Ask the host university well in advance for information on how to find a room. The host university will often arrange accommodation for incoming exchange students, so it is important to get in contact at an early stage. The TU Delft exchange programme database, specifically the student reports, contain information on this subject for each individual university.
Sublet your room
You may want to try to sublet your student room while you are away. Ask your housing association or house owner about the possibilities. There are often international students that come to the TU Delft for an exchange who need student housing for a temporary period. Ask the international officer for possible sub-tenants.
On the website www.onderhuur.net you can offer your student room free of charge and you can also find information about rules and legislation and tips for subletting. For questions about subletting and sublet contracts, you can also contact the student support point of the VSSD. They have standard sublet contract available (in Dutch and English).
Alternate options are housing websites or Facebook Groups.