how can i modelize a component to increase temperature with simscape?

hello all,

i'm trying to modelize a system with a personnal domain. this domain contain 2 variable: a temperature in K and a flow rate in kg/s. the system is composed by a flow rate generator in kg/s and a component that increase de temperature. the output of the flow rate generator go to the input of the component and the output of the component go to the input of the generator.

my problem: to works, the system needs a reference node. the only choice i have is to put the temperature to 0 K somewhere. but if i do this, the temperature can't increase.

How can i solve this problem please?

here are the components that i have modelize and the system. http://cjoint.com/?BKhjQeMgNeQ

Thanks for yours answers.