"Modelo de simulação de um refrigerador por absorção/difusão operando em regime transiente"

Abstract

In this study, a model for the transient simulation of a refrigerator for absorption / distribution containing ammonia (as refrigerant) water (absorbent fluid) and hydrogen (as inert gas) is displayed. The proposed simulation model was developed from mass balances, energy and entropy in each component of the cycle. The mathematical model was validated from direct measurement of the temporal evolution of the temperature on the wall of the refrigerator components studied. Simulation results in permanent regime gave rise to the initial conditions, boundary and stopping criteria required for transient simulation refrigerator studied. Results obtained through the proposed model in the transient regime were compared with experimental results. Under these conditions the model developed presented regular predictive capability for determining the transient period. With the simulation results in the transient regime was possible to understand the definition of a maximum drive power of the refrigerator manufacturer. Power extrapolated that around 10% above the nominal value, ceases production of the refrigerator cold. This is because the internal generator with its accumulated small volume solution makes the solution does not pour into the external generator. This fact interrupts the working cycle, since the external generator with low levels of non-lean solution to the absorber solution transfer tube. It was observed among other operating characteristics of the refrigerator in the transient settling time small scale. For example, given 20 seconds time interval as in the transient regime the stationary condition occurred in about 60 seconds for the initial power of 70 W and 80 W abruptly changed to from 60 W to 70 W, the establishment of a stall condition occurs in about 80 seconds.