Exterior convection coefficient zero for interzone surfaces
Posted by Michael J. Witte on 22 January 2010 07:11 PM
When two surfaces are linked as interzone surfaces, the "exterior" side of these surfaces does not really exist. EnergyPlus links the two surfaces by using the inside temperature of surface A as the outside temperature of surface B, and the reverse. For example:

Zone1WestWall has an outside boundary of Surface = Zone2EastWall

Zone2EastWall has an outside boundary of Surface = Zone1WestWall

Let's say that at hour 2, the inside surface temperature of Zone1WestWall is 19C, and the inside temperature of Zone2EastWall is 22C. When the heat balance is calculated for Zone1WestWall its outside surface temperature will be set to 22C. Likewise, when the heat balance is calculated for Zone2EastWall its outside surface temperature will be set to 19C. So, for interzone surfaces, h ext does not apply. That is why it is reported as zero.

Mike



Posted on: 20 Jan 2010 02:38 AM
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I have analized the obtained results and are the following:



P_203_6_0_0 (west interior wall belonging to outer zone):

- h in = 3,447

- h ext = 0



P_203_5_0_0 (South interior wall belonging to outer zone):

- h in = 3,296

- h ext = 0



P_203_6_0_0 (east interior wall belonging to outer zone):

- h in = 2,866

- h ext = 0



On the other hand:



P_214_4_0_10004 (west interior wall belonging to inner zone):

- h in = 2,556 --> This coefficient should be the same as the exterior coefficient of the same surface in the adjacent zone, isn't it?, so equal to h ext of P_203_6_0_0. Which is the explanation to this results?

- h ext = 0



P_214_5_0_10002 (south interior wall belonging to inner zone):

- h in = 2,568

- h ext = 0



P_214_2_0_10000 (east interior wall belonging to inner zone):

- h in = 2,556

- h ext = 0

(90 vote(s))
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