A simple kettle element will of course be sufficient for upto 100°C
To get the temperature down you need a cooling system, what springs readily to mind of course is a refrigerator.
Just a note of warning, water and electricity are dangerous bed fellows.
On that note perhaps one of those vortex air units would be safer - they blow hot in one direction and cold in the other, nominally to 100°C
see: -
http://www.airtxinternational.com/how_vortex_tubes_work.php
