Question-and-Answer Resource for the Building Energy Modeling Community
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The minimum and maximum indoor temperatures describe when the windows are allowed to open, so when the interior temperatures drop below 22C, the windows close. When temperature go above 26C, the windows also close.
In your model, i'm guessing in the summer your indoor temperatures will at some point go above 26C, since naturally ventilated buildings typically will float this high in most climates. The windows all close at this point, but since you still have internal gains and envelope gains which contribute heat to the building, causing the temperature to continue to rise.
Since the windows are closed and there is no HVAC system, there is no way for the building to lose heat, so heat perpetually increases in the space until the climate has cooled enough to allow the building to cool below 26C and your windows are able to open again.
In the winter, your windows stay open until the building drops below 22C, in which case the windows close. The building still loses heat through the envelope however, so the air temperatures inside fall below the 22C threshold.
I would suggest looking into adding controls for the outdoor temperature as well as in the indoor temperature. Maybe switch your 26C limit to the outdoor temperature limit so that the windows are able to be opened in the summer.
