Performance of a new solid adsorption ice maker with solar energy regeneration

A predictive model for an adsorption solar cooling system using the activated carbon-methanol pair and its numerical simulation are presented. This model accounts for instantaneous heat and mass transfers in each one of the machine components along a characteristic average day for each month. The solar powered ice maker consists of the following basic components: a reactor containing an adsorptive bed coupled to a static solar collector covered by Transparent Insulation Material (TIM), a condenser and an evaporator. A uniform pressure model for the reactor is considered. The bed's radial temperature distribution is determined by means of a one-dimensional numerical method based on a finite difference technique. The machine's performance is evaluated according to meteorological data valid for the hottest six months in Joao Pessoa (7 degrees 8'S, 34 degrees 50'WG), whose climate is typically hot and humid. The results are compared with those obtained from an identical system with a single cover solar collector. These last data are then compared to the results obtained in a particular month from the experimental study of a prototype with equivalent components, tested in Tunisia. The TIM cover's system proved to be about 40% more efficient than the single cover solar system. The average net solar COP was 0.13 for the TIM cover system during the six month considered period. This corresponds to 7-10 kg/day of ice production per square meter of solar collection surface, respectively, for March and December, with solar irradiations ranging from 20 to 23 MJ/m(2), during the October-March period. (C) 2000 Elsevier Science Ltd. All rights reserved.