The Senior Mechanical Engineering students at Saint Martin’s College designed and built a unique, safe air conditioning/refrigeration bench experimentation apparatus. The apparatus is currently used as laboratory equipment to support instruction in four thermal engineering courses. This system demonstrates the fundamentals of the refrigeration cycle and psychrometric properties of air, as well as some fundamental concepts in heat transfer, heat exchangers, and thermodynamics. The refrigeration cycle working fluid is R-134a. The cycle operates with pressures between 760 kPa and 210 kPa, and with temperatures between 44 °C and −7 °C with flow rate of 6.8 kg/h. The apparatus is equipped with an instrumentation package to monitor the psychrometric properties of the effected air inside the ductwork. In addition the instrumentation package contains instrumentation to monitor the working fluid properties via computerized data logging equipment. Technical details about the uniqueness of this design and operation are given in the article.Copyright © 2003 by ASME