Metal foam could be key to compact systems

USA: Researchers claim to have demonstrated that the use of open cell metal foam increases evaporation performance and could lead to the development of more compact air-conditioning and refrigeration systems.

A team at the USA’s Oak Ridge National Laboratory (ORNL) has been researching the properties of open cell metal foams in the heat exchange process for a number of years.

Metal foams are low weight, have high to very high specific surface area (up to over 10000m²/m³), have high gas permeability, and have relatively high thermal conductivity (for open cell bodies). Due to these properties, open cell metal foams have been studied for many heat transfer applications, especially as a material for constructing efficient compact heat exchangers.

Researchers at ORNL have now found that a porous open cell metal foam layer in the tubes of a small-scale evaporator increases the liquid refrigerant’s boiling rate, creating an enhanced pool-boiling process that can accommodate much higher heat fluxes compared to conventional technology.