Modelling a Simple Vacuum Cooling

Hi! I am a complete newbie to simulink. I want to model a basic vacuum cooling, just a chamber and a flow rate source to reduce the pressure inside. I need water to evaporate at low pressures (around 4.2 kPa to 0.8 kPa). Is this possible? And which system should I use? I was thinking doing it in moist air but then two-phase fluid must be the appropriate one. But, I'm most worried if this is even going to work in simulink given the very low pressure requirement.