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Re: [EnergyPlus_Support] External surface gains & losses





Thanks David.


From: David Scheer <david@xxxxxxxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Monday, July 6, 2009 9:35:11 AM
Subject: Re: [EnergyPlus_Support] External surface gains & losses

Doesn't exist.  All heat balance in the room air is through convection from surfaces and air into and out of a zone.  Convection is a product of temperature difference between surface and air.  Surface temperature is a product of solar radiation (direct and diffuse), longwave radiation from other surfaces, lights and people, and from conduction through the wall.  The best you can do to get wall conductive gains/losses is to look at surface convection gains/losses (Surface Interior Convection Heat Rate), but since this also includes the other components above, there i really no way to directly get wall conduction.  DesignBuilder (incorrectly) reports Opaque Surface Inside Face Conduction .... which is actually the energy moving from the surface to the interior of the construction.

Good luck, and let us know if you figure out a good way of reporting that important metric.

David

On Sun, Jul 5, 2009 at 2:54 AM, v s <vs114@yahoo. com> wrote:


I can't find the output variable for gains and losses for an external wall.
Any help?

Thanks
vaggelis


From: v s <vs114@yahoo. com>
To: EnergyPlus_Support@ yahoogroups. com
Sent: Saturday, July 4, 2009 6:37:27 PM
Subject: Re: [EnergyPlus_ Support] Add a basement?

Thank you Dr. Li.

Vaggelis


From: YuanLu å??å?­ Li <yli006@hotmail. com>
To: Linda <energyplus_support@ yahoogroups. com>
Sent: Friday, July 3, 2009 11:18:16 PM
Subject: RE: [EnergyPlus_ Support] Add a basement?


The argument is the same.  Your floor is helping to cool the building by the ground temperature.  Therefore, by insulating the floor to ground, the cooling bill goes up and the heating bill comes down. 
 
One of my students will be looking at the use of basement in a tropical country for energy saving. 
 
My hunch is that the saving will be small, because the temperature difference for cooling from ground is small.   Heat conduction through the basement wall is too slow.

 Dr. Li  



To: EnergyPlus_Support@ yahoogroups. com
From: vs114@yahoo. com
Date: Fri, 3 Jul 2009 08:27:39 -0700
Subject: Re: [EnergyPlus_ Support] Add a basement?



In the beggining there was no basement.
The climate is warm, so both heat and cool have almost the same importance.
Without any insulation for the floor and having 20cm isulation for the rest dwelling, i get 1500 kwh/year for heat
and 650 kwh/year for cooling.
With 10cm insulation at the floor (on the ground) and everything else the same, i get 150 kwh for heat and 3700 for cooling.
I' ve tried the ground temperature and the outside boundary condition set to surface but i get almost the same results.
Any idea?
If i add a basement, will  this help the enormous cooling needs?

Thank you all.
Vaggelis.

From: YuanLu å??å?­ Li <yli006@hotmail. com>
To: Linda <energyplus_support@ yahoogroups. com>
Sent: Friday, July 3, 2009 12:56:31 AM
Subject: RE: [EnergyPlus_ Support] Add a basement

I wonder where you added the floor insulation.
 
The basement is being heated by the ground below.
 
If you insulated the basement floor, you have lost the ground heating.

If you have a walk out basement, make sure to insurate the exposed basement wall to R12 or more. Ground temperature is generally warmer than the outdoor exposed temperature.  Ice is a good insulator at the groun durface.
 
Normal basement wall in Canada is insulated. at least, to  one meter below the ground level, to R8 or more.  Water mains are buried two meters below ground, and  will not freeze in Winter, even when the outdoor temperature is at -18 degree C.
 

 Dr. Li  



To: EnergyPlus_Support@ yahoogroups. com
From: vs114@yahoo. com
Date: Thu, 2 Jul 2009 10:30:43 -0700
Subject: Re: [EnergyPlus_ Support] Add a basement



The problem i had and drive me to the solution of "basement"
was that when the floor had NO insulation, i needed 500Kwh for heating.
When i added 3mm insulation, i needed 2500Kwh for heating.

Is this logical?
(warm climate)



From: Linda Lawrie <linda@fortlawrie. com>
To: EnergyPlus_Support@ yahoogroups. com
Sent: Thursday, July 2, 2009 8:18:24 PM
Subject: Re: [EnergyPlus_ Support] Add a basement

A "walk out basement" might be below grade on one or more walls.  There will be a warning message that it can't do the height specific calculations it uses on surfaces/walls.  The warning can be ignored.


At 11:09 AM 7/2/2009, v s wrote:


My outside boundary conditions for the basement is ground.
What is the "warning messages on a walk out basement"?
Will i have any other problems?






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