Heat Pipe Applications in Sorption Refrigerators

Abstract

Some sorption refrigeration machines (sorption technologies) developed in Belarus are presented in this paper with emphasises on different heat pipes application: conventional heat pipes, heat pipe panels, loop heat pipes, vapour-dynamic thermosyphons, etc. Heat pipes are very flexible systems with regards to the effective thermal control. They can easily be implemented inside sorption refrigerators and other types of refrigerators [1]. Their heat transfer coefficients are typically in the range of 103–105 W/m2K, therefore lead to smaller area and mass of heat exchangers. Sorption machines are used for more than 50 years, but recently its parameters became competitive with the vapour compression cycles. One of possibilities to improve the sorption machines parameters is heat pipe (HP) application as thermal control systems. Sorption machines, or sorption technologies is a collective indication of refrigeration machines and heat pumps, in which the mechanically driven compressors is replaced by a thermally driven (for example by heat pipes) thermo-chemical, or thermo-physical sorption loops. Sorption technologies mostly are working with natural refrigerants (NH3, H2O). They can be built from a few tens of watts (refrigerator in mini-bar of hotel room) to the megawatts scale developed for industry.