Abstract: A heat exchanger including a tube stack having a plurality of microtubes; a first header coupled with a heat exchanger refrigerant fluid inlet and configured to introduce refrigerant fluid traveling in a first direction into the tube stack; and a second header coupled to a heat exchanger refrigerant fluid outlet and having a second header passage configured to receive refrigerant fluid traveling in the first direction through some of the microtubes and discharge the received refrigerant fluid in a second direction to some of the microtubes. The first header has a first header passage configured to receive refrigerant fluid traveling in the second direction and discharge the received refrigerant fluid in the first direction to some of the microtubes. The second header further configured to receive refrigerant fluid traveling in the first direction and discharge the received refrigerant to the heat exchanger refrigerant fluid outlet.

Abstract: A microtube heat exchanger is disclosed, including two end plates with an array of holes or openings and an array of microtubes disposed in the array of openings between the two end plates. The heat exchanger can be used in environmental control systems, including systems for aerospace applications.

Abstract: A heat exchanger including a tube stack having a plurality of microtubes configured to transfer heat from a refrigerant to an external fluid. The heat exchanger includes an inlet housing disposed adjacent to a fluid-inlet side of the tube stack. The inlet housing includes a reservoir where refrigerant is stored and where, due to gravity, liquid of the refrigerant pools in a bottom of the reservoir. The heat exchanger includes a wicking insert disposed at a tube stack opening of inlet housing adjacent to and covering the fluid-inlet side of the tube stack. The wicking insert has a porous structure configured to provide a capillary force within the porous structure, and is disposed within the pooled liquid to draw the liquid from the bottom of the reservoir through the porous structure of the wicking insert by the capillary force.