Ivanova L. High-efficiency low-temperature coolers for gases and liquids for energy-saving technologies

Ivanova L.V., High-efficiency low-temperature coolers for gases and liquids for energy-saving technologies. – The manuscript. Thesis for scientific degree of candidate of technical sciences, Specialty 05.14.06 – Odessa National Polytechnic University, Odessa, 2018. The thesis is devoted to the development of evaporative coolers for water and air with a reduced cooling limit from the temperature of a wet thermometer to the dewpoint temperature of the outside air. Modeling of heat and mass transfer processes in indirect coolers has been performed. The use of evaporative coolers with a reduced cooling limit requires solving the problem associated with the danger of full saturation of the auxiliary airflow in the heat-mass-exchange apparatus has been shown. The analysis of the conditions of such a hazard has been carried out and recommendations for its prevention has been developed. An experimental study made it possible to specify the workloads on a film type heat and mass transfer apparatus, taking into account the critical phenomena and the values of the actual wetted surface of multichannel heat and mass transfer devices. The efficiency of evaporative cooling processes has been determined depending on the initial parameters of outside air and the ratio of the contacting gas and liquid flows, and recommendations has been developed for calculating and designing low-temperature coolers. Based on the experimental data, an analysis of the fundamental capabilities of the developed evaporative water and air coolers Chg and Chw has been performed, which showed that with a decrease in the initial moisture content of air, the cooling level decreases significantly, and the degree of approach to the cooling limit decreases. The recommendations for advisable ratio of contacting gas and liquid flows and rational flow raits in liquid circuits of Chw water cooler has been worked. The general ecological analysis of new solutions with practical use of low-temperature evaporative coolers will significantly reduce the negative contribution to global climate change has been realized. Keywords: low-temperature evaporative cooling, air conditioning, hydro-aerodynamics, heat and mass transfer, environmental impact.