The 22-year-old played five songs, including Only Girl (In The World) and Cheers, which she dedicated to "all the semi-alcoholics in the world".
Rihanna said the album had been recorded late at night after she came off stage on her Last Girl On Earth world tour.
"I'd be doing vocals at 4am with a raspy voice," she joked.
The record, Rihanna's fifth in six years, marks a return to the singer's pop roots after the bleak nihilism of last year's Rated R.
That album, recorded in the wake of the star's assault by then-boyfriend Chris Brown, had a much darker tone - presaged by single Russian Roulette, which talked about a subservient, violent relationship.
One track from the new album, S&M, revisits those themes, with Rihanna declaring, "sticks and stones may break my bones, but whips and chains excite me".
But most of the new material presented a more carefree side to the Barbadian star.
Fizzing synths, club beats and sing-along chants featured heavily, with three songs - Only Girl, What's My Name and S&M - produced by Norwegian team Stargate.
The duo previously collaborated with Rihanna on dance tracks like Don't Stop The Music and Rude Boy.
Cheers, which the singer also referred to by its working title, Drink It Up, was a funky, loping guitar groove dedicated to a night on the town.
Despite its lyrical content, Rihanna confessed she was "too busy" to drink alcohol, and "hardly ever gets any sleep".
The night concluded with a strummed, acoustic ballad called California King Bed, about a couple who sleep beside each other but feel "10,000 miles apart".
Dressed in a figure-hugging white dress with a bold floral print, Rihanna sang along while her new music played, and chatted bashfully to a small audience of invited fans and journalists.
She revealed that the new album would also contain a duet with R&B star Drake and a collaboration with hotly-tipped rapper Nicki Minaj on a track called Raining Men.
"Thanks for coming along tonight, this really means a lot to me," she said. "Thank you for coming to hear my silly music."
Loud is due for release in the UK in November.
Pop star Rihanna has unveiled tracks from her forthcoming album, Loud, at a club in London.