Pl tell me the reason for heavy sweating in the head area during sleep at night, with no discomfort, in a fully airconditioned room?

Night sweats. Night sweats can be related to activity prior to sleeping, eating prior to sleeping, viral and bacterial infections, restless leg syndrome, malignancies, or unknown causes. If you are having weight loss or fevers then the symptom is more significant. Visit your primary doctor to get a full physical examination and blood workup.
Possibly. Menopause, fever, chronic infection, other hormone imbalances (thryoid), problems affecting hypothalamus, alcohol, nitrates, msg, hypoglycemia, too many blankets!