Novel Connections for Non-Metallic, Flexible, Thin, Microchannel Heat Exchangers

Neema Pourmohamadian, Mike L. Philpott, Mark A. Shannon
2004 ASME 2nd International Conference on Microchannels and Minichannels   unpublished
Non-metallic, flexible, thin, microchannel heat exchangers made from heat-sealable polyimide films have recently been developed for refrigeration and air-conditioning applications. In order for these heat exchangers to function properly and independently, robust and reliable connectors are needed. The connectors must be easy to manufacture and assemble, hold high pressures without leaking, resist a pullout force, and have the ability to connect to standard tubing and piping and different heat
more » ... nd different heat exchangers together in series and parallel. Three uniquely different functional prototype connector designs have been developed, manufactured, and tested. The first includes a machined metal connector internally embedded within the heat exchanger that is capable of holding pressures up to 0.83 MPa and 65.5 N of pullout force before failure. The second connector design includes a two-piece polymer assembly containing an o-ring used to seal around the inlet and outlet holes of the heat exchanger. The design incorporates a 10-degree wedge that creates the sealing force when fully assembled with the heat exchanger and has been pressure tested to 1.83 MPa without leaking and 73.6 N of pullout force applied before failure. A variation of the design allows multiple heat exchangers to connect in series and in parallel. Finally, the third design contains no additional parts and connects two heat exchangers together by thermally bonding the inlet of one heat exchanger to the outlet of another. The thermally bonded connection was able to hold pressures greater than 2.07 MPa. Finally, fatigue testing of the heat exchangers is conducted using an Instron machine to develop a stress amplitude versus number of cycles to failure diagram for the zero pressure case. iv
doi:10.1115/icmm2004-2439 fatcat:mjyk3yv5xbcmzgf2ulzffvwqnm