Моделирование работы термотрансформаторов циклического действия

Abstract

The article is focused on modeling a solar powered adsorption thermotransformerand analyzing the efficiency of its cyclic operation on the basis of the program developed in the Matlab software package. The thermotrans-formeruses the energy of solar radiation and the mechanical energy of pressure drop in the apparfatuse in the process of daily changes in ambient temperatures. The program is based on a simplified thermodynamic cycle of the thermotransformer built in the Klaperon diagram and consisting of the following processes: isosteric heating and cooling, desorption and adsorption, condensation and boiling. The program algorithm consists of two computational blocks, which help calculate the maximum thermal exergy supplied to the thermotransformer in the daytime heated by the energy of solar radiation from the generator and the minimum exergy removed from the thermotransformer at night from the evaporator, when useful cooling work is performed. Using the calculated characteristics of the operating couples of thermal transformers (activated carbon (AC) - ammonia, AC - methylamine and AC – ethylamine) the dependences of exergy coefficients were obtained relatively to the changes in the main temperature characteristics of the thermodynamic cycle. The adsorption capacity of the working couples was determined by the Dubinin-Radushkevich’s structural equations. The system analysis of modeling made it possible to obtain qualitative and quantitative assessments of thermodynamic perfection of the cyclic thermotransformers’ operation at different working couples and to determine their application areas. The developed program makes it possible to carry out a system analysis of the cyclic thermtransformers’ operation in the part of determining the range and parameters of efficiency of its thermodynamic perfection. The program allows studying the nature of the dependences of the coefficients of the adsorption capacity of different adsorbates with different sorbents in different temperature conditions. The program helps investigate the dependences of the thermodynamic coefficients of various cyclic thermal transformers on dispersed working vapors on the temperatures of adsorption, condensation and environment. The software analysis showed that the degree of thermodynamic perfection in the cyclic thermal transformer on the AC-ammonia working couple is higher than on the AC-methylamine and AC-ethylamine working couples, the pressure values in the installations for the latter couples are 2-2.5 times lower, and the last working couple is approaching atmospheric