Meditate mindfully instead of sleeping

Often around 2:00 p.m. after eating, my body falls tired. So I have to stop studying. I am myself a long term meditator, but I rarely meditate when I am tired. Is meditation a good substitute for sleep? In other words, around 2:00 p.m., if I am going to meditate mindfully for an hour instead of sleeping, will this meditation be able to replace sleep?