Development of a Piezoelectric Microcompressor for a Joule-Thomson Microcryocooler

In this paper we discuss the development of a microcompressor (MC) theoretically capable of delivering pressure ratios from 16:1 to 25:1 for design flow rates, of about 0.15 std. cm/s, intended to provide flow for a mixed refrigerant Joule-Thomson (J-T) microcryocooler. The J-T microcryocooler supports on-chip cooling applications, such as terahertz and infrared imaging sensors operating at about 77 K that require less than 5 mW of net refrigeration. The high pressure ratio of the compressor is enabled by minimizing dead volume and using a 10 mm diameter metalized polyamide membrane 500 μm thick that is actuated by a lead zirconium titanate piezoelectric (PZT) stack. With a stroke of about 28 μm and a swept volume of about 2 mm, the design flow rate could be achieved with a drive frequency of about 100 Hz. The entire microcryocooler, compressor module, sensor, and thermal integration module are expected to occupy less than 10 cm volume. At present the compressor module demonstrates a pressure ratio of 21:1 when blanked off and has a volume less than 2 cm. Numerous design iterations to achieve the 21:1 ratio, studies comparing stroke and volume vs. frequency to achieve design flow rates, and measured power consumption as a function of drive frequency are discussed. Design alternatives for the valves in the compressor head, including passive micro electromechanical systems (MEMS) and active PZT, with preparations to measure pressure ratios and flow rates with both valve types also presented.

[1]  B. Hok,et al.  A silicon self-aligned non-reverse valve , 1991, TRANSDUCERS '91: 1991 International Conference on Solid-State Sensors and Actuators. Digest of Technical Papers.

[2]  Xing Yang,et al.  Simulation and experimental studies on a piezoelectrically actuated microdiaphragm air pump , 2006 .

[3]  E. S. Kim,et al.  Micropump based on PZT unimorph and one-way parylene valves , 2004 .

[4]  Jinn-Cherng Yang,et al.  Low Power Consumption PZT Actuated Micro-Pump , 2006, 2006 International Microsystems, Package, Assembly Conference Taiwan.

[5]  Bo Li,et al.  Development of large flow rate, robust, passive micro check valves for compact piezoelectrically actuated pumps , 2005 .

[6]  Jan Peirs,et al.  A micro gas turbine unit for electric power generation: design and testing of turbine and compressor , 2003 .

[7]  Harold Gamble,et al.  Fabrication and characterization of a micromachined passive valve , 2003 .

[8]  K. Yamamoto,et al.  New bi-directional valve-less silicon micro pump controlled by driving waveform , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).

[9]  T Gerlach,et al.  A new micropump principle of the reciprocating type using pyramidic micro flowchannels as passive valves , 1995 .

[10]  Nesbitt W. Hagood,et al.  Design, fabrication, and testing of a piezoelectrically driven high flow rate micro-pump , 2000, ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium on Applications of Ferroelectrics (IEEE Cat. No.00CH37076).

[11]  Torsten Gerlach,et al.  Working principle and performance of the dynamic micropump , 1995 .

[12]  P. Woias,et al.  A self-priming and bubble-tolerant piezoelectric silicon micropump for liquids and gases , 1998, Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176.

[13]  T. Gerlach,et al.  Pumping gases by a silicon micro pump with dynamic passive valves , 1997, Proceedings of International Solid State Sensors and Actuators Conference (Transducers '97).