Then it'd just be a way of getting the word out somehow - honestly the classic "putting up fliers in my dept/SU" can and does work sometimes!
Your SU might have some kind of way to connect students looking for places to live over the summer with those subletting potentially too?
Also ask your flatmates and friends on your course if they are/know someone who needs that - network about it.
Finally you can also advertise on certain websites designed for that like spareroom although responses might be very variable on that (and particularly if you're planning to leave your things in situ over the summer, you may be less keen on that!).