I do not think it is about the ACL at all. I think it is about mutual club to club benefits and we do not know what it involves.
It could an investment in the club, in exchange for providing an outlet for promising Tianjin players to be showcased in the A-League or perhaps good Tianjin players coming on short loans to get experience abroad while their wages are subsidised by Tianjin.
Of course I have no idea what is really involved, but this is just an abstract example of what came to my mind as potential options. Others may have better ideas.