summer thermal stability

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JanStadtherr
Posts: 2

summer thermal stability

Postby JanStadtherr » Tue May 22, 2018 2:51 pm

Hi guys,

I've encountered a problem, which is against all my logical thinking and I'm kinda desperate about solving it. So decided to share it with you, hoping you can figure it out or at least show me the right way to solve it.

I'm working on summer thermal stability for residential house. My client decides to change glazing type for all windows of its house. I found all glazing layers in IGDB which perfectly matches calculated values with technical list of glazing manufacturer. Now to the core of problem. SHGC of first type of glazing was calculated 0,488. After changing glazing type SHGC was calculated 0,514. The change will affect solar gains and therefore the mean air temperature inside rooms should be higher. Well, its not and its even lower. In the hope of solving the bug I've turned energyplus results upward down. I found out with higher solar gains there is higher thermal accumulation to the constructions such as floors and ceilings (i set adiabatic adjacency to see if is it transfer or accumulation). For simulation i used the same exact model, all i change was glazing type. I might be just blind or overworked but still it doesnt make any sense to me.
Does anyone encountered such a mystery?

Thank you for any tips or help to solve this.

Best regards,

Jan
Luis Sousa
Posts: 364
Location: Stroud

Re: summer thermal stability

Postby Luis Sousa » Tue May 22, 2018 5:00 pm

Hi Jan,

Could it be that the glazing U-value is lower for the SHGC_0,514 case?

BR,
Luis
JanStadtherr
Posts: 2

Re: summer thermal stability

Postby JanStadtherr » Wed May 23, 2018 8:46 am

...one more thing i've noticed.
I run simulation with simple glazing method where is only SHGC and U value for both cases. In this simulation all results go with physical behavior, higher SHGC (0.514) and higher U value give higher mean air temperature. So why this doesnt work with material layers method? thank you for any tip.

BR
Jan
Luis Sousa
Posts: 364
Location: Stroud

Re: summer thermal stability

Postby Luis Sousa » Fri Jun 29, 2018 11:02 am

Hi,

My suggestion would be to have a look a zone heat balance (with surfaces hourly results) and also at the window heat transfer values, and compare the results for both cases to understand why the temperature does not rise when the SHGC is higher.

BR,
Luis

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