Helia,Sounds like solar loads to me. Hey so I noticed that four of your surfaces where titled to be adiabatic but where actually set to be externally adjacent, that your file was in E+ 5, that you had no building object and that you where running at 12 timesteps. Also I noticed you mention PCM in the file name. I went ahead and updated your file and fixed some issues and have attached it to this email. Possibly your summer cooling loads will make more since with this updated version.