thermal simulation of complex fenestration in energyplus
i want to do energy simulation of a single room with a vacuum glazing using energyplus. the BSDF file of vacuum glazing is generated using LBNL window 7.7.10 software. after energyplus simulation when I check the envelope summary from HTML file, the U-value (5.288W/m2-K) of the glazing is much higher than the Window simulation result (2.38 W/m2-K). as a result, the energy consumption also higher even than a double clear IGU. could anyone please explain the reason? why the U-value of complex glazing is changed in energyplus simulation?
Did you export the idf code from WINDOW? Are you just looking at glazing u-values, not considering frame? Are perhaps the u-values that are high without the air films? The results in WINDOW should be with air films.
What do you mean by idf code? I have generated the idf file from window software to use it in energyplus. I compare the air-conditioning load of both double clear IGU and vacuum glazing unit. And it was found that air conditioning load is higher for VGU. Whereas, u-valu of VGU is lower than the IGU.
What do your SHGCs look like? Check it in the Exterior Fenestration section of the html
Heating energy? Cooling energy? Is your building with high internal gain? too many infos are missing to give you help