How to query drupal timefield data
Think of it as "the number of seconds since the the start of the day". To get the number of hours from that:

59400 / 60 / 60 = 16.5


So 16.5 hours since the start of the day: 16:30, or 4:30PM.

If you're looking to get something meaningful out of '16.5' for display on the front end, the timefield module has a theme function:

$formatted = theme('timefield_formatter', array('time' =&gt; $time));


Or if you have the value in the field of an entity object, you could use field_view_field() instead. The theme function has more options, you'd need to scan through the module code to understand what these are and which you might want to use.