Don't think that yesterday's PlaNYC hoopla has sapped the city's energy for more planning announcements: Today City Hall announced a development team to create an "unprecedented mixed-income community" on the Brig, a former prison site bordering Fort Greene and the Brooklyn Navy Yard. A partnership called Navy Green will convert the 103,000-square-foot site, which served first as a forties-era naval prison and later as an INS detention center and minimum-security city pen into what plans say is an energy-efficient complex of 434 townhouses and apartments, including dozens of co-ops priced for families earning under $92,000 per year. As these early drawings show (one above, one after the jump), the sparkly towers and new retail are planned for the site — the city mentions an ecofriendly dry cleaner as a potential tenant — under a design that grew out of community workshops in 2003. The conversion, due to start by this summer, illustrates the aggressive hunt for city-owned land that Mayor Bloomberg promised in his speech yesterday. And it'll give New Yorkers the rare chance to come and go from a military prison at their leisure.