BarberMcMurry Architects have released three concept designs for the US$100m (€90.2m, £75.9m) Knoxville Science Museum in Knoxville, Tennessee, that variously feature a green roof, a terracotta screen and a treehouse.

The museum will occupy 150,000 sq ft (14,000 sq m) and will include indoor and outdoor dining areas, an event space, meeting and maker spaces, and will incorporate the three city garages surrounding the property.

The firm was tasked with creating designs that incorporate green technology and offer views of downtown Knoxville and/or the Smoky Mountains.

The first concept offers a more traditional approach and features a two-storey building, combining stone, wood and metal, with a walkable green roof, that will enable visitors to look down into the museum through skylights, and a 200ft (60m) glass observation tower, offering panoramic views of the city.

Inspired by Knoxville's status as the 'Maker City' due to its community of makers, artists, creatives and independent manufacturers, the second concept comprises of locally-sourced Tennessee marble, painted metal and a perforated terracotta screen. The three-storey building features exhibit space and a two-storey maker space offering downtown views. An atrium will connect all three floors and bring in natural light.

The design also includes an indoor-outdoor café, with views of downtown, the riverfront and the Smoky Mountains, while an on-site greenhouse will provide an agricultural and biological education space.

The third and final design was inspired by the elements – air, fire and water – and incorporates glass, metal and stone. It will feature a green roof, social terrace and a treehouse with views of the top of the mountains.

"I just want everyone to know that this gives certainty to the project, that it is moving along," said Jim Clayton, speaking at a presentation unveiling the designs at the Knoxville Civic Auditorium. "It's going to take some time to complete the design and to build the science museum."

The new attraction is expected to open in December 2021, with work due to start in Q2 or Q3 2020.