you all would be so kind as to entertain another slightly off topic electrical question.Â
In my hangar I just installed an evaporative cooler and it is powered by a newly purchased 20 amp 220 volt circuit breaker.Â
Due to an internal problem in the toggle switch out at the unit there was a direct short because when I closed the 20 amp circuit breaker(s) about 3 seconds later the entire power to the hanger was shut off because the 60 amp feed circuit breaker out at the house opened.
This was kind of surprising because I assume that if there was a short out at the evaporative cooler unit then the new 20 amp circuit breaker that I've installed for that circuit would have opened before the main 60 amp circuit breaker that feeds the entire hanger would open.
I removed the toggle switch at the unit and directly wired the 220 volt wires to the unit wires and it's working perfectly (so I have a discussion with Mastercool about getting a replacement toggle switch) but regardless I have concluded that the wires out to the unit are fine and the unit motor is working fine so my only concern at this point is why would the 20 amp circuit breaker not open and why would it stay closed long enough to require the main feed 60 amp circuit breaker to open?Â
I have another 20 amp circuit breaker that I could install in circuit however I figured I would ask the collective what their thoughts were first.
And BTW... the evaporative cooler is taking 100 degree outside Arizona air and making it 80° as it enters the hanger however a 3000 square foot steel building without insulation in the Arizona Sun is a bit hard to cool. Any suggestions on hanger insulation?
Thanks,
Bill Hunter
On Sat, Jul 28, 2018, 12:32 Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
| Quote: | At 02:08 PM 7/28/2018, you wrote:
| Quote: | Sorry for the slightly off topic post (however this is for a machine installed inside my airplane hangar).
I am looking for a pushbutton switch to replace the broken one on my hydraulic lift.Ă‚
It's a push button momentary contact on single pole single throw switch.Ă‚Â The diameter of the hole in the panel is 0.894 inches / 22.72 MM.Ă‚
The switch that broke is labeled CHNT NP4 and it has other numbers on it such as GB140 48.5 and it's a 10 amp switch.Ă‚ Ă‚
It is a switch that you push and hold in the button and then a relay closes to energize the electric motor that moves the hydraulic pump.
Again, sorry about the off-topic post however I've spent 30 minutes on the Google with no success but I'm sure there's a guy on this forum that will recognize this switch immediately and know exactly where to find one (or one that will work).
Thanks!!!Ă‚
Bill Hunter |
There is nothing electrically special about this
switch other than the fact that it's normally open.
You probably want to get the door operable ASAP
so go to a hardware store and get ANY normally open
P.B. Here's one example at Lowes.
https://goo.gl/66gez5
Wire it into place temporarily . . . mgiht even let it
dangle on the wires wrapped with tape to keep the
electrons from tunning onto the floor.
Then order one of these:
https://goo.gl/pTKXPT
It will directly replace the switch that's broken
and will be delivered to your door in a few days
for free.
 Bob . . .
|
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alec(at)alecmyers.com
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| Posted: Mon Jul 30, 2018 12:35 pm Post subject: 220 VAC Circuit Breaker Question |
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| Quote: | From a physics point of view, there’s no difference between keeping heat out and keeping heat in. Any kind of convection allows heat to transport more easily, and should probably be avoided.
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What’s the “radiant barrier” effect?
On Jul 30, 2018, at 10:07 AM, Charlie England <ceengland7(at)gmail.com> wrote:
probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe
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ceengland7(at)gmail.com
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| Posted: Mon Jul 30, 2018 1:20 pm Post subject: 220 VAC Circuit Breaker Question |
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You left out one method.  (conduction)
Here are some links for light reading:
https://www.google.com/search?q=convection+vs+conduction+vs+radiation&oq=convection+vs+conduction+vs+radiation&aqs=chrome..69i57j0l3.9568j0j7&sourceid=chrome&ie=UTF-8
For a quick demo, go stand in the sun for a few minutes, then raise an
umbrella between you and the sun, and wait another few minutes.
(Covering the outside of the umbrella with foil or pure white would
improve performance.) Which way is cooler for you?
I mentioned the air gap/ flow trick because if the air is trapped it
will eventually reach the same temp as the skin, and then try to heat
the barrier directly. With a bit of air flow between skin & radiant
barrier, the air gap stays cooler, and there's less temperature
differential trying to force its way through the conductive insulation
barrier (the polystyrene, fiberglass, etc).
Charlie
On 7/30/2018 3:34 PM, Alec Myers wrote:
| Quote: |
>From a physics point of view, there’s no difference between keeping heat out and keeping heat in. Any kind of convection allows heat to transport more easily, and should probably be avoided.
What’s the “radiant barrier” effect?
On Jul 30, 2018, at 10:07 AM, Charlie England <ceengland7(at)gmail.com> wrote:
probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe
|
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alec(at)alecmyers.com
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| Posted: Mon Jul 30, 2018 1:41 pm Post subject: 220 VAC Circuit Breaker Question |
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I think you’re overestimating how much heat gets conducted through a good insulation material like foam, or glass wool. All the wall cavities in my house are stuffed with spray foam or mineral wool because any kind of convection conducts heat much faster than if the space were filled with a solid.
There are three reasons not to fill a heat barrier with a good insulator - if you can evacuate the space, like in a thermos flask , then no gas means no convention. Or, alternatively, you need transparency, like in double glazed window panels. Windows don’t transmit light when full of foam. (Even there, you fill the gap with argon.) And I guess the third one would be if the temperature you’re trying to insulate is so hot that any reasonably priced insulator would melt.
On Jul 30, 2018, at 5:20 PM, Charlie England <ceengland7(at)gmail.com> wrote:
You left out one method. (conduction)
Here are some links for light reading:
https://www.google.com/search?q=convection+vs+conduction+vs+radiation&oq=convection+vs+conduction+vs+radiation&aqs=chrome..69i57j0l3.9568j0j7&sourceid=chrome&ie=UTF-8
For a quick demo, go stand in the sun for a few minutes, then raise an umbrella between you and the sun, and wait another few minutes. (Covering the outside of the umbrella with foil or pure white would improve performance.) Which way is cooler for you?
I mentioned the air gap/ flow trick because if the air is trapped it will eventually reach the same temp as the skin, and then try to heat the barrier directly. With a bit of air flow between skin & radiant barrier, the air gap stays cooler, and there's less temperature differential trying to force its way through the conductive insulation barrier (the polystyrene, fiberglass, etc).
Charlie
On 7/30/2018 3:34 PM, Alec Myers wrote:
| Quote: |
>From a physics point of view, there’s no difference between keeping heat out and keeping heat in. Any kind of convection allows heat to transport more easily, and should probably be avoided.
What’s the “radiant barrier” effect?
On Jul 30, 2018, at 10:07 AM, Charlie England <ceengland7(at)gmail.com> wrote:
probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe
|
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alec(at)alecmyers.com
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| Posted: Mon Jul 30, 2018 1:45 pm Post subject: 220 VAC Circuit Breaker Question |
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Actually scratch that last one: furnaces, gas forges and pottery kilns are all insulated with refractory brick. Not with air gaps.
On Jul 30, 2018, at 5:41 PM, Alec Myers <alec(at)alecmyers.com> wrote:
I think you’re overestimating how much heat gets conducted through a good insulation material like foam, or glass wool. All the wall cavities in my house are stuffed with spray foam or mineral wool because any kind of convection conducts heat much faster than if the space were filled with a solid.
There are three reasons not to fill a heat barrier with a good insulator - if you can evacuate the space, like in a thermos flask , then no gas means no convention. Or, alternatively, you need transparency, like in double glazed window panels. Windows don’t transmit light when full of foam. (Even there, you fill the gap with argon.) And I guess the third one would be if the temperature you’re trying to insulate is so hot that any reasonably priced insulator would melt.
On Jul 30, 2018, at 5:20 PM, Charlie England <ceengland7(at)gmail.com> wrote:
You left out one method. (conduction)
Here are some links for light reading:
https://www.google.com/search?q=convection+vs+conduction+vs+radiation&oq=convection+vs+conduction+vs+radiation&aqs=chrome..69i57j0l3.9568j0j7&sourceid=chrome&ie=UTF-8
For a quick demo, go stand in the sun for a few minutes, then raise an umbrella between you and the sun, and wait another few minutes. (Covering the outside of the umbrella with foil or pure white would improve performance.) Which way is cooler for you?
I mentioned the air gap/ flow trick because if the air is trapped it will eventually reach the same temp as the skin, and then try to heat the barrier directly. With a bit of air flow between skin & radiant barrier, the air gap stays cooler, and there's less temperature differential trying to force its way through the conductive insulation barrier (the polystyrene, fiberglass, etc).
Charlie
On 7/30/2018 3:34 PM, Alec Myers wrote:
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> From a physics point of view, there’s no difference between keeping heat out and keeping heat in. Any kind of convection allows heat to transport more easily, and should probably be avoided.
What’s the “radiant barrier” effect?
On Jul 30, 2018, at 10:07 AM, Charlie England <ceengland7(at)gmail.com> wrote:
probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe
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BARRY CHECK 6
Joined: 15 Mar 2011
Posts: 738
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| Posted: Mon Jul 30, 2018 1:52 pm Post subject: 220 VAC Circuit Breaker Question |
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A radiant surface reflects heat back up away from it. [i.e.: The reflective aluminum on the foam.]
BUT! If there is NO place to reflect the heat up to the heat is just transmitted through the radiant surface and into the surface below it.
It is part of the principal that dense materials hold more heat than less dense materials.
As you move your hand closer to a hot frying pan you feel more and more heat. In the first process the air between the pan and your hand is insulating the heat. The second process is the pan is insulating the heat from the flames. In the third process putting your hand directly into the flames you have no insulation at all.
Its the same principle of layering clothes, but in reverse. If there are not enough layers or the layers too tight the heat from your body does not stay put within a barrier and you loose body heat to the outside world.
Conduction
Convection
Radiation
Barry
On Mon, Jul 30, 2018 at 4:39 PM Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:
| Quote: | --> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)>
>From a physics point of view, there’s no difference between keeping heat out and keeping heat in. Any kind of convection allows heat to transport more easily, and should probably be avoided.
What’s the “radiant barrier” effect?
On Jul 30, 2018, at 10:07 AM, Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:
 probably get best results if you can 'air gap' between the metal skin and the radiant barrier (foil) and allow some air flow in at the bottom & out at the top. Direct contact kinda kills the radiant barrier effect & tries to heat the foam through conduction. Basically a bigger version of a radiant barrier around an exhaust pipe
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