Consider the implications of + , + , + + = 0 + W, == for an open system. Adiabatic System For an insulated pipe with negligible changes in potential and kinetic energy, positive work done by the fluid flowing in the pipe on the surroundings implies that the enthalpy input is the enthalpy output. Hint equal to larger than less than Steam Saturated liquid water enters a pipe at 212F and leaves the pipe as saturated steam at the same temperature and pressure. In the absence of any kinetic or potential energy changes or any shaft work, Q must be Hint negative zero positive Elevation Change The outlet stream of a process is 100 ft higher than the inlet stream near the earth's surface. If Q,Ak , and AH are all zero for the process, then We must be Hint positive zero negative Reducing the Enthalpy Rate In the absence of any kinetic or potential energy changes and any work, a process stream undergoing a negative change in H requires that Q be Hint negative zero positive Turbine For the process streams entering and exiting a turbine engine powering an aircraft, W, is Hint positive zero negative Power Plant For a typical power plant for which W, and Q are both negative and for which potential and kinetic energy changes are negligible, AH must be Hint positve zero negative