Does HOMER calculate if the load applied just for night usage?

If you are asking whether you can specify a primary load that is zero throughout the day and greater than zero during the night, the answer is yes.  You can enter the load either by specifying a 24-hour load profile, or you can develop your own load data elsewhere and import it into HOMER as a text file.  For more information, please click Help on HOMER’s Primary Load Inputs window.