Rendering of the Barbara and Morton Mandel Design Gallery. Courtesy Aniphase.

The coffers of the Smithsonian's Cooper-Hewitt, National Design Museum in New York are a bit fuller after the institution received its largest-ever gift: $10 million from the Morton and Barbara Mandel Family Foundation. The museum, closed for renovations since July 2011, will reopen in the fall with 60 percent more gallery space.

The donation was made on behalf of Barbara Mandel, a longtime trustee and board chair at the Cooper-Hewitt, and her husband Morton. In return, the museum's new 6,000-square-foot third-floor gallery will be christened the Barbara and Morton Mandel Design Gallery. The renovated museum will also offer visitors new interactive experiences and improved digital access to the museum's 217,000 object collection.

Director Caroline Baumann called the gift "a game changer for Cooper-Hewitt as we prepare for our grand opening," and praised the Mandels as "visionaries who have supported our mission for almost two decades." The expansion and renovation project, which is being undertaken by New York-based firms Diller Scofidio + Renfro, Gluckman Mayner Architects and Beyer Blinder Belle Architects & Planners, is expected to cost $79 million.