Modeling and simulation of a small-scale solar-powered absorption cooling system in three cities with a tropical climate

Abstract

This study assessed through numerical simulations, the technical feasibility of a solar-powered absorption cooling system for a small-scale application in an office building in three different cities with a tropical climate in Ecuador. The model and simulations were performed using the dynamic transient software TRNSYS and were compared and validated using experimental data obtained from a real-life system with main components: 12 m2 vacuum tube solar thermal collector array, a 4.5 kW LiBr/H2O single-effect absorption chiller, a 6 kW fan coil and a 100 l sensible cold store. The results of the simulation showed a good agreement with the experimental data with a deviation of 8.5%. The validated model was used to undertake a parametric study to determine capacities of systems that will be applicable to three Ecuadorian cities: Guayaquil, Manta and San Cristobal. The system capacity predicted by the model for the Ecuadorian cities has the following components: 24 m2 evacuated tube collector field, a 20 kW heat exchanger, a 15 kW single-stage LiBr/H2O absorption chiller, a 35 kW cooling tower and a cold storage tank of 2 m3. The results showed that the proposed system could meet most of the required cooling load (90% for Guayaquil and San Cristobal, and 71% for Manta, considering a set point of 24°C) of a typical single-story office building with.