I am really amazed by the way it looks right now. The negative is that the windows on the right side of the room are not windows, but this made me think that it is possibly better without the windows. So i will change my model and render it tomorrow again. And those i will publish here. So check it out!
And please give me comment to help me with improving my skills.
). I think you should rotate the suns position to let the sun shine through the arched windows. Maybe add some light fixtures as well. Keep us posted!