Repositori URV

Identifier: TDX:274

Handle: https://hdl.handle.net/20.500.11797/TDX274

Authors:
Taboas Touceda, Francisco

Abstract:
In the last years, a demand of small power cooling refrigeration equipment driven by thermal low temperature has appeared, pushed by the possibilities of taking advantage of thermal solar energy or waste heat. The ammonia/water absorption technology is postulated as an alternative to the typical air conditioning systems driven solar energy (like adsorption with silica-gel, or absorption with water lithium bromide). This is because they can be adapted for a small power equipment, due to it's great possibilities of size reduction, and does not need cooling towers to operate.The centre of technological innovation CREVER, with the collaboration of the University of Vigo, proposed an investigation project titled 'Development of advanced components for the design and manufacture of small power refrigeration cooling machines working with the NH3-H2O pair and driven by low temperature sources'. This project was focused in the development of tools for the three devices identified as critical in its design: absorber, desorber and the distillation column. In the development of this project the plate heat exchangers were identified as a suitable solution because they can reduce the load of refrigerant, and can work with low temperature gradients.This thesis has been made within the framework of this project and has as its main objective an experimental study of the process of boiling ammonia/water mixture in a channel of a plate heat exchanger. This study was made in the conditions of operation of a desorber of an ammonia/water absorption machine, showing the effect in the heat transfer boiling coefficients of the mass flux, heat flux, pressure and concentration of the mixture. The conditions of the experimental tests have varied from 0.33 to 0.65 of the ammonia mass fraction, bein