Sorry for the template not being present, when I use my phone it doesn't show up. I am trying the problem about liquefying liquid nitrogen, and I am having my first problem finding the latent heat of vaporization at 280.6 K. I try using trouton's rule, and I get a domain error because the inside is negative with a power of 0.38. I can't really tell if my drawing is right, I am assuming that the order in which it enters the system is a throttle valve, then a heat exchanger. Some vapor leaves the system, which is the combined throttle valve and heat exchanger, before entering the heat exchanger. Then, the rest goes through the heat exchanger.