In the future release of Sense Server, any user with a 32-bit browser can connect to a x64 server. Thus the Server release will also only be in x64 bit, but as long as the browser is supported it is possible to connect with either 32bit or 64bit browsers. The client system requirement for the Sense Server edition will be released at a later point, along with the server. You may read more about the server here: Qlik Introduces Next-Generation Data Visualization and Discovery Application – Qlik Sense | Qlik .
Sense Desktop is run as a program on it's own and cannot run in a 32-bit environment.