A rack system which includes a rack frame and at least one reservoir for housing at least one rack-mounted immersion case is disclosed. The rack frame is configured to slidably accommodate racking and de-racking operations of the at least one rack-mounted immersion case. The at least one collapsible reservoir, which is configured to store a fluid therein, is fluidly connected to the at least one rack-mounted immersion case, has a first portion fixedly connected to the at least one rack-mounted immersion case, and a second portion fixedly connected to the rack frame. The at least one collapsible reservoir is configured to respectively collapse and expand along a racked space and a de-racked space, the racked and de-racked spaces being defined between a backplane of the at least one rack-mounted immersion case and a backplane of the rack frame, the de-racked space being larger than the racked space.