Re: [EnergyPlus_Support] Water film on a building wall

[fred buhl <wfbuhl@xxxxxxx>]

C1, if positive, is the film coefficient for the surface outside face. 
C2 through C7 are used
to calculate the outside air temperature. Then C1 is used in the outside 
face heat balance to
get the surface temperature. If C1 is negative, C2 - C7 are used to 
directly calculate the surface
temperature and C1 is ignored. Mike - is this right.

I think you are stuck with setting the outside face surface temperature, 
using C5 and precalculated
surface temperatures in put through a schedule.

Fred Buhl

HSIEH Chun-Ming wrote:

>Hello,
>
>I want to simply have a idea about how the building energy use decreases
>when a thin water film system is installed on a specified wall of a 
>building.
>Heat is removed by water evaporation from the wall so that the 
>temperature of outside wall reduces.
>Therefore, we can also save the electric power of air conditioners
>due to the temperature decrease of wall.
> From the experiment results, we know how much water evaporated during 
>the daytime.
>Is there any good way to simulate this kind of situation?
>
>I am thinking of using the Other side Coefficients, but I am not sure 
>how to do it.
>Actually, two ways are available for us.
>One is to set the temperature of outside wall directly.
>The other way is to set both the film coefficient and the outside air 
>temperature.
>Under the assumption of how much heat was removed (the amount of water 
>evapoated) from the experiment,
>I want to use the later one instead of setting the wall temperature 
>directly if it is a possibile way.
>
> From the Input-Output Reference,  there is a equation in the part of 
>Other Side Coefficients.
>However, C1, the combined convective film coefficient  was not shown in 
>the equation.
>I wonder how this coefficient works in the calculation?
>Does it simply act as a coefficient for the temperature difference
>between the outside temperature and air temperature.
>It seems that a higher C1 gives a higher temperature of wall.
>
>Do you have ideas to simulate the water film system by using another method?
>Is there any simple way to remove 50 W/m2, for example, from the outside 
>wall in the simulation?
>Thank you very much.
>
>Chunming
>
>
>
>
>[Non-text portions of this message have been removed]
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