A high-end condominium and hotel project that has been planned for years near the South Carolina Aquarium got an official launch party Tuesday, as developers and city officials sought to raise the project’s visibility.

The 7 Calhoun development will include a 75-room luxury hotel and 47 residential units, whose residents will be able to pay for hotel services such as housekeeping and room service.

“Having a very high-quality hotel there is something we hoped for for quite some time,” said Charleston Mayor Joe Riley. “A hotel gives energy and life to an area.”

Construction on 7 Calhoun will start once about half the condos have been pre-sold — a common practice for condo projects — and they won’t come cheap. The units will range from about $750,000 to over $3 million.

Some high-end condo projects in the area have wound up in foreclosure, and many developers have switched to building apartments, but the developers of 7 Calhoun sound confident.

“We think the market is ready,” said Wally Seinsheimer, who with Ross Bowker and East West Partners has been working on the project since the city selected them to develop the site in 2006.

Charleston, said Bowker, is “the perfect world of demand and location.”

The city is consistently ranked among the most in-demand travel locations, and high-end homes on the small peninsula are in limited supply.

“This is a very special part of our city that is becoming increasingly more so,” Riley said. “Charleston merits this and can support it.”

The city played an active role in planning the area’s development, and sold the north and south ends of the block bounded by Concord, Calhoun and Laurens streets to the development group for $16 million. The center of the site is reserved for a public park about the size of Marion Square.

“The design of the park is almost complete, and it will be gorgeous,” said Riley. “It’s going to be a great park with fields for kids to play on, a playground, and fountains.”

The north end of the property will include the 7 Calhoun and an office building known as 25 Calhoun, which opened last year.

The hotel site sits across Concord Street from the aquarium complex, and across Calhoun Street from the planned International African American Museum. It also sits on the site of a former public housing complex.

Concord Park used to be the Ansonborough Fields housing complex. The 162 low-income homes that once occupied the land were demolished in 1992 because of pollution discovered in the soil and damage from flooding.

The current plan calls for construction of apartments that would be rented to elderly residents with low to moderate incomes, on the Laurens Street end of the property.