Posted by aywitb on January 23, 2015, 7:34 pm
If these 2 rooms had exactly the same furniture in them and both faced the
sun exactly the same but one room had all black furniture and flooring and
one had all white furniture and flooring would the temperatures be the same
in them during the day in full sun? The amount of sunlight hitting them is
the same so they should be the same temp, right?
Posted by Morris Dovey on January 23, 2015, 11:13 pm
On 1/23/15 1:34 PM, aywitb@gmail.com wrote:
> If these 2 rooms had exactly the same furniture in them and both
> faced the sun exactly the same but one room had all black furniture
> and flooring and one had all white furniture and flooring would the
> temperatures be the same in them during the day in full sun? The
> amount of sunlight hitting them is the same so they should be the
> same temp, right?
One room would have slightly higher air temperature, the other slightly
higher furniture/floor temperature.
You might /feel/ slightly warmer in the room with white furniture and
flooring.
But it might be difficult to distinguish. :-)
--
Morris Dovey
http://www.iedu.com/Solar/
Posted by Morris Dovey on January 24, 2015, 3:59 am
On 1/23/15 6:17 PM, Bob F wrote:
> Morris Dovey wrote:
>> On 1/23/15 1:34 PM, aywitb@gmail.com wrote:
>>> If these 2 rooms had exactly the same furniture in them and both
>>> faced the sun exactly the same but one room had all black furniture
>>> and flooring and one had all white furniture and flooring would the
>>> temperatures be the same in them during the day in full sun? The
>>> amount of sunlight hitting them is the same so they should be the
>>> same temp, right?
>>
>> One room would have slightly higher air temperature, the other
>> slightly higher furniture/floor temperature.
>>
>> You might /feel/ slightly warmer in the room with white furniture and
>> flooring.
>
> I would expect the white room to radiate more of the light energy back out of
> the windows before it heats anything, thereby reducing the room temp. Higher
> floor/furniture temp will all be transferred to the air. Kind of like a white
> car compared to a black car.
Windows? Methinks we were both making unstated (unwarranted)
assumptions. My bad.
My real-life "windows" were thermal diodes. :-)
BTW, it does appear possible to construct a closed system such that, at
equilibrium, one object within can be warmer than another. Fascinating
stuff!
--
Morris Dovey
http://www.iedu.com/Solar/Panels
Posted by Dan Coby on January 24, 2015, 8:14 am
On 1/23/2015 7:59 PM, Morris Dovey wrote:>
> BTW, it does appear possible to construct a closed system such that, at
> equilibrium, one object within can be warmer than another. Fascinating
> stuff!
>
I will bite. How does one create a closed system in thermal equilibrium
with objects at different temperatures?
Are you calling a system with an outside source (sunlight) coming into
it and heat radiating out, a 'closed' system?
Dan
Posted by Morris Dovey on January 24, 2015, 8:58 am
On 1/24/15 2:14 AM, Dan Coby wrote:
> On 1/23/2015 7:59 PM, Morris Dovey wrote:>
> > BTW, it does appear possible to construct a closed system such that, at
> > equilibrium, one object within can be warmer than another. Fascinating
> > stuff!
> >
>
> I will bite. How does one create a closed system in thermal equilibrium
> with objects at different temperatures?
By creating an object that more readily absorbs energy than emits it. I
ran across some interesting projects while researching absorber
geometries, but didn’t bookmark because the material didn’t relate in a
practical way to what I was doing.
> Are you calling a system with an outside source (sunlight) coming into
> it and heat radiating out, a 'closed' system?
Nope. I just thought Bob might find the idea interesting.
--
Morris Dovey
http://www.iedu.com/Solar/
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> faced the sun exactly the same but one room had all black furniture
> and flooring and one had all white furniture and flooring would the
> temperatures be the same in them during the day in full sun? The
> amount of sunlight hitting them is the same so they should be the
> same temp, right?