The rejuvenating power of naps has been known about for some time, with various studies showing that even a short nap can increase alertness. While a nap of around two hours is of most benefit as it encompasses all stages of sleep, a power nap of up to 30 minutes is certainly better than nothing. It's not long enough for you to enter deep sleep (and consequently risk feeling worse than before), but it's long enough to take the edge off your need to actually go to bed.
