nir-vana innovation network

A research group from a Spanish public university has developed a novel adiabatic membrane-based micro-absorber for refrigeration machines.
The device is built on non-corrosive and light-weight plàstic material. Furthermore, 3D printers could be used to manufacture the panels of the absorber which drasctically reduces manufacturing costs and also reduces its size to one fourth comparin to corrent commercially available solutions.
This technology can be used in cooling systems at homes, vehicles, electronic equipment or any other system requiring cooling, thus expanding the sectors of application of this type of technology.
This new micro-absorber uses air as a working fluid to cool the solution coming from the generator of the machine (the solution can be pre-cooled using any conventional system). In addition, the increase in solution temperature at the inlet of the generator reduces the amount of heat to be input, contributing to increase machine efficiency
Conventional absorbers use shell and tube exchangers, fundamentally having a horizontal configuration, with simultaneous heat extraction, in addition to other layouts, such as streams and droplets (having an adiabatic configuration), bubbles, rectangular and annular microchannels with porous membranes, spiral tubes, etc. However, none of them has been implemented in commercial absorption machines.
In contrast, the proposed micro-absorber is based on rectangular microchannel technology preventing the passage of the solution but not the vapor. Another novel feature lies in the adiabatic configuration using microporous membranes. The porous membranes have high porosity (equal to or greater than 80%) and prevent the solution from going through them, allowing only vapor to go through. The solutions to be used can be any of those used in absorption cooling systems (water-lithium bromide, ammonia-water, ammonia-lithium nitrate, water-lithium chloride, etc.).
The microchannels are made by completely perforating a flat plastic plate (base plate). The upper and lower parts of the base plate are covered with porous membranes (PTFE or the like) and these membranes are secured to the base plate by means of thin porous plates (securing plates) made of any stiff plastic material offering negligible resistance to the vapor going through them. The vapor to be absorbed in the microchannels circulates through the rectangular cavities in contact with the securing plates. The length of the microchannels in the direction in which fluid circulates is equal to or less than 5 cm. The absorber is sized according to application requirements in order to absorb all the vapor coming from the evaporator of the absorption machine: it can be built using a single base plate or several base plates assembled in parallel.
The researchers are looking for license and technical cooperation agreement with refrigeration machines manufactures for prototype develompent and field testing.

Advantages & innovations

Innovative aspects: - Advanced adiabatic micro-absorber structure. - Rectangular microchannel and microporous membrane technology. - It uses plastic material. - It can be processed in 3D printers. - It uses air as a working fluid for cooling the solution. Advantages: - It uses microchannels for the exchanger, instead of tubes or shells. - It reduces the size to one fourth with respect to conventional solutions. - It uses plastic material with the subsequent savings in weight and cost. - Other corrosive materials are eliminated. - It can be processed in 3D printers. - It uses air as a working fluid to cool the solution.

Stage of development

Under development/lab tested

Partner sought

Looking for licence and/or technical cooperation agreement with refrigeration machines manufactures for prototype develompent and field testing. Specific area of activity of the partner: Absorption machines for cooling greater than or less than 15 kW.