Emulation of semi-active flow control for evaporator superheat regulation

This paper considers superheat control of a vapor compression cooling cycle. Earlier research presented a hybrid expansion valve (HEV) that combines fast-acting mechanical pressure control with a slower electronic controller to regulate superheat, providing significant improvements in superheat control over standard valves. This paper shows that these improvements can be recreated with a simpler implementation of purely electronic control and a single expansion valve actuator. Simulations explore the actuator requirements, and experiments using a commercially available thermally-actuated MEMS valve show that the control architecture is suitable for both single and multiple evaporator systems, provided the actuator is fast enough.