The reigning champions failed to reach the play-offs after crashing to defeat against Leinster on Friday night.
But head coach Tandy remains upbeat and reckons the Swansea-based region will benefit from the campaign.
"We have a young group who have shown throughout the season that we have a bright future," said Tandy.
"There was a huge turnover of players at the end of last season, but we've settled over the past 12 months and a number of players have really kicked on, among them Scott Baldwin, Ryan Bevington, Joe Rees, Lloyd Peers, James King, Sam Lewis, Ben John and Tom Habberfield.
"All those boys have experienced Heineken Cup rugby and not looked out of place.
"Throw in a strong core of Lions and Wales boys and that's a good mix. So we're in an exciting place, and the future looks bright.
"We are disappointed not to successfully defend our title, but we aren't going to dwell on that disappointment.
"That said, I told the group in the changing room at Leinster to remember the feeling.
"We were in the same place 12 months earlier and felt the other side of rugby, but Friday evening was painful for the boys and I want them to use it as a motivator for next season."
In truth the Ospreys title defence was derailed far earlier in the season. They lost their first three matches and did incredibly well to remain in the running.
"There's a big summer for a lot of the boys internationally, but we need to come back refreshed and we need to make a positive statement in the opening weeks of next season," said Tandy.
"Ultimately, it wasn't Friday night that cost us. We're disappointed with the result and some of the tries, but there was a big effort from the boys in Dublin and we played some good rugby.
"It was the first three weeks of the season that did for us, losing three on the bounce, two at home to teams that finished above us.
"We have to make sure we don't do that next season as it left us with a mountain to climb."