L5 slide 8: Refrigerant through a throttle (ENGR5003)

L5 slide 8: Refrigerant through a throttleFrom lectureCurrent specThird1 marks2 min

ENGR5003 Lecture 5, slide 8 (Q2 - Understanding throttling)

Refrigerant passes through a throttling valve from a high-pressure state to a low-pressure state. There is no heat transfer and no shaft work. Which change is most directly associated with the throttling process?

Formulas you may need

Throttling: $h_1 = h_2$ (from the SFEE with $q = w = 0$ , KE and PE neglected) (learn this)

AThe refrigerant produces useful shaft work.BThe enthalpy remains approximately constant while the pressure decreases.CThe entropy always decreases because the pressure decreases.DThe temperature must increase.