Abstract: A freeze resistant aqueous coolant solution for use in Perkins tube type heat exchangers is formed of one or more metal salts selected from the alkali metals of Group IA and the alkaline earth metals of Group IIA of the Periodic Table. Depending upon the composition of the metal tubes of the heat exchanger, the concentration of the metal salt ranges from about 5% to about 10% by weight of the solution and the pH of the solution ranges between 7.3 and 11.5.

Abstract: Recovery of ethanol from the exhaust stacks of a bread-baking oven is achieved by passing the stack emissions through an adiabatic humidifier where the emissions are humidified to near saturation. The unevaporated water content of the humidifier is collected for separation of the ethanol content. The humidified emissions are passed from the humidifier to the vaporization chamber of a heat exchanger where the gas content of the humidified emissions is separated from the moisture content thereof, and the moisture content is collected for recovery of the ethanol content.

Abstract: A rotary absorption heat pump assembly. The assembly comprises a generator (2), condenser (3), evaporator (4), absorbent cooler (5), and absorber (1), all operatively associated to function as components of an absorption-type heat pump of high efficiency and superior operating characteristics. The heat pump is characterized by the presence of a tapered cylindrical absorber (1) which receives and processes, in the form of a very thin peripheral film ("d"), a predetermined amount of absorbent solution. The absorber (1) is arranged in abutting end-to-end relationship to the generator (2), with which it communicates. The condenser (3) and evaporator (4) are arranged end-to-end outside of the absorber (1) and absorbent cooler (5), concentrically therewith and radially spaced therefrom.

Abstract: A Perkins tube type rotary heat exchanger of improved efficiency wherein the Perkins tube evaporation sections are outwardly displaced from the condensation sections by offsetting and/or splaying, to substantially occupy the evaporation sections with Perkins tube working fluid while substantially eliminating the presence of fluid from a major portion of the condensation sections during operation of the heat exchanger. This has the effect of maximizing the internal evaporative area within the evaporation sections and also of maximizing the internal condensing area within the condensation sections of the Perkins tubes, thereby materially increasing the energy recovery and effectiveness of the heat exchanger.